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Inheritance

1

Autosomal dominant inheritance HP:0000006

PTEN-positive BRRS follows autosomal dominant inheritance. Each child of an individual with a germline pathogenic PTEN variant has a 50% chance of inheriting it, with variable expression. De novo variants occur, so an unremarkable family history does not exclude PHTS. A PHTS study confirmed de novo variants in 20 of 187 families (10.7%); the 47.6% estimate was restricted to 20 of 42 probands with informative familial testing, not a BRRS-specific population rate.

Autosomal dominant inheritance

Show evidence (4 references)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"PHTS is inherited in an autosomal dominant manner."

GeneReviews states the autosomal dominant inheritance of PHTS, which subsumes BRRS.

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"Each child of an affected individual has a 50% chance of inheriting the pathogenic variant and developing PHTS."

GeneReviews gives the 50% transmission risk implied by autosomal dominant inheritance.

PMID:22595938 SUPPORT PRIMARY RESULT Human Clinical

"Twenty mutations were confirmed as de novo through familial testing (grade 5) by the Eng research laboratory or testing in a CLIA-certified facility, leading to a conservatively calculated de novo mutation frequency of 10.7% (20/187) within all eligible families."

The full PHTS cohort denominator was 187 unrelated families; this is not a BRRS-only estimate.

+ 1 more reference

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Subtypes

1

10q23 contiguous-gene deletion (PTEN + BMPR1A) MONDO:0012830

Deletions encompassing both PTEN and BMPR1A can combine BRRS-like macrocephaly and developmental findings with juvenile polyposis. Infantile gastrointestinal disease can be severe, but reported deletion carriers have variable onset and severity; deletion size alone does not predict gastrointestinal severity. Copy-number analysis defines the deletion and its gene content. The chromosome 10q23 deletion ontology term covers a broader interval-associated syndrome; the pattern described here specifically includes both genes.

Show evidence (3 references)

PMID:18510548 SUPPORT Human Clinical

"Recently, 10q23 microdeletions involving the PTEN and BMPR1A genes were found in four patients with infantile juvenile polyposis. It was hypothesized that a combined and synergistic effect of the deletion of both genes would explain the condition."

Establishes the contiguous-deletion entity and the original two-gene synergy hypothesis.

PMID:18510548 SUPPORT Human Clinical

"All patients had macrocephaly, dysmorphic features, retardation and congenital abnormalities."

Documents the BRRS-like core (macrocephaly, developmental delay) in deletion carriers. This evidence is limited because this is a four-patient series.

PMID:18510548 REFUTE Human Clinical

"No clear correlation was found between ages at onset or severity of gastrointestinal symptoms and the sizes of the deletions."

Recorded as REFUTE against the simple dose/size-severity model: deletion size does not predict severity, which is why this subtype is described as variable rather than uniformly severe.

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Mechanistic Hypotheses

3

Canonical PI3K-AKT-mTOR dose-sensitive overgrowth

canonical_pi3k_akt_mtor CANONICAL

Evidence balance 2 support

PTEN lipid-phosphatase loss increases PIP3-dependent AKT signaling and downstream mTOR activity, contributing to abnormal growth. This is a central mechanism in PTEN-positive BRRS, but does not establish a single causal route for every clinical feature or explain all PTEN-negative presentations.

Show evidence (2 references)

PMID:9593664 SUPPORT PRIMARY RESULT In Vitro

"Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring."

Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.

PMID:35594551 SUPPORT BACKGROUND Human Clinical

"In PHTS, loss of PTEN function leads to disinhibition of the PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase)-AKT–mTOR pathway"

The trial introduction summarizes established PHTS signaling biology; the clinical trial did not itself measure this molecular chain.

Altered PTEN localization and abundance in neurodevelopment

pten_localization_neurodevelopment EMERGING

Evidence balance 2 support

The cytoplasmic-predominant Ptenm3m4 mouse supports a contribution of PTEN localization and dosage to neuronal growth, glial proliferation, and microglial function. Both nuclear and cytoplasmic Pten are reduced, so it does not isolate localization from protein abundance. Its behavioral and cellular findings do not establish an autism-versus-cancer division in patients or a basis for changing cancer surveillance.

Show evidence (2 references)

PMID:24470394 SUPPORT PRIMARY RESULT Model Organism

"The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight."

The model combines reduced Pten abundance with altered localization and shows regional brain enlargement.

PMID:32055008 SUPPORT BACKGROUND Model Organism

"It is important to note that although we observe decreased nuclear Pten in the brain of the Ptenm3m4 mouse, we also observe decreased cytoplasmic Pten"

The authors explicitly acknowledge the abundance/localization confound in interpreting the model.

PI3K-independent overgrowth via focal adhesion signaling

pi3k_independent_overgrowth EMERGING

Evidence balance 2 support

An edited TTN p.Cys5096Arg HEK293T model showed impaired contact inhibition and altered focal adhesion kinase readouts. AKT and ERK phosphorylation decreased, despite lower PTEN protein, so the observations do not support canonical AKT hyperactivation in these cells. The proposed TTN-dependent growth mechanism remains a candidate based on one functionally tested variant; neither human disease causality nor response to mTOR inhibitors was established.

Show evidence (2 references)

PMID:29263846 SUPPORT PRIMARY RESULT In Vitro

"suggested lack of contact inhibition in mutant cells"

Edited HEK293T cells continued proliferating after confluence; one TTN variant was tested.

PMID:29263846 SUPPORT PRIMARY RESULT In Vitro

"we note paradoxical downstream readouts of decreased phosphorylation of AKT and ERK1/2"

The measured signaling direction differs from canonical PTEN-loss hyperactivation.

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Discussions and Knowledge Gaps

2

What is the actual, prospectively measured cancer risk in individuals ascertained as BRRS in childhood, as opposed to risk inferred from adult, cancer-ascertained Cowden syndrome cohorts?

KNOWLEDGE GAP OPEN gap_brrs_pediatric_ascertained_cancer_risk

Attached to

pathophysiology#Lifelong Multiorgan Cancer Predisposition

The cancer surveillance imposed on children diagnosed with BRRS rests on allelism with Cowden syndrome rather than on direct BRRS-cohort incidence data. The original BRRS delineation explicitly noted that malignancy had not been formally documented in BRRS, and contemporary reviews flag that existing PHTS risk estimates come from strongly ascertained, mostly adult cohorts with an acknowledged absence of pediatric research. If BRRS-ascertained carriers have materially different risk, current pediatric surveillance may be either over- or under-calibrated.

Proposed experiments

Prospective pediatric BRRS cancer-incidence cohort

brrs-prospective-pediatric-cohort

A prospective, multicenter cohort of individuals ascertained in childhood by BRRS clinical criteria and followed into adulthood, reporting age- and site-specific cancer incidence separately for PTEN-positive and PTEN-negative participants.

Show evidence (2 references)

PMID:33140411 SUPPORT REVIEW SYNTHESIS Human Clinical

"Although these estimates provide guidance for clinical care, discrepancies between studies, sample sizes, retrospective designs, strongly ascertained cases, and lack of pediatric research emphasizes that data should be interpreted with great caution."

Explicitly identifies the absence of pediatric data and ascertainment bias as the gap.

PMID:31609537 SUPPORT REVIEW SYNTHESIS Human Clinical

"We acknowledge the limited understanding of the natural history of childhood-onset PHTS as a cancer predisposition syndrome and present a summary of important management considerations."

A pediatric-focused review stating directly that the natural history of childhood-onset PHTS as a cancer predisposition syndrome is poorly understood.

What explains clinically diagnosed BRRS without an identified germline PTEN variant after contemporary testing, and what cancer risks do these individuals carry?

KNOWLEDGE GAP OPEN gap_brrs_mutation_negative_cases

Attached to

pathophysiology#Germline PTEN Loss of Function

The classic BRRS series identified PTEN variants in 26 of 43 cases. This historical yield depends on ascertainment and testing methods and is not a current universal residual fraction. Structural and promoter variants warrant appropriate testing. A TTN study reported a candidate association and an edited-cell phenotype, but did not establish TTN as a BRRS disease gene. KLLN methylation was studied in Cowden/Cowden-like patients and is not an established explanation for BRRS. Cancer-risk estimates for PTEN-confirmed PHTS cannot automatically be applied to this unresolved group.

Proposed experiments

Genomic reanalysis of PTEN-mutation-negative BRRS

brrs-mutation-negative-genomics

Genome sequencing with deep-intronic, promoter, structural-variant, and somatic-mosaicism analysis on a cohort of PTEN-mutation-negative clinical BRRS cases, paired with long-term cancer outcome follow-up.

Show evidence (3 references)

PMID:10400993 SUPPORT Human Clinical

"Mutations were identified in 26 of 43 (60%) BRR cases."

Quantifies the incomplete molecular yield that defines this gap.

PMID:10400993 SUPPORT Human Clinical

"Comparisons between BRR and a previously studied group of 37 CS families suggested an increased likelihood of identifying a germline PTEN mutation in families with either CS alone or both CS and BRR when compared with BRR alone"

Documents that BRRS-alone families have a lower PTEN detection rate, sharpening the question of what underlies mutation-negative BRRS.

PMID:29263846 SUPPORT Human Clinical

"The remaining cases are of unknown genetic etiology."

The TTN study frames the remaining genetic etiology as unknown; its candidate findings do not resolve this clinical group.

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Pathophysiology

11

Germline PTEN Loss of Function

A heterozygous germline pathogenic PTEN variant is the initiating lesion in PTEN-positive BRRS. Reduced PTEN lipid-phosphatase function impairs PIP3 dephosphorylation. The classic BRRS cohort identified variants in 26 of 43 cases; this mechanism is not demonstrated in every PTEN-negative clinical presentation. Conformance identifies the constitutional tumor-suppressor lesion; it does not establish a requirement for a somatic second hit in every PTEN-associated lesion.

PTEN hgnc:9588

PIP3 3-phosphatase activity GO:0016314 ↓ DECREASED

Downstream

PIP3 Accumulation Reduced PTEN catalytic activity impairs removal of the 3-phosphate from PIP3.

Lifelong Multiorgan Cancer Predisposition Germline PTEN dysfunction predisposes to malignancy through tissue-dependent growth and tumor-suppressor mechanisms; this edge does not require universal biallelic PTEN loss.

Brain Enlargement PTEN dysfunction alters neural cell size and glial production in experimental models; the relative contributions to human BRRS macrocephaly remain unresolved.

Microglial Activation Reduced and mislocalized Pten in the germline mouse model is associated with microglial activation.

Penile freckling Penile macules are a recognized phenotype in PTEN-positive BRRS, but the pigmentary intermediates are not established.

Global developmental delay PTEN-associated neurodevelopmental and motor dysfunction includes this clinical manifestation; the specific causal cellular intermediates are unresolved.

Autism PTEN-associated neurodevelopmental and motor dysfunction includes this clinical manifestation; the specific causal cellular intermediates are unresolved.

Intellectual disability PTEN-associated neurodevelopmental and motor dysfunction includes this clinical manifestation; the specific causal cellular intermediates are unresolved.

Hypotonia PTEN-associated neurodevelopmental and motor dysfunction includes this clinical manifestation; the specific causal cellular intermediates are unresolved.

Motor delay A recognized neurodevelopmental manifestation, without a proven single cellular intermediary.

Delayed speech and language development A recognized neurodevelopmental manifestation, without a proven single cellular intermediary.

Show evidence (2 references)

PMID:9593664 SUPPORT PRIMARY RESULT In Vitro

"Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring."

Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.

PMID:10400993 SUPPORT Human Clinical

"Mutations were identified in 26 of 43 (60%) BRR cases."

Quantifies the germline PTEN detection rate in a dedicated BRRS cohort, supporting both the causal gene assignment and the incomplete molecular yield.

PIP3 Accumulation

Loss of PTEN lipid-phosphatase activity allows accumulation of PIP3, a membrane lipid second messenger. This does not require increased activity of PI3K itself.

Experimental models

PTEN lipid-phosphatase biochemical and 293-cell assays OTHER PTEN catalytic perturbation and lipid substrate measurements.

Downstream

AKT Activation PIP3-dependent membrane recruitment enables AKT activation within the PTEN-regulated signaling pathway.

Show evidence (2 references)

PMID:9593664 SUPPORT PRIMARY RESULT In Vitro

"Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring."

Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.

PMID:9593664 SUPPORT PRIMARY RESULT In Vitro

"Further, transfection of the catalytically inactive mutant of PTEN (C124S) caused PtdIns(3,4,5)P3 accumulation in the absence of insulin stimulation."

The catalytically inactive construct caused PIP3 accumulation in transfected human 293 cells; this is a mechanistic assay, not a BRRS patient allele experiment.

AKT Activation

AKT activation is a proximal signaling consequence of impaired PTEN function and connects lipid signaling to downstream growth regulators.

PI3K/AKT signaling GO:0043491 ↑ INCREASED

Downstream

mTOR Overactivity AKT-dependent regulation of intermediary growth-control proteins promotes mTOR signaling.

Show evidence (1 reference)

PMID:35594551 SUPPORT BACKGROUND Human Clinical

"In PHTS, loss of PTEN function leads to disinhibition of the PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase)-AKT–mTOR pathway"

The trial introduction summarizes established PHTS signaling biology; the clinical trial did not itself measure this molecular chain.

mTOR Overactivity

Excess mTOR signaling contributes to abnormal cell growth and provides the rationale for trials of mTOR inhibitors in PHTS.

mTOR signaling GO:0031929 ↑ INCREASED

Downstream

Hamartomatous Tissue Overgrowth Increased growth signaling contributes to hamartomatous overgrowth, with tissue-specific and potentially additional genetic events incompletely defined.

Show evidence (1 reference)

PMID:35594551 SUPPORT BACKGROUND Human Clinical

"In PHTS, loss of PTEN function leads to disinhibition of the PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase)-AKT–mTOR pathway"

The trial introduction summarizes established PHTS signaling biology; the clinical trial did not itself measure this molecular chain.

Hamartomatous Tissue Overgrowth

Unrestrained growth signaling produces hamartomas: benign, disorganized overgrowths composed of cell types native to the tissue of origin. In BRRS this is expressed predominantly as hamartomatous polyps distributed throughout the gastrointestinal tract, subcutaneous and visceral lipomas, and vascular lesions, and it is the substrate for the syndrome's structural burden in childhood.

adipocyte CL:0000136 intestinal epithelial cell CL:0002563 endothelial cell CL:0000115

Downstream

Hamartomatous polyposis

Lipoma

Hemangioma

PTEN Hamartoma of Soft Tissue Formation PHOST is one distinctive form of mesenchymal overgrowth within PHTS; its tissue-specific development is not fully explained by the general overgrowth phenotype.

Show evidence (2 references)

PMID:9352843 SUPPORT Human Clinical

"Bannayan-Riley-Ruvalcaba syndrome is a congenital syndrome with characteristic features of macrocephaly, cognitive and motor dysfunction, subcutaneous and visceral lipomas and hemangiomas, and intestinal juvenile polyposis."

Enumerates the hamartomatous tissue lesions (lipomas, hemangiomas, intestinal polyposis) that constitute this overgrowth node in BRRS.

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis."

The GeneReviews definition of BRRS, confirming hamartomatous polyposis and lipomas as defining tissue-level manifestations.

PTEN Hamartoma of Soft Tissue Formation

PHOST is a distinctive, unencapsulated mesenchymal lesion found in PHTS, including BRRS presentations. Mature adipose and fibrous or myxoid tissue are intermixed with abnormal veins, thick-walled arteries, small vessels, and occasional arteriovenous communications. It commonly infiltrates muscle, fascia, and subcutis and may cause pain and swelling. It is one of several PHTS-associated vascular/connective tissue lesions, not a synonym for all vascular malformations.

adipocyte CL:0000136 endothelial cell CL:0000115 fibroblast CL:0000057

Downstream

Arteriovenous malformation Arteriovenous communications can be a component of PHOST. This does not imply that all BRRS arteriovenous malformations are PHOST.

Show evidence (3 references)

PMID:22446940 SUPPORT Human Clinical

"We designate this disorganized overgrowth of essentially mesenchymal elements as PTEN hamartoma of soft tissue."

The defining pathological description of PHOST, establishing this node as a distinct lesion entity rather than a generic vascular malformation.

PMID:22446940 SUPPORT Human Clinical

"Lesions manifested by 15 years of age, normally with pain and swelling, and were most often located in the lower extremity."

Establishes the pediatric onset and the clinical burden (pain, swelling) that makes this node the target of lesion-directed therapy in BRRS.

PMID:22446940 SUPPORT PRIMARY RESULT Human Clinical

"Thus, PHOST is only one of several vascular anomalies and connective tissue overgrowths that occur in PTHS, some of which have more than one tissue type."

The pathology series explicitly distinguishes PHOST from other PHTS lesions; PTHS is the source spelling.

Brain Enlargement

Brain enlargement is a structural consequence of PTEN dysfunction. The Ptenm3m4 model shows regional enlargement with neuronal soma hypertrophy and increased glial production. These model findings provide candidate cellular contributors to human macrocephaly, without establishing a uniform course or excluding other causes of enlarged head circumference in individual patients.

Animal models

Germline Ptenm3m4 mouse Mus musculus measures Regional brain weight and cellular size/proliferation readouts.

Downstream

Macrocephaly Increased brain size contributes to enlarged head circumference.

Show evidence (2 references)

PMID:24470394 SUPPORT PRIMARY RESULT Model Organism

"The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight."

The model combines reduced Pten abundance with altered localization and shows regional brain enlargement.

PMID:24470394 SUPPORT PRIMARY RESULT Model Organism

"The cytoplasm-predominant protein caused cellular hypertrophy limited to the soma and led to increased NG2 cell proliferation and accumulation of glia."

Homozygous Ptenm3m4 mice showed neuronal soma hypertrophy and increased glial production. These findings do not demonstrate generalized neuronal progenitor proliferation in human BRRS.

Microglial Activation

Ptenm3m4 mouse tissue and primary microglia show increased activation, including altered morphology and complement C1q expression. This is a model-derived mechanism rather than established human BRRS neuropathology.

Experimental models

Ptenm3m4 primary neuron-microglia co-cultures CO CULTURE Iba1/C1q expression and phagocytic capacity.

Animal models

Germline Ptenm3m4 mouse Mus musculus measures In vivo astrogliosis and microglial activation in mutant mice.

Downstream

Enhanced Microglial Synaptic Pruning Activated mutant microglia have enhanced phagocytic and pruning capacity in co-culture; neuronal genotype also affects the result.

Show evidence (1 reference)

PMID:32055008 SUPPORT PRIMARY RESULT In Vitro

"We found increased Iba1 and C1q expression with enhanced phagocytic capacity in Ptenm3m4/m3m4 microglia, indicating microglial activation."

Primary mouse microglial assays show activation and enhanced phagocytosis.

Enhanced Microglial Synaptic Pruning

Mutant microglia reduce synaptic-marker colocalization in neuron-microglia co-cultures, while mutant neurons cultured alone show more synapses. In vivo, synaptic marker expression also decreases with age in the Ptenm3m4 model. These experiments do not establish that excessive pruning causes autism, developmental delay, or hypotonia in human BRRS.

Experimental models

Ptenm3m4 primary neuron-microglia co-cultures CO CULTURE Synaptophysin/PSD-95 colocalization and microglial uptake assays.

Show evidence (1 reference)

PMID:32055008 SUPPORT PRIMARY RESULT In Vitro

"However, in a systemic germline Ptenm3m4/m3m4 mutant system, our data suggest cross-talk between neurons and microglia, resulting in significantly increased synaptic pruning in Ptenm3m4/m3m4 mutants compared with PtenWT/WT mice."

The co-culture results support genotype-dependent neuron-microglia interactions. Synapse abundance was assessed with pre/post-synaptic marker colocalization, not electrophysiological function.

Lifelong Multiorgan Cancer Predisposition

A germline pathogenic PTEN variant confers multiorgan cancer predisposition. PTEN-positive BRRS is managed within the PHTS spectrum, but precise BRRS-ascertained cancer incidence has not been established. Tumor development can involve additional somatic events; universal loss of the second PTEN allele is not assumed. PHTS risk estimates do not establish risks for PTEN-negative clinical BRRS.

Downstream

Breast carcinoma

Thyroid carcinoma

Endometrial carcinoma

Renal cell carcinoma

Colon cancer

Melanoma

Show evidence (5 references)

PMID:10400993 SUPPORT Human Clinical

"Thus, PTEN mutation-positive CS and BRR may be different presentations of a single syndrome and, hence, both should receive equal attention with respect to cancer surveillance."

The study supports shared surveillance for molecularly confirmed PTEN-positive BRRS and Cowden syndrome, not a measured equality of their cancer incidence.

PMID:10400993 NO_EVIDENCE Human Clinical

"CS is characterized by multiple hamartomas and an increased risk of benign and malignant disease of the breast, thyroid and central nervous system, whilst the presence of cancer has not been formally documented in BRR."

Recorded as NO_EVIDENCE because it asserts an absence of evidence rather than supporting or refuting the node: malignancy had not been formally established in BRRS-ascertained cohorts. It is retained to make explicit that the cancer risk attributed to BRRS is inferred from allelism with Cowden syndrome rather than from direct BRRS-cohort incidence data.

PMID:22252256 SUPPORT Human Clinical

"Lifetime risks for a variety of cancers, now extending to colorectal cancer, kidney cancer, and melanoma, are increased in patients with PTEN mutations."

The prospective PHTS cohort establishing that germline PTEN carriers, the molecular class to which PTEN-positive BRRS belongs, carry elevated multiorgan cancer risk.

+ 2 more references

Impaired Contact Inhibition in TTN Variant Cells

HEK293T cells edited to carry TTN p.Cys5096Arg continued proliferating after confluence, accompanied by altered FAK abundance/phosphorylation and reduced AKT/ERK phosphorylation. This isolated experimental branch describes candidate biology in PTEN-wildtype BRRS; it is not an established causal route to human hamartomas.

Experimental models

TTN p.Cys5096Arg edited HEK293T cells CELL LINE Growth after confluence and associated signaling readouts.

Show evidence (2 references)

PMID:29263846 SUPPORT PRIMARY RESULT In Vitro

"suggested lack of contact inhibition in mutant cells"

Edited HEK293T cells continued proliferating after confluence; one TTN variant was tested.

PMID:29263846 SUPPORT PRIMARY RESULT In Vitro

"we note paradoxical downstream readouts of decreased phosphorylation of AKT and ERK1/2"

The measured signaling direction differs from canonical PTEN-loss hyperactivation.

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Histopathology

1

PTEN hamartoma of soft tissue

Unencapsulated lesions contain mature adipose and dense or myxoid fibrous tissue mixed with abnormal venous channels, tortuous thick-walled arteries, and small vessels. Some contain arteriovenous connections, lymphoid follicles, metaplastic bone, or hypertrophic nerves. Histologic recognition warrants evaluation for PHTS, but does not independently establish a germline PTEN variant.

Show evidence (3 references)

PMID:22446940 SUPPORT PRIMARY RESULT Human Clinical

"a variable admixture of mature adipocytic and dense and/or myxoid fibrous tissues"

The selected pathology series defines the nonvascular stromal components.

PMID:22446940 SUPPORT PRIMARY RESULT Human Clinical

"tortuous, thick-walled arteries with concentric muscular hyperplasia and relatively small lumens"

This describes characteristic vascular architecture in PHOST.

PMID:22446940 SUPPORT PRIMARY RESULT Human Clinical

"Histopathologic recognition of PHOST should prompt a detailed clinical evaluation, including family history, as well as possible genetic testing for a PTEN mutation."

The authors frame PHOST as a diagnostic clue requiring clinical and molecular evaluation.

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Pathograph

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Phenotypes

28

Blood 1

Hematochezia HP:0002573

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"BRRS patients with polyps may present with abdominal pain, hematochezia, anemia, invagination, constipation, or diarrhea"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Breast 1

Breast carcinoma HP:0003002

Show evidence (3 references)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"The lifetime risk of developing breast cancer is 85%, with an average age of diagnosis between 38 and 46 years."

GeneReviews gives the lifetime breast cancer risk and the adult age range at which it is realized.

PMID:22252256 SUPPORT Human Clinical

"Estimated lifetime risks were, respectively, 85.2% (95% CI, 71.4%-99.1%), 35.2% (19.7%-50.7%), 28.2% (17.1%-39.3%), 9.0% (3.8%-14.1%), 33.6% (10.4%-56.9%), and 6% (1.6%-9.4%)."

Prospective PHTS cohort reporting the 85.2% lifetime breast cancer risk, the first value in the ordered list of breast, thyroid, endometrium, colorectum, kidney, and melanoma.

PMID:33140411 SUPPORT REVIEW SYNTHESIS Human Clinical

"The tumor spectrum included female breast cancer (CLTRs including sex-specific estimates at age 60-70: 67% to 85%), endometrium cancer (19% to 28%), thyroid cancer (6% to 38%), renal cancer (2% to 24%), colorectal cancer (9% to 32%), and melanoma (0% to 6%)."

Gives the cross-cohort ranges for every cancer site curated in this entry, which is why the descriptions frame risk as a range rather than a single point estimate.

Cardiovascular 2

Hemangioma HP:0001028

Show evidence (1 reference)

PMID:9352843 SUPPORT Human Clinical

"Bannayan-Riley-Ruvalcaba syndrome is a congenital syndrome with characteristic features of macrocephaly, cognitive and motor dysfunction, subcutaneous and visceral lipomas and hemangiomas, and intestinal juvenile polyposis."

Names subcutaneous and visceral hemangiomas among the characteristic BRRS features.

Arteriovenous malformation HP:0100026

Show evidence (3 references)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Another frequent finding was vascular abnormalities, namely, hemangiomas (8/33) and AVMs (6/33)."

Names arteriovenous malformations specifically (not merely "vascular malformations") and gives the BRRS report-level frequency, 6 of 33.

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Notably, AVMs can occur in the CNS and carry a potential risk of bleeding and complications related to mass effects"

Supports the clinical significance of AVMs in BRRS, including the CNS location that drives imaging and intervention decisions.

PMID:10400993 SUPPORT Human Clinical

"Additional features observed in BRR, which may also occur in a minority of CS patients, include Hashimoto's thyroiditis, vascular malformations and mental retardation."

This evidence is limited because this source establishes vascular malformations broadly as a BRRS feature but does not specify the arteriovenous subtype that this phenotype is bound to.

Digestive 3

Hamartomatous polyposis HP:0004390

Sequelae: Hematochezia Intussusception

Show evidence (3 references)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis."

GeneReviews names intestinal hamartomatous polyposis as a defining BRRS feature.

PMID:34754688 SUPPORT Human Clinical

"The esophagogastroduodenoscopy (EGD) and colonoscopy revealed an erosive gastric mucosa as well as numerous polyps throughout the gastrointestinal tract."

A BRRS case report documenting polyp distribution across both upper and lower gastrointestinal tract, supporting the diffuse rather than colon-restricted pattern.

PMID:22672595 SUPPORT Human Clinical

"The cumulative risk of developing benign gastrointestinal polyps was 70% at age 60."

Multinational PTEN-carrier cohort quantifying the cumulative burden of benign gastrointestinal polyps.

Colon cancer HP:0003003

Show evidence (2 references)

PMID:22672595 SUPPORT Human Clinical

"Benign gastrointestinal lesions are common in PTEN mutation carriers, and a three- to four-fold increased lifetime risk of colorectal cancer compared with the general population may exist."

Multinational PTEN-carrier cohort quantifying the relative colorectal cancer risk that justifies colonoscopic surveillance.

url:https://www.ncbi.nlm.nih.gov/books/NBK1488/?report=printable SUPPORT REVIEW SYNTHESIS Human Clinical

"These polyps are not believed to increase the risk for colorectal cancer."

In the BRRS clinical-characteristics section this refers to gastrointestinal hamartomatous polyps. It distinguishes their complications from the broader PTEN-associated cancer risk.

Intussusception HP:0002576

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"BRRS patients with polyps may present with abdominal pain, hematochezia, anemia, invagination, constipation, or diarrhea"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Endocrine 3

Hashimoto thyroiditis HP:0000872

Show evidence (1 reference)

PMID:10400993 SUPPORT Human Clinical

"Additional features observed in BRR, which may also occur in a minority of CS patients, include Hashimoto's thyroiditis, vascular malformations and mental retardation."

Documents Hashimoto thyroiditis as a recognized BRRS feature.

Thyroid carcinoma HP:0002890

Show evidence (1 reference)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"The lifetime risk for thyroid cancer (usually follicular, rarely papillary, but never medullary thyroid cancer) is approximately 35%."

GeneReviews gives the thyroid cancer lifetime risk and its histologic pattern.

Thyroid nodule HP:0025388

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"From the included studies, the majority of outlined thyroid changes were nodules"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Genitourinary 3

Penile freckling HP:0031447

Show evidence (6 references)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis."

GeneReviews names pigmented macules of the glans penis as a defining BRRS feature.

PMID:10400993 SUPPORT Human Clinical

"Pigmented macules of the glans penis, delayed motor development and neonatal or infant onset are noted only in BRR."

This historical comparison described penile macules in BRRS. It is not a contemporary estimate of diagnostic specificity across all PHTS presentations.

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Pigmented penile macules were described in the majority of male reports (21/28)."

The denominator is 28 publications describing male cases, not the number of male patients. No patient frequency is inferred.

+ 3 more references

Endometrial carcinoma HP:0012114

Show evidence (1 reference)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"The risk for endometrial cancer may approach 28%."

GeneReviews gives the endometrial cancer lifetime risk estimate.

Renal cell carcinoma HP:0005584

Show evidence (1 reference)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"The lifetime risk for renal cell cancer (predominantly of papillary histology) is 34%."

GeneReviews gives the renal cell carcinoma lifetime risk and histologic pattern.

Head and Neck 1

Macrocephaly FREQUENT HP:0000256

Show evidence (3 references)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis."

GeneReviews names macrocephaly as a defining feature of BRRS.

PMID:28526761 SUPPORT Human Clinical

"Macrocephaly (average head circumference of + 5.7 SD) with developmental delay, ID and/or ASD were the most common presenting signs/symptoms (66 %)."

Supports the disease-phenotype association and quantifies the severity of macrocephaly in pediatric PHTS (mean head circumference +5.7 SD). Note this 66% figure is a composite presenting-symptom statistic (macrocephaly together with developmental delay, ID and/or ASD), not a macrocephaly frequency, so it is not used to set the frequency band.

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"A total of 83 pediatric patients with BRRS were identified. The most common clinical findings were macrocephaly (77%) and developmental disorders (63%)."

The patient-level 77% estimate supports FREQUENT. The same review also reports macrocephaly in 32 of 33 publications, but publication counts cannot be used as patient frequencies. Incomplete case reporting and publication selection limit generalization of the patient-level estimate.

Integument 1

Cafe-au-lait spot HP:0000957

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"the most frequently mentioned were café au lait spots, verrucous papules, and subcutaneous hemangiomas"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Musculoskeletal 6

Lipoma HP:0012032

Show evidence (3 references)

PMID:10400993 SUPPORT Human Clinical

"The partial clinical overlap in these two syndromes is exemplified by the hallmark features of BRR: macrocephaly and multiple lipomas, the latter of which occur in a minority of individuals with CS."

Identifies multiple lipomas as a hallmark BRRS feature that discriminates it from Cowden syndrome, where lipomas are a minority finding.

PMID:10400993 SUPPORT Human Clinical

"Additionally, the presence of lipomas was correlated with the presence of PTEN mutation in BRR patients"

Documents the genotype-phenotype correlation between lipomas and a detectable PTEN variant within BRRS.

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Lipomas were mentioned in more than half of the cases (18/33), and the second most common lesion was gastrointestinal polyps (16/33)."

These are counts of publications among 33 reviewed studies, not counts of affected patients. They support recurring reports of lipomas and polyps but do not establish patient-level frequencies.

Hypotonia HP:0001252

Show evidence (2 references)

PMID:29263846 SUPPORT BACKGROUND Human Clinical

"Muscle weakness and hypotonia cause affected BRRS infants to appear"

Names hypotonia explicitly in BRRS infants and links it to the delayed motor development curated in this entry.

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"some PTEN pathogenic variant carriers can suffer from muscle hypotonia, which is associated with motor delay"

BRRS systematic review naming muscle hypotonia and its association with motor delay. The hedged wording ("some") is why no frequency band is asserted.

Pectus excavatum HP:0000767

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Particularly associated with BRRS are musculocutaneous findings such as pectus excavatum, scoliosis, and joint hypermobility"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Scoliosis HP:0002650

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Particularly associated with BRRS are musculocutaneous findings such as pectus excavatum, scoliosis, and joint hypermobility"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Joint hypermobility HP:0001382

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Particularly associated with BRRS are musculocutaneous findings such as pectus excavatum, scoliosis, and joint hypermobility"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Myopathy HP:0003198

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Prenatal overgrowth and musculoskeletal system disorders such as myopathy of proximal muscles and scoliosis are other clinical features commonly found among individuals with BRRS"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Nervous System 6

Global developmental delay HP:0001263

Show evidence (2 references)

PMID:28526761 SUPPORT Human Clinical

"Macrocephaly (average head circumference of + 5.7 SD) with developmental delay, ID and/or ASD were the most common presenting signs/symptoms (66 %)."

Establishes developmental delay as part of the leading presentation in a pediatric PHTS cohort.

PMID:34983360 SUPPORT REVIEW SYNTHESIS Human Clinical

"Intellectual disability and developmental delay (global, motor and speech and language) were also reported frequently."

Systematic review confirming that global, motor, and speech-language delay are frequent in constitutional PTEN variant carriers.

Autism HP:0000717

Show evidence (2 references)

PMID:34983360 SUPPORT REVIEW SYNTHESIS Human Clinical

"Meta-analysis using a random effects model estimated pooled prevalence of ASD characteristics at 25% (95% CI 16-33%), although this should be interpreted cautiously due to possible biases in existing literature."

The pooled estimate concerns ASD characteristics in heterogeneous PTEN cohorts. It supports the association, but is not used to assign a BRRS-specific frequency for diagnosed autism.

PMID:28526761 SUPPORT Human Clinical

"It is recognised that 5% - 10 % of children with macrocephaly and autism spectrum disorder (ASD) and/or intellectual disability (ID) have a heterozygous pathogenic mutation in the PTEN tumour suppressor gene that is associated with PTEN hamartoma tumour syndrome."

Supports the reciprocal clinical rule that macrocephaly plus ASD should prompt PTEN testing.

Intellectual disability HP:0001249

Show evidence (2 references)

PMID:10400993 SUPPORT Human Clinical

"Additional features observed in BRR, which may also occur in a minority of CS patients, include Hashimoto's thyroiditis, vascular malformations and mental retardation."

Documents cognitive impairment (reported using the era's terminology) as a recognized BRRS feature.

PMID:34983360 SUPPORT REVIEW SYNTHESIS Human Clinical

"Intellectual disability and developmental delay (global, motor and speech and language) were also reported frequently."

Systematic review confirming intellectual disability is frequently reported in PTEN carriers.

Motor delay HP:0001270

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Motor delay is the most common developmental disorder among patients"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Delayed speech and language development HP:0000750

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"ranging from normal psychomotor development and mild motor or speech delay to severe intellectual disability"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Seizure HP:0001250

Show evidence (1 reference)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Single cases of scoliosis, seizures, intracranial hypertension, and intracranial tumor treatment were also presented"

The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts of publications.

Neoplasm 1

Melanoma HP:0002861

Show evidence (1 reference)

PMID:22252256 SUPPORT Human Clinical

"Lifetime risks for a variety of cancers, now extending to colorectal cancer, kidney cancer, and melanoma, are increased in patients with PTEN mutations."

Establishes melanoma as part of the confirmed germline PTEN cancer spectrum in a prospective cohort.

🧬

Genetic Associations

2

PTEN

Gene: PTEN hgnc:9588 gene page relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (6 references)

PMID:34754688 SUPPORT Human Clinical

"Bannayan-Riley-Ruvalcaba syndrome (BRRS) is a rare genetic disorder caused by germline mutations in the phosphatase and tensin homolog (PTEN) gene."

Directly assigns germline PTEN variants as the cause of BRRS.

PMID:10400993 SUPPORT Human Clinical

"Mutations were identified in 26 of 43 (60%) BRR cases."

Establishes the approximately 60% germline PTEN detection rate in a dedicated BRRS cohort.

PMID:10400993 SUPPORT Human Clinical

"Among CS, BRR and BRR/CS overlap families that are PTEN mutation positive, the mutation spectra appear similar."

Supports the claim that the BRRS mutation spectrum is not distinguishable from that of Cowden syndrome.

+ 3 more references

TTN

Gene: TTN hgnc:12403 gene page relationship_type: SUSCEPTIBILITY variant_origin: GERMLINE

Show evidence (3 references)

PMID:29263846 SUPPORT Human Clinical

"We exome-sequenced 35 unrelated PTEN-wildtype patients with classic presentation of BRRS and identified TTN germline missense variants in 12/35 (34%) patients."

The primary human genetic observation: rare TTN missense variants in about a third of PTEN-wildtype classic BRRS patients.

PMID:29263846 SUPPORT In Vitro

"suggested lack of contact inhibition in mutant cells"

Cell-based functional support for one TTN variant. Limited to the cell assay, with evidence_source IN_VITRO because it is an edited-cell phenotype, not a demonstration of the human disease mechanism.

PMID:29263846 SUPPORT Human Clinical

"our observations suggest TTN as a candidate predisposing gene in classic PTEN-wildtype BRRS patients, perhaps suggesting this syndrome join the growing list of Titinopathies"

The authors' own framing as a candidate gene, which is why this is curated as SUSCEPTIBILITY rather than CAUSATIVE.

🔬

Variants

3

PTEN p.Arg130Ter Pathogenic

Gene: PTEN hgnc:9588 single nucleotide variant

Variant detail: Nonsense

Recurrent PTEN nonsense variant c.388C>T (p.Arg130Ter) on NM_000314.8 / NP_000305.3, reported as pathogenic in GeneReviews. The source notes that classifications were supplied by its authors and not independently verified by GeneReviews staff. This is a PHTS allele, not specific to one clinical presentation.

Show evidence (1 reference)

url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/ SUPPORT REVIEW SYNTHESIS Human Clinical

"p.Arg130Ter ... Recurrent pathogenic variants ... Variants listed in the table have been provided by the authors."

Table 6 of GeneReviews lists these three recurrent pathogenic PTEN variants and pairs their nucleotide and protein changes. The description records the relevant allele and the source classification caveat.

PTEN p.Arg233Ter Pathogenic

Gene: PTEN hgnc:9588 single nucleotide variant

Variant detail: Nonsense

Recurrent PTEN nonsense variant c.697C>T (p.Arg233Ter) on NM_000314.8 / NP_000305.3, reported as pathogenic in GeneReviews. The source notes that classifications were supplied by its authors and not independently verified by GeneReviews staff. This is a PHTS allele, not specific to one clinical presentation.

Show evidence (1 reference)

url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/ SUPPORT REVIEW SYNTHESIS Human Clinical

"Recurrent pathogenic variants ... p.Arg233Ter ... Variants listed in the table have been provided by the authors."

Table 6 of GeneReviews lists these three recurrent pathogenic PTEN variants and pairs their nucleotide and protein changes. The description records the relevant allele and the source classification caveat.

PTEN p.Arg335Ter Pathogenic

Gene: PTEN hgnc:9588 single nucleotide variant

Variant detail: Nonsense

Recurrent PTEN nonsense variant c.1003C>T (p.Arg335Ter) on NM_000314.8 / NP_000305.3, reported as pathogenic in GeneReviews. The source notes that classifications were supplied by its authors and not independently verified by GeneReviews staff. This is a PHTS allele, not specific to one clinical presentation.

Show evidence (2 references)

url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/ SUPPORT REVIEW SYNTHESIS Human Clinical

"Recurrent pathogenic variants ... p.Arg335Ter ... Variants listed in the table have been provided by the authors."

Table 6 of GeneReviews lists these three recurrent pathogenic PTEN variants and pairs their nucleotide and protein changes. The description records the relevant allele and the source classification caveat.

PMID:10353779 SUPPORT PRIMARY RESULT Human Clinical

"We have identified a germline mutation, R335X, in PTEN in a family consisting of two female members with the phenotypic findings of CS and two male members with the phenotypic findings of BZS."

This family directly links the recurrent stop variant to both Cowden and BRRS/Bannayan-Zonana presentations.

💊

Medical Actions

12

Lifelong Cancer Surveillance

Action: cancer surveillance Ontology label: Cancer Screening NCIT:C15406

Individuals with a germline pathogenic PTEN variant and a BRRS phenotype require long-term PHTS cancer-risk management. Recent guidelines differ in starting ages, intervals, and the evidence for renal and endometrial surveillance. The 2025 international consensus and 2026 ERN GENTURIS recommendations are therefore described separately below. Personal and family history, prior lesions, local guidance, and shared decision-making inform the plan. Molecularly negative clinical BRRS requires individualized assessment; the same cancer risk is not established. Genotype-based surveillance stratification is not supported by current evidence.

Show evidence (4 references)

PMID:10400993 SUPPORT Human Clinical

"Thus, PTEN mutation-positive CS and BRR may be different presentations of a single syndrome and, hence, both should receive equal attention with respect to cancer surveillance."

The primary justification for applying full Cowden-equivalent surveillance to PTEN-positive BRRS.

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"As targeted treatment is still lacking, symptom relief and long-term surveillance remain the main management strategies."

BRRS-specific systematic review confirming that surveillance plus symptom-directed care, rather than any disease-modifying therapy, is the management mainstay.

PMID:39937242 SUPPORT REVIEW SYNTHESIS Human Clinical

"at this time, it is not felt that genotype-specific recommendations could be made for individuals with PHTS"

The consensus explicitly rejects genotype-specific surveillance recommendations at present.

+ 1 more reference

PHTS Surveillance: 2025 International Consensus

Action: cancer surveillance Ontology label: Cancer Screening NCIT:C15406

The 2025 international consensus recommends annual breast MRI from age 25 and annual mammography from age 40. Thyroid ultrasound begins at age 12, then every 3-5 years when normal or every 2-3 years for clinically nonactionable nodules. Baseline colonoscopy is recommended at 35-40 years, with 1-3-year follow-up for a high adenoma burden, large polyps, or high-grade dysplasia. Routine endometrial surveillance, if offered, should be within a clinical trial; abnormal uterine bleeding requires evaluation. Renal ultrasound every two years from 35-40 may be considered as expert opinion. These recommendations concern PTEN-confirmed PHTS, not BRRS-specific trial evidence.

Show evidence (7 references)

PMID:39937242 SUPPORT REVIEW SYNTHESIS Human Clinical

"Women with PHTS should undergo annual breast MRI (with contrast) from age 25 years and additional surveillance with breast mammography (with digital breast tomosynthesis) starting at age 40 years until 75 to 80 years of age."

The consensus breast imaging recommendation is stated with its age thresholds.

PMID:39937242 SUPPORT REVIEW SYNTHESIS Human Clinical

"From age 12 years, individuals with PHTS should undergo baseline thyroid ultrasound."

The 2025 consensus begins thyroid ultrasound at 12 years.

PMID:39937242 SUPPORT REVIEW SYNTHESIS Human Clinical

"We recommend surveillance with thyroid ultrasound every 3 to 5 years for individuals with PHTS and without nodules seen on initial thyroid ultrasound and every 2 to 3 years for individuals with clinically nonactionable nodules seen on initial thyroid ultrasound."

Intervals depend on the initial ultrasound findings.

+ 4 more references

PHTS Surveillance: 2026 ERN GENTURIS Guideline

Action: cancer surveillance Ontology label: Cancer Screening NCIT:C15406

The 2026 ERN GENTURIS guideline recommends breast MRI surveillance from age 25, with mammography every 1-2 years considered from age 40 or according to national guidance. Thyroid ultrasound starts between 10 and 18 years, annually initially, then every 2-3 years after two examinations without suspicious findings. Endometrial surveillance is probably appropriate from 35-40 years using at least annual transvaginal ultrasonography, with biopsy considered. Renal baseline imaging is offered at 35-40; when normal, further regular renal screening is not recommended. Baseline colonoscopy at 35-40 determines follow-up by polyp number, size, and pathology; only hamartomas or no polyps may permit general-population screening or repeat colonoscopy after 5-10 years. A baseline skin examination is suggested at 30, with further assessment according to findings or symptoms.

Show evidence (11 references)

url:https://www.nature.com/articles/s41431-026-02181-z/tables/3 SUPPORT REVIEW SYNTHESIS Human Clinical

"Surveillance for breast cancer with MRI should probably start at age 25."

Recommendation 3 gives the MRI starting age.

url:https://www.nature.com/articles/s41431-026-02181-z SUPPORT REVIEW SYNTHESIS Human Clinical

"In addition, mammography every 1–2 years can be considered, preferably from the age of 40 years"

The full guideline text describes mammography in addition to annual MRI and allows alignment with national surveillance guidance.

url:https://www.nature.com/articles/s41431-026-02181-z/tables/3 SUPPORT REVIEW SYNTHESIS Human Clinical

"Surveillance for thyroid cancer should probably start between 10 and 18 years of age."

Recommendation 8 gives an age range, rather than a universal starting age.

+ 8 more references

Gastrointestinal Polyp Management

Action: endoscopic polypectomy Ontology label: Surgical Procedure NCIT:C15329

Platform: Surgery

Symptomatic gastrointestinal polyps require evaluation and endoscopic management according to size, histology, and complications. Childhood bleeding, anemia, obstruction, or intussusception may warrant assessment before routine adult cancer-screening ages. Severe or recurrent disease can require surgery.

Show evidence (2 references)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"Polypectomies of hamartomatous polyps were also frequent, with two cases of proctocolectomy and subtotal colectomy due to severe symptom burden and recurrence"

The BRRS review records endoscopic polyp removal and surgery for severe recurrent disease.

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"BRRS patients with polyps may present with abdominal pain, hematochezia, anemia, invagination, constipation, or diarrhea"

These complications motivate symptom-directed care independently of routine screening ages.

Symptomatic Management of Hamartomatous Lesions

Action: surgical excision Ontology label: Surgical Procedure NCIT:C15329

Platform: Surgery

Lipomas, vascular lesions, and other benign manifestations are treated the same way as their sporadic counterparts, with excision reserved for lesions causing pain, functional impairment, deformity, or diagnostic uncertainty rather than performed prophylactically.

Show evidence (2 references)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"Treatment for the benign and malignant manifestations of PHTS is the same as for their sporadic counterparts."

GeneReviews establishes the principle of treating manifestations as for sporadic disease.

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"cutaneous lesions should be excised only if malignancy is suspected or symptoms (e.g., pain, deformity, increased scarring) are significant."

GeneReviews supports restricting excision to symptomatic or suspicious lesions.

Developmental and Behavioral Support

Action: rehabilitation Ontology label: Rehabilitation NCIT:C15315

Platform: Behavioral / lifestyle

Because developmental delay, intellectual disability, and autism spectrum characteristics are core to the BRRS presentation, early developmental assessment and intervention (speech, motor, and educational support) is a management priority independent of the cancer-surveillance agenda.

Show evidence (2 references)

PMID:28526761 SUPPORT Human Clinical

"Early paediatric diagnosis is important for institution of medical and developmental surveillance as well as for testing other at- risk family members."

Supports developmental surveillance and support as an explicit goal of early pediatric diagnosis.

url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/ SUPPORT REVIEW SYNTHESIS Human Clinical

"Referral to an early intervention program is recommended for access to occupational, physical, speech, and feeding therapy as well as infant mental health services, special educators, and sensory impairment specialists."

The updated GeneReviews chapter specifies multidisciplinary early intervention for developmental difficulties.

mTOR Inhibitor Therapy

Action: mTOR inhibitor pharmacotherapy Ontology label: Pharmacotherapy NCIT:C15986

Agent: everolimus CHEBI:68478

Platform: Small molecule

Everolimus targets the mTOR overactivity that follows PTEN loss, giving a direct mechanistic rationale. A 6-month phase II randomized placebo-controlled trial in 46 individuals with PHTS (eligible ages 5 to 45 years) found the drug tolerable but did not meet its primary neurocognitive endpoint, with gastrointestinal adverse events more common on treatment. mTOR inhibition therefore remains investigational for the neurodevelopmental features of BRRS and is not routine care.

Mechanism Target:

INHIBITS mTOR Overactivity — Pharmacologic inhibition of mTOR is the molecular target; clinical benefit for each indication requires separate evidence.

Show evidence (3 references)

PMID:35594551 SUPPORT Human Clinical

"PTEN hamartoma tumor syndrome (PHTS) is a complex neurodevelopmental disorder characterized by mechanistic target of rapamycin (mTOR) overactivity."

Establishes the mechanistic rationale for mTOR inhibition in PHTS.

PMID:35594551 REFUTE Human Clinical

"Changes in the primary endpoint between groups from baseline to Month 6 were not apparent"

Recorded as REFUTE for the claim of neurocognitive efficacy. The randomized trial's primary endpoint was null, which is why this treatment is curated as investigational rather than established.

PMID:35594551 SUPPORT Human Clinical

"Gastrointestinal adverse events were more common in the everolimus group"

Documents the principal treatment-emergent toxicity signal in the trial.

Sirolimus for Vascular Anomalies

Action: mTOR inhibitor pharmacotherapy Ontology label: Pharmacotherapy NCIT:C15986

Agent: sirolimus CHEBI:9168

Platform: Small molecule

Sirolimus (rapamycin) is the lesion-directed mTOR-inhibitor use in BRRS, distinct from the neurocognitive indication that the everolimus trial tested and missed. It is used off-label for symptomatic vascular anomalies when other treatments have failed, and the BRRS-specific published experience is a single pediatric case in the 2024 systematic review. Evidence is therefore anecdotal, and this is curated as an off-label option under investigation rather than standard care.

Mechanism Target:

INHIBITS mTOR Overactivity — Pharmacologic inhibition of mTOR is the molecular target; clinical benefit for each indication requires separate evidence.

Show evidence (3 references)

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"mTOR inhibitors have been investigated in patients with vascular anomalies when previous treatments were ineffective"

Establishes the lesion-directed indication. This evidence is limited because it describes an investigational, salvage-setting use rather than established efficacy.

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"only one study reported the use of rapamycin"

Quantifies how thin the BRRS-specific evidence is: a single report among 33 reviewed articles, which is why this is curated as anecdotal rather than standard care.

PMID:39256443 SUPPORT REVIEW SYNTHESIS Human Clinical

"There is no established standard treatment for PHTS patients"

Confirms the absence of an established standard therapy in PHTS, the framing under which any mTOR-inhibitor use in BRRS should be read.

Genetic Counseling and Cascade Testing

Action: Genetic Counseling NCIT:C15240

Platform: Behavioral / lifestyle

Genetic counseling covers the autosomal dominant 50% transmission risk, the variable expressivity that lets one PTEN variant produce BRRS in one relative and Cowden syndrome in another, and the value of predictive testing in at-risk relatives so that carriers can enter surveillance.

Show evidence (3 references)

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"When a PTEN pathogenic variant has been identified in a proband, molecular genetic testing of asymptomatic at-risk relatives can identify those who have the family-specific pathogenic variant and warrant ongoing surveillance."

GeneReviews supports cascade testing of at-risk relatives to direct surveillance.

PMID:10353779 SUPPORT Human Clinical

"To our knowledge, this is the first report that shows the presence of separate subjects with CS and with BZS in a single family associated with a single germline PTEN mutation."

Supports counseling about intrafamilial variable expressivity: the same variant can produce either BRRS or Cowden syndrome in different relatives.

url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf SUPPORT REVIEW SYNTHESIS Human Clinical

"Once the PTEN pathogenic variant has been identified in an affected family member, prenatal and preimplantation genetic testing are possible."

GeneReviews supports reproductive counseling after the familial molecular diagnosis is established.

Investigational Sirolimus for Colon Polyposis

Action: mTOR inhibitor pharmacotherapy Ontology label: Pharmacotherapy NCIT:C15986

Agent: sirolimus CHEBI:9168

Platform: Small molecule

A small adult PHTS trial found fewer colorectal polyps in the two participants completing a year of sirolimus, without a change in polyposis stage. Drug-related pneumonitis and recurrent vaginal candidiasis caused withdrawals. This remains investigational and does not establish colorectal cancer prevention or a pediatric BRRS indication.

Mechanism Target:

INHIBITS mTOR Overactivity — Pharmacologic inhibition of mTOR is the molecular target; clinical benefit for each indication requires separate evidence.

Show evidence (4 references)

PMID:40478255 SUPPORT PRIMARY RESULT Human Clinical

"Five participants were enrolled, with 2 completing the planned study course."

The published completion count limits interpretation of efficacy.

PMID:40478255 SUPPORT PRIMARY RESULT Human Clinical

"For the patients completing the study, polyp numbers decreased"

A within-person observation in two completers is not controlled evidence of benefit.

PMID:40478255 SUPPORT PRIMARY RESULT Human Clinical

"there was not a change in polyposis staging despite the reduction in total colorectal polyp burden."

The trial did not establish a reduction in colonoscopy or colectomy requirements.

+ 1 more reference

Physical and Occupational Therapy

Action: rehabilitation Ontology label: Rehabilitation NCIT:C15315

Platform: Behavioral / lifestyle

Physical therapy supports mobility and addresses hypotonia and orthopedic complications. Occupational therapy targets fine-motor and adaptive difficulties, with equipment and support tailored to individual function.

Show evidence (2 references)

url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/ SUPPORT REVIEW SYNTHESIS Human Clinical

"Physical therapy is recommended to maximize mobility and to reduce the risk for later-onset orthopedic complications (e.g., contractures, scoliosis, hip dislocation)."

The updated GeneReviews chapter describes management of gross motor dysfunction.

url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/ SUPPORT REVIEW SYNTHESIS Human Clinical

"Occupational therapy is recommended for difficulty with fine motor skills that affect adaptive function such as feeding, grooming, dressing, and writing."

The chapter distinguishes fine-motor and adaptive support from gross motor therapy.

Individualized Risk-Reducing Surgery

Action: risk-reducing surgical procedures Ontology label: Surgical Procedure NCIT:C15329

Platform: Surgery

For PTEN-confirmed PHTS, risk-reducing mastectomy may be discussed as an alternative to breast surveillance with an experienced high-risk breast team, generally after age 25. Counseling considers individual risk, surgical complications, reconstruction, and preferences. Routine hysterectomy is not recommended by the 2025 international consensus; decisions are individualized, including uterine pathology and reproductive plans. These are adult risk-management options, not routine interventions for children with BRRS.

Show evidence (3 references)

PMID:39937242 SUPPORT REVIEW SYNTHESIS Human Clinical

"Given the high lifetime risk of female breast cancer and second primary breast cancer in individuals with PHTS and pathogenic or likely pathogenic variants in PTEN, we recommend discussing the options of surveillance versus RRM with an experienced high-risk breast clinic team."

The guideline recommends a discussion of alternatives rather than universal preventive surgery.

PMID:39937242 SUPPORT REVIEW SYNTHESIS Human Clinical

"Generally, RRM should only be considered in individuals older than 25 years of age, unless otherwise clinically indicated"

The usual age threshold is explicitly qualified.

PMID:39937242 SUPPORT REVIEW SYNTHESIS Human Clinical

"We do not recommend routine hysterectomy for endometrial cancer risk reduction in PHTS individuals with a uterus."

The consensus opposes routine hysterectomy and recommends individualized assessment.

🔬

Diagnosis

3

PTEN Molecular Genetic Testing

A heterozygous germline pathogenic PTEN variant establishes molecular PHTS in an individual with a BRRS phenotype. A negative result does not exclude a clinical BRRS presentation, but does not establish the same cancer risk. GeneReviews describes PTEN sequence analysis followed by deletion/duplication analysis, and promoter-region analysis when these are unrevealing. Copy-number testing can identify whole-gene or multiexon deletions; chromosomal microarray can define larger contiguous deletions including PTEN and BMPR1A. Test sensitivity depends on the assay used. KLLN promoter methylation findings in Cowden/Cowden-like cohorts do not establish a BRRS-specific etiology or routine BRRS diagnostic assay. Primer design must distinguish PTEN from its homologous pseudogene PTENP1.

Show evidence (4 references)

PMID:18510548 SUPPORT Human Clinical

"The sizes of the deletions were analyzed using single nucleotide polymorphism array analysis."

Supports the need for array-based rather than sequencing-only testing to detect the 10q23 contiguous deletions described in this section.

PMID:20301661 SUPPORT REVIEW SYNTHESIS Human Clinical

"The diagnosis of PHTS is established in a proband by identification of a heterozygous germline PTEN pathogenic variant on molecular genetic testing."

GeneReviews states the molecular basis of establishing the PHTS diagnosis.

url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf SUPPORT REVIEW SYNTHESIS Human Clinical

"If a pathogenic variant is not identified with deletion/duplication analysis, perform sequence analysis of the PTEN promoter region for variants that decrease PTEN gene expression."

The July 2026 PTEN Hamartoma Tumor Syndrome GeneReviews chapter by Tramontana and Yehia retains the sequence, copy-number, then promoter testing approach.

+ 1 more reference

Clinical Recognition in Childhood

BRRS is recognized clinically in a child with macrocephaly plus some combination of hamartomatous gastrointestinal polyposis, multiple lipomas, and pigmented macules of the glans penis, often alongside developmental delay or autism spectrum features. Because dermatologic, gastrointestinal, and thyroid findings are age-dependent, their absence at first assessment does not exclude the diagnosis.

Show evidence (2 references)

PMID:37900693 SUPPORT REVIEW SYNTHESIS Human Clinical

"This syndrome is occasionally diagnosed in childhood due to the occurrence of multiple gastrointestinal polyps, autism spectrum disorders, and intellectual disability."

Guideline statement describing the childhood route to diagnosis that characterizes the BRRS presentation.

PMID:28526761 SUPPORT Human Clinical

"Dermatological, GI and thyroid abnormalities are age dependent and may not be present at the time of diagnosis, requiring regular monitoring and medical surveillance."

Supports the caution that age-dependent features may be absent at initial pediatric assessment.

Imaging of Suspected PHOST

MRI can show an infiltrative lesion spanning muscle, fascia, and subcutaneous tissue, with adipose components, enlarged serpiginous vessels, and small arteriovenous fistulae with dilated draining veins. Imaging guides assessment of a symptomatic lesion; histology distinguishes PHOST from other vascular and connective-tissue abnormalities.

Show evidence (1 reference)

PMID:22446940 SUPPORT PRIMARY RESULT Human Clinical

"Magnetic resonance imaging generally showed an infiltrative soft tissue lesion involving the muscle, fascia, and subcutis with frequently enlarged, serpiginous vessels, small arteriovenous fistulae with disproportionately dilated draining veins, and a prominent adipocytic component."

Imaging findings come from the PHOST pathology series, not a screening study of all BRRS patients.

📊

Prevalence

1

Worldwide

Unknown Unknown

The population prevalence of BRRS is unknown. Published case series and PHTS cancer cohorts do not establish a population prevalence for the clinical BRRS phenotype.

Show evidence (1 reference)

PMID:29263846 SUPPORT BACKGROUND Human Clinical

"The true prevalence of BRRS is unknown, although it is generally considered rare."

The introduction explicitly states the absence of a reliable BRRS prevalence estimate.

🔀

Differential Diagnoses

2

Conditions with similar clinical presentations that must be differentiated from Bannayan-Riley-Ruvalcaba Syndrome:

Cowden Syndrome MONDO:0008021

Overlapping Features PTEN-related Cowden syndrome is an overlapping presentation of PHTS, often recognized through adult mucocutaneous manifestations or cancer. BRRS emphasizes childhood macrocephaly, lipomas, polyposis, and developmental findings. The labels are not mutually exclusive, and surveillance follows the molecular PHTS diagnosis.

Show evidence (1 reference)

PMID:10400993 SUPPORT Human Clinical

"Pigmented macules of the glans penis, delayed motor development and neonatal or infant onset are noted only in BRR."

Gives the specific features that separate BRRS from Cowden syndrome clinically.

Juvenile Polyposis Syndrome MONDO:0017380

Overlapping Features Juvenile polyposis shares hamartomatous gastrointestinal polyps with BRRS. Macrocephaly, lipomas, and genital lentigines favor the BRRS phenotype. Deletions encompassing both PTEN and BMPR1A can produce overlapping features, so these distinctions are not absolute.

Show evidence (1 reference)

PMID:9352843 SUPPORT Human Clinical

"It has been suggested that Bannayan-Riley-Ruvalcaba syndrome may be a variant of juvenile polyposis coli because of the shared features of intestinal juvenile polyps."

Documents the historical diagnostic confusion between BRRS and juvenile polyposis based on shared polyp histology.

📊

Related Datasets

1

Neural gene expression in Pten knock-in mice at 6-weeks of age GEO:GSE59318

Mouse neural transcriptome data comparing Ptenm3m4 genotypes and wild-type controls. The microglial study reused cortical differential-expression data for neuroinflammatory and synaptic pathway analysis; this is a model-organism dataset, not a human BRRS cohort.

Mus musculus BULK RNA SEQ

Show evidence (2 references)

GEO:GSE59318 SUPPORT PRIMARY RESULT Model Organism

"The goal of this study was to assess the changes in the neural transcriptome of Ptenm3m4 mice, in order to better understand their ASD-related phenotypes."

The GEO record identifies the model and transcriptomic objective.

PMID:32055008 SUPPORT BACKGROUND Model Organism

"The cortical transcriptome of 6-week-old Ptenm3m4 mice (GSE59318) mimics that of idiopathic autism, as described in detail in Tilot et al."

This paper identifies the accession it reanalyzed; the comparison with autism is a model transcriptomic analogy, not evidence of human sampling.

🔬

Clinical Trials

2

NCT02991807 PHASE_II COMPLETED

Randomized parallel-group everolimus versus placebo study in 46 individuals with PTEN-confirmed PHTS. Six months of treatment did not improve the primary neurocognitive composite endpoint. Secondary signals were exploratory and not adjusted for multiple comparisons; gastrointestinal adverse events were more common with everolimus.

Show evidence (3 references)

clinicaltrials:NCT02991807 SUPPORT PRIMARY RESULT Human Clinical

"Investigators are conducting research to evaluate the potential safety and efficacy of RAD001 (everolimus) in this patient population, and the potential neurocognitive benefits from treatment with RAD001 or placebo for a six month period."

The cached registry summary states the intervention and objective; the completed status comes from the live registry.

PMID:35594551 REFUTE Human Clinical

"Changes in the primary endpoint between groups from baseline to Month 6 were not apparent"

Recorded as REFUTE for the claim of neurocognitive efficacy. The randomized trial's primary endpoint was null, which is why this treatment is curated as investigational rather than established.

PMID:35594551 SUPPORT Human Clinical

"Gastrointestinal adverse events were more common in the everolimus group"

Documents the principal treatment-emergent toxicity signal in the trial.

NCT04094675 PHASE_II COMPLETED

Single-group open-label sirolimus study for colon polyposis in adults with a pathogenic PTEN variant. Five participants enrolled and two completed one year. Polyp numbers decreased in the completers without a change in polyposis stage. Two participants withdrew because of likely drug-related toxicity, and clinical benefit beyond polyp counts remains unproven.

Show evidence (4 references)

clinicaltrials:NCT04094675 SUPPORT PRIMARY RESULT Human Clinical

"This study is investigating sirolimus and its effect on the number of colon polyps in patients with Cowden syndrome and polyposis over a 1 year period."

The registry summary identifies the indication and planned duration.

PMID:40478255 SUPPORT PRIMARY RESULT Human Clinical

"Five participants were enrolled, with 2 completing the planned study course."

The published completion count limits interpretation of efficacy.

PMID:40478255 SUPPORT PRIMARY RESULT Human Clinical

"For the patients completing the study, polyp numbers decreased"

A within-person observation in two completers is not controlled evidence of benefit.

+ 1 more reference

🧫

Experimental Models

3

Ptenm3m4 primary neuron-microglia co-cultures CO_CULTURE

Genotype combinations test cell-autonomous and cross-cell effects on phagocytosis and synaptic-marker abundance. Mutant neurons alone have more synaptic marker colocalization, whereas addition of mutant microglia lowers it. The assay does not measure human cognition or directly demonstrate autism causation.

Organism

Mus musculus NCBITaxon:10090

Cell source

Primary mouse cortical neurons and microglia with differing Pten genotypes

Culture

Neuron-microglia co-cultures and neuronal monoculture controls

Publication

PMID:32055008

Pathograph links

Microglial Activation measures observes: cellular Iba1/C1q expression and phagocytic capacity.

Show evidence (1 reference)

PMID:32055008 SUPPORT PRIMARY RESULT In Vitro

"We found increased Iba1 and C1q expression with enhanced phagocytic capacity in Ptenm3m4/m3m4 microglia, indicating microglial activation."

Primary mouse microglial assays show activation and enhanced phagocytosis.

Enhanced Microglial Synaptic Pruning measures observes: cellular Synaptophysin/PSD-95 colocalization and microglial uptake assays.

Show evidence (1 reference)

PMID:32055008 SUPPORT PRIMARY RESULT In Vitro

"However, in a systemic germline Ptenm3m4/m3m4 mutant system, our data suggest cross-talk between neurons and microglia, resulting in significantly increased synaptic pruning in Ptenm3m4/m3m4 mutants compared with PtenWT/WT mice."

The co-culture results support genotype-dependent neuron-microglia interactions. Synapse abundance was assessed with pre/post-synaptic marker colocalization, not electrophysiological function.

Show evidence (2 references)

PMID:32055008 SUPPORT PRIMARY RESULT In Vitro

"We found increased Iba1 and C1q expression with enhanced phagocytic capacity in Ptenm3m4/m3m4 microglia, indicating microglial activation."

Primary mouse microglial assays show activation and enhanced phagocytosis.

PMID:32055008 SUPPORT PRIMARY RESULT In Vitro

"However, in a systemic germline Ptenm3m4/m3m4 mutant system, our data suggest cross-talk between neurons and microglia, resulting in significantly increased synaptic pruning in Ptenm3m4/m3m4 mutants compared with PtenWT/WT mice."

The co-culture results support genotype-dependent neuron-microglia interactions. Synapse abundance was assessed with pre/post-synaptic marker colocalization, not electrophysiological function.

TTN p.Cys5096Arg edited HEK293T cells CELL_LINE

Wild-type, heterozygous, and homozygous TTN p.Cys5096Arg cells were compared for growth after confluence, viability, migration, and signaling. Contact inhibition was impaired; AKT and ERK phosphorylation decreased. Altered FAK readouts support a candidate growth pathway but do not prove TTN causality in BRRS or therapeutic response.

Organism

Homo sapiens NCBITaxon:9606

Cell source

CRISPR-Cas9 edited HEK293T cells

Publication

PMID:29263846

Pathograph links

Impaired Contact Inhibition in TTN Variant Cells measures observes: cellular Growth after confluence and associated signaling readouts.

Show evidence (2 references)

PMID:29263846 SUPPORT PRIMARY RESULT In Vitro

"suggested lack of contact inhibition in mutant cells"

Edited HEK293T cells continued proliferating after confluence; one TTN variant was tested.

+ 1 more reference

Show evidence (3 references)

PMID:29263846 SUPPORT PRIMARY RESULT In Vitro

"suggested lack of contact inhibition in mutant cells"

Edited HEK293T cells continued proliferating after confluence; one TTN variant was tested.

PMID:29263846 SUPPORT PRIMARY RESULT In Vitro

"we note paradoxical downstream readouts of decreased phosphorylation of AKT and ERK1/2"

The measured signaling direction differs from canonical PTEN-loss hyperactivation.

PMID:29263846 SUPPORT PRIMARY RESULT In Vitro

"Functional interrogation of I-band variant p.Cys5096Arg identified in one of our classic BRRS patients, using CRISPR-Cas9 genome-edited cell lines, reveals an increased growth and lack of contact inhibition phenotype"

The study functionally tested one candidate allele in an engineered cell line.

PTEN lipid-phosphatase biochemical and 293-cell assays OTHER

Recombinant protein assays establish PIP3 dephosphorylation at position 3. Transfection of catalytically inactive PTEN C124S increases cellular PIP3, while PTEN overexpression reduces insulin-induced PIP3 without changing PI3K activation. These experiments establish biochemical function rather than clinical pathogenicity of a BRRS allele.

Organism

Homo sapiens NCBITaxon:9606

Cell source

Human 293 cells and purified recombinant PTEN

Publication

PMID:9593664

Pathograph links

PIP3 Accumulation measures observes: molecular PTEN catalytic perturbation and lipid substrate measurements.

Show evidence (2 references)

PMID:9593664 SUPPORT PRIMARY RESULT In Vitro

"Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring."

Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.

+ 1 more reference

Show evidence (2 references)

PMID:9593664 SUPPORT PRIMARY RESULT In Vitro

"Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring."

Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.

PMID:9593664 SUPPORT PRIMARY RESULT In Vitro

"Further, transfection of the catalytically inactive mutant of PTEN (C124S) caused PtdIns(3,4,5)P3 accumulation in the absence of insulin stimulation."

The catalytically inactive construct caused PIP3 accumulation in transfected human 293 cells; this is a mechanistic assay, not a BRRS patient allele experiment.

🐁

Animal Models

1

Germline Ptenm3m4 mouse

A germline knock-in model with cytoplasmic-predominant Pten and reduced total protein. Homozygotes show region-specific brain enlargement, neuronal soma hypertrophy, increased NG2-cell proliferation and glial accumulation, astrogliosis, and microglial activation. Behavioral findings include sex-dependent increased social motivation and poor balance with preserved recognition memory. This model does not isolate nuclear localization from protein abundance and is not a human BRRS genotype.

Species

Mus musculus

Genotype

Ptenm3m4/m3m4; heterozygous and wild-type littermate comparisons

Background

CD-1 background after backcrossing

Publication

PMID:24470394

Pathograph links

Brain Enlargement measures observes: tissue Regional brain weight and cellular size/proliferation readouts.

Show evidence (2 references)

PMID:24470394 SUPPORT PRIMARY RESULT Model Organism

"The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight."

The model combines reduced Pten abundance with altered localization and shows regional brain enlargement.

+ 1 more reference

Microglial Activation measures observes: tissue In vivo astrogliosis and microglial activation in mutant mice.

Show evidence (1 reference)

PMID:24470394 SUPPORT PRIMARY RESULT Model Organism

"The animals also exhibit significant astrogliosis and microglial activation, indicating a neuroinflammatory phenotype."

The primary mouse study documents the in vivo phenotype.

A homozygous engineered mouse combines altered localization and reduced Pten dosage. It cannot stratify cancer surveillance for heterozygous human PTEN carriers.

Show evidence (4 references)

PMID:24470394 SUPPORT PRIMARY RESULT Model Organism

"The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight."

The model combines reduced Pten abundance with altered localization and shows regional brain enlargement.

PMID:24470394 SUPPORT PRIMARY RESULT Model Organism

"The cytoplasm-predominant protein caused cellular hypertrophy limited to the soma and led to increased NG2 cell proliferation and accumulation of glia."

Homozygous Ptenm3m4 mice showed neuronal soma hypertrophy and increased glial production. These findings do not demonstrate generalized neuronal progenitor proliferation in human BRRS.

PMID:24470394 SUPPORT PRIMARY RESULT Model Organism

"The Pten(m3m4) model displays sex-specific increases in social motivation, poor balance and normal recognition memory"

The measured behavioral profile differs from simply labeling mice autistic.

+ 1 more reference

{ }

Source YAML

click to show

name: Bannayan-Riley-Ruvalcaba Syndrome
creation_date: "2026-08-03T00:00:00Z"
description: >-
  Bannayan-Riley-Ruvalcaba syndrome (BRRS) is a congenital overgrowth phenotype characterized by macrocephaly,
  hamartomatous intestinal polyposis, lipomas, vascular lesions, and pigmented genital macules, with variable
  developmental delay, hypotonia, and autism spectrum characteristics. Individuals with a heterozygous
  germline pathogenic PTEN variant have PTEN hamartoma tumor syndrome (PHTS); clinically diagnosed BRRS
  also includes individuals without an identified PTEN variant. Loss of PTEN lipid-phosphatase activity
  impairs PIP3 dephosphorylation and promotes growth signaling through AKT and mTOR. PTEN-positive BRRS
  and Cowden syndrome can occur within one family and share PHTS cancer surveillance. Cancer risks in
  PTEN-negative clinical BRRS remain uncertain.
category: Mendelian
disease_term:
  preferred_term: Bannayan-Riley-Ruvalcaba syndrome
  term:
    id: MONDO:0007924
    label: Bannayan-Riley-Ruvalcaba syndrome
synonyms:
- BRRS
- Bannayan-Zonana syndrome
- Bannayan syndrome
- Riley-Smith syndrome
- Ruvalcaba-Myhre-Smith syndrome
- Macrocephaly with multiple lipomas and hemangiomas
parents:
- Autosomal dominant hereditary syndrome
- Hereditary cancer syndrome
- PTEN hamartoma tumor syndrome
prevalence:
- population: Worldwide
  measure_type: UNKNOWN
  prevalence_class: UNKNOWN
  notes: >-
    The population prevalence of BRRS is unknown. Published case series and PHTS cancer cohorts do not
    establish a population prevalence for the clinical BRRS phenotype.
  evidence:
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: The true prevalence of BRRS is unknown, although it is generally considered rare.
    explanation: >-
      The introduction explicitly states the absence of a reliable BRRS prevalence estimate.
inheritance:
- name: Autosomal dominant inheritance
  description: >-
    PTEN-positive BRRS follows autosomal dominant inheritance. Each child of an individual with a germline
    pathogenic PTEN variant has a 50% chance of inheriting it, with variable expression. De novo variants
    occur, so an unremarkable family history does not exclude PHTS. A PHTS study confirmed de novo variants
    in 20 of 187 families (10.7%); the 47.6% estimate was restricted to 20 of 42 probands with informative
    familial testing, not a BRRS-specific population rate.
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "PHTS is inherited in an autosomal dominant manner."
    explanation: GeneReviews states the autosomal dominant inheritance of PHTS, which subsumes BRRS.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Each child of an affected individual has a 50% chance of inheriting the pathogenic variant and developing PHTS."
    explanation: GeneReviews gives the 50% transmission risk implied by autosomal dominant inheritance.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:22595938
    reference_title: Estimate of de novo mutation frequency in probands with PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Twenty mutations were confirmed as de novo through familial testing (grade 5) by the Eng research laboratory or testing in a CLIA-certified facility, leading to a conservatively calculated de novo mutation frequency of 10.7% (20/187) within all eligible families.
    explanation: >-
      The full PHTS cohort denominator was 187 unrelated families; this is not a BRRS-only estimate.
  - reference: PMID:22595938
    reference_title: Estimate of de novo mutation frequency in probands with PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: If analysis is restricted to only those probands with known familial testing results (grade 1 and 5 probands, n=42), a maximum de novo mutation frequency of 47.6% (20/42) is obtained.
    explanation: >-
      The upper estimate depends on restricting the denominator to probands with informative family testing.
has_subtypes:
- name: 10q23 deletion
  display_name: 10q23 contiguous-gene deletion (PTEN + BMPR1A)
  description: >-
    Deletions encompassing both PTEN and BMPR1A can combine BRRS-like macrocephaly and developmental findings
    with juvenile polyposis. Infantile gastrointestinal disease can be severe, but reported deletion carriers
    have variable onset and severity; deletion size alone does not predict gastrointestinal severity.
    Copy-number analysis defines the deletion and its gene content. The chromosome 10q23 deletion ontology
    term covers a broader interval-associated syndrome; the pattern described here specifically includes
    both genes.
  evidence:
  - reference: PMID:18510548
    reference_title: Variable phenotypes associated with 10q23 microdeletions involving the PTEN and BMPR1A genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Recently, 10q23 microdeletions involving the PTEN and BMPR1A genes were found in four patients with infantile juvenile polyposis. It was hypothesized that a combined and synergistic effect of the deletion of both genes would explain the condition."
    explanation: >-
      Establishes the contiguous-deletion entity and the original two-gene synergy hypothesis.
  - reference: PMID:18510548
    reference_title: Variable phenotypes associated with 10q23 microdeletions involving the PTEN and BMPR1A genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All patients had macrocephaly, dysmorphic features, retardation and congenital abnormalities."
    explanation: >-
      Documents the BRRS-like core (macrocephaly, developmental delay) in deletion carriers. This evidence
      is limited because this is a four-patient series.
  - reference: PMID:18510548
    reference_title: Variable phenotypes associated with 10q23 microdeletions involving the PTEN and BMPR1A genes.
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    snippet: "No clear correlation was found between ages at onset or severity of gastrointestinal symptoms and the sizes of the deletions."
    explanation: >-
      Recorded as REFUTE against the simple dose/size-severity model: deletion size does not predict severity,
      which is why this subtype is described as variable rather than uniformly severe.
  subtype_term:
    preferred_term: 10q23 contiguous deletion involving PTEN and BMPR1A
    term:
      id: MONDO:0012830
      label: chromosome 10q23 deletion syndrome
mechanistic_hypotheses:
- hypothesis_group_id: canonical_pi3k_akt_mtor
  hypothesis_label: Canonical PI3K-AKT-mTOR dose-sensitive overgrowth
  status: CANONICAL
  description: >-
    PTEN lipid-phosphatase loss increases PIP3-dependent AKT signaling and downstream mTOR activity, contributing
    to abnormal growth. This is a central mechanism in PTEN-positive BRRS, but does not establish a single
    causal route for every clinical feature or explain all PTEN-negative presentations.
  evidence:
  - reference: PMID:9593664
    reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring.
    explanation: >-
      Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: In PHTS, loss of PTEN function leads to disinhibition of the PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase)-AKT–mTOR pathway
    explanation: >-
      The trial introduction summarizes established PHTS signaling biology; the clinical trial did not
      itself measure this molecular chain.
- hypothesis_group_id: pten_localization_neurodevelopment
  hypothesis_label: Altered PTEN localization and abundance in neurodevelopment
  status: EMERGING
  description: >-
    The cytoplasmic-predominant Ptenm3m4 mouse supports a contribution of PTEN localization and dosage
    to neuronal growth, glial proliferation, and microglial function. Both nuclear and cytoplasmic Pten
    are reduced, so it does not isolate localization from protein abundance. Its behavioral and cellular
    findings do not establish an autism-versus-cancer division in patients or a basis for changing cancer
    surveillance.
  evidence:
  - reference: PMID:24470394
    reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight.
    explanation: >-
      The model combines reduced Pten abundance with altered localization and shows regional brain enlargement.
  - reference: PMID:32055008
    reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: BACKGROUND
    snippet: It is important to note that although we observe decreased nuclear Pten in the brain of the Ptenm3m4 mouse, we also observe decreased cytoplasmic Pten
    explanation: >-
      The authors explicitly acknowledge the abundance/localization confound in interpreting the model.
- hypothesis_group_id: pi3k_independent_overgrowth
  hypothesis_label: PI3K-independent overgrowth via focal adhesion signaling
  status: EMERGING
  description: >-
    An edited TTN p.Cys5096Arg HEK293T model showed impaired contact inhibition and altered focal adhesion
    kinase readouts. AKT and ERK phosphorylation decreased, despite lower PTEN protein, so the observations
    do not support canonical AKT hyperactivation in these cells. The proposed TTN-dependent growth mechanism
    remains a candidate based on one functionally tested variant; neither human disease causality nor
    response to mTOR inhibitors was established.
  evidence:
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: suggested lack of contact inhibition in mutant cells
    explanation: >-
      Edited HEK293T cells continued proliferating after confluence; one TTN variant was tested.
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: we note paradoxical downstream readouts of decreased phosphorylation of AKT and ERK1/2
    explanation: >-
      The measured signaling direction differs from canonical PTEN-loss hyperactivation.
pathophysiology:
- name: Germline PTEN Loss of Function
  biological_scale: MOLECULAR
  description: >-
    A heterozygous germline pathogenic PTEN variant is the initiating lesion in PTEN-positive BRRS. Reduced PTEN lipid-phosphatase function impairs PIP3 dephosphorylation. The classic BRRS cohort identified variants in 26 of 43 cases; this mechanism is not demonstrated in every PTEN-negative clinical presentation. Conformance identifies the constitutional tumor-suppressor lesion; it does not establish a requirement for a somatic second hit in every PTEN-associated lesion.
  genes:
  - preferred_term: PTEN
    term:
      id: hgnc:9588
      label: PTEN
  molecular_functions:
  - preferred_term: PIP3 3-phosphatase activity
    term:
      id: GO:0016314
      label: phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase activity
    modifier: DECREASED
  evidence:
  - reference: PMID:9593664
    reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring.
    explanation: >-
      Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mutations were identified in 26 of 43 (60%) BRR cases."
    explanation: >-
      Quantifies the germline PTEN detection rate in a dedicated BRRS cohort, supporting both the causal
      gene assignment and the incomplete molecular yield.
  downstream:
  - target: PIP3 Accumulation
    causal_link_type: DIRECT
    description: >-
      Reduced PTEN catalytic activity impairs removal of the 3-phosphate from PIP3.
    evidence:
    - reference: PMID:9593664
      reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring.
      explanation: >-
        Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.
    - reference: PMID:9593664
      reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: Further, transfection of the catalytically inactive mutant of PTEN (C124S) caused PtdIns(3,4,5)P3 accumulation in the absence of insulin stimulation.
      explanation: >-
        The catalytically inactive construct caused PIP3 accumulation in transfected human 293 cells;
        this is a mechanistic assay, not a BRRS patient allele experiment.
  - target: Lifelong Multiorgan Cancer Predisposition
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Germline PTEN dysfunction predisposes to malignancy through tissue-dependent growth and tumor-suppressor
      mechanisms; this edge does not require universal biallelic PTEN loss.
    evidence:
    - reference: PMID:33140411
      reference_title: A review on age-related cancer risks in PTEN hamartoma tumor syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: Patients with PTEN hamartoma tumor syndrome (PHTS, comprising Cowden, Bannayan-Riley-Ruvalcaba, and Proteus-like syndromes) are at increased risk of developing cancer due to pathogenic PTEN germline variants.
      explanation: >-
        The clinical review supports PTEN-associated cancer predisposition without identifying a universal
        second-hit mechanism.
  - target: Brain Enlargement
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      PTEN dysfunction alters neural cell size and glial production in experimental models; the relative
      contributions to human BRRS macrocephaly remain unresolved.
    evidence:
    - reference: PMID:24470394
      reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight.
      explanation: >-
        The model combines reduced Pten abundance with altered localization and shows regional brain enlargement.
    - reference: PMID:24470394
      reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: The cytoplasm-predominant protein caused cellular hypertrophy limited to the soma and led to increased NG2 cell proliferation and accumulation of glia.
      explanation: >-
        Homozygous Ptenm3m4 mice showed neuronal soma hypertrophy and increased glial production. These
        findings do not demonstrate generalized neuronal progenitor proliferation in human BRRS.
  - target: Microglial Activation
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Reduced and mislocalized Pten in the germline mouse model is associated with microglial activation.
    evidence:
    - reference: PMID:24470394
      reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: The animals also exhibit significant astrogliosis and microglial activation, indicating a neuroinflammatory phenotype.
      explanation: >-
        The observation is from Ptenm3m4 mice and is not a demonstrated lesion in human BRRS.
  - target: Penile freckling
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Penile macules are a recognized phenotype in PTEN-positive BRRS, but the pigmentary intermediates
      are not established.
    evidence:
    - reference: PMID:20301661
      reference_title: PTEN Hamartoma Tumor Syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis."
      explanation: >-
        GeneReviews names pigmented macules of the glans penis as a defining BRRS feature.
      quote_role: REVIEW_SYNTHESIS
  - target: Global developmental delay
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      PTEN-associated neurodevelopmental and motor dysfunction includes this clinical manifestation; the
      specific causal cellular intermediates are unresolved.
    evidence:
    - reference: PMID:28526761
      reference_title: A retrospective chart review of the features of PTEN hamartoma tumour syndrome in children.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Macrocephaly (average head circumference of + 5.7  SD) with developmental delay, ID and/or ASD were the most common presenting signs/symptoms (66 %)."
      explanation: >-
        Establishes developmental delay as part of the leading presentation in a pediatric PHTS cohort.
  - target: Autism
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      PTEN-associated neurodevelopmental and motor dysfunction includes this clinical manifestation; the
      specific causal cellular intermediates are unresolved.
    evidence:
    - reference: PMID:34983360
      reference_title: "Behavioural and psychological features of PTEN mutations: a systematic review of the literature and meta-analysis of the prevalence of autism spectrum disorder characteristics."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Meta-analysis using a random effects model estimated pooled prevalence of ASD characteristics at 25% (95% CI 16-33%), although this should be interpreted cautiously due to possible biases in existing literature."
      explanation: >-
        The pooled estimate concerns ASD characteristics in heterogeneous PTEN cohorts. It supports the
        association, but is not used to assign a BRRS-specific frequency for diagnosed autism.
      quote_role: REVIEW_SYNTHESIS
  - target: Intellectual disability
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      PTEN-associated neurodevelopmental and motor dysfunction includes this clinical manifestation; the
      specific causal cellular intermediates are unresolved.
    evidence:
    - reference: PMID:10400993
      reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Additional features observed in BRR, which may also occur in a minority of CS patients, include Hashimoto's thyroiditis, vascular malformations and mental retardation."
      explanation: >-
        Documents cognitive impairment (reported using the era's terminology) as a recognized BRRS feature.
  - target: Hypotonia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      PTEN-associated neurodevelopmental and motor dysfunction includes this clinical manifestation; the
      specific causal cellular intermediates are unresolved.
    evidence:
    - reference: PMID:29263846
      reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Muscle weakness and hypotonia cause affected BRRS infants to appear"
      explanation: >-
        Names hypotonia explicitly in BRRS infants and links it to the delayed motor development curated
        in this entry.
      quote_role: BACKGROUND
  - target: Motor delay
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      A recognized neurodevelopmental manifestation, without a proven single cellular intermediary.
    evidence:
    - reference: PMID:39256443
      reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: Motor delay is the most common developmental disorder among patients
      explanation: >-
        The BRRS systematic review supports this manifestation; no patient frequency is inferred from
        counts of publications.
  - target: Delayed speech and language development
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      A recognized neurodevelopmental manifestation, without a proven single cellular intermediary.
    evidence:
    - reference: PMID:39256443
      reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: ranging from normal psychomotor development and mild motor or speech delay to severe intellectual disability
      explanation: >-
        The BRRS systematic review supports this manifestation; no patient frequency is inferred from
        counts of publications.
  conforms_to: germline_two_hit_tumor_predisposition#Constitutional First-Hit Tumor Suppressor Inactivation
- name: PIP3 Accumulation
  biological_scale: MOLECULAR
  description: >-
    Loss of PTEN lipid-phosphatase activity allows accumulation of PIP3, a membrane lipid second messenger.
    This does not require increased activity of PI3K itself.
  evidence:
  - reference: PMID:9593664
    reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring.
    explanation: >-
      Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.
  - reference: PMID:9593664
    reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: Further, transfection of the catalytically inactive mutant of PTEN (C124S) caused PtdIns(3,4,5)P3 accumulation in the absence of insulin stimulation.
    explanation: >-
      The catalytically inactive construct caused PIP3 accumulation in transfected human 293 cells; this
      is a mechanistic assay, not a BRRS patient allele experiment.
  downstream:
  - target: AKT Activation
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      PIP3-dependent membrane recruitment enables AKT activation within the PTEN-regulated signaling pathway.
    evidence:
    - reference: PMID:35594551
      reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: In PHTS, loss of PTEN function leads to disinhibition of the PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase)-AKT–mTOR pathway
      explanation: >-
        The trial introduction summarizes established PHTS signaling biology; the clinical trial did not
        itself measure this molecular chain.
- name: AKT Activation
  biological_scale: MOLECULAR
  description: >-
    AKT activation is a proximal signaling consequence of impaired PTEN function and connects lipid signaling
    to downstream growth regulators.
  biological_processes:
  - preferred_term: PI3K/AKT signaling
    term:
      id: GO:0043491
      label: phosphatidylinositol 3-kinase/protein kinase B signal transduction
    modifier: INCREASED
  evidence:
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: In PHTS, loss of PTEN function leads to disinhibition of the PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase)-AKT–mTOR pathway
    explanation: >-
      The trial introduction summarizes established PHTS signaling biology; the clinical trial did not
      itself measure this molecular chain.
  downstream:
  - target: mTOR Overactivity
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      AKT-dependent regulation of intermediary growth-control proteins promotes mTOR signaling.
    evidence:
    - reference: PMID:35594551
      reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: In PHTS, loss of PTEN function leads to disinhibition of the PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase)-AKT–mTOR pathway
      explanation: >-
        The trial introduction summarizes established PHTS signaling biology; the clinical trial did not
        itself measure this molecular chain.
- name: mTOR Overactivity
  conforms_to: "mtorc1_hyperactivation#Constitutive mTORC1 Hyperactivation"
  biological_scale: MOLECULAR
  description: >-
    Excess mTOR signaling contributes to abnormal cell growth and provides the rationale for trials of
    mTOR inhibitors in PHTS.
  biological_processes:
  - preferred_term: mTOR signaling
    term:
      id: GO:0031929
      label: TOR signaling
    modifier: INCREASED
  evidence:
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: In PHTS, loss of PTEN function leads to disinhibition of the PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase)-AKT–mTOR pathway
    explanation: >-
      The trial introduction summarizes established PHTS signaling biology; the clinical trial did not
      itself measure this molecular chain.
  downstream:
  - target: Hamartomatous Tissue Overgrowth
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Increased growth signaling contributes to hamartomatous overgrowth, with tissue-specific and potentially
      additional genetic events incompletely defined.
    evidence:
    - reference: PMID:35594551
      reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: mTOR overactivity leads to enhanced cell growth, underlying the increased risk for cancer and abnormal tissue growth seen in PHTS
      explanation: >-
        This mechanistic rationale is background synthesis in the clinical trial, not a trial efficacy
        result.
- name: Hamartomatous Tissue Overgrowth
  conforms_to: "mtorc1_hyperactivation#Hamartomatous Overgrowth and Dysplastic Lesion Formation"
  biological_scale: TISSUE
  description: >-
    Unrestrained growth signaling produces hamartomas: benign, disorganized overgrowths
    composed of cell types native to the tissue of origin. In BRRS this is expressed
    predominantly as hamartomatous polyps distributed throughout the gastrointestinal
    tract, subcutaneous and visceral lipomas, and vascular lesions, and it is the
    substrate for the syndrome's structural burden in childhood.
  cell_types:
  - preferred_term: adipocyte
    term:
      id: CL:0000136
      label: adipocyte
  - preferred_term: intestinal epithelial cell
    term:
      id: CL:0002563
      label: intestinal epithelial cell
  - preferred_term: endothelial cell
    term:
      id: CL:0000115
      label: endothelial cell
  evidence:
  - reference: PMID:9352843
    reference_title: Localization of the Bannayan-Riley-Ruvalcaba syndrome gene to chromosome 10q23.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Bannayan-Riley-Ruvalcaba syndrome is a congenital syndrome with characteristic features of macrocephaly, cognitive and motor dysfunction, subcutaneous and visceral lipomas and hemangiomas, and intestinal juvenile polyposis."
    explanation: >-
      Enumerates the hamartomatous tissue lesions (lipomas, hemangiomas, intestinal polyposis) that constitute
      this overgrowth node in BRRS.
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis."
    explanation: >-
      The GeneReviews definition of BRRS, confirming hamartomatous polyposis and lipomas as defining tissue-level
      manifestations.
    quote_role: REVIEW_SYNTHESIS
  downstream:
  - target: Hamartomatous polyposis
    causal_link_type: DIRECT
  - target: Lipoma
    causal_link_type: DIRECT
  - target: Hemangioma
    causal_link_type: DIRECT
  - target: PTEN Hamartoma of Soft Tissue Formation
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      PHOST is one distinctive form of mesenchymal overgrowth within PHTS; its tissue-specific development
      is not fully explained by the general overgrowth phenotype.
- name: PTEN Hamartoma of Soft Tissue Formation
  biological_scale: TISSUE
  description: >-
    PHOST is a distinctive, unencapsulated mesenchymal lesion found in PHTS, including BRRS presentations.
    Mature adipose and fibrous or myxoid tissue are intermixed with abnormal veins, thick-walled arteries,
    small vessels, and occasional arteriovenous communications. It commonly infiltrates muscle, fascia,
    and subcutis and may cause pain and swelling. It is one of several PHTS-associated vascular/connective
    tissue lesions, not a synonym for all vascular malformations.
  cell_types:
  - preferred_term: adipocyte
    term:
      id: CL:0000136
      label: adipocyte
  - preferred_term: endothelial cell
    term:
      id: CL:0000115
      label: endothelial cell
  - preferred_term: fibroblast
    term:
      id: CL:0000057
      label: fibroblast
  evidence:
  - reference: PMID:22446940
    reference_title: "PTEN hamartoma of soft tissue: a distinctive lesion in PTEN syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We designate this disorganized overgrowth of essentially mesenchymal elements as PTEN hamartoma of soft tissue."
    explanation: >-
      The defining pathological description of PHOST, establishing this node as a distinct lesion entity
      rather than a generic vascular malformation.
  - reference: PMID:22446940
    reference_title: "PTEN hamartoma of soft tissue: a distinctive lesion in PTEN syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lesions manifested by 15 years of age, normally with pain and swelling, and were most often located in the lower extremity."
    explanation: >-
      Establishes the pediatric onset and the clinical burden (pain, swelling) that makes this node the
      target of lesion-directed therapy in BRRS.
  - reference: PMID:22446940
    reference_title: "PTEN hamartoma of soft tissue: a distinctive lesion in PTEN syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Thus, PHOST is only one of several vascular anomalies and connective tissue overgrowths that occur in PTHS, some of which have more than one tissue type.
    explanation: >-
      The pathology series explicitly distinguishes PHOST from other PHTS lesions; PTHS is the source
      spelling.
  downstream:
  - target: Arteriovenous malformation
    causal_link_type: DIRECT
    description: >-
      Arteriovenous communications can be a component of PHOST. This does not imply that all BRRS arteriovenous
      malformations are PHOST.
    evidence:
    - reference: PMID:22446940
      reference_title: "PTEN hamartoma of soft tissue: a distinctive lesion in PTEN syndromes."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: numerous small vessels (arteries, veins, and indeterminate channels), and (d) occasional arteriovenous communications
      explanation: >-
        The series identifies arteriovenous connections as one possible vascular component of the lesion.
- name: Brain Enlargement
  biological_scale: TISSUE
  description: >-
    Brain enlargement is a structural consequence of PTEN dysfunction. The Ptenm3m4 model shows regional
    enlargement with neuronal soma hypertrophy and increased glial production. These model findings provide
    candidate cellular contributors to human macrocephaly, without establishing a uniform course or excluding
    other causes of enlarged head circumference in individual patients.
  evidence:
  - reference: PMID:24470394
    reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight.
    explanation: >-
      The model combines reduced Pten abundance with altered localization and shows regional brain enlargement.
  - reference: PMID:24470394
    reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: The cytoplasm-predominant protein caused cellular hypertrophy limited to the soma and led to increased NG2 cell proliferation and accumulation of glia.
    explanation: >-
      Homozygous Ptenm3m4 mice showed neuronal soma hypertrophy and increased glial production. These
      findings do not demonstrate generalized neuronal progenitor proliferation in human BRRS.
  downstream:
  - target: Macrocephaly
    causal_link_type: DIRECT
    description: >-
      Increased brain size contributes to enlarged head circumference.
- name: Microglial Activation
  biological_scale: CELLULAR
  description: >-
    Ptenm3m4 mouse tissue and primary microglia show increased activation, including altered morphology
    and complement C1q expression. This is a model-derived mechanism rather than established human BRRS
    neuropathology.
  evidence:
  - reference: PMID:32055008
    reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: We found increased Iba1 and C1q expression with enhanced phagocytic capacity in Ptenm3m4/m3m4 microglia, indicating microglial activation.
    explanation: >-
      Primary mouse microglial assays show activation and enhanced phagocytosis.
  downstream:
  - target: Enhanced Microglial Synaptic Pruning
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Activated mutant microglia have enhanced phagocytic and pruning capacity in co-culture; neuronal
      genotype also affects the result.
    evidence:
    - reference: PMID:32055008
      reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: We found increased Iba1 and C1q expression with enhanced phagocytic capacity in Ptenm3m4/m3m4 microglia, indicating microglial activation.
      explanation: >-
        Primary mouse microglial assays show activation and enhanced phagocytosis.
    - reference: PMID:32055008
      reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: However, in a systemic germline Ptenm3m4/m3m4 mutant system, our data suggest cross-talk between neurons and microglia, resulting in significantly increased synaptic pruning in Ptenm3m4/m3m4 mutants compared with PtenWT/WT mice.
      explanation: >-
        The co-culture results support genotype-dependent neuron-microglia interactions. Synapse abundance
        was assessed with pre/post-synaptic marker colocalization, not electrophysiological function.
- name: Enhanced Microglial Synaptic Pruning
  biological_scale: CELLULAR
  description: >-
    Mutant microglia reduce synaptic-marker colocalization in neuron-microglia co-cultures, while mutant
    neurons cultured alone show more synapses. In vivo, synaptic marker expression also decreases with
    age in the Ptenm3m4 model. These experiments do not establish that excessive pruning causes autism,
    developmental delay, or hypotonia in human BRRS.
  evidence:
  - reference: PMID:32055008
    reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: However, in a systemic germline Ptenm3m4/m3m4 mutant system, our data suggest cross-talk between neurons and microglia, resulting in significantly increased synaptic pruning in Ptenm3m4/m3m4 mutants compared with PtenWT/WT mice.
    explanation: >-
      The co-culture results support genotype-dependent neuron-microglia interactions. Synapse abundance
      was assessed with pre/post-synaptic marker colocalization, not electrophysiological function.
- name: Lifelong Multiorgan Cancer Predisposition
  biological_scale: ORGANISM
  description: >-
    A germline pathogenic PTEN variant confers multiorgan cancer predisposition. PTEN-positive BRRS is
    managed within the PHTS spectrum, but precise BRRS-ascertained cancer incidence has not been established.
    Tumor development can involve additional somatic events; universal loss of the second PTEN allele
    is not assumed. PHTS risk estimates do not establish risks for PTEN-negative clinical BRRS.
  evidence:
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Thus, PTEN mutation-positive CS and BRR may be different presentations of a single syndrome and, hence, both should receive equal attention with respect to cancer surveillance."
    explanation: >-
      The study supports shared surveillance for molecularly confirmed PTEN-positive BRRS and Cowden syndrome,
      not a measured equality of their cancer incidence.
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: NO_EVIDENCE
    evidence_source: HUMAN_CLINICAL
    snippet: "CS is characterized by multiple hamartomas and an increased risk of benign and malignant disease of the breast, thyroid and central nervous system, whilst the presence of cancer has not been formally documented in BRR."
    explanation: >-
      Recorded as NO_EVIDENCE because it asserts an absence of evidence rather than supporting or refuting
      the node: malignancy had not been formally established in BRRS-ascertained cohorts. It is retained
      to make explicit that the cancer risk attributed to BRRS is inferred from allelism with Cowden syndrome
      rather than from direct BRRS-cohort incidence data.
  - reference: PMID:22252256
    reference_title: Lifetime cancer risks in individuals with germline PTEN mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lifetime risks for a variety of cancers, now extending to colorectal cancer, kidney cancer, and melanoma, are increased in patients with PTEN mutations."
    explanation: >-
      The prospective PHTS cohort establishing that germline PTEN carriers, the molecular class to which
      PTEN-positive BRRS belongs, carry elevated multiorgan cancer risk.
  - reference: PMID:33140411
    reference_title: A review on age-related cancer risks in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patients with PTEN hamartoma tumor syndrome (PHTS, comprising Cowden, Bannayan-Riley-Ruvalcaba, and Proteus-like syndromes) are at increased risk of developing cancer due to pathogenic PTEN germline variants."
    explanation: >-
      Explicitly includes BRRS within the PHTS group carrying germline-PTEN-driven cancer risk.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patients with BRRS are considered to share the same lifetime risk of cancer as individuals with Cowden syndrome, however, it has not been confirmed by formal studies"
    explanation: >-
      This BRRS-specific review identifies shared cancer risk as a clinical assumption without formal
      BRRS-cohort confirmation.
    quote_role: REVIEW_SYNTHESIS
  downstream:
  - target: Breast carcinoma
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Thyroid carcinoma
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Endometrial carcinoma
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Renal cell carcinoma
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Colon cancer
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Melanoma
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: Impaired Contact Inhibition in TTN Variant Cells
  biological_scale: CELLULAR
  description: >-
    HEK293T cells edited to carry TTN p.Cys5096Arg continued proliferating after confluence, accompanied
    by altered FAK abundance/phosphorylation and reduced AKT/ERK phosphorylation. This isolated experimental
    branch describes candidate biology in PTEN-wildtype BRRS; it is not an established causal route to
    human hamartomas.
  evidence:
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: suggested lack of contact inhibition in mutant cells
    explanation: >-
      Edited HEK293T cells continued proliferating after confluence; one TTN variant was tested.
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: we note paradoxical downstream readouts of decreased phosphorylation of AKT and ERK1/2
    explanation: >-
      The measured signaling direction differs from canonical PTEN-loss hyperactivation.
phenotypes:
- category: Growth
  name: Macrocephaly
  description: >-
    Macrocephaly is a cardinal BRRS feature and often prompts recognition in childhood. It was reported
    in 77% of 83 published pediatric cases in a systematic review. A separate pediatric PHTS cohort reported
    a mean head circumference of +5.7 standard deviations; its composite presenting-symptom statistic
    does not measure macrocephaly frequency alone.
  phenotype_term:
    preferred_term: Macrocephaly
    term:
      id: HP:0000256
      label: Macrocephaly
  frequency: FREQUENT
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis."
    explanation: >-
      GeneReviews names macrocephaly as a defining feature of BRRS.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:28526761
    reference_title: A retrospective chart review of the features of PTEN hamartoma tumour syndrome in children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Macrocephaly (average head circumference of + 5.7  SD) with developmental delay, ID and/or ASD were the most common presenting signs/symptoms (66 %)."
    explanation: >-
      Supports the disease-phenotype association and quantifies the severity of macrocephaly in pediatric
      PHTS (mean head circumference +5.7 SD). Note this 66% figure is a composite presenting-symptom statistic
      (macrocephaly together with developmental delay, ID and/or ASD), not a macrocephaly frequency, so
      it is not used to set the frequency band.
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A total of 83 pediatric patients with BRRS were identified. The most common clinical findings were macrocephaly (77%) and developmental disorders (63%)."
    explanation: >-
      The patient-level 77% estimate supports FREQUENT. The same review also reports macrocephaly in 32
      of 33 publications, but publication counts cannot be used as patient frequencies. Incomplete case
      reporting and publication selection limit generalization of the patient-level estimate.
    quote_role: REVIEW_SYNTHESIS
- category: Gastrointestinal
  name: Hamartomatous polyposis
  description: >-
    Hamartomatous polyps occur throughout the gastrointestinal tract, from stomach to
    colon, and are a defining BRRS feature that frequently prompts the childhood
    diagnosis. Polyps may be numerous and of mixed histologic type, and can present with
    bleeding, anemia, abdominal pain, or intussusception.
  phenotype_term:
    preferred_term: Hamartomatous polyposis
    term:
      id: HP:0004390
      label: Hamartomatous polyposis
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis."
    explanation: >-
      GeneReviews names intestinal hamartomatous polyposis as a defining BRRS feature.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:34754688
    reference_title: "Diffuse Gastrointestinal Polyposis in Bannayan-Riley-Ruvalcaba Syndrome: A Rare Phenotype Among Phosphatase and Tensin Homolog Hamartoma Tumor Syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The esophagogastroduodenoscopy (EGD) and colonoscopy revealed an erosive gastric mucosa as well as numerous polyps throughout the gastrointestinal tract."
    explanation: >-
      A BRRS case report documenting polyp distribution across both upper and lower gastrointestinal tract,
      supporting the diffuse rather than colon-restricted pattern.
  - reference: PMID:22672595
    reference_title: Is colorectal surveillance indicated in patients with PTEN mutations?
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The cumulative risk of developing benign gastrointestinal polyps was 70% at age 60."
    explanation: >-
      Multinational PTEN-carrier cohort quantifying the cumulative burden of benign gastrointestinal polyps.
  sequelae:
  - target: Hematochezia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      A clinical complication of intestinal polyps.
    evidence:
    - reference: PMID:39256443
      reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: BRRS patients with polyps may present with abdominal pain, hematochezia, anemia, invagination, constipation, or diarrhea
      explanation: >-
        The BRRS systematic review supports this manifestation; no patient frequency is inferred from
        counts of publications.
  - target: Intussusception
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      A clinical complication of intestinal polyps.
    evidence:
    - reference: PMID:39256443
      reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: BRRS patients with polyps may present with abdominal pain, hematochezia, anemia, invagination, constipation, or diarrhea
      explanation: >-
        The BRRS systematic review supports this manifestation; no patient frequency is inferred from
        counts of publications.
- category: Dermatologic
  name: Lipoma
  description: >-
    Multiple subcutaneous and visceral lipomas are characteristic of BRRS. They may become large and cause
    site-dependent compression or cosmetic problems. A classic BRRS cohort found an association between
    lipomas and detection of a PTEN variant.
  phenotype_term:
    preferred_term: Lipoma
    term:
      id: HP:0012032
      label: Lipoma
  evidence:
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The partial clinical overlap in these two syndromes is exemplified by the hallmark features of BRR: macrocephaly and multiple lipomas, the latter of which occur in a minority of individuals with CS."
    explanation: >-
      Identifies multiple lipomas as a hallmark BRRS feature that discriminates it from Cowden syndrome,
      where lipomas are a minority finding.
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Additionally, the presence of lipomas was correlated with the presence of PTEN mutation in BRR patients"
    explanation: >-
      Documents the genotype-phenotype correlation between lipomas and a detectable PTEN variant within
      BRRS.
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lipomas were mentioned in more than half of the cases (18/33), and the second most common lesion was gastrointestinal polyps (16/33)."
    explanation: >-
      These are counts of publications among 33 reviewed studies, not counts of affected patients. They
      support recurring reports of lipomas and polyps but do not establish patient-level frequencies.
    quote_role: REVIEW_SYNTHESIS
- category: Dermatologic
  name: Penile freckling
  description: >-
    Pigmented macules of the glans penis are a characteristic diagnostic clue in boys with macrocephaly
    and other BRRS findings. Genital lentigines more broadly have been reported in both sexes, as early
    as infancy and sometimes only during adolescence. Their absence in a young child does not exclude
    BRRS.
  phenotype_term:
    preferred_term: Pigmented macules of the glans penis
    term:
      id: HP:0031447
      label: Penile freckling
  diagnostic: true
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis."
    explanation: >-
      GeneReviews names pigmented macules of the glans penis as a defining BRRS feature.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Pigmented macules of the glans penis, delayed motor development and neonatal or infant onset are noted only in BRR."
    explanation: >-
      This historical comparison described penile macules in BRRS. It is not a contemporary estimate of
      diagnostic specificity across all PHTS presentations.
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Pigmented penile macules were described in the majority of male reports (21/28)."
    explanation: >-
      The denominator is 28 publications describing male cases, not the number of male patients. No patient
      frequency is inferred.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: One of the pathognomonic findings in BRRS is lentiginous genital macules which can be present in both males and females
    explanation: >-
      Genital lentigines are not restricted to males, although the penile phenotype is anatomically specific.
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: It is frequently reported in pediatric BRRS cases in patients as young as 1 year old
    explanation: >-
      The sign may be present in infancy and is not restricted to peripubertal onset.
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Nevertheless, genital speckles can also develop later in adolescence; therefore, the absence of lentigines alone is not a plausible reason to exclude BRRS
    explanation: >-
      Variable age at appearance limits the sensitivity of this sign in young children.
- category: Neurologic
  name: Global developmental delay
  description: >-
    Global, motor, and speech-language developmental delays occur in the PTEN spectrum and may accompany
    macrocephaly at childhood presentation. Their severity varies; combined developmental disorder estimates
    do not establish the frequency of global developmental delay specifically.
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:28526761
    reference_title: A retrospective chart review of the features of PTEN hamartoma tumour syndrome in children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Macrocephaly (average head circumference of + 5.7  SD) with developmental delay, ID and/or ASD were the most common presenting signs/symptoms (66 %)."
    explanation: >-
      Establishes developmental delay as part of the leading presentation in a pediatric PHTS cohort.
  - reference: PMID:34983360
    reference_title: "Behavioural and psychological features of PTEN mutations: a systematic review of the literature and meta-analysis of the prevalence of autism spectrum disorder characteristics."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Intellectual disability and developmental delay (global, motor and speech and language) were also reported frequently."
    explanation: >-
      Systematic review confirming that global, motor, and speech-language delay are frequent in constitutional
      PTEN variant carriers.
    quote_role: REVIEW_SYNTHESIS
- category: Neurobehavioral
  name: Autism
  description: >-
    Autism diagnoses and autism spectrum characteristics are reported in BRRS and the wider PTEN spectrum.
    A meta-analysis estimated ASD characteristics in 25% across heterogeneous PTEN-related cohorts, some
    including clinically diagnosed Cowden/BRRS without an identified PTEN variant. This is not a BRRS-specific
    prevalence of formally diagnosed autism. Ascertainment, possible cohort overlap, assessment differences,
    and publication bias limit interpretation. Macrocephaly with autism warrants consideration of PTEN
    testing.
  phenotype_term:
    preferred_term: Autism spectrum characteristics
    term:
      id: HP:0000717
      label: Autism
  evidence:
  - reference: PMID:34983360
    reference_title: "Behavioural and psychological features of PTEN mutations: a systematic review of the literature and meta-analysis of the prevalence of autism spectrum disorder characteristics."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Meta-analysis using a random effects model estimated pooled prevalence of ASD characteristics at 25% (95% CI 16-33%), although this should be interpreted cautiously due to possible biases in existing literature."
    explanation: >-
      The pooled estimate concerns ASD characteristics in heterogeneous PTEN cohorts. It supports the
      association, but is not used to assign a BRRS-specific frequency for diagnosed autism.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:28526761
    reference_title: A retrospective chart review of the features of PTEN hamartoma tumour syndrome in children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "It is recognised that 5% - 10 % of children with macrocephaly and autism spectrum disorder (ASD) and/or intellectual disability (ID) have a heterozygous pathogenic mutation in the PTEN tumour suppressor gene that is associated with PTEN hamartoma tumour syndrome."
    explanation: >-
      Supports the reciprocal clinical rule that macrocephaly plus ASD should prompt PTEN testing.
- category: Neurologic
  name: Intellectual disability
  description: >-
    Intellectual disability of variable severity occurs in BRRS and contributes to educational and support
    needs.
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Additional features observed in BRR, which may also occur in a minority of CS patients, include Hashimoto's thyroiditis, vascular malformations and mental retardation."
    explanation: >-
      Documents cognitive impairment (reported using the era's terminology) as a recognized BRRS feature.
  - reference: PMID:34983360
    reference_title: "Behavioural and psychological features of PTEN mutations: a systematic review of the literature and meta-analysis of the prevalence of autism spectrum disorder characteristics."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Intellectual disability and developmental delay (global, motor and speech and language) were also reported frequently."
    explanation: >-
      Systematic review confirming intellectual disability is frequently reported in PTEN carriers.
    quote_role: REVIEW_SYNTHESIS
- category: Neurologic
  name: Hypotonia
  description: >-
    Hypotonia and muscle weakness may contribute to delayed motor development in BRRS. The available clinical
    descriptions do not establish a uniformly central origin for the tone abnormality.
  phenotype_term:
    preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia
  evidence:
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Muscle weakness and hypotonia cause affected BRRS infants to appear"
    explanation: >-
      Names hypotonia explicitly in BRRS infants and links it to the delayed motor development curated
      in this entry.
    quote_role: BACKGROUND
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "some PTEN pathogenic variant carriers can suffer from muscle hypotonia, which is associated with motor delay"
    explanation: >-
      BRRS systematic review naming muscle hypotonia and its association with motor delay. The hedged
      wording ("some") is why no frequency band is asserted.
    quote_role: REVIEW_SYNTHESIS
- category: Cardiovascular
  name: Hemangioma
  description: >-
    Cutaneous and visceral hemangiomas are part of the original BRRS description and
    contribute to the syndrome's vascular burden. Historical synonyms for the disorder
    explicitly reference multiple hemangiomas alongside lipomas.
  phenotype_term:
    preferred_term: Hemangioma
    term:
      id: HP:0001028
      label: Hemangioma
  evidence:
  - reference: PMID:9352843
    reference_title: Localization of the Bannayan-Riley-Ruvalcaba syndrome gene to chromosome 10q23.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Bannayan-Riley-Ruvalcaba syndrome is a congenital syndrome with characteristic features of macrocephaly, cognitive and motor dysfunction, subcutaneous and visceral lipomas and hemangiomas, and intestinal juvenile polyposis."
    explanation: >-
      Names subcutaneous and visceral hemangiomas among the characteristic BRRS features.
- category: Cardiovascular
  name: Arteriovenous malformation
  description: >-
    Vascular malformations, including arteriovenous lesions, occur in BRRS and may
    require imaging or intervention. They are shared with the wider PHTS spectrum but
    are more characteristic of the BRRS presentation.
  phenotype_term:
    preferred_term: Arteriovenous malformation
    term:
      id: HP:0100026
      label: Arteriovenous malformation
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Another frequent finding was vascular abnormalities, namely, hemangiomas (8/33) and AVMs (6/33)."
    explanation: >-
      Names arteriovenous malformations specifically (not merely "vascular malformations") and gives the
      BRRS report-level frequency, 6 of 33.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Notably, AVMs can occur in the CNS and carry a potential risk of bleeding and complications related to mass effects"
    explanation: >-
      Supports the clinical significance of AVMs in BRRS, including the CNS location that drives imaging
      and intervention decisions.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Additional features observed in BRR, which may also occur in a minority of CS patients, include Hashimoto's thyroiditis, vascular malformations and mental retardation."
    explanation: >-
      This evidence is limited because this source establishes vascular malformations broadly as a BRRS
      feature but does not specify the arteriovenous subtype that this phenotype is bound to.
- category: Endocrine
  name: Hashimoto thyroiditis
  description: >-
    Hashimoto thyroiditis is a reported benign thyroid manifestation in BRRS. Thyroid nodules, imaging
    abnormalities, and thyroid carcinoma are distinct findings and do not by themselves establish autoimmune
    thyroiditis.
  phenotype_term:
    preferred_term: Hashimoto thyroiditis
    term:
      id: HP:0000872
      label: Hashimoto thyroiditis
  evidence:
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Additional features observed in BRR, which may also occur in a minority of CS patients, include Hashimoto's thyroiditis, vascular malformations and mental retardation."
    explanation: >-
      Documents Hashimoto thyroiditis as a recognized BRRS feature.
- category: Neoplastic
  name: Breast carcinoma
  description: >-
    Breast cancer risk is increased in women with a germline pathogenic PTEN variant. Older PHTS cohorts
    estimated lifetime risk around 85%, but ascertainment and study design influence these estimates.
    They are not direct incidence estimates for children ascertained with BRRS, and do not establish risk
    in PTEN-negative clinical BRRS.
  phenotype_term:
    preferred_term: Breast carcinoma
    term:
      id: HP:0003002
      label: Breast carcinoma
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The lifetime risk of developing breast cancer is 85%, with an average age of diagnosis between 38 and 46 years."
    explanation: >-
      GeneReviews gives the lifetime breast cancer risk and the adult age range at which it is realized.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:22252256
    reference_title: Lifetime cancer risks in individuals with germline PTEN mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Estimated lifetime risks were, respectively, 85.2% (95% CI, 71.4%-99.1%), 35.2% (19.7%-50.7%), 28.2% (17.1%-39.3%), 9.0% (3.8%-14.1%), 33.6% (10.4%-56.9%), and 6% (1.6%-9.4%)."
    explanation: >-
      Prospective PHTS cohort reporting the 85.2% lifetime breast cancer risk, the first value in the
      ordered list of breast, thyroid, endometrium, colorectum, kidney, and melanoma.
  - reference: PMID:33140411
    reference_title: A review on age-related cancer risks in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The tumor spectrum included female breast cancer (CLTRs including sex-specific estimates at age 60-70: 67% to 85%), endometrium cancer (19% to 28%), thyroid cancer (6% to 38%), renal cancer (2% to 24%), colorectal cancer (9% to 32%), and melanoma (0% to 6%)."
    explanation: >-
      Gives the cross-cohort ranges for every cancer site curated in this entry, which is why the descriptions
      frame risk as a range rather than a single point estimate.
    quote_role: REVIEW_SYNTHESIS
- category: Neoplastic
  name: Thyroid carcinoma
  description: >-
    Differentiated thyroid carcinoma, including follicular and papillary histologies, occurs in the PTEN
    spectrum and may present in childhood. The older approximately 35% lifetime estimate is derived from
    PHTS cohorts rather than a BRRS-specific prospective study.
  phenotype_term:
    preferred_term: Thyroid carcinoma
    term:
      id: HP:0002890
      label: Thyroid carcinoma
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The lifetime risk for thyroid cancer (usually follicular, rarely papillary, but never medullary thyroid cancer) is approximately 35%."
    explanation: >-
      GeneReviews gives the thyroid cancer lifetime risk and its histologic pattern.
    quote_role: REVIEW_SYNTHESIS
- category: Neoplastic
  name: Endometrial carcinoma
  description: >-
    Endometrial cancer risk is elevated in the PTEN spectrum. Older PHTS estimates approached 28%; BRRS-specific
    incidence is not established. Surveillance recommendations differ between recent guidelines.
  phenotype_term:
    preferred_term: Endometrial carcinoma
    term:
      id: HP:0012114
      label: Endometrial carcinoma
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The risk for endometrial cancer may approach 28%."
    explanation: >-
      GeneReviews gives the endometrial cancer lifetime risk estimate.
    quote_role: REVIEW_SYNTHESIS
- category: Neoplastic
  name: Renal cell carcinoma
  description: >-
    Renal cell carcinoma occurs in the PTEN spectrum, including papillary histology. The often-cited 34%
    lifetime estimate comes from older PHTS data and should not be read as a BRRS-specific risk or a universally
    accepted estimate.
  phenotype_term:
    preferred_term: Renal cell carcinoma
    term:
      id: HP:0005584
      label: Renal cell carcinoma
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The lifetime risk for renal cell cancer (predominantly of papillary histology) is 34%."
    explanation: >-
      GeneReviews gives the renal cell carcinoma lifetime risk and histologic pattern.
    quote_role: REVIEW_SYNTHESIS
- category: Neoplastic
  name: Colon cancer
  description: >-
    Colorectal cancer risk is increased in germline PTEN variant carriers, who may have mixed gastrointestinal
    polyp histologies. The hamartomatous BRRS polyps themselves are not established colorectal cancer
    precursors.
  phenotype_term:
    preferred_term: Colorectal carcinoma
    term:
      id: HP:0003003
      label: Colon cancer
  evidence:
  - reference: PMID:22672595
    reference_title: Is colorectal surveillance indicated in patients with PTEN mutations?
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Benign gastrointestinal lesions are common in PTEN mutation carriers, and a three- to four-fold increased lifetime risk of colorectal cancer compared with the general population may exist."
    explanation: >-
      Multinational PTEN-carrier cohort quantifying the relative colorectal cancer risk that justifies
      colonoscopic surveillance.
  - reference: url:https://www.ncbi.nlm.nih.gov/books/NBK1488/?report=printable
    reference_title: PTEN Hamartoma Tumor Syndrome - GeneReviews® - NCBI Bookshelf
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: These polyps are not believed to increase the risk for colorectal cancer.
    explanation: >-
      In the BRRS clinical-characteristics section this refers to gastrointestinal hamartomatous polyps.
      It distinguishes their complications from the broader PTEN-associated cancer risk.
- category: Neoplastic
  name: Melanoma
  description: >-
    An older germline PTEN cohort reported increased melanoma risk. Its magnitude and surveillance implications
    remain uncertain and are not established specifically for BRRS-ascertained individuals.
  phenotype_term:
    preferred_term: Melanoma
    term:
      id: HP:0002861
      label: Melanoma
  evidence:
  - reference: PMID:22252256
    reference_title: Lifetime cancer risks in individuals with germline PTEN mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lifetime risks for a variety of cancers, now extending to colorectal cancer, kidney cancer, and melanoma, are increased in patients with PTEN mutations."
    explanation: >-
      Establishes melanoma as part of the confirmed germline PTEN cancer spectrum in a prospective cohort.
- name: Pectus excavatum
  category: Musculoskeletal
  description: >-
    Pectus excavatum is a reported BRRS musculoskeletal finding.
  phenotype_term:
    preferred_term: Pectus excavatum
    term:
      id: HP:0000767
      label: Pectus excavatum
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Particularly associated with BRRS are musculocutaneous findings such as pectus excavatum, scoliosis, and joint hypermobility
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Scoliosis
  category: Musculoskeletal
  description: >-
    Scoliosis contributes to orthopedic follow-up needs in BRRS.
  phenotype_term:
    preferred_term: Scoliosis
    term:
      id: HP:0002650
      label: Scoliosis
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Particularly associated with BRRS are musculocutaneous findings such as pectus excavatum, scoliosis, and joint hypermobility
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Joint hypermobility
  category: Musculoskeletal
  description: >-
    Joint hypermobility is part of the BRRS musculoskeletal phenotype.
  phenotype_term:
    preferred_term: Joint hypermobility
    term:
      id: HP:0001382
      label: Joint hypermobility
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Particularly associated with BRRS are musculocutaneous findings such as pectus excavatum, scoliosis, and joint hypermobility
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Myopathy
  category: Musculoskeletal
  description: >-
    Proximal myopathy has been described in BRRS, in addition to hypotonia and motor delay.
  phenotype_term:
    preferred_term: Myopathy
    term:
      id: HP:0003198
      label: Myopathy
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Prenatal overgrowth and musculoskeletal system disorders such as myopathy of proximal muscles and scoliosis are other clinical features commonly found among individuals with BRRS
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Hematochezia
  category: Gastrointestinal
  description: >-
    Gastrointestinal polyps can present with rectal bleeding.
  phenotype_term:
    preferred_term: Hematochezia
    term:
      id: HP:0002573
      label: Hematochezia
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: BRRS patients with polyps may present with abdominal pain, hematochezia, anemia, invagination, constipation, or diarrhea
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Intussusception
  category: Gastrointestinal
  description: >-
    Intestinal hamartomatous polyps can be complicated by intussusception.
  phenotype_term:
    preferred_term: Intussusception
    term:
      id: HP:0002576
      label: Intussusception
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: BRRS patients with polyps may present with abdominal pain, hematochezia, anemia, invagination, constipation, or diarrhea
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Thyroid nodule
  category: Endocrine
  description: >-
    Thyroid nodules are common among the thyroid findings reported in BRRS and must be distinguished from
    carcinoma and autoimmune thyroiditis.
  phenotype_term:
    preferred_term: Thyroid nodule
    term:
      id: HP:0025388
      label: Thyroid nodule
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: From the included studies, the majority of outlined thyroid changes were nodules
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Cafe-au-lait spot
  category: Dermatologic
  description: >-
    Cafe-au-lait macules occur in BRRS but are not specific for the syndrome.
  phenotype_term:
    preferred_term: Cafe-au-lait spot
    term:
      id: HP:0000957
      label: Cafe-au-lait spot
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: the most frequently mentioned were café au lait spots, verrucous papules, and subcutaneous hemangiomas
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Motor delay
  category: Neurologic
  description: >-
    Delayed motor milestones occur in BRRS, including in association with hypotonia.
  phenotype_term:
    preferred_term: Motor delay
    term:
      id: HP:0001270
      label: Motor delay
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Motor delay is the most common developmental disorder among patients
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Delayed speech and language development
  category: Neurologic
  description: >-
    Speech and language delay may occur with or without broader developmental impairment.
  phenotype_term:
    preferred_term: Delayed speech and language development
    term:
      id: HP:0000750
      label: Delayed speech and language development
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: ranging from normal psychomotor development and mild motor or speech delay to severe intellectual disability
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
- name: Seizure
  category: Neurologic
  description: >-
    Seizures are reported in BRRS and the wider PTEN spectrum; evaluation depends on clinical findings.
    No BRRS-specific frequency is assigned.
  phenotype_term:
    preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Single cases of scoliosis, seizures, intracranial hypertension, and intracranial tumor treatment were also presented
    explanation: >-
      The BRRS systematic review supports this manifestation; no patient frequency is inferred from counts
      of publications.
genetic:
- name: PTEN
  notes: >-
    Heterozygous germline pathogenic PTEN variants establish PHTS and cause PTEN-positive BRRS. Sequence
    variants and deletions occur, and the spectrum overlaps Cowden syndrome. The classic clinically ascertained
    BRRS study identified variants in 26 of 43 cases (60%). Detection rates depend on ascertainment and
    assay coverage; a negative test does not exclude the clinical BRRS phenotype. The spectrum includes
    nonsense, missense, splice, small insertion/deletion, and larger copy-number variants. In selected
    BRRS/overlap cases without a previously identified intragenic variant, deletion analysis found additional
    diagnoses.
  gene_term:
    preferred_term: PTEN
    term:
      id: hgnc:9588
      label: PTEN
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  evidence:
  - reference: PMID:34754688
    reference_title: "Diffuse Gastrointestinal Polyposis in Bannayan-Riley-Ruvalcaba Syndrome: A Rare Phenotype Among Phosphatase and Tensin Homolog Hamartoma Tumor Syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Bannayan-Riley-Ruvalcaba syndrome (BRRS) is a rare genetic disorder caused by germline mutations in the phosphatase and tensin homolog (PTEN) gene."
    explanation: >-
      Directly assigns germline PTEN variants as the cause of BRRS.
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mutations were identified in 26 of 43 (60%) BRR cases."
    explanation: >-
      Establishes the approximately 60% germline PTEN detection rate in a dedicated BRRS cohort.
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Among CS, BRR and BRR/CS overlap families that are PTEN mutation positive, the mutation spectra appear similar."
    explanation: >-
      Supports the claim that the BRRS mutation spectrum is not distinguishable from that of Cowden syndrome.
  - reference: PMID:10353779
    reference_title: Phenotypic findings of Cowden syndrome and Bannayan-Zonana syndrome in a family associated with a single germline mutation in PTEN.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We have identified a germline mutation, R335X, in PTEN in a family consisting of two female members with the phenotypic findings of CS and two male members with the phenotypic findings of BZS."
    explanation: >-
      A single PTEN nonsense variant segregating with both Cowden and BRRS phenotypes in one family, the
      key intrafamilial evidence for allelism.
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf
    reference_title: "https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Germline pathogenic variants have been found throughout PTEN and include missense, nonsense, and splice site variants, small deletions, insertions, and large deletions.
    explanation: >-
      The GeneReviews molecular-genetics section describes the spectrum, including sequence and structural
      variants.
  - reference: PMID:12844284
    reference_title: Germline PTEN promoter mutations and deletions in Cowden/Bannayan-Riley-Ruvalcaba syndrome result in aberrant PTEN protein and dysregulation of the phosphoinositol-3-kinase/Akt pathway.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Thus 3 (11%) of 27 patients with BRRS or BRRS/CS-overlap had PTEN deletions.
    explanation: >-
      This additional yield is in a selected subgroup without previously PCR-detected intragenic variants,
      not 11% of all BRRS. The promoter-variant cases in this study had Cowden syndrome.
- name: TTN
  notes: >-
    TTN is a candidate predisposing locus in PTEN-wildtype BRRS. The discovery study identified germline
    missense variants in 12 of 35 unrelated classic BRRS probands. Functional study of one edited variant
    suggested impaired contact inhibition, but does not establish pathogenicity of all variants or a validated
    disease-gene relationship. This susceptibility annotation denotes a research candidate and is not
    a basis for predictive clinical testing or treatment selection.
  gene_term:
    preferred_term: TTN
    term:
      id: hgnc:12403
      label: TTN
  relationship_type: SUSCEPTIBILITY
  variant_origin: GERMLINE
  evidence:
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We exome-sequenced 35 unrelated PTEN-wildtype patients with classic presentation of BRRS and identified TTN germline missense variants in 12/35 (34%) patients."
    explanation: >-
      The primary human genetic observation: rare TTN missense variants in about a third of PTEN-wildtype
      classic BRRS patients.
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "suggested lack of contact inhibition in mutant cells"
    explanation: >-
      Cell-based functional support for one TTN variant. Limited to the cell assay, with evidence_source
      IN_VITRO because it is an edited-cell phenotype, not a demonstration of the human disease mechanism.
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "our observations suggest TTN as a candidate predisposing gene in classic PTEN-wildtype BRRS patients, perhaps suggesting this syndrome join the growing list of Titinopathies"
    explanation: >-
      The authors' own framing as a candidate gene, which is why this is curated as SUSCEPTIBILITY rather
      than CAUSATIVE.
diagnosis:
- name: PTEN Molecular Genetic Testing
  description: >-
    A heterozygous germline pathogenic PTEN variant establishes molecular PHTS in an individual with a
    BRRS phenotype. A negative result does not exclude a clinical BRRS presentation, but does not establish
    the same cancer risk. GeneReviews describes PTEN sequence analysis followed by deletion/duplication
    analysis, and promoter-region analysis when these are unrevealing. Copy-number testing can identify
    whole-gene or multiexon deletions; chromosomal microarray can define larger contiguous deletions including
    PTEN and BMPR1A. Test sensitivity depends on the assay used. KLLN promoter methylation findings in
    Cowden/Cowden-like cohorts do not establish a BRRS-specific etiology or routine BRRS diagnostic assay.
    Primer design must distinguish PTEN from its homologous pseudogene PTENP1.
  evidence:
  - reference: PMID:18510548
    reference_title: Variable phenotypes associated with 10q23 microdeletions involving the PTEN and BMPR1A genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The sizes of the deletions were analyzed using single nucleotide polymorphism array analysis."
    explanation: >-
      Supports the need for array-based rather than sequencing-only testing to detect the 10q23 contiguous
      deletions described in this section.
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The diagnosis of PHTS is established in a proband by identification of a heterozygous germline PTEN pathogenic variant on molecular genetic testing."
    explanation: >-
      GeneReviews states the molecular basis of establishing the PHTS diagnosis.
    quote_role: REVIEW_SYNTHESIS
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf
    reference_title: "https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: If a pathogenic variant is not identified with deletion/duplication analysis, perform sequence analysis of the PTEN promoter region for variants that decrease PTEN gene expression.
    explanation: >-
      The July 2026 PTEN Hamartoma Tumor Syndrome GeneReviews chapter by Tramontana and Yehia retains
      the sequence, copy-number, then promoter testing approach.
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf
    reference_title: "https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Special consideration should be taken when designing PTEN-specific primers to ensure specificity and to avoid cross-amplification of this pseudogene
    explanation: >-
      GeneReviews, PTEN Hamartoma Tumor Syndrome (July 2026 revision): The molecular-genetics technical note identifies PTENP1 as a source of assay cross-amplification.
- name: Clinical Recognition in Childhood
  description: >-
    BRRS is recognized clinically in a child with macrocephaly plus some combination of
    hamartomatous gastrointestinal polyposis, multiple lipomas, and pigmented macules of
    the glans penis, often alongside developmental delay or autism spectrum features.
    Because dermatologic, gastrointestinal, and thyroid findings are age-dependent, their
    absence at first assessment does not exclude the diagnosis.
  evidence:
  - reference: PMID:37900693
    reference_title: Clinical Guidelines for Diagnosis and Management of Cowden Syndrome/PTEN Hamartoma Tumor Syndrome in Children and Adults-Secondary Publication.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This syndrome is occasionally diagnosed in childhood due to the occurrence of multiple gastrointestinal polyps, autism spectrum disorders, and intellectual disability."
    explanation: >-
      Guideline statement describing the childhood route to diagnosis that characterizes the BRRS presentation.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:28526761
    reference_title: A retrospective chart review of the features of PTEN hamartoma tumour syndrome in children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Dermatological, GI and thyroid abnormalities are age dependent and may not be present at the time of diagnosis, requiring regular monitoring and medical surveillance."
    explanation: >-
      Supports the caution that age-dependent features may be absent at initial pediatric assessment.
- name: Imaging of Suspected PHOST
  description: >-
    MRI can show an infiltrative lesion spanning muscle, fascia, and subcutaneous tissue, with adipose
    components, enlarged serpiginous vessels, and small arteriovenous fistulae with dilated draining veins.
    Imaging guides assessment of a symptomatic lesion; histology distinguishes PHOST from other vascular
    and connective-tissue abnormalities.
  evidence:
  - reference: PMID:22446940
    reference_title: "PTEN hamartoma of soft tissue: a distinctive lesion in PTEN syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Magnetic resonance imaging generally showed an infiltrative soft tissue lesion involving the muscle, fascia, and subcutis with frequently enlarged, serpiginous vessels, small arteriovenous fistulae with disproportionately dilated draining veins, and a prominent adipocytic component.
    explanation: >-
      Imaging findings come from the PHOST pathology series, not a screening study of all BRRS patients.
treatments:
- name: Lifelong Cancer Surveillance
  description: >-
    Individuals with a germline pathogenic PTEN variant and a BRRS phenotype require long-term PHTS cancer-risk
    management. Recent guidelines differ in starting ages, intervals, and the evidence for renal and endometrial
    surveillance. The 2025 international consensus and 2026 ERN GENTURIS recommendations are therefore
    described separately below. Personal and family history, prior lesions, local guidance, and shared
    decision-making inform the plan. Molecularly negative clinical BRRS requires individualized assessment;
    the same cancer risk is not established. Genotype-based surveillance stratification is not supported
    by current evidence.
  treatment_term:
    preferred_term: cancer surveillance
    term:
      id: NCIT:C15406
      label: Cancer Screening
  evidence:
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Thus, PTEN mutation-positive CS and BRR may be different presentations of a single syndrome and, hence, both should receive equal attention with respect to cancer surveillance."
    explanation: >-
      The primary justification for applying full Cowden-equivalent surveillance to PTEN-positive BRRS.
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "As targeted treatment is still lacking, symptom relief and long-term surveillance remain the main management strategies."
    explanation: >-
      BRRS-specific systematic review confirming that surveillance plus symptom-directed care, rather
      than any disease-modifying therapy, is the management mainstay.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: at this time, it is not felt that genotype-specific recommendations could be made for individuals with PHTS
    explanation: >-
      The consensus explicitly rejects genotype-specific surveillance recommendations at present.
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf
    reference_title: "https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Regardless of clinical phenotype, individuals with a germline PTEN pathogenic variant are thought to have the same cancer risks.
    explanation: >-
      The updated GeneReviews chapter bases shared PHTS risk management on a germline pathogenic PTEN
      variant.
- name: 'PHTS Surveillance: 2025 International Consensus'
  description: >-
    The 2025 international consensus recommends annual breast MRI from age 25 and annual mammography from
    age 40. Thyroid ultrasound begins at age 12, then every 3-5 years when normal or every 2-3 years for
    clinically nonactionable nodules. Baseline colonoscopy is recommended at 35-40 years, with 1-3-year
    follow-up for a high adenoma burden, large polyps, or high-grade dysplasia. Routine endometrial surveillance,
    if offered, should be within a clinical trial; abnormal uterine bleeding requires evaluation. Renal
    ultrasound every two years from 35-40 may be considered as expert opinion. These recommendations concern
    PTEN-confirmed PHTS, not BRRS-specific trial evidence.
  treatment_term:
    preferred_term: cancer surveillance
    term:
      id: NCIT:C15406
      label: Cancer Screening
  evidence:
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Women with PHTS should undergo annual breast MRI (with contrast) from age 25 years and additional surveillance with breast mammography (with digital breast tomosynthesis) starting at age 40 years until 75 to 80 years of age.
    explanation: >-
      The consensus breast imaging recommendation is stated with its age thresholds.
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: From age 12 years, individuals with PHTS should undergo baseline thyroid ultrasound.
    explanation: >-
      The 2025 consensus begins thyroid ultrasound at 12 years.
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: We recommend surveillance with thyroid ultrasound every 3 to 5 years for individuals with PHTS and without nodules seen on initial thyroid ultrasound and every 2 to 3 years for individuals with clinically nonactionable nodules seen on initial thyroid ultrasound.
    explanation: >-
      Intervals depend on the initial ultrasound findings.
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: We recommend that all individuals with PHTS undergo a baseline colonoscopy at 35–40 years.
    explanation: >-
      This is routine baseline surveillance, distinct from earlier symptom-directed evaluation.
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Individuals with PHTS and a high colon polyp burden (five or more tubular adenomas), or polyps greater than or equal to 1 cm in diameter or with high-grade dysplasia, should undergo colonoscopy at a 1- to 3-year interval, as directed by their gastroenterologist.
    explanation: >-
      The shorter interval is conditional on polyp burden, size, or dysplasia.
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: If the decision to offer surveillance for endometrial cancer is made, this should be part of a clinical trial.
    explanation: >-
      The 2025 recommendation reflects limited evidence for routine endometrial surveillance.
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Starting at the age of 35–40 years, a surveillance ultrasound every 2 years for renal cell carcinoma may be considered in individuals with PHTS.
    explanation: >-
      This is explicitly an expert-opinion recommendation with limited evidence.
- name: 'PHTS Surveillance: 2026 ERN GENTURIS Guideline'
  description: >-
    The 2026 ERN GENTURIS guideline recommends breast MRI surveillance from age 25, with mammography every
    1-2 years considered from age 40 or according to national guidance. Thyroid ultrasound starts between
    10 and 18 years, annually initially, then every 2-3 years after two examinations without suspicious
    findings. Endometrial surveillance is probably appropriate from 35-40 years using at least annual
    transvaginal ultrasonography, with biopsy considered. Renal baseline imaging is offered at 35-40;
    when normal, further regular renal screening is not recommended. Baseline colonoscopy at 35-40 determines
    follow-up by polyp number, size, and pathology; only hamartomas or no polyps may permit general-population
    screening or repeat colonoscopy after 5-10 years. A baseline skin examination is suggested at 30,
    with further assessment according to findings or symptoms.
  treatment_term:
    preferred_term: cancer surveillance
    term:
      id: NCIT:C15406
      label: Cancer Screening
  evidence:
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Surveillance for breast cancer with MRI should probably start at age 25.
    explanation: >-
      Recommendation 3 gives the MRI starting age.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z
    reference_title: "ERN GENTURIS cancer surveillance guideline for individuals with PTEN hamartoma tumour syndrome (PHTS) | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: In addition, mammography every 1–2 years can be considered, preferably from the age of 40 years
    explanation: >-
      The full guideline text describes mammography in addition to annual MRI and allows alignment with
      national surveillance guidance.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Surveillance for thyroid cancer should probably start between 10 and 18 years of age.
    explanation: >-
      Recommendation 8 gives an age range, rather than a universal starting age.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Individuals should be offered surveillance for thyroid cancer annually initially. Individuals with two ultrasound examinations with no suspicious findings should probably be re-scanned at an increased interval of two to three years as clinically indicated.
    explanation: >-
      Recommendation 9 distinguishes initial annual imaging from longer intervals after normal scans.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: If surveillance for endometrial cancer is offered, it should probably start at 35-40 years.
    explanation: >-
      The European guideline differs from the 2025 international consensus on endometrial surveillance.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: If surveillance for endometrial cancer is offered, it should probably be via transvaginal ultrasonography done at least annually. Endometrial biopsy can be considered.
    explanation: >-
      Recommendation 12 identifies the proposed modality and interval.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Individuals should be offered a baseline imaging exam at age 35–40 years for renal cell carcinoma (RCC).
    explanation: >-
      Recommendation 14 specifies baseline renal imaging.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Where renal baseline imaging is normal, further regular surveillance is not recommended, just follow-up based on signs and symptoms.
    explanation: >-
      The renal footnote differs materially from the 2025 consensus suggestion of repeated imaging.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Baseline colonoscopy should be undertaken at 35–40 years to assess polyp load, preferably in an expert centre. Interval of monitoring is guided by the number, size and pathology of resected polyps.
    explanation: >-
      Recommendation 15 bases subsequent colonoscopy on the findings.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: In individuals with only hamartomas or no polyps at baseline colonoscopy, colorectal cancer surveillance may follow general population guidelines. However, a repeat colonoscopy after 5 to 10 years can be considered.
    explanation: >-
      Recommendation 16 distinguishes hamartomas from higher-risk polyp findings.
  - reference: url:https://www.nature.com/articles/s41431-026-02181-z/tables/3
    reference_title: "Table 3 Guideline recommendations. | European Journal of Human Genetics"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Individuals probably should have a baseline skin examination performed by a doctor with expertise in this condition at age 30, further surveillance as required
    explanation: >-
      Recommendation 17 gives baseline skin assessment without assuming annual lifelong dermatologic screening.
- name: Gastrointestinal Polyp Management
  description: >-
    Symptomatic gastrointestinal polyps require evaluation and endoscopic management according to size,
    histology, and complications. Childhood bleeding, anemia, obstruction, or intussusception may warrant
    assessment before routine adult cancer-screening ages. Severe or recurrent disease can require surgery.
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: endoscopic polypectomy
    term:
      id: NCIT:C15329
      label: Surgical Procedure
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Polypectomies of hamartomatous polyps were also frequent, with two cases of proctocolectomy and subtotal colectomy due to severe symptom burden and recurrence
    explanation: >-
      The BRRS review records endoscopic polyp removal and surgery for severe recurrent disease.
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: BRRS patients with polyps may present with abdominal pain, hematochezia, anemia, invagination, constipation, or diarrhea
    explanation: >-
      These complications motivate symptom-directed care independently of routine screening ages.
- name: Symptomatic Management of Hamartomatous Lesions
  description: >-
    Lipomas, vascular lesions, and other benign manifestations are treated the same way
    as their sporadic counterparts, with excision reserved for lesions causing pain,
    functional impairment, deformity, or diagnostic uncertainty rather than performed
    prophylactically.
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: surgical excision
    term:
      id: NCIT:C15329
      label: Surgical Procedure
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Treatment for the benign and malignant manifestations of PHTS is the same as for their sporadic counterparts."
    explanation: >-
      GeneReviews establishes the principle of treating manifestations as for sporadic disease.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "cutaneous lesions should be excised only if malignancy is suspected or symptoms (e.g., pain, deformity, increased scarring) are significant."
    explanation: >-
      GeneReviews supports restricting excision to symptomatic or suspicious lesions.
    quote_role: REVIEW_SYNTHESIS
- name: Developmental and Behavioral Support
  description: >-
    Because developmental delay, intellectual disability, and autism spectrum
    characteristics are core to the BRRS presentation, early developmental assessment and
    intervention (speech, motor, and educational support) is a management priority
    independent of the cancer-surveillance agenda.
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: rehabilitation
    term:
      id: NCIT:C15315
      label: Rehabilitation
  evidence:
  - reference: PMID:28526761
    reference_title: A retrospective chart review of the features of PTEN hamartoma tumour syndrome in children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Early paediatric diagnosis is important for institution of medical and developmental surveillance as well as for testing other at- risk family members."
    explanation: >-
      Supports developmental surveillance and support as an explicit goal of early pediatric diagnosis.
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/
    reference_title: "PTEN Hamartoma Tumor Syndrome - GeneReviews® - NCBI Bookshelf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Referral to an early intervention program is recommended for access to occupational, physical, speech, and feeding therapy as well as infant mental health services, special educators, and sensory impairment specialists.
    explanation: >-
      The updated GeneReviews chapter specifies multidisciplinary early intervention for developmental
      difficulties.
- name: mTOR Inhibitor Therapy
  description: >-
    Everolimus targets the mTOR overactivity that follows PTEN loss, giving a direct mechanistic rationale.
    A 6-month phase II randomized placebo-controlled trial in 46 individuals with PHTS (eligible ages
    5 to 45 years) found the drug tolerable but did not meet its primary neurocognitive endpoint, with
    gastrointestinal adverse events more common on treatment. mTOR inhibition therefore remains investigational
    for the neurodevelopmental features of BRRS and is not routine care.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: mTOR inhibitor pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: everolimus
      term:
        id: CHEBI:68478
        label: everolimus
  target_mechanisms:
  - target: mTOR Overactivity
    treatment_effect: INHIBITS
    description: >-
      Pharmacologic inhibition of mTOR is the molecular target; clinical benefit for each indication requires
      separate evidence.
  evidence:
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "PTEN hamartoma tumor syndrome (PHTS) is a complex neurodevelopmental disorder characterized by mechanistic target of rapamycin (mTOR) overactivity."
    explanation: >-
      Establishes the mechanistic rationale for mTOR inhibition in PHTS.
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    snippet: "Changes in the primary endpoint between groups from baseline to Month 6 were not apparent"
    explanation: >-
      Recorded as REFUTE for the claim of neurocognitive efficacy. The randomized trial's primary endpoint
      was null, which is why this treatment is curated as investigational rather than established.
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Gastrointestinal adverse events were more common in the everolimus group"
    explanation: >-
      Documents the principal treatment-emergent toxicity signal in the trial.
- name: Sirolimus for Vascular Anomalies
  description: >-
    Sirolimus (rapamycin) is the lesion-directed mTOR-inhibitor use in BRRS, distinct from
    the neurocognitive indication that the everolimus trial tested and missed. It is used
    off-label for symptomatic vascular anomalies when other treatments have failed, and the
    BRRS-specific published experience is a single pediatric case in the 2024 systematic
    review. Evidence is therefore anecdotal, and this is curated as an off-label option
    under investigation rather than standard care.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: mTOR inhibitor pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: sirolimus
      term:
        id: CHEBI:9168
        label: sirolimus
  target_mechanisms:
  - target: mTOR Overactivity
    treatment_effect: INHIBITS
    description: >-
      Pharmacologic inhibition of mTOR is the molecular target; clinical benefit for each indication requires
      separate evidence.
  evidence:
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "mTOR inhibitors have been investigated in patients with vascular anomalies when previous treatments were ineffective"
    explanation: >-
      Establishes the lesion-directed indication. This evidence is limited because it describes an investigational,
      salvage-setting use rather than established efficacy.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "only one study reported the use of rapamycin"
    explanation: >-
      Quantifies how thin the BRRS-specific evidence is: a single report among 33 reviewed articles, which
      is why this is curated as anecdotal rather than standard care.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:39256443
    reference_title: A systematic review of Bannayan - Riley - Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "There is no established standard treatment for PHTS patients"
    explanation: >-
      Confirms the absence of an established standard therapy in PHTS, the framing under which any mTOR-inhibitor
      use in BRRS should be read.
    quote_role: REVIEW_SYNTHESIS
- name: Genetic Counseling and Cascade Testing
  description: >-
    Genetic counseling covers the autosomal dominant 50% transmission risk, the
    variable expressivity that lets one PTEN variant produce BRRS in one relative and
    Cowden syndrome in another, and the value of predictive testing in at-risk relatives
    so that carriers can enter surveillance.
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:20301661
    reference_title: PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "When a PTEN pathogenic variant has been identified in a proband, molecular genetic testing of asymptomatic at-risk relatives can identify those who have the family-specific pathogenic variant and warrant ongoing surveillance."
    explanation: >-
      GeneReviews supports cascade testing of at-risk relatives to direct surveillance.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:10353779
    reference_title: Phenotypic findings of Cowden syndrome and Bannayan-Zonana syndrome in a family associated with a single germline mutation in PTEN.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "To our knowledge, this is the first report that shows the presence of separate subjects with CS and with BZS in a single family associated with a single germline PTEN mutation."
    explanation: >-
      Supports counseling about intrafamilial variable expressivity: the same variant can produce either
      BRRS or Cowden syndrome in different relatives.
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf
    reference_title: "https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/pdf/Bookshelf_NBK1488.pdf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Once the PTEN pathogenic variant has been identified in an affected family member, prenatal and preimplantation genetic testing are possible.
    explanation: >-
      GeneReviews supports reproductive counseling after the familial molecular diagnosis is established.
- name: Investigational Sirolimus for Colon Polyposis
  description: >-
    A small adult PHTS trial found fewer colorectal polyps in the two participants completing a year of
    sirolimus, without a change in polyposis stage. Drug-related pneumonitis and recurrent vaginal candidiasis
    caused withdrawals. This remains investigational and does not establish colorectal cancer prevention
    or a pediatric BRRS indication.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: mTOR inhibitor pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: sirolimus
      term:
        id: CHEBI:9168
        label: sirolimus
  target_mechanisms:
  - target: mTOR Overactivity
    treatment_effect: INHIBITS
    description: >-
      Pharmacologic inhibition of mTOR is the molecular target; clinical benefit for each indication requires
      separate evidence.
  evidence:
  - reference: PMID:40478255
    reference_title: Sirolimus for Colon Polyposis in PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Five participants were enrolled, with 2 completing the planned study course.
    explanation: >-
      The published completion count limits interpretation of efficacy.
  - reference: PMID:40478255
    reference_title: Sirolimus for Colon Polyposis in PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: For the patients completing the study, polyp numbers decreased
    explanation: >-
      A within-person observation in two completers is not controlled evidence of benefit.
  - reference: PMID:40478255
    reference_title: Sirolimus for Colon Polyposis in PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: there was not a change in polyposis staging despite the reduction in total colorectal polyp burden.
    explanation: >-
      The trial did not establish a reduction in colonoscopy or colectomy requirements.
  - reference: PMID:40478255
    reference_title: Sirolimus for Colon Polyposis in PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Withdrawals were due to side effects likely related to sirolimus for 2 subjects (pneumonitis after 6 weeks requiring withdrawal and recurrent vaginal candidiasis leading to withdrawal after 3 months)
    explanation: >-
      Two likely treatment-related withdrawals limit tolerability in the small pilot study.
- name: Physical and Occupational Therapy
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: rehabilitation
    term:
      id: NCIT:C15315
      label: Rehabilitation
  description: >-
    Physical therapy supports mobility and addresses hypotonia and orthopedic complications. Occupational
    therapy targets fine-motor and adaptive difficulties, with equipment and support tailored to individual
    function.
  evidence:
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/
    reference_title: "PTEN Hamartoma Tumor Syndrome - GeneReviews® - NCBI Bookshelf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Physical therapy is recommended to maximize mobility and to reduce the risk for later-onset orthopedic complications (e.g., contractures, scoliosis, hip dislocation).
    explanation: >-
      The updated GeneReviews chapter describes management of gross motor dysfunction.
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/
    reference_title: "PTEN Hamartoma Tumor Syndrome - GeneReviews® - NCBI Bookshelf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Occupational therapy is recommended for difficulty with fine motor skills that affect adaptive function such as feeding, grooming, dressing, and writing.
    explanation: >-
      The chapter distinguishes fine-motor and adaptive support from gross motor therapy.
- name: Individualized Risk-Reducing Surgery
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: risk-reducing surgical procedures
    term:
      id: NCIT:C15329
      label: Surgical Procedure
  description: >-
    For PTEN-confirmed PHTS, risk-reducing mastectomy may be discussed as an alternative to breast surveillance
    with an experienced high-risk breast team, generally after age 25. Counseling considers individual
    risk, surgical complications, reconstruction, and preferences. Routine hysterectomy is not recommended
    by the 2025 international consensus; decisions are individualized, including uterine pathology and
    reproductive plans. These are adult risk-management options, not routine interventions for children
    with BRRS.
  evidence:
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Given the high lifetime risk of female breast cancer and second primary breast cancer in individuals with PHTS and pathogenic or likely pathogenic variants in PTEN, we recommend discussing the options of surveillance versus RRM with an experienced high-risk breast clinic team.
    explanation: >-
      The guideline recommends a discussion of alternatives rather than universal preventive surgery.
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Generally, RRM should only be considered in individuals older than 25 years of age, unless otherwise clinically indicated
    explanation: >-
      The usual age threshold is explicitly qualified.
  - reference: PMID:39937242
    reference_title: "Cancer and Overgrowth Manifestations of PTEN Hamartoma Tumor Syndrome: Management Recommendations from the International PHTS Consensus Guidelines Working Group."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: We do not recommend routine hysterectomy for endometrial cancer risk reduction in PHTS individuals with a uterus.
    explanation: >-
      The consensus opposes routine hysterectomy and recommends individualized assessment.
differential_diagnoses:
- name: Cowden Syndrome
  description: >-
    PTEN-related Cowden syndrome is an overlapping presentation of PHTS, often recognized through adult
    mucocutaneous manifestations or cancer. BRRS emphasizes childhood macrocephaly, lipomas, polyposis,
    and developmental findings. The labels are not mutually exclusive, and surveillance follows the molecular
    PHTS diagnosis.
  evidence:
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Pigmented macules of the glans penis, delayed motor development and neonatal or infant onset are noted only in BRR."
    explanation: >-
      Gives the specific features that separate BRRS from Cowden syndrome clinically.
  disease_term:
    preferred_term: PTEN-related Cowden syndrome
    term:
      id: MONDO:0008021
      label: Cowden syndrome 1
- name: Juvenile Polyposis Syndrome
  description: >-
    Juvenile polyposis shares hamartomatous gastrointestinal polyps with BRRS. Macrocephaly, lipomas,
    and genital lentigines favor the BRRS phenotype. Deletions encompassing both PTEN and BMPR1A can produce
    overlapping features, so these distinctions are not absolute.
  evidence:
  - reference: PMID:9352843
    reference_title: Localization of the Bannayan-Riley-Ruvalcaba syndrome gene to chromosome 10q23.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "It has been suggested that Bannayan-Riley-Ruvalcaba syndrome may be a variant of juvenile polyposis coli because of the shared features of intestinal juvenile polyps."
    explanation: >-
      Documents the historical diagnostic confusion between BRRS and juvenile polyposis based on shared
      polyp histology.
  disease_term:
    preferred_term: juvenile polyposis syndrome
    term:
      id: MONDO:0017380
      label: juvenile polyposis syndrome
discussions:
- discussion_id: gap_brrs_pediatric_ascertained_cancer_risk
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    What is the actual, prospectively measured cancer risk in individuals ascertained as
    BRRS in childhood, as opposed to risk inferred from adult, cancer-ascertained Cowden
    syndrome cohorts?
  attaches_to:
  - pathophysiology#Lifelong Multiorgan Cancer Predisposition
  rationale: >-
    The cancer surveillance imposed on children diagnosed with BRRS rests on allelism with
    Cowden syndrome rather than on direct BRRS-cohort incidence data. The original BRRS
    delineation explicitly noted that malignancy had not been formally documented in BRRS,
    and contemporary reviews flag that existing PHTS risk estimates come from strongly
    ascertained, mostly adult cohorts with an acknowledged absence of pediatric research.
    If BRRS-ascertained carriers have materially different risk, current pediatric
    surveillance may be either over- or under-calibrated.
  proposed_experiments:
  - experiment_id: brrs-prospective-pediatric-cohort
    name: Prospective pediatric BRRS cancer-incidence cohort
    description: >-
      A prospective, multicenter cohort of individuals ascertained in childhood by BRRS
      clinical criteria and followed into adulthood, reporting age- and site-specific
      cancer incidence separately for PTEN-positive and PTEN-negative participants.
  evidence:
  - reference: PMID:33140411
    reference_title: A review on age-related cancer risks in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Although these estimates provide guidance for clinical care, discrepancies between studies, sample sizes, retrospective designs, strongly ascertained cases, and lack of pediatric research emphasizes that data should be interpreted with great caution."
    explanation: >-
      Explicitly identifies the absence of pediatric data and ascertainment bias as the gap.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:31609537
    reference_title: "PTEN Hamartoma tumor syndrome in childhood: A review of the clinical literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We acknowledge the limited understanding of the natural history of childhood-onset PHTS as a cancer predisposition syndrome and present a summary of important management considerations."
    explanation: >-
      A pediatric-focused review stating directly that the natural history of childhood-onset PHTS as
      a cancer predisposition syndrome is poorly understood.
    quote_role: REVIEW_SYNTHESIS
- discussion_id: gap_brrs_mutation_negative_cases
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    What explains clinically diagnosed BRRS without an identified germline PTEN variant after contemporary
    testing, and what cancer risks do these individuals carry?
  attaches_to:
  - pathophysiology#Germline PTEN Loss of Function
  rationale: >-
    The classic BRRS series identified PTEN variants in 26 of 43 cases. This historical yield depends
    on ascertainment and testing methods and is not a current universal residual fraction. Structural
    and promoter variants warrant appropriate testing. A TTN study reported a candidate association and
    an edited-cell phenotype, but did not establish TTN as a BRRS disease gene. KLLN methylation was studied
    in Cowden/Cowden-like patients and is not an established explanation for BRRS. Cancer-risk estimates
    for PTEN-confirmed PHTS cannot automatically be applied to this unresolved group.
  proposed_experiments:
  - experiment_id: brrs-mutation-negative-genomics
    name: Genomic reanalysis of PTEN-mutation-negative BRRS
    description: >-
      Genome sequencing with deep-intronic, promoter, structural-variant, and
      somatic-mosaicism analysis on a cohort of PTEN-mutation-negative clinical BRRS cases,
      paired with long-term cancer outcome follow-up.
  evidence:
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mutations were identified in 26 of 43 (60%) BRR cases."
    explanation: >-
      Quantifies the incomplete molecular yield that defines this gap.
  - reference: PMID:10400993
    reference_title: PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Comparisons between BRR and a previously studied group of 37 CS families suggested an increased likelihood of identifying a germline PTEN mutation in families with either CS alone or both CS and BRR when compared with BRR alone"
    explanation: >-
      Documents that BRRS-alone families have a lower PTEN detection rate, sharpening the question of
      what underlies mutation-negative BRRS.
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The remaining cases are of unknown genetic etiology."
    explanation: >-
      The TTN study frames the remaining genetic etiology as unknown; its candidate findings do not resolve
      this clinical group.
references:
- reference: PMID:20301661
  title: PTEN Hamartoma Tumor Syndrome.
  tags:
  - GeneReviews
notes: >-
  BRRS denotes a clinical presentation that overlaps molecularly confirmed PHTS and Cowden syndrome. Clinical
  labels, molecular diagnosis, and ascertainment must be distinguished when interpreting cancer risks,
  phenotype frequencies, and experimental models.
histopathology:
- name: PTEN hamartoma of soft tissue
  context: Resected PHOST lesions in the PHTS spectrum
  description: >-
    Unencapsulated lesions contain mature adipose and dense or myxoid fibrous tissue mixed with abnormal
    venous channels, tortuous thick-walled arteries, and small vessels. Some contain arteriovenous connections,
    lymphoid follicles, metaplastic bone, or hypertrophic nerves. Histologic recognition warrants evaluation
    for PHTS, but does not independently establish a germline PTEN variant.
  evidence:
  - reference: PMID:22446940
    reference_title: "PTEN hamartoma of soft tissue: a distinctive lesion in PTEN syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: a variable admixture of mature adipocytic and dense and/or myxoid fibrous tissues
    explanation: >-
      The selected pathology series defines the nonvascular stromal components.
  - reference: PMID:22446940
    reference_title: "PTEN hamartoma of soft tissue: a distinctive lesion in PTEN syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: tortuous, thick-walled arteries with concentric muscular hyperplasia and relatively small lumens
    explanation: >-
      This describes characteristic vascular architecture in PHOST.
  - reference: PMID:22446940
    reference_title: "PTEN hamartoma of soft tissue: a distinctive lesion in PTEN syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Histopathologic recognition of PHOST should prompt a detailed clinical evaluation, including family history, as well as possible genetic testing for a PTEN mutation.
    explanation: >-
      The authors frame PHOST as a diagnostic clue requiring clinical and molecular evaluation.
animal_models:
- name: Germline Ptenm3m4 mouse
  species: Mus musculus
  genotype: Ptenm3m4/m3m4; heterozygous and wild-type littermate comparisons
  background: CD-1 background after backcrossing
  description: >-
    A germline knock-in model with cytoplasmic-predominant Pten and reduced total protein. Homozygotes
    show region-specific brain enlargement, neuronal soma hypertrophy, increased NG2-cell proliferation
    and glial accumulation, astrogliosis, and microglial activation. Behavioral findings include sex-dependent
    increased social motivation and poor balance with preserved recognition memory. This model does not
    isolate nuclear localization from protein abundance and is not a human BRRS genotype.
  publication: PMID:24470394
  evidence:
  - reference: PMID:24470394
    reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight.
    explanation: >-
      The model combines reduced Pten abundance with altered localization and shows regional brain enlargement.
  - reference: PMID:24470394
    reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: The cytoplasm-predominant protein caused cellular hypertrophy limited to the soma and led to increased NG2 cell proliferation and accumulation of glia.
    explanation: >-
      Homozygous Ptenm3m4 mice showed neuronal soma hypertrophy and increased glial production. These
      findings do not demonstrate generalized neuronal progenitor proliferation in human BRRS.
  - reference: PMID:24470394
    reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: The Pten(m3m4) model displays sex-specific increases in social motivation, poor balance and normal recognition memory
    explanation: >-
      The measured behavioral profile differs from simply labeling mice autistic.
  - reference: url:https://pure.mpg.de/rest/items/item_2175436_2/component/file_2175464/content
    reference_title: "https://pure.mpg.de/rest/items/item_2175436_2/component/file_2175464/content"
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: Mice were backcrossed onto the CD-1 outbred strain for at least ﬁve generations to reduce the impact of genetic heterogeneity on the results.
    explanation: >-
      The full manuscript specifies the mouse background and backcrossing; this is the Tilot et al. 2014
      model paper.
  modeled_mechanisms:
  - target: Brain Enlargement
    relationship: MEASURES
    description: >-
      Regional brain weight and cellular size/proliferation readouts.
    model_scale: TISSUE
    evidence:
    - reference: PMID:24470394
      reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: The homozygous Pten(m3m4) mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight.
      explanation: >-
        The model combines reduced Pten abundance with altered localization and shows regional brain enlargement.
    - reference: PMID:24470394
      reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: The cytoplasm-predominant protein caused cellular hypertrophy limited to the soma and led to increased NG2 cell proliferation and accumulation of glia.
      explanation: >-
        Homozygous Ptenm3m4 mice showed neuronal soma hypertrophy and increased glial production. These
        findings do not demonstrate generalized neuronal progenitor proliferation in human BRRS.
  - target: Microglial Activation
    relationship: MEASURES
    description: >-
      In vivo astrogliosis and microglial activation in mutant mice.
    model_scale: TISSUE
    evidence:
    - reference: PMID:24470394
      reference_title: Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: The animals also exhibit significant astrogliosis and microglial activation, indicating a neuroinflammatory phenotype.
      explanation: >-
        The primary mouse study documents the in vivo phenotype.
  notes: >-
    A homozygous engineered mouse combines altered localization and reduced Pten dosage. It cannot stratify
    cancer surveillance for heterozygous human PTEN carriers.
experimental_models:
- name: Ptenm3m4 primary neuron-microglia co-cultures
  experimental_model_type: CO_CULTURE
  organism:
    preferred_term: Mus musculus
    term:
      id: NCBITaxon:10090
      label: Mus musculus
  cell_source: Primary mouse cortical neurons and microglia with differing Pten genotypes
  culture_system: Neuron-microglia co-cultures and neuronal monoculture controls
  description: >-
    Genotype combinations test cell-autonomous and cross-cell effects on phagocytosis and synaptic-marker
    abundance. Mutant neurons alone have more synaptic marker colocalization, whereas addition of mutant
    microglia lowers it. The assay does not measure human cognition or directly demonstrate autism causation.
  publication: PMID:32055008
  evidence:
  - reference: PMID:32055008
    reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: We found increased Iba1 and C1q expression with enhanced phagocytic capacity in Ptenm3m4/m3m4 microglia, indicating microglial activation.
    explanation: >-
      Primary mouse microglial assays show activation and enhanced phagocytosis.
  - reference: PMID:32055008
    reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: However, in a systemic germline Ptenm3m4/m3m4 mutant system, our data suggest cross-talk between neurons and microglia, resulting in significantly increased synaptic pruning in Ptenm3m4/m3m4 mutants compared with PtenWT/WT mice.
    explanation: >-
      The co-culture results support genotype-dependent neuron-microglia interactions. Synapse abundance
      was assessed with pre/post-synaptic marker colocalization, not electrophysiological function.
  modeled_mechanisms:
  - target: Microglial Activation
    relationship: MEASURES
    description: >-
      Iba1/C1q expression and phagocytic capacity.
    model_scale: CELLULAR
    evidence:
    - reference: PMID:32055008
      reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: We found increased Iba1 and C1q expression with enhanced phagocytic capacity in Ptenm3m4/m3m4 microglia, indicating microglial activation.
      explanation: >-
        Primary mouse microglial assays show activation and enhanced phagocytosis.
  - target: Enhanced Microglial Synaptic Pruning
    relationship: MEASURES
    description: >-
      Synaptophysin/PSD-95 colocalization and microglial uptake assays.
    model_scale: CELLULAR
    evidence:
    - reference: PMID:32055008
      reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: However, in a systemic germline Ptenm3m4/m3m4 mutant system, our data suggest cross-talk between neurons and microglia, resulting in significantly increased synaptic pruning in Ptenm3m4/m3m4 mutants compared with PtenWT/WT mice.
      explanation: >-
        The co-culture results support genotype-dependent neuron-microglia interactions. Synapse abundance
        was assessed with pre/post-synaptic marker colocalization, not electrophysiological function.
- name: TTN p.Cys5096Arg edited HEK293T cells
  experimental_model_type: CELL_LINE
  organism:
    preferred_term: Homo sapiens
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  cell_source: CRISPR-Cas9 edited HEK293T cells
  description: >-
    Wild-type, heterozygous, and homozygous TTN p.Cys5096Arg cells were compared for growth after confluence,
    viability, migration, and signaling. Contact inhibition was impaired; AKT and ERK phosphorylation
    decreased. Altered FAK readouts support a candidate growth pathway but do not prove TTN causality
    in BRRS or therapeutic response.
  publication: PMID:29263846
  evidence:
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: suggested lack of contact inhibition in mutant cells
    explanation: >-
      Edited HEK293T cells continued proliferating after confluence; one TTN variant was tested.
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: we note paradoxical downstream readouts of decreased phosphorylation of AKT and ERK1/2
    explanation: >-
      The measured signaling direction differs from canonical PTEN-loss hyperactivation.
  - reference: PMID:29263846
    reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: Functional interrogation of I-band variant p.Cys5096Arg identified in one of our classic BRRS patients, using CRISPR-Cas9 genome-edited cell lines, reveals an increased growth and lack of contact inhibition phenotype
    explanation: >-
      The study functionally tested one candidate allele in an engineered cell line.
  modeled_mechanisms:
  - target: Impaired Contact Inhibition in TTN Variant Cells
    relationship: MEASURES
    description: >-
      Growth after confluence and associated signaling readouts.
    model_scale: CELLULAR
    evidence:
    - reference: PMID:29263846
      reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: suggested lack of contact inhibition in mutant cells
      explanation: >-
        Edited HEK293T cells continued proliferating after confluence; one TTN variant was tested.
    - reference: PMID:29263846
      reference_title: Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome.
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: we note paradoxical downstream readouts of decreased phosphorylation of AKT and ERK1/2
      explanation: >-
        The measured signaling direction differs from canonical PTEN-loss hyperactivation.
- name: PTEN lipid-phosphatase biochemical and 293-cell assays
  experimental_model_type: OTHER
  organism:
    preferred_term: Homo sapiens
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  cell_source: Human 293 cells and purified recombinant PTEN
  description: >-
    Recombinant protein assays establish PIP3 dephosphorylation at position 3. Transfection of catalytically
    inactive PTEN C124S increases cellular PIP3, while PTEN overexpression reduces insulin-induced PIP3
    without changing PI3K activation. These experiments establish biochemical function rather than clinical
    pathogenicity of a BRRS allele.
  publication: PMID:9593664
  evidence:
  - reference: PMID:9593664
    reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring.
    explanation: >-
      Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.
  - reference: PMID:9593664
    reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: Further, transfection of the catalytically inactive mutant of PTEN (C124S) caused PtdIns(3,4,5)P3 accumulation in the absence of insulin stimulation.
    explanation: >-
      The catalytically inactive construct caused PIP3 accumulation in transfected human 293 cells; this
      is a mechanistic assay, not a BRRS patient allele experiment.
  modeled_mechanisms:
  - target: PIP3 Accumulation
    relationship: MEASURES
    description: >-
      PTEN catalytic perturbation and lipid substrate measurements.
    model_scale: MOLECULAR
    evidence:
    - reference: PMID:9593664
      reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: Purified recombinant PTEN catalyzed dephosphorylation of PtdIns(3,4,5)P3, specifically at position 3 on the inositol ring.
      explanation: >-
        Biochemical assays establish the direct PIP3 3-phosphatase activity of PTEN.
    - reference: PMID:9593664
      reference_title: "The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate."
      supports: SUPPORT
      evidence_source: IN_VITRO
      quote_role: PRIMARY_RESULT
      snippet: Further, transfection of the catalytically inactive mutant of PTEN (C124S) caused PtdIns(3,4,5)P3 accumulation in the absence of insulin stimulation.
      explanation: >-
        The catalytically inactive construct caused PIP3 accumulation in transfected human 293 cells;
        this
        is a mechanistic assay, not a BRRS patient allele experiment.
datasets:
- accession: GEO:GSE59318
  title: Neural gene expression in Pten knock-in mice at 6-weeks of age
  description: >-
    Mouse neural transcriptome data comparing Ptenm3m4 genotypes and wild-type controls. The microglial
    study reused cortical differential-expression data for neuroinflammatory and synaptic pathway analysis;
    this is a model-organism dataset, not a human BRRS cohort.
  organism:
    preferred_term: Mus musculus
    term:
      id: NCBITaxon:10090
      label: Mus musculus
  data_type: BULK_RNA_SEQ
  evidence:
  - reference: GEO:GSE59318
    reference_title: Neural gene expression in Pten knock-in mice at 6-weeks of age
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: The goal of this study was to assess the changes in the neural transcriptome of Ptenm3m4 mice, in order to better understand their ASD-related phenotypes.
    explanation: >-
      The GEO record identifies the model and transcriptomic objective.
  - reference: PMID:32055008
    reference_title: Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: BACKGROUND
    snippet: The cortical transcriptome of 6-week-old Ptenm3m4 mice (GSE59318) mimics that of idiopathic autism, as described in detail in Tilot et al.
    explanation: >-
      This paper identifies the accession it reanalyzed; the comparison with autism is a model transcriptomic
      analogy, not evidence of human sampling.
variants:
- name: PTEN p.Arg130Ter
  description: >-
    Recurrent PTEN nonsense variant c.388C>T (p.Arg130Ter) on NM_000314.8 / NP_000305.3, reported as pathogenic
    in GeneReviews. The source notes that classifications were supplied by its authors and not independently
    verified by GeneReviews staff. This is a PHTS allele, not specific to one clinical presentation.
  gene:
    preferred_term: PTEN
    term:
      id: hgnc:9588
      label: PTEN
  variant_type: single nucleotide variant
  type: Nonsense
  clinical_significance: PATHOGENIC
  evidence:
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/
    reference_title: "PTEN Hamartoma Tumor Syndrome - GeneReviews® - NCBI Bookshelf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: p.Arg130Ter ... Recurrent pathogenic variants ... Variants listed in the table have been provided by the authors.
    explanation: >-
      Table 6 of GeneReviews lists these three recurrent pathogenic PTEN variants and pairs their nucleotide and protein changes. The description records the relevant allele and the source classification caveat.
- name: PTEN p.Arg233Ter
  description: >-
    Recurrent PTEN nonsense variant c.697C>T (p.Arg233Ter) on NM_000314.8 / NP_000305.3, reported as pathogenic
    in GeneReviews. The source notes that classifications were supplied by its authors and not independently
    verified by GeneReviews staff. This is a PHTS allele, not specific to one clinical presentation.
  gene:
    preferred_term: PTEN
    term:
      id: hgnc:9588
      label: PTEN
  variant_type: single nucleotide variant
  type: Nonsense
  clinical_significance: PATHOGENIC
  evidence:
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/
    reference_title: "PTEN Hamartoma Tumor Syndrome - GeneReviews® - NCBI Bookshelf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Recurrent pathogenic variants ... p.Arg233Ter ... Variants listed in the table have been provided by the authors.
    explanation: >-
      Table 6 of GeneReviews lists these three recurrent pathogenic PTEN variants and pairs their nucleotide and protein changes. The description records the relevant allele and the source classification caveat.
- name: PTEN p.Arg335Ter
  description: >-
    Recurrent PTEN nonsense variant c.1003C>T (p.Arg335Ter) on NM_000314.8 / NP_000305.3, reported as
    pathogenic in GeneReviews. The source notes that classifications were supplied by its authors and
    not independently verified by GeneReviews staff. This is a PHTS allele, not specific to one clinical
    presentation.
  gene:
    preferred_term: PTEN
    term:
      id: hgnc:9588
      label: PTEN
  variant_type: single nucleotide variant
  type: Nonsense
  clinical_significance: PATHOGENIC
  evidence:
  - reference: url:https://www.ncbi.nlm.nih.gov/sites/books/NBK1488/
    reference_title: "PTEN Hamartoma Tumor Syndrome - GeneReviews® - NCBI Bookshelf"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: Recurrent pathogenic variants ... p.Arg335Ter ... Variants listed in the table have been provided by the authors.
    explanation: >-
      Table 6 of GeneReviews lists these three recurrent pathogenic PTEN variants and pairs their nucleotide and protein changes. The description records the relevant allele and the source classification caveat.
  - reference: PMID:10353779
    reference_title: Phenotypic findings of Cowden syndrome and Bannayan-Zonana syndrome in a family associated with a single germline mutation in PTEN.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: We have identified a germline mutation, R335X, in PTEN in a family consisting of two female members with the phenotypic findings of CS and two male members with the phenotypic findings of BZS.
    explanation: >-
      This family directly links the recurrent stop variant to both Cowden and BRRS/Bannayan-Zonana presentations.
clinical_trials:
- name: NCT02991807
  phase: PHASE_II
  status: COMPLETED
  description: >-
    Randomized parallel-group everolimus versus placebo study in 46 individuals with PTEN-confirmed PHTS.
    Six months of treatment did not improve the primary neurocognitive composite endpoint. Secondary signals
    were exploratory and not adjusted for multiple comparisons; gastrointestinal adverse events were more
    common with everolimus.
  evidence:
  - reference: clinicaltrials:NCT02991807
    reference_title: A Randomized Double-Blind Controlled Trial of Everolimus in Individuals With PTEN Mutations (RAD001XUS257T)
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Investigators are conducting research to evaluate the potential safety and efficacy of RAD001 (everolimus) in this patient population, and the potential neurocognitive benefits from treatment with RAD001 or placebo for a six month period.
    explanation: >-
      The cached registry summary states the intervention and objective; the completed status comes from
      the live registry.
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    snippet: "Changes in the primary endpoint between groups from baseline to Month 6 were not apparent"
    explanation: >-
      Recorded as REFUTE for the claim of neurocognitive efficacy. The randomized trial's primary endpoint
      was null, which is why this treatment is curated as investigational rather than established.
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Gastrointestinal adverse events were more common in the everolimus group"
    explanation: >-
      Documents the principal treatment-emergent toxicity signal in the trial.
  notes: >-
    The registry lists phases I/II and actual enrollment of 46; the publication describes phase II. The
    trial used parallel allocation. NCT02461446 is a separate observational natural-history study, not
    this drug trial.
- name: NCT04094675
  phase: PHASE_II
  status: COMPLETED
  description: >-
    Single-group open-label sirolimus study for colon polyposis in adults with a pathogenic PTEN variant.
    Five participants enrolled and two completed one year. Polyp numbers decreased in the completers without
    a change in polyposis stage. Two participants withdrew because of likely drug-related toxicity, and
    clinical benefit beyond polyp counts remains unproven.
  evidence:
  - reference: clinicaltrials:NCT04094675
    reference_title: Sirolimus for Cowden Syndrome With Colon Polyposis
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: This study is investigating sirolimus and its effect on the number of colon polyps in patients with Cowden syndrome and polyposis over a 1 year period.
    explanation: >-
      The registry summary identifies the indication and planned duration.
  - reference: PMID:40478255
    reference_title: Sirolimus for Colon Polyposis in PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Five participants were enrolled, with 2 completing the planned study course.
    explanation: >-
      The published completion count limits interpretation of efficacy.
  - reference: PMID:40478255
    reference_title: Sirolimus for Colon Polyposis in PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: For the patients completing the study, polyp numbers decreased
    explanation: >-
      A within-person observation in two completers is not controlled evidence of benefit.
  - reference: PMID:40478255
    reference_title: Sirolimus for Colon Polyposis in PTEN Hamartoma Tumor Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: there was not a change in polyposis staging despite the reduction in total colorectal polyp burden.
    explanation: >-
      The trial did not establish a reduction in colonoscopy or colectomy requirements.
  notes: >-
    The registry lists the study as completed with five participants. The publication describes stopping
    recruitment before the target was met because of slow enrollment. This adult PHTS trial is not a pediatric
    BRRS-specific efficacy study.

📚

References & Deep Research

References

1

PMID:20301661

PTEN Hamartoma Tumor Syndrome.

No top-level findings curated for this source.

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Evaluations and curation notes (2)

Review BRRS clinical scope, mechanisms, models, trials, and surveillance using cached full texts · 2026-09-27T20:22:40Z · View source

Reviewed the complete original entry, both existing CREATE/EDIT histories, the matching deep-research report and citation sidecar, and the underlying cached evidence. This is a noninfectious Mendelian phenotype and was eligible for the review sweep. The branch was created from current main and rebased before edits. The eight-dimensional content review found and corrected substantial overstatement and under-consumption: 1. Phenotypes: corrected macrocephaly to the patient-level 77% estimate rather than 32/33 publications; qualified other publication-count denominators; removed a BRRS-specific autism frequency derived from heterogeneous PTEN cohorts. Added musculoskeletal, thyroid, skin, developmental, seizure, and polyp-complication findings. Penile macules are no longer described as exclusively peripubertal or as proof that all genital lentigines are male-limited. Human findings remain distinct from model observations. 2. Subtypes: retained the PTEN/BMPR1A contiguous-deletion overlap with variable severity. Bound the chromosome 10q23 deletion concept while explicitly noting its broader interval scope; did not relabel all deletion carriers as severe infantile juvenile polyposis. Added verified differential-diagnosis bindings. 3. Mechanisms: separated PIP3 accumulation, AKT activation, and mTOR overactivity. Used primary PTEN biochemical evidence. Removed the claim that every BRRS feature is explained by one signaling chain. Distinguished PHOST from other vascular lesions and added its histology and MRI findings. Removed universal second-hit dependence and thyroid autoimmunity as a downstream consequence of cancer predisposition. Reframed Ptenm3m4 findings as combined localization/dosage effects, not a human autism-versus-cancer discriminator; isolated microglial activation/pruning observations from unproven human behavioral causality. TTN cell findings are an explicitly provisional, separate branch. 4. Treatments/trials: separated 2025 international and 2026 ERN GENTURIS surveillance schedules instead of blending their conflicting renal, thyroid, and endometrial recommendations. Added the completed everolimus trial and the sirolimus colon-polyposis trial with its 2025 results, two completers among five participants, unchanged polyposis stage, and treatment-limiting toxicity. Preserved the negative everolimus primary endpoint and exploratory nature of secondary findings. Added individualized risk-reducing surgery discussion, polyp management, rehabilitation, and contemporary GeneReviews developmental support. Drug targets are mTOR rather than an unproven direct PHOST-lesion inhibition claim. 5. Genetics: distinguished clinically diagnosed BRRS from PTEN-confirmed PHTS; corrected the de novo denominators (20/187 versus 20/42 with informative family testing). Added recurrent PTEN nonsense variants with transcript context and source-classification caveats. Added structural-variant yield and technical testing considerations. Removed KLLN methylation as an established BRRS cause or routine diagnostic test; TTN remains a candidate association rather than an established diagnostic locus. 6. Diagnostics: expanded the sequence/copy-number/promoter testing approach, PTENP1 assay caveat, and PHOST imaging/pathology recognition. Clinical absence of age-dependent manifestations does not exclude BRRS. Cancer-risk estimates are not automatically extended to PTEN-negative clinical cases. 7. References: used the available full scientific texts of the BRRS systematic review, GeneReviews chapter, PHOST pathology study, PTEN cancer cohorts/reviews, de novo study, TTN study, localization and microglial models, everolimus trial, and current cancer guidelines. Reviewed the 2024 review's image-only phenotype table independently of its publication counts. The initial older HTML GeneReviews cache was superseded for new management/genetics evidence by a newly fetched July 2026 PDF; the PDF's autogenerated URL title is retained rather than hand-edited. The 2025 sirolimus paper was discovered through the live registry and read in full including its table. Review synthesis and primary model/clinical results are distinguished with quote_role and evidence_source. 8. Overall consumption: added one whole-animal model, three non-animal experimental systems, a verified GEO transcriptomic dataset, three structured variants, two clinical trials, and PHOST pathology/imaging. Model-to-mechanism links state what the experiments measure. GSE59318 is mouse transcriptomic data, not a human cohort. Remaining uncertain claims (including TTN causality, human pruning-behavior causation, and BRRS-ascertained cancer incidence) are explicitly limited rather than promoted to established facts. Source-specific cautions: the ASD meta-analysis mixes recruitment designs and, in two cohorts, clinical diagnoses without identified PTEN variants; its publication-bias-adjusted estimate differs from its headline estimate. The July 2026 GeneReviews chapter uses age four versus seven for earliest thyroid cancer in different sections and calls the everolimus study a crossover trial; neither inconsistency was propagated (primary publication and registry specify parallel allocation). The sirolimus paper's trial-stopping language concerns recruitment before its target was met; the registry's current status is COMPLETED. The sirolimus Table 1 prints 10% for several one-of-five categories; these inconsistent percentages were not imported. No new cache file was hand-authored; all new/refreshed caches were generated with the reference fetcher, and GEO was verified with the dataset recipe. The original entry's nosological/process note was reviewed. Its useful disease-level point, overlap between BRRS and PHTS/Cowden with molecularly informed surveillance, is retained in concise disease prose. The previous argument that a childhood BRRS label itself always obligates Cowden-equivalent cancer surveillance was narrowed to molecularly confirmed PHTS. No repository-wide lumping/splitting or schema change is made by this review.

Create: Bannayan-Riley-Ruvalcaba Syndrome · 2026-08-04T00:54:55Z · View source

De novo curation of BRRS as a standalone entry, paralleling the existing Cowden_Syndrome entry (both are PHTS subtypes; BRRS previously existed only as a ~20-line subtype stub inside PTEN_Hamartoma_Tumor_Syndrome). Deep research: claude_code provider (research/Bannayan-Riley-Ruvalcaba_Syndrome-deep-research-claude_code.md; 27 web searches, 24 citations, 998s). DR output was treated as leads only: every PMID was independently fetched and every snippet verified as an exact substring of the cached abstract or full text. DR-suggested figures were re-derived from the cached source rather than copied; where the report gave a percentage, the underlying count was quoted instead (e.g. genital macules curated as 21/28 male reports). GeneReviews baseline: PMID:20301661 (PTEN Hamartoma Tumor Syndrome) fetched, tagged, and cross-referenced; the BRRS core tetrad and full surveillance schedule are curated from it. Five-node pathograph from germline PTEN loss through PIP3/PI3K-AKT-mTOR hyperactivation to hamartomatous overgrowth, neurodevelopmental dysregulation, and lifelong multiorgan cancer predisposition, with no orphan nodes. Central curated insight: PTEN-positive BRRS and Cowden syndrome are allelic, so a childhood BRRS diagnosis obligates lifelong Cowden-equivalent cancer surveillance; the entry records via PARTIAL evidence that this risk is inferred from allelism and has not been confirmed in BRRS-ascertained cohorts. Honest negative-result curation: the everolimus phase II RCT (PMID:35594551) missed its primary neurocognitive endpoint, curated with supports REFUTE so mTOR inhibition reads as investigational rather than established. TTN curated as SUSCEPTIBILITY (not CAUSATIVE) per the authors own candidate-gene framing. Two KNOWLEDGE_GAP discussions with proposed experiments cover pediatric-ascertained cancer risk and the PTEN-mutation-negative 40 percent. Validation: schema clean, term validation passed, 95/95 snippets verified against cached references, compliance 89.3 percent global / 89.7 percent weighted. A pre-PR red-team self-review was run in a fresh-context subagent; it raised 3 blocking findings (macrocephaly frequency band anchored on the wrong statistic, AVM phenotype asserted on evidence that only said vascular malformations, hypotonia evidence that never mentioned hypotonia) and these were fixed by re-quoting already-cached full text. Also from that review: ascertainment caveat added to the PTEN detection rate (60 percent classic vs 75/83 modern), cancer risks reframed as cross-cohort ranges, autism band choice documented explicitly, the historical-absence cancer snippet retyped from PARTIAL to NO_EVIDENCE, and sirolimus added as the lesion-directed mTOR use distinct from the negative neurocognitive everolimus trial.

Claude Code ▸

Bannayan–Riley–Ruvalcaba Syndrome (BRRS) — Comprehensive Research Report

claude-haiku-4-5-20251001, claude-opus-5[1m] 24 citations 2026-08-03T20:22:44.443204

Bannayan–Riley–Ruvalcaba Syndrome (BRRS) — Comprehensive Research Report

Prepared: 2026-08-03 · Target: kb/disorders/Bannayan-Riley-Ruvalcaba_Syndrome.yaml · Category: Mendelian (autosomal dominant, tumor-predisposition / overgrowth)

⚠️ Curator preflight — read this before you copy anything into YAML

Three things will bite you on this entry, so let's get them out of the way first.

1. Named Entity Confusion risk here is HIGH. BRRS is a triple eponym collision that got merged in the early 1990s — Bannayan–Zonana syndrome, Riley–Smith syndrome, and Ruvalcaba–Myhre–Smith syndrome were three separately-named conditions that turned out to be one thing. Several databases (NORD included) still file it under ruvalcaba-syndrome. Adjacent traps: Riley–Day syndrome (familial dysautonomia, IKBKAP/ELP1 — completely unrelated), Ruvalcaba syndrome (a distinct skeletal-dysplasia eponym), and Cowden syndrome (MONDO:0016063, OMIM:158350), which is the same gene and arguably the same disease but a different KB entity. A deep-research report on "Bannayan syndrome" that talks mostly about breast/thyroid cancer surveillance in adults has probably drifted into Cowden. Run just preflight-dr <report> MONDO:0007924 and expect the canonical gene to be PTEN.

2. Every ontology ID below is a candidate. My local OAK install in this worktree is broken (the Python 3.14 pyhornedowl failure), so I could not verify a single HP/GO/CL/UBERON/CHEBI/NCIT identifier against the authority. Treat the term tables as leads and run just validate-terms before committing. I've flagged the ones I'm least sure about.

3. Quotes marked "verbatim" came from the Europe PMC abstractText field, which is the real abstract — but the reference validator is the arbiter, not me. Run just fetch-reference PMID:xxxxx then just validate-references for each one. Two abstracts I could not retrieve (Marsh 1997 Nat Genet is a letter with no abstract at all; Parisi 2001 has no abstractText in Europe PMC) — do not invent snippets for those.

1. Disease Information

Overview

Bannayan–Riley–Ruvalcaba syndrome is a rare congenital overgrowth and hamartoma disorder, present from birth, defined by the combination of macrocephaly, hamartomatous intestinal polyposis, lipomas, vascular malformations, and pigmented macules of the glans penis (genital lentiginosis), frequently with developmental delay and/or autism spectrum disorder. It is one of the historical clinical presentations now unified under the molecular umbrella of PTEN hamartoma tumor syndrome (PHTS).

The single most consequential fact for a knowledge base: BRRS and Cowden syndrome are, mechanistically, the same disease. Marsh et al. established this in 1999 and Lachlan et al. confirmed it clinically in 2007; GeneReviews now states flatly that the historical phenotypes "represent a unified disease spectrum under the PHTS designation" and that PHTS has no clinical diagnostic criteria of its own — molecular confirmation of a germline PTEN variant is the diagnosis.

Verbatim (PMID:10400993, Marsh et al. 1999, Hum Mol Genet 8:1461–72): "Thus, PTEN mutation-positive CS and BRR may be different presentations of a single syndrome and, hence, both should receive equal attention with respect to cancer surveillance."

BRRS is best understood as the pediatric-onset end of the PHTS spectrum (overgrowth, lipomas, polyps, neurodevelopment) and Cowden syndrome as the adult-onset end (mucocutaneous lesions, breast/thyroid/endometrial cancer), with the same gene and age-related penetrance connecting them.

Identifiers

Resource	Identifier	Notes
MONDO	`MONDO:0007924`	Verified against EBI OLS4; label "Bannayan-Riley-Ruvalcaba syndrome"; not obsolete
OMIM	`153480`	Formerly "Bannayan-Zonana syndrome" / "Ruvalcaba-Myhre-Smith syndrome"
Orphanet	`ORPHA:109`
UMLS	`C0265326`
MedGen	`78554`
DOID	`DOID:0050657`
NCIT	`NCIT:C3939`
SNOMED CT	`21984008`
ICD-9	`759.6`
ICD-10-CM	MONDO xref says `E71.440` — ⚠️ suspicious; most clinical sources use `Q85.8` (other phakomatoses, NEC). Verify before curating.
ICD-11	MONDO carries foundation ID `357383447`; the practical stem code is in the LD2x hamartoma-syndrome block. Verify.
Gene (HGNC)	`hgnc:9588` (PTEN); OMIM `*601728`; UniProt `P60484`

Synonyms and alternative names

From the MONDO record: BRRS, Bannayan syndrome, Bannayan–Zonana syndrome (BZS), Riley–Smith syndrome, Myhre–Riley–Smith syndrome, Ruvalcaba–Myhre–Smith syndrome (RMSS), "macrocephaly with multiple lipomas and hemangiomas." Also encountered: macrocephaly–multiple lipomas–hemangiomata syndrome, Bannayan–Ruvalcaba–Riley syndrome.

Nature of the evidence base

Overwhelmingly aggregated disease-level and case-level literature, not EHR-derived. The definitive BRRS-specific evidence is a 2024 systematic review of 83 published pediatric cases from 33 articles (PMID:39256443) — all case reports and small series, which the authors explicitly flag as high risk of bias. The large quantitative datasets (cancer risk, GI phenotype) all come from Cowden-ascertained PHTS cohorts (Cleveland Clinic, Dutch/European registries) and must be attributed as PHTS-wide rather than BRRS-specific. A very recent unbiased population signal exists (All of Us / UK Biobank) but is still a preprint as of December 2025.

2. Etiology

Primary cause

Heterozygous germline loss-of-function variants in PTEN (phosphatase and tensin homolog), at 10q23.31. PTEN is a haploinsufficient tumor suppressor; loss of its lipid-phosphatase activity releases the brake on PI3K–AKT–mTOR signaling.

Detection rate in BRRS specifically: ~60% in the classic ascertained series.

Verbatim (PMID:10400993): "In this study, constitutive DNA samples from 43 BRR individuals comprising 16 sporadic and 27 familial cases, 11 of which were families with both CS and BRR, were screened for PTEN mutations. Mutations were identified in 26 of 43 (60%) BRR cases."

The 2024 pediatric systematic review reports a much higher rate — 75/83 (90%) — but that reflects modern ascertainment (patients are increasingly defined by having the variant). The earlier Marsh 1998 series found 4/7 (57%) in Bannayan–Zonana families.

Verbatim (PMID:9467011, Marsh et al. 1998, Hum Mol Genet 7:507–15): "Germline PTEN mutations were identified in four of seven (57%) BZS families studied. Interestingly, none of these mutations was observed in the PTPase core motif."

That last clause is a real, curatable genotype–phenotype observation: BRRS-associated variants were not found in the phosphatase core motif, whereas Cowden variants clustered there (43% of CD mutations in exon 5).

Genetic risk factors beyond PTEN

TTN (titin) — candidate second gene for PTEN-wildtype BRRS. This is the most important non-PTEN finding and is BRRS-specific rather than Cowden-derived.

Verbatim (PMID:29263846, Yehia, Ni & Eng 2017, npj Genom Med 2:37): "We exome-sequenced 35 unrelated PTEN-wildtype patients with classic presentation of BRRS and identified TTN germline missense variants in 12/35 (34%) patients... Rare TTN variants (MAF ≤ 0.0001) are enriched in classic BRRS patients compared to BRRS-like (OR = 2.7, 95% CI 1.21-5.94, p = 1.6 × 10⁻²) and multiple population controls (OR = 2.2, 95% CI 1.01-4.20, p = 4.7 × 10⁻²)."

Functional support: CRISPR-edited cells carrying the I-band variant p.Cys5096Arg showed "increased growth and lack of contact inhibition... associated with increased levels of or phosphorylation of focal adhesion kinase (FAK)." The authors propose BRRS may "join the growing list of Titinopathies." Curation note: this is a candidate gene — use relationship_type: SUSCEPTIBILITY or MODIFIER, not causal, and tag evidence_source: IN_VITRO for the FAK/CRISPR arm.

Other PTEN-wildtype routes (established in Cowden-like, extrapolate cautiously to BRRS): - KLLN/KILLIN germline promoter hypermethylation — 37% of 123 PTEN-mutation-negative Cowden/Cowden-like patients; downregulates KILLIN ~250-fold with normal PTEN transcription (Bennett, Mester & Eng 2010, JAMA 304:2724–31, PMID:21177507). Associated with ~3-fold higher breast cancer and >2-fold higher renal cancer prevalence than germline PTEN variants. Assigned OMIM #615107 (Cowden syndrome 4). - SDHB/*SDHD germline variants — 3 SDHB and 7 SDHD among 74 PTEN-negative Cowden-like individuals with elevated MnSOD (Ni et al. 2008, Am J Hum Genet 83:261–8, PMID:18678321). - Additional unexpected cancer-predisposition gene variants in PTEN-wildtype CS/BRRS (Yehia et al. 2018, PLoS Genet*).

Environmental risk factors

None established. BRRS is a monogenic Mendelian disorder with no documented environmental cause, no infectious trigger, and no lifestyle risk factor for the syndrome itself. This is a legitimate "not applicable" for the KB — do not fabricate.

Downstream cancer risk in carriers plausibly interacts with generic exposures (UV for the ~6% melanoma risk; diagnostic radiation given the tumor predisposition), but I found no BRRS/PHTS-specific gene–environment interaction study. Age is the dominant non-genetic modifier of expression — penetrance is strongly age-related, which is the reason BRRS and Cowden look like different diseases at different life stages.

Protective factors

No genetic protective variants or modifier alleles are documented. No dietary or lifestyle protective factor has been demonstrated. The only genuinely "protective" intervention is surveillance-based early detection, which is secondary prevention, not risk reduction.

Gene–environment interactions

Not characterized for BRRS. Report this as a knowledge gap — a discussions entry with kind: KNOWLEDGE_GAP is the honest treatment.

3. Phenotypes

BRRS-specific frequencies (best available source)

From the 2024 systematic review of 83 pediatric BRRS patients (PMID:39256443, Kapačinskaitė et al., Sci Rep 14, doi:10.1038/s41598-024-71991-2). These are frequencies among published pediatric case reports — publication bias is severe, so use qualitative FrequencyEnum bands rather than curating the exact percentages as population frequencies. Per docs/frequency-evidence-guidelines.md, the mapping below is my suggestion; when a number is soft, omit frequency: entirely.

Phenotype	Reported frequency	Suggested `FrequencyEnum`	Candidate HP term (⚠️ verify)
Macrocephaly	77% (also 94% in PHTS overall per GeneReviews; often >5 SD above mean)	`VERY_FREQUENT`	`HP:0000256` Macrocephaly
Developmental disorders (DD/ASD)	63%	`FREQUENT`	`HP:0001263` Global developmental delay; `HP:0000717` Autism
Pigmented genital macules (males)	75% (21/28 males)	`VERY_FREQUENT` (males)	⚠️ no confident HP term — search "penile freckling"/"lentigines"; fallback `HP:0007565`
Skin manifestations (any)	64%	`FREQUENT`	`HP:0000951` Abnormality of the skin
Lipomas	>50% (18/33)	`FREQUENT`	`HP:0012032` Lipoma
Gastrointestinal polyps	48%	`FREQUENT`	⚠️ hamartomatous polyposis — verify `HP:0004390` vs `HP:0200008`
Thyroid changes	36%	`OCCASIONAL`–`FREQUENT`	`HP:0000820` Abnormal thyroid morphology
Hemangiomas	24%	`OCCASIONAL`	`HP:0001028` Hemangioma
Arteriovenous malformations	18%	`OCCASIONAL`	`HP:0100026` Arteriovenous malformation

Verbatim (PMID:39256443): "A total of 83 pediatric patients with BRRS were identified. The most common clinical findings were macrocephaly (77%) and developmental disorders (63%)."

Demographics from the same review: male predominance 60/83 (72%) — almost certainly an ascertainment artifact, since genital lentiginosis is a male-only diagnostic clue; median age 8 years; de novo variants in up to 48%.

Additional features (established in the older literature, frequencies less firm)

Neonatal macrosomia / large birth weight; accelerated linear growth in early childhood; muscular hypotonia and proximal myopathy (a genuinely BRRS-flavored feature, sometimes with lipid storage on muscle biopsy); joint hyperextensibility; pectus excavatum; scoliosis; café-au-lait macules; frontal bossing and dolichocephaly; downslanting palpebral fissures; Hashimoto thyroiditis (Gorlin et al. 1992, Am J Med Genet 44:307–14, PMID:1336932 — expanded the BRRS phenotype to include Hashimoto thyroiditis, present in 7 of their cases); high-arched palate; enlarged perivascular Virchow–Robin spaces on brain MRI.

Phenotype characteristics

Onset: congenital / neonatal for macrocephaly and macrosomia; infancy–early childhood for lipomas, vascular anomalies, and developmental concerns; peripubertal/adolescent (age ~10+) for genital lentiginosis; adult for the epithelial cancers.
Severity: highly variable, even within a single family carrying the identical variant. Lachlan et al. (2007, J Med Genet 44:579–85) concluded BRRS and CS are "one condition with variable expression and age-related penetrance" and argued it is "not helpful to split PTEN-related disorders into separate clinical syndromes."
Progression: the overgrowth features are largely stable/static after early childhood (macrocephaly does not progress; some lipomas enlarge). The tumor-predisposition component is progressive with age — new lesions and malignancies accrue lifelong. Vascular anomalies (PTEN hamartoma of soft tissue) are typically progressive and symptomatic, presenting with pain and swelling.
Quality-of-life impact: driven mostly by (a) neurodevelopment — intellectual disability, ASD, attention and processing-speed deficits; (b) pain and functional impairment from intramuscular vascular/soft-tissue hamartomas (one case in the Kurek series required amputation); (c) the psychological burden of lifelong cancer surveillance. I found no BRRS-specific EQ-5D/SF-36/PROMIS data — this is a real gap; the sirolimus vascular-anomaly experience reports "significant improvement in patient quality of life" without a validated instrument. Do not curate a QoL number.

Neurodevelopmental detail

PTEN is now recognized as one of the commonest monogenic causes of ASD with macrocephaly (~10% of ASD-plus-macrocephaly cases). GeneReviews: neurodevelopmental disorders in ~35% of children with PHTS; epilepsy 6–17% vs ~1% general population. Frazier et al. 2015 (Mol Psychiatry, PMID:25288137) found PTEN-ASD specifically associated with prominent white-matter abnormalities and "strong reductions in processing speed and working memory," with white-matter abnormality mediating the relationship between PTEN protein level and full-scale IQ. A 2024 systematic review of PHTS neurology (Dhawan, Baitamouni, Liu & Eng, Neurology 103(7):e209844, PMID:39250745) screened 1,996 articles and included 90 — but 54% were case reports, so the neurological evidence base is thin.

4. Genetic / Molecular Information

Causal gene

PTEN, 10q23.31, 9 exons, encoding a 403-amino-acid dual-specificity protein/lipid phosphatase. HGNC hgnc:9588 (note this repo's lowercase-prefix convention). OMIM *601728. UniProt P60484. A processed pseudogene, PTENP1 on chromosome 9, cross-amplifies during PCR and must be designed around — a practical testing caveat worth capturing.

Variant spectrum

Types: missense, nonsense, frameshift, splice-site, small indels, and whole-exon to whole-gene deletions. All classes are represented.
Exon 5 hotspot: "Nearly 40%" of PHTS variants fall in exon 5, which encodes the phosphatase (PTPase) core motif (HCXXGXXR, residues ~123–130). Marsh 1998 found 13/30 (43%) of Cowden variants in exon 5, with 7/30 (23%) inside the core motif itself — and notably none of the Bannayan–Zonana variants in the core motif.
Recurrent variants: c.388C>T (p.Arg130Ter), c.697C>T (p.Arg233Ter), c.1003C>T (p.Arg335Ter). R233X was seen in two unrelated Cowden families and one BZS family in the Marsh 1998 series — direct evidence for allelism.
Detection method yield (GeneReviews): coding-region sequencing ≤80%; deletion/duplication analysis 3–11%; promoter-region sequencing ~10% (do not skip the promoter).
Origin: germline for the syndrome; de novo in up to 48% of BRRS cases per the 2024 review — so a negative family history is common and does not argue against the diagnosis. Somatic PTEN loss is separately one of the most frequent events in sporadic cancer (glioblastoma, endometrial, prostate) — mechanistically informative but not part of the BRRS entry.
Population frequency: PTEN loss-of-function variants are extremely rare in gnomAD; the gene is strongly LoF-constrained. Recent unbiased biobank data suggest carriers are far commoner than the clinic-based estimate: an All of Us analysis found 55 P/LP carriers among 414,830 participants (~1 in 7,500), ~26-fold above historical estimates, with 43.5% having a cancer diagnosis (median age at first cancer 48 y). ⚠️ This is a medRxiv preprint (PMID:41480035, Dec 2025) — cite as preliminary, evidence_source: HUMAN_CLINICAL but flag preprint status. GeneReviews gives ~1 in 9,000 (All of Us) to 1 in 13,000 (UK Biobank).
Functional consequence: loss of function / haploinsufficiency is the dominant mechanism. Some missense alleles act as dominant negatives (the PTEN dimer means a catalytically dead monomer can poison the wild-type partner) — mechanistically important and worth a distinct pathophysiology node. Missense variants generally associate with milder phenotypes than truncating variants.

Genotype–phenotype correlations

From Marsh 1999 (BRRS-specific):

Verbatim (PMID:10400993): "Genotype-phenotype analyses within the BRR group suggested a number of correlations, including the association of PTEN mutation and cancer or breast fibroadenoma in any given CS, BRR or BRR/CS overlap family (P = 0.014), and, in particular, truncating mutations were associated with the presence of cancer and breast fibroadenoma in a given family (P = 0.024). Additionally, the presence of lipomas was correlated with the presence of PTEN mutation in BRR patients (P = 0.028)."

From Tan 2012 and GeneReviews (PHTS-wide): promoter variants → breast cancer; nonsense variants → colorectal cancer; frameshift variants overrepresented in thyroid cancer; missense variants overrepresented in ASD. Caveat for curation: these are cohort-level associations from ascertained series and should be curated with the association language, not as deterministic rules.

Verbatim (PMID:22252256): "Promoter mutations were associated with breast cancer, whereas colorectal cancer was associated with nonsense mutations."

Modifier genes

Not formally established. TTN (above) is a candidate contributing/modifying locus in PTEN-wildtype disease. Second somatic hits in PTEN and downstream PI3K-pathway lesions modulate lesion-level behavior but are not germline modifiers.

Epigenetics

Germline KLLN promoter hypermethylation (see §2) — a bona fide germline epigenetic etiology within the PHTS/Cowden-like spectrum, and one of the more elegant examples in human genetics: PTEN and KLLN share a bidirectional promoter, and the methylation silences KILLIN without touching PTEN transcription.
Somatic PTEN promoter methylation in tumors is a common second-hit mechanism.

Chromosomal abnormalities

Whole-gene and multi-exon PTEN deletions account for 3–11% of cases and are missed by sequencing alone — MLPA or CMA is required to complete the workup. Larger 10q23 contiguous-gene deletions spanning PTEN and BMPR1A produce a severe juvenile-polyposis-plus-BRRS phenotype in infancy and are worth curating as a distinct, more severe presentation.

5. Environmental Information

Not applicable as an etiology. No environmental factor, toxin, radiation exposure, occupational exposure, dietary factor, or infectious agent has been implicated in causing BRRS. There is no NCBI Taxon organism to associate.

The only defensible environmental content is downstream and generic: UV exposure as a modifiable contributor to the melanoma component (lifetime risk up to 6%, earliest reported age 3 years), which is why "sun protection" appears in the parent-education recommendations of the 2024 systematic review. Curate that as prevention guidance, not as an etiologic environmental factor.

6. Mechanism / Pathophysiology

The causal chain, upstream → downstream

Node 1 — Germline PTEN haploinsufficiency (MOLECULAR). One PTEN allele is inactivated in every cell from conception. Because PTEN is dose-sensitive, even 50% protein reduction perturbs signaling; tissue-specific second hits (somatic mutation, LOH, promoter methylation) deepen the loss focally and explain the patchy, hamartomatous distribution of lesions.

Node 2 — Loss of PIP₃ 3-phosphatase activity (MOLECULAR). PTEN's canonical function is dephosphorylating the 3-position of the inositol ring of phosphatidylinositol 3,4,5-trisphosphate (PIP₃), converting it back to PIP₂ — it is the direct antagonist of class I PI3K. Established by Maehama & Dixon 1998 (J Biol Chem 273:13375–8, PMID:9593664), who showed PTEN overexpression reduced insulin-induced PtdIns(3,4,5)P₃ in 293 cells and that purified recombinant PTEN dephosphorylates PIP₃ specifically at the 3-position. Marsh 1999 frames it in disease terms: "PTEN maps to 10q23 and encodes a dual specificity phosphatase, a substrate of which is phosphatidylinositol 3,4,5-triphosphate, a phospholipid in the phosphatidylinositol 3-kinase pathway."

Node 3 — Constitutive PI3K–AKT–mTORC1 pathway activation (CELLULAR). PIP₃ accumulates at the plasma membrane → PH-domain recruitment of AKT and PDK1 → AKT phosphorylation (Thr308/Ser473) → inhibition of TSC1/TSC2 → RHEB-GTP → mTORC1 activation → S6K1/4E-BP1 phosphorylation → increased cap-dependent translation, ribosome biogenesis, and cell mass. In parallel AKT phosphorylates and inactivates FOXO transcription factors, GSK3β, and BAD.

Node 4a — Increased cell growth, proliferation, and survival (CELLULAR). Net effect: increased cell size (not just number), increased proliferation, suppressed apoptosis, suppressed autophagy, loss of contact inhibition.

Node 4b — Cell-size / soma-size enlargement (CELLULAR). This is the specific mechanism behind macrocephaly and neuronal hypertrophy, and it's mTORC1-driven — which is why it is pharmacologically addressable.

Node 5 — Tissue-level hamartomatous overgrowth (TISSUE). Disorganized overgrowth of mature mesenchymal and epithelial elements — the definition of a hamartoma. Produces lipomas, GI polyps, PTEN hamartoma of soft tissue, and cerebellar dysplastic gangliocytoma.

Node 6 — Organism-level manifestations (ORGANISM). Macrocephaly, macrosomia, accelerated linear growth, ASD/DD, and lifelong tumor predisposition.

Parallel / non-canonical arms worth separate nodes

Protein-phosphatase and phosphatase-independent functions. PTEN also dephosphorylates protein substrates (e.g. FAK) and has scaffolding functions. The BRRS TTN work lands here: the p.Cys5096Arg variant produced "increased growth and lack of contact inhibition phenotype associated with increased levels of or phosphorylation of focal adhesion kinase (FAK)" — a PI3K-independent route to the same overgrowth output. Good candidate for an ALTERNATIVE or EMERGING mechanistic_hypotheses group.
Nuclear PTEN. PTEN shuttles to the nucleus, where it maintains chromosomal integrity and promotes RAD51-dependent DNA repair, independent of lipid phosphatase activity. Variants disrupting nuclear localization signals segregate with the ASD-predominant phenotype rather than the cancer phenotype (the basis of the Pten^m3m4^ mouse; §15). This is arguably the single most interesting mechanistic split in PHTS: where PTEN is, not just how much there is, determines whether you get autism or cancer. Curate as competing/complementary hypothesis groups.
Neurodevelopmental arm. PTEN loss in neurons → mTORC1 → increased soma size, exuberant dendritic arborization, aberrant synaptic connectivity, and (per the m3m4 mouse work) microglial activation with excessive synaptic pruning. Downstream: macrocephaly, white-matter abnormality, ASD, epilepsy.
Vascular arm. PI3K–AKT is a core endothelial/angiogenic pathway; PTEN loss produces the fast-flow vascular anomalies and intramuscular AVM-like lesions. Tan et al. 2007 (J Med Genet 44:594–602) found vascular anomalies in 14/26 (54%) of PTEN carriers, 57% multiple, 85% intramuscular on cross-sectional imaging, and 86% fast-flow.

Cellular processes, cell types, and compartments

Element	Candidate term (⚠️ verify all)
PIP₃ 3-phosphatase activity	`GO:0016314` phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase activity
PI3K signaling	`GO:0014065` phosphatidylinositol 3-kinase signaling
PI3K/AKT signal transduction	`GO:0043491` phosphatidylinositol 3-kinase/protein kinase B signal transduction
TOR signaling	`GO:0031929` TOR signaling; `GO:0038202` TORC1 signaling
Proliferation	`GO:0008284` positive regulation of cell population proliferation
Apoptosis suppression	`GO:0043066` negative regulation of apoptotic process
Autophagy	`GO:0006914` autophagy
Neuron projection development	`GO:0010975` regulation of neuron projection development
Organism growth	`GO:0035264` multicellular organism growth
Angiogenesis	`GO:0001525` angiogenesis
DNA repair (nuclear PTEN)	`GO:0006281` DNA repair
Adipocyte	`CL:0000136`
Fibroblast	`CL:0000057`
Endothelial cell	`CL:0000115`
Neuron	`CL:0000540`
Microglial cell	`CL:0000129`
Purkinje cell / cerebellar granule cell	`CL:0000121` / `CL:0000120`
Thyroid follicular cell	`CL:0002258`
Intestinal epithelial cell	`CL:0002563`
Keratinocyte	`CL:0000312`
Cytosol / plasma membrane / nucleus	`GO:0005829` / `GO:0005886` / `GO:0005634`
PIP₃	`CHEBI:16618` (1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate) ⚠️

Metabolic, immune, and tissue-damage dimensions

Metabolic: AKT–mTORC1 activation shifts cells toward anabolic metabolism (glucose uptake, glycolysis, lipogenesis, protein synthesis). PTEN-carrier humans and Pten⁺/⁻ mice show enhanced insulin sensitivity — a notable, counterintuitive metabolic phenotype of the syndrome.
Immune: no autoimmunity is intrinsic to the mechanism, except that Hashimoto thyroiditis is overrepresented (Gorlin 1992: 7 cases) — mechanism unresolved, a legitimate knowledge gap. Microglial (innate CNS immune) activation is a key finding in the m3m4 mouse.
Tissue damage: BRRS is a disease of disorganized overgrowth, not of degeneration. There is no oxidative-stress/ischemia/fibrosis/necrosis core mechanism. The exceptions are secondary: mass effect and compression from lipomas and soft-tissue hamartomas, GI bleeding and intussusception from polyps, and high-output/steal physiology from fast-flow vascular lesions.

Molecular profiling

BRRS-specific omics are essentially absent. What exists is from PHTS/model systems: transcriptome and (phospho)proteome characterization of the cytoplasmic-predominant Pten^m3m4^ brain (npj Genom Med 2021), alternative-splicing landscape of the same model (Transl Psychiatry 2020), and a neural transcriptome study linking constitutional Pten dysfunction to idiopathic human ASD (PMID:25754085). Cortical transcriptomics in m3m4 showed upregulation of myeloid cell activation, myeloid cell migration, and phagocytosis pathways. No BRRS metabolomics, lipidomics, spatial transcriptomics, or single-cell atlas exists that I could find. Curate as gaps.

7. Anatomical Structures Affected

Organ level

Primary (directly affected by the germline lesion): - Brain (UBERON:0000955) — megalencephaly, enlarged perivascular spaces, white-matter abnormality, cortical malformations; cerebellum (UBERON:0002037) for dysplastic gangliocytoma / Lhermitte–Duclos disease - Skin and subcutis (UBERON:0002097) — lipomas, hemangiomas, café-au-lait macules, acral keratoses - Penis / external genitalia (UBERON:0000989) — pigmented macules of the glans, the BRRS-defining sign - Gastrointestinal tract — colon (UBERON:0001155), also ileum, duodenum, stomach, esophagus. Heald 2010 documented polyps throughout: "There were one to innumerable polyps in the colorectum, ileum, duodenum, stomach, and/or esophagus, with 24 subjects having both upper and lower GI polyps." - Skeletal muscle (UBERON:0001134) — intramuscular PTEN hamartoma of soft tissue; proximal myopathy - Adipose tissue (UBERON:0001013) — lipomatous overgrowth - Thyroid gland (UBERON:0002046) — goiter, nodules, Hashimoto thyroiditis, differentiated carcinoma - Blood vessels (UBERON:0001981) — fast-flow malformations, AVMs

Secondary / later-emerging (the PHTS cancer spectrum): breast (UBERON:0000310), endometrium (UBERON:0001295), kidney (UBERON:0002113), skin (melanoma), colon (carcinoma).

Body systems: nervous, integumentary, digestive, endocrine, musculoskeletal, cardiovascular (vascular malformations), reproductive.

Tissue, cell, and subcellular level

Fundamentally a disease of mesenchymal + epithelial tissues in combination. Kurek's definition of PTEN hamartoma of soft tissue is the clearest tissue-level statement available:

Verbatim (PMID:22446940, Kurek et al. 2012, Am J Surg Pathol 36:671–87): "We designate this disorganized overgrowth of essentially mesenchymal elements as PTEN hamartoma of soft tissue."

Its components, per the same abstract: "(1) a variable admixture of mature adipocytic and dense and/or myxoid fibrous tissues (50% to 90% of surface area); (2) a vascular component (10% to 50% of surface area)... (3) lymphoid follicles (50%); (4) foci of bone (20%); and (5) hypertrophic nerves with 'onion bulb' proliferation of periaxonal spindled cells (9%)."

Subcellular: plasma membrane (PIP₃ pool, PTEN's site of action), cytosol, and nucleus — with the nuclear/cytoplasmic partition being mechanistically load-bearing (§6).

Lateralization: lesions are multifocal and asymmetric, not systematically lateralized. Kurek: lesions "most often located in the lower extremity," 20% multifocal, occasionally involving contiguous muscles. Macrocephaly is symmetric.

8. Temporal Development

Onset: congenital. Macrocephaly is present at birth or emerges in the first two years — "nearly all children by age 2" per the German pediatric guideline. Neonatal macrosomia is common. Onset pattern is insidious/chronic, not acute.
Lesion timing: Kurek — soft-tissue hamartomas "manifested by 15 years of age, normally with pain and swelling." Genital lentiginosis typically appears around/after puberty, which is why it is a poor sign in toddlers. GI polyps present in ~25–30% of pediatric cases (GeneReviews) but 93% of endoscoped adult carriers.
Stages: there is no formal staging system. A useful three-phase framing for the KB: (i) congenital/infantile overgrowth phase (macrocephaly, macrosomia, hypotonia, early lipomas/vascular lesions); (ii) childhood neurodevelopmental phase (DD, ASD, epilepsy) with emerging polyps and thyroid nodules; (iii) adult neoplastic phase (breast, thyroid, endometrial, renal, colorectal cancer, melanoma).
Progression rate: slow and variable. The overgrowth features are largely static; the neoplastic risk is cumulative and age-dependent.
Course: chronic, lifelong, progressive with respect to tumor risk. Not relapsing-remitting, not episodic. No spontaneous remission of the syndrome. Individual lesions may regress with mTOR-inhibitor therapy (see §12).
Critical periods: early childhood for neurodevelopmental intervention; age 10–12 for the start of thyroid surveillance (thyroid cancer reported as young as age 4–7); age ~30 for breast surveillance; age 35 for colonoscopy. Genetic diagnosis at any age is the intervention that unlocks all the rest.

9. Inheritance and Population

Epidemiology

Prevalence: unknown/not documented. Orphanet does not assign a prevalence class to ORPHA:109. A widely circulated figure of ~1 per 200,000 appears in secondary sources without a strong primary citation — do not curate it as a sourced prevalence; use prevalence_class: NOT_YET_DOCUMENTED or ULTRA_RARE with measure_type: UNKNOWN.
The molecularly-defined denominator is far larger than the clinically-defined one. GeneReviews cites ~1 in 9,000 (All of Us) to 1 in 13,000 (UK Biobank) for germline PTEN P/LP carriers; the 2025 All of Us preprint reports 1 in 7,500 (55/414,830), ~26-fold above historical estimates. These are PHTS-wide, not BRRS, and describe carriers, not diagnosed patients. If you curate them, do it on a PHTS/Cowden entry or with an explicit note; measure_type: CARRIER_FREQUENCY is arguably the honest classification.
Incidence: no reliable estimate exists.

Inheritance

Pattern: autosomal dominant (HP:0000006). PTEN is MONDO:0007924's canonical causal gene.
De novo rate: up to 48% of BRRS cases (2024 systematic review) — high, consistent with a severe pediatric-onset presentation.
Penetrance: essentially complete for some feature (macrocephaly is near-obligate) but strongly age-related and organ-specific for the tumor phenotypes. Unbiased biobank data suggest penetrance is considerably lower than clinic-ascertained estimates — a live and important controversy. Curate the clinic-based lifetime risks with an explicit ascertainment caveat.
Expressivity: markedly variable, including within families sharing an identical variant. This is the central clinical-genetics message of Lachlan 2007.
Anticipation: not a feature (no repeat expansion mechanism).
Germline mosaicism: reported in PTEN and relevant to recurrence counseling in apparently-de-novo families, but rare and not well quantified. Somatic mosaicism is a recognized cause of segmental/atypical presentations and of negative blood-based testing in a clinically convincing patient — this matters for diagnostics.
Founder effects / consanguinity / carrier frequency: none — irrelevant for a dominant de-novo-prone condition. No population-specific founder variant is described.

Population demographics

Ethnic/geographic: no population is over-represented; cases are reported worldwide with no endemic distribution.
Sex ratio: published pediatric BRRS cases run ~72% male (60/83), but this is very likely ascertainment bias from the male-specific genital-lentiginosis sign. The underlying autosomal-dominant inheritance predicts 1:1. Curate the 1:1 expectation and note the reporting skew.
Age distribution: BRRS as a label is applied predominantly in childhood (median age 8 in the review); the same genotype in adults is usually labeled Cowden syndrome.

10. Diagnostics

Clinical evaluation

Occipitofrontal circumference — the highest-yield single measurement; macrocephaly is often >5 SD above mean.
Genital examination in males for pigmented macules of the glans penis (75% of male cases) — pathognomonic-adjacent and free.
Dermatologic exam for lipomas, hemangiomas, café-au-lait macules, trichilemmomas/acral keratoses (the latter more Cowden-flavored).
Developmental/neurobehavioral assessment, including formal ASD evaluation.

Imaging and functional testing

Brain MRI — megalencephaly, enlarged Virchow–Robin spaces, white-matter changes; the cerebellar "tiger-striped" appearance of Lhermitte–Duclos disease. A dedicated BRRS MRI series exists (Bhargava et al., AJNR 35:402, PMID:23907246).
MRI for soft-tissue/vascular lesions — Kurek: "an infiltrative soft tissue lesion involving the muscle, fascia, and subcutis with frequently enlarged, serpiginous vessels, small arteriovenous fistulae with disproportionately dilated draining veins, and a prominent adipocytic component." Distinguishing PHOST from a true AVM matters because it changes management.
Thyroid ultrasound — the pediatric surveillance workhorse.
Esophagogastroduodenoscopy + colonoscopy — mixed polyposis, upper and lower.
EEG where seizures are suspected (epilepsy 6–17%).

Biopsy and pathology

GI polyps in PHTS are a mixed polyposis — this is a frequent diagnostic pitfall, because people expect pure hamartomas. Heald 2010: "Of the 64, half had hyperplastic polyps" and the conclusion — "PTEN-associated CS should be considered a mixed polyp syndrome, with hyperplastic polyps most prevalent, with a risk of early onset colorectal cancer." Hamartomatous, ganglioneuromatous, juvenile, inflammatory, hyperplastic, and adenomatous polyps all occur.
PTEN hamartoma of soft tissue has the distinctive histology quoted in §7, and per Kurek "its identification should prompt a thorough investigation for PHTS" — i.e. the pathologist can make the syndromic diagnosis.
Immunohistochemistry for PTEN loss in lesional tissue is supportive.

Genetic testing (the definitive test)

Since PHTS has no clinical diagnostic criteria, molecular confirmation is the diagnosis. Recommended approach:

Single-gene PTEN testing — full coding sequence plus the promoter region (~10% of variants are promoter). Design around the PTENP1 pseudogene.
Deletion/duplication analysis (MLPA) — mandatory adjunct; 3–11% of variants.
Multigene hamartomatous-polyposis / hereditary-cancer panel where the phenotype is ambiguous (differentiating from STK11, SMAD4, BMPR1A, AKT1, PIK3CA).
Chromosomal microarray — detects the 10q23 contiguous-gene deletions involving PTEN + BMPR1A, and is often the first test in a child presenting with DD/macrocephaly.
WES/WGS — reasonable in the undiagnosed-DD pathway; also the route by which TTN was implicated in PTEN-wildtype BRRS.
Not applicable: karyotype (too coarse), FISH (superseded by MLPA/CMA), mtDNA testing, repeat-expansion testing.
If PTEN-negative but clinically classic: consider KLLN germline methylation testing, SDHB/SDHD, and mosaicism (test lesional tissue, not just blood).

Omics-based diagnostics

Not established for BRRS. No validated RNA-seq, proteomic, metabolomic, epigenomic (other than the KLLN methylation assay), or liquid-biopsy diagnostic exists. A methylated KILLIN/PTEN plasma assay has been explored for thyroid/breast cancer detection but is not a clinical diagnostic for BRRS.

Clinical criteria and differential diagnosis

The International Cowden Consortium operational criteria (and the Cleveland Clinic PTEN risk calculator, Tan et al. 2011) select who to test; they do not diagnose PHTS. Historical BRRS clinical criteria required macrocephaly plus two of: hamartomatous polyps, lipomas, genital lentiginosis.

Differential diagnosis:

Condition	Distinguishing features
Cowden syndrome (`MONDO:0016063`)	Same gene, same disease — adult mucocutaneous/cancer presentation. Distinguish by age and presentation, not biology
Peutz–Jeghers (STK11)	Perioral/buccal mucocutaneous pigmentation (not genital-only); polyps show characteristic smooth-muscle arborization
Juvenile polyposis (SMAD4, BMPR1A)	Juvenile polyps; HHT overlap if SMAD4; no macrocephaly/lipomas
Proteus syndrome (AKT1 mosaic)	Progressive, asymmetric, distorting overgrowth; cerebriform connective tissue nevus
PIK3CA-related overgrowth (PROS/CLOVES)	Mosaic, segmental; same pathway, different node
Neurofibromatosis type 1	Café-au-lait + neurofibromas + Lisch nodules; macrocephaly overlaps — a genuine clinical trap
Simpson–Golabi–Behmel, Sotos, Weaver	Other overgrowth syndromes; distinguish by facies, skeletal findings, and gene
Isolated benign macrocephaly	The commonest real-world alternative in a well child

Screening of asymptomatic individuals

Cascade testing of at-risk first-degree relatives is the key intervention, and given up-to-48% de novo rates, parental testing is essential for recurrence counseling. There is no newborn screening and no population carrier screening for PTEN. Prenatal/preimplantation testing is technically available once a familial variant is known.

11. Outcome / Prognosis

Life expectancy: not formally quantified for BRRS. With surveillance, life expectancy is thought to approach normal; the drivers of mortality are the malignancies, not the overgrowth. Do not curate a survival number — I found none that is BRRS-specific and defensible.
Cancer risk (PHTS-wide, from clinic-ascertained cohorts):

Verbatim (PMID:22252256, Tan et al. 2012, Clin Cancer Res 18:400–7): "Elevated SIRs were found for carcinomas of the breast [25.4, 95% confidence interval (CI), 19.8-32.0], thyroid (51.1, 38.1-67.1), endometrium (42.9, 28.1-62.8), colorectum (10.3, 5.6-17.4), kidney (30.6, 17.8-49.4), and melanoma (8.5, 4.1-15.6). Estimated lifetime risks were, respectively, 85.2% (95% CI, 71.4%-99.1%), 35.2% (19.7%-50.7%), 28.2% (17.1%-39.3%), 9.0% (3.8%-14.1%), 33.6% (10.4%-56.9%), and 6% (1.6%-9.4%)."

GeneReviews gives comparable ranges (breast 85–91%, thyroid 33–35%, endometrial 28–48%, renal 30–35%, colorectal 17%, melanoma up to 6%) plus soft-tissue sarcoma SIR 10.7 (95% CI 3.9–23.7), median age 46. Later European work (Hendricks et al., Clin Genet 2021; JNCI 2023) gives lower estimates — breast 54–76%, endometrial 6–22%, thyroid 9–21% — reflecting less-biased ascertainment. Curate the range with both anchors and an explicit ascertainment caveat; a single point estimate here would be misleading. - Colorectal cancer, early onset: Heald 2010 — "Nine (13%) subjects had colorectal cancer, all younger than the age of 50. The adjusted standardized incidence ratio was 224.1 (95% confidence interval, 109.3-411.3; P < .0001)." - Morbidity and disability: dominated by neurodevelopmental outcome (intellectual disability, ASD, epilepsy) and by pain/functional loss from soft-tissue and vascular lesions — Kurek reported resected specimens 1.2–25 cm, with amputation required in one patient. GI morbidity from bleeding, anemia, intussusception, and repeated polypectomy. - Complications: early-onset colorectal carcinoma; differentiated thyroid carcinoma (reported as young as 4–7 years); Lhermitte–Duclos disease with mass effect/hydrocephalus; hemorrhage and high-output physiology from fast-flow vascular lesions; recurrent surgical morbidity. - Recovery potential: the germline lesion is not reversible. Individual lesions respond to surgery and, partially, to mTOR inhibition. Developmental gains occur with early intervention. Surveillance is the single largest determinant of outcome. - Prognostic factors: variant type (truncating → higher cancer risk per Marsh 1999; promoter → breast; nonsense → colorectal); age; adherence to surveillance; presence and extent of vascular/soft-tissue hamartomas; severity of neurodevelopmental impairment. No validated prognostic biomarker exists.

12. Treatment

There is no disease-modifying or curative therapy. Management is surveillance + symptom-directed intervention + genetic counseling. The 2024 systematic review is blunt about it: "As targeted treatment is still lacking, symptom relief and long-term surveillance remain the main management strategies."

Surgical / interventional (the mainstay)

Per the 2024 review, surgery was the treatment of choice, described in 19 of 33 articles: - Lipoma excision — for pain, disfigurement, compression. treatment_term: NCIT:C15329 Surgical Procedure ⚠️ - Endoscopic polypectomy — for bleeding, obstruction, dysplasia. ⚠️ verify NCIT term for polypectomy - Thyroidectomy — 4 pediatric cases in the review; prophylactic thyroidectomy is debated in PHTS and is not standard, unlike in MEN2. NCIT:C15289-adjacent ⚠️ - Vascular anomaly management — embolization, sclerotherapy, or resection. Because PHOST is not a true AVM, embolization outcomes are less predictable than for classic AVM. - Resection of Lhermitte–Duclos lesions where symptomatic.

Pharmacotherapy — mTOR inhibitors

Mechanistically the obvious move: PTEN loss → mTORC1 hyperactivation → inhibit mTOR. Results so far are mixed, and this nuance must survive into the KB.

Sirolimus (rapamycin) — CHEBI:9168 ⚠️; therapeutic_modality: SMALL_MOLECULE; treatment_term: NCIT:C15986 Pharmacotherapy. - Komiya et al. 2019 (The Oncologist 24:1510, doi:10.1634/theoncologist.2019-0514): first human interventional study in Cowden/PTEN patients; 18 patients, 16 families; 56-day course. Well tolerated; regression of skin and GI lesions by dermoscopy/endoscopy, improved cerebellar function score at 1 month, and suppressed mTOR signaling in surrogate tissue. Pilot-scale — no efficacy claim. - Open-label sirolimus 2 mg daily × 1 year for colon polyposis in PHTS (NCT04094675, Nov 2018 – Jun 2024) — published in Clin Transl Gastroenterol. - Case-level use in pediatric BRRS for AVM: the 2024 review notes one pediatric case, with AVM size reduction and symptom relief within 6 months. - Sirolimus for PHTS vascular anomalies: well tolerated, patient-reported QoL improvement (n=6).

Everolimus — CHEBI:68478 ⚠️. The one properly controlled trial is negative for its primary endpoint: - Srivastava et al. 2022 (Hum Mol Genet 31:3393–404, PMID:35594551): 6-month phase II, randomized, double-blind, placebo-controlled, everolimus 4.5 mg/m², ages 5–45, n=46 (24 everolimus / 22 placebo). Primary neurocognitive composite: no group difference (Cohen's d = −0.10, p = 0.518); GI adverse events significantly more common on everolimus (p < 0.001). - Curate this honestly. An entry that lists "mTOR inhibitors" as treatment for PHTS neurocognitive symptoms without the negative RCT would be misleading. It is a good candidate for an evidence item with supports: REFUTE or PARTIAL.

Targeted / advanced therapeutics

None approved. No gene therapy, gene editing, cell therapy, RNA-based therapy, or immunotherapy exists for BRRS. PI3K/AKT inhibitors are conceptually attractive and used in PIK3CA-related overgrowth (alpelisib) but are not established in PHTS. Do not extrapolate.

Pharmacogenomics

No PHTS-specific pharmacogenomic guidance. Standard CPIC guidance applies to any drugs used for the cancers that arise.

Supportive, rehabilitative, and counseling

Early intervention, physical therapy (NCIT:C15302), occupational therapy, speech therapy — for hypotonia, motor delay, and language delay. therapeutic_modality: BEHAVIORAL.
ASD-specific behavioral intervention and educational support.
Antiseizure medication where epilepsy is present.
Genetic counseling (NCIT:C15240) — recurrence risk 50% per offspring; parental testing given the high de novo rate; discussion of prenatal/PGT options; cascade testing of relatives.
Multidisciplinary care is the explicit recommendation of the 2024 review: "periodic multidisciplinary care that should be individualized to fit every patient's needs."

Treatment strategy

Individualized, lesion-directed, and surveillance-anchored. No treatment algorithm or decision tree is standardized. No combination-therapy regimen exists (so regimen_term is not applicable here).

13. Prevention

Primary prevention: not possible. The disorder is germline and congenital. No vaccination, no modifiable exposure, no risk-factor modification prevents BRRS. The only true primary prevention available is reproductive — preimplantation genetic testing or prenatal diagnosis once a familial variant is identified, which is a family-planning decision requiring genetic counseling, not a public-health intervention.
Secondary prevention: this is where essentially all the benefit lives. Surveillance recommendations (synthesizing GeneReviews, the 2020 European guideline (Tischkowitz et al., Eur J Hum Genet 28:1387–93, PMC7608293), the 2025 pediatric update (Clin Cancer Res 31(2):234), and the German pediatric guideline):

Target	Recommendation
Thyroid	Annual clinical exam + thyroid ultrasound from age 12 (some centers from age 10; every 2–3 y under age 7 if no nodules). Cancer reported as young as 4–7 y
Breast	Monthly self-exam from 18; clinical exam q6–12 mo from 25; annual mammogram + breast MRI from 30
Endometrium	Assessment q1–2 y from age 30–35; educate about abnormal bleeding
Colon	Colonoscopy from age 35, q5 y (sooner/more often if polyp burden is high — and note the early-onset CRC signal)
Kidney	Renal imaging q1–2 y from age 40
Skin	Annual comprehensive dermatologic exam; sun protection education
Brain	MRI as clinically indicated; q3–12 mo if Lhermitte–Duclos present
Pediatric extras	Annual dermatologic exam; annual abdominal ultrasound; testicular ultrasound from ~age 10; ongoing psychomotor/neurodevelopmental assessment (German guideline)

Yield data exist and are modest but real: thyroid ultrasound surveillance detected DTC in 2/43 (4.65%) of PHTS patients before age 18 in one expertise centre.

Tertiary prevention: management of polyp burden to prevent CRC; management of vascular lesions to prevent hemorrhage; neurodevelopmental support to maximize function.
Risk stratification: the Cleveland Clinic PTEN score (Tan et al. 2011) identifies who should be tested; variant type provides coarse organ-risk stratification.
Immunization, public-health, and environmental interventions: not applicable.

14. Other Species / Natural Disease

Naturally occurring BRRS in other species: none reported. I found no OMIA entry for a spontaneous PTEN hamartoma syndrome in companion animals or wildlife, and no veterinary breed predisposition. There is no VBO breed to assign.
Zoonotic potential / cross-species transmission: not applicable — it's a germline genetic disorder.
PTEN orthologs are deeply conserved, which is what makes the modeling work: mouse Pten (NCBI Gene 19211, NCBITaxon:10090), rat Pten, zebrafish has two paralogs ptena/ptenb (NCBITaxon:7955), Drosophila Pten (NCBITaxon:7227), C. elegans daf-18 (NCBITaxon:6239). The daf-18 connection is a nice piece of comparative biology: the insulin/IGF-1–PI3K–DAF-16/FOXO axis controlling dauer formation and lifespan in worms is the same pathway that, dysregulated in humans, produces hamartomas. Conserved mechanism, wildly different phenotypic readout.
Comparative pathology: somatic PTEN loss is a recurrent event in spontaneous canine and feline tumors (canine osteosarcoma, melanoma, glioma), making dogs an incidental comparative-oncology resource — but that is somatic tumor biology, not the germline syndrome.

15. Model Organisms

Mouse (`NCBITaxon:10090`) — the workhorse

Model	Design	Phenotype	Citation
Pten⁺/⁻ (constitutive het)	Germline heterozygous null — the direct genocopy of human PHTS	Multi-organ hyperplasia and neoplasia (thyroid, endometrium, GI, lymphoid); increased insulin sensitivity. Homozygous null is embryonic lethal, establishing the dominant/haploinsufficient mechanism	Di Cristofano et al. 1998 Nat Genet; Podsypanina et al. 1999 PNAS
Nse-Cre / GFAP-Cre conditional brain Pten KO	Neuron- or glia-restricted deletion	"Deletion of Pten in mouse brain causes seizures, ataxia and defects in soma size resembling Lhermitte-Duclos disease" — a near-exact recapitulation of the human cerebellar phenotype	Backman et al. 2001 Nat Genet 29:396–403, PMID:11726927; Kwon et al. 2001, PMID:11726928
Nse-Cre Pten KO (cortex/hippocampus)	Deletion in limited differentiated neuronal populations	Abnormal social interaction, exaggerated response to sensory stimuli, macrocephaly, increased dendritic arborization — the founding PTEN autism model	Kwon et al. 2006 Neuron 50:377–88, PMID:16675393
Pten^m3m4^ (knock-in)	Disrupts 2 of 4 putative nuclear localization signals → cytoplasm-predominant PTEN with nuclear depletion; normal total protein	Macrocephaly from megencephaly, neuronal soma hypertrophy, gliosis, autism-like behavior; microglial activation with enhanced synaptic pruning; cortical upregulation of myeloid activation/migration/phagocytosis pathways	Sarn et al. 2020 Mol Psychiatry, doi:10.1038/s41380-020-0681-0
Nuclear-predominant Pten model	Complementary partition mutant	Impaired social and perseverative behavior, microglial activation, increased oxytocinergic activity	Mol Autism 2021, doi:10.1186/s13229-021-00448-4
Pten^m3m4^ multi-omics	—	Transcriptome/(phospho)proteome and alternative-splicing characterization of the autism-like brain	npj Genom Med 2021; Transl Psychiatry 2020

Why the m3m4 model matters for this entry: it demonstrates that subcellular mislocalization of PTEN — with normal expression level — is sufficient to produce the neurodevelopmental arm of PHTS. That's a genuine mechanistic dissociation between the ASD phenotype and the cancer phenotype, and it maps directly onto the human genotype–phenotype observation that missense variants are overrepresented in ASD. It is the strongest argument for curating the neurodevelopmental and neoplastic arms as separate pathophysiology branches.

Other systems

Zebrafish (NCBITaxon:7955): ptena/ptenb double mutants are embryonic lethal with hyperbranched vasculature; single mutants are viable and tumor-prone — a useful vascular/angiogenesis model given the BRRS vascular phenotype.
Drosophila (NCBITaxon:7227): Pten mutants show classic cell-size and organ-size overgrowth; the system where the PI3K–TOR growth-control logic was largely worked out.
C. elegans (NCBITaxon:6239): daf-18, the insulin/IGF-1–DAF-16 axis.
Cell and in vitro: patient-derived fibroblasts and LCLs; patient iPSC-derived neurons and cortical organoids show increased soma size, altered proliferation, and synaptic phenotypes, and are the most translationally relevant human system currently available; CRISPR-edited isogenic lines (the route used for the TTN p.Cys5096Arg functional work). MorPhiC has not, to my knowledge, targeted PTEN — worth checking morphic.bio before asserting either way.

Recapitulation and limitations

Recapitulates well: macrocephaly/megalencephaly, neuronal soma enlargement, Lhermitte–Duclos-like cerebellar pathology, ASD-like social deficits, seizures, multi-organ tumor predisposition, enhanced insulin sensitivity.

Does NOT recapitulate: genital lentiginosis (no analog), the human GI mixed-polyp spectrum in its full form, the specific human cancer-organ distribution (mouse tumor spectrum skews differently — thyroid/endometrial/lymphoid rather than breast-dominant), PTEN hamartoma of soft tissue as a defined entity, and the human developmental/cognitive profile in any fine-grained way. Mouse background strain strongly modifies tumor spectrum. Any curated evidence item drawn from these should carry evidence_source: MODEL_ORGANISM and must not be the sole support for a human phenotype — and given the m3m4 findings are load-bearing for the ASD mechanism but unconfirmed in human tissue, a discussions entry with kind: HUMAN_MODEL_MISMATCH is warranted rather than a plain KNOWLEDGE_GAP.

Model databases

MGI (mouse), Alliance of Genome Resources, IMPC/KOMP, IMSR/JAX for strain availability, ZFIN, FlyBase, WormBase, Cellosaurus for lines.

Appendix A — Suggested `mechanistic_hypotheses` and `discussions`

Things I'd flag as genuinely unsettled, worth curating as structured discussion rather than prose:

nuclear_vs_cytoplasmic_pten (competing hypothesis groups). Whether the ASD/neurodevelopmental arm is driven by loss of nuclear PTEN function (DNA repair, m3m4 evidence) versus by cytoplasmic PIP₃/mTORC1 excess. status: EMERGING. Attaches to the neurodevelopmental branch.
ttn_as_brrs_gene — KNOWLEDGE_GAP / EMERGING. TTN enrichment in PTEN-wildtype BRRS is statistically modest (OR 2.2–2.7, p ≈ 0.02–0.05, single lab, no replication cohort published that I found). Do not curate TTN as causal.
phts_penetrance_ascertainment — KNOWLEDGE_GAP. Clinic-ascertained lifetime cancer risks (breast 85%) versus biobank-derived risks (54–76%, and much lower overall penetrance in All of Us/UK Biobank) differ enough to change clinical advice. Unresolved.
mtor_inhibition_efficacy — KNOWLEDGE_GAP. Sirolimus pilots are positive on biomarkers and lesions; the only randomized everolimus trial missed its neurocognitive primary endpoint. Whether mTOR inhibition helps any PHTS outcome durably is open.
hashimoto_thyroiditis_mechanism — KNOWLEDGE_GAP. Autoimmune thyroiditis is overrepresented since Gorlin 1992; no mechanism connects PTEN loss to thyroid autoimmunity.
brrs_cowden_entity_boundary. Worth an explicit note: this KB models BRRS and Cowden as separate entries while the literature treats them as one disease. Consider a Grouping over the PHTS entries with grouping_basis: [SHARED_MECHANISM, CLINICAL_CONVENTION] and a grouping_rationale that records exactly this lump/split tension — a NECESSARY HAS_GENE criterion on PTEN would make the boundary auditable.

Appendix B — Suggested `conforms_to` module targets

Check these against kb/modules/ before asserting: - The PI3K–AKT–mTOR overgrowth logic here has no dedicated module yet — BRRS/PHTS would be a strong flagship if one is created (candidate: pi3k_akt_mtor_overgrowth). - genome_instability_mutation — the nuclear-PTEN/RAD51 arm plausibly conforms. - sustaining_proliferative_signaling — constitutive PI3K–AKT mitogenic signaling is exactly this hallmark node. - evading_growth_suppressors — PTEN is a canonical tumor suppressor; the two-hit/haploinsufficiency logic fits. - tumor_angiogenesis — for the vascular malformation arm, though the fit is imperfect (these are malformations, not tumor neovasculature).

References (with PMIDs)

Verbatim abstract text retrieved and usable as evidence snippets (still run just fetch-reference + just validate-references):

PMID:10400993 — Marsh DJ, Kum JB, Lunetta KL, et al. PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome. Hum Mol Genet. 1999;8(8):1461-72. doi:10.1093/hmg/8.8.1461
PMID:9467011 — Marsh DJ, Coulon V, Lunetta KL, et al. Mutation spectrum and genotype-phenotype analyses in Cowden disease and Bannayan-Zonana syndrome. Hum Mol Genet. 1998;7(3):507-15. doi:10.1093/hmg/7.3.507
PMID:22252256 — Tan MH, Mester JL, Ngeow J, Rybicki LA, Orloff MS, Eng C. Lifetime cancer risks in individuals with germline PTEN mutations. Clin Cancer Res. 2012;18(2):400-7.
PMID:20600018 — Heald B, Mester J, Rybicki L, Orloff MS, Burke CA, Eng C. Frequent gastrointestinal polyps and colorectal adenocarcinomas in a prospective series of PTEN mutation carriers. Gastroenterology. 2010;139(6):1927-33.
PMID:22446940 — Kurek KC, Howard E, Tennant LB, et al. PTEN hamartoma of soft tissue: a distinctive lesion in PTEN syndromes. Am J Surg Pathol. 2012;36(5):671-87.
PMID:29263846 — Yehia L, Ni Y, Eng C. Germline TTN variants are enriched in PTEN-wildtype Bannayan-Riley-Ruvalcaba syndrome. npj Genom Med. 2017;2:37. doi:10.1038/s41525-017-0039-y
PMID:31609537 — Macken WL, Tischkowitz M, Lachlan KL. PTEN hamartoma tumor syndrome in childhood: A review of the clinical literature. Am J Med Genet C. 2019.
PMID:39256443 — Kapačinskaitė M, Stratica N, Adomaitienė I, Rascon J, Vaišnytė B. A systematic review of Bannayan-Riley-Ruvalcaba syndrome. Sci Rep. 2024;14. doi:10.1038/s41598-024-71991-2

Cited but abstract not independently retrieved verbatim — verify before quoting:

PMID:9241266 — Marsh DJ, et al. Germline mutations in PTEN are present in Bannayan-Zonana syndrome. Nat Genet. 1997;16(4):333-4. ⚠️ Letter — no abstract exists. Cannot supply a snippet.
PMID:11332402 — Parisi MA, et al. The spectrum and evolution of phenotypic findings in PTEN mutation positive cases of Bannayan-Riley-Ruvalcaba syndrome. J Med Genet. 2001;38(1):52-8. ⚠️ No abstractText in Europe PMC; use PMC1734718 full text.
PMID:1336932 — Gorlin RJ, et al. Bannayan-Riley-Ruvalcaba syndrome. Am J Med Genet. 1992;44(3):307-14.
PMID:9593664 — Maehama T, Dixon JE. The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate. J Biol Chem. 1998;273(22):13375-8.
PMID:12938083 — Eng C. PTEN: one gene, many syndromes. Hum Mutat. 2003.
PMID:11726927 / PMID:11726928 — Backman SA et al.; Kwon CH et al. Nat Genet. 2001.
PMID:16675393 — Kwon CH, Luikart BW, Powell CM, et al. Pten regulates neuronal arborization and social interaction in mice. Neuron. 2006;50(3):377-88.
PMID:18678321 — Ni Y, Zbuk KM, Sadler T, et al. Germline mutations and variants in the succinate dehydrogenase genes in Cowden and Cowden-like syndromes. Am J Hum Genet. 2008;83(2):261-8.
PMID:21177507 — Bennett KL, Mester J, Eng C. Germline epigenetic regulation of KILLIN in Cowden and Cowden-like syndrome. JAMA. 2010;304(24):2724-31.
PMID:25288137 — Frazier TW, et al. Molecular and phenotypic abnormalities in individuals with germline heterozygous PTEN mutations and autism. Mol Psychiatry. 2015.
PMID:25754085 — Neural transcriptome of constitutional Pten dysfunction in mice and its relevance to human idiopathic ASD.
PMID:23907246 — Bhargava R, et al. Bannayan-Riley-Ruvalcaba syndrome: MRI neuroimaging features in a series of 7 patients. AJNR. 2014;35(2):402.
PMID:35594551 — Srivastava S, et al. A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome. Hum Mol Genet. 2022;31(20):3393-404.
PMID:39250745 — Dhawan A, Baitamouni S, Liu D, Eng C. Clinical Neurologic Features and Evaluation of PTEN Hamartoma Tumor Syndrome: A Systematic Review. Neurology. 2024;103(7):e209844.
PMID:31433955 — Yehia L, Keel E, Eng C. The Clinical Spectrum of PTEN Mutations. Annu Rev Med. 2020.
Tischkowitz M, Colas C, Pouwels S, et al. Cancer Surveillance Guideline for individuals with PTEN hamartoma tumour syndrome. Eur J Hum Genet. 2020;28:1387-93. (PMC7608293)
Komiya T, Blumenthal GM, DeChowdhury R, et al. A Pilot Study of Sirolimus in Subjects with Cowden Syndrome or Other Syndromes Characterized by Germline Mutations in PTEN. The Oncologist. 2019;24(12):1510. (PMC6975943)
Hendricks LAJ, et al. A review on age-related cancer risks in PTEN hamartoma tumor syndrome. Clin Genet. 2021. (PMC7839546) · Cancer risks by sex and variant type in PHTS. JNCI. 2023.
Update on Pediatric Surveillance Recommendations for PTEN Hamartoma Tumor Syndrome, DICER1-Related Tumor Predisposition, and Tuberous Sclerosis Complex. Clin Cancer Res. 2025;31(2):234.
PMID:41480035 — Population-based Characterization of PTEN Hamartoma Tumor Syndrome. medRxiv preprint, Dec 2025 — cite as preliminary.
Sarn N, et al. Cytoplasmic-predominant Pten increases microglial activation and synaptic pruning in a murine model with autism-like phenotype. Mol Psychiatry. 2021. (PMC8159731)
GeneReviews: PTEN Hamartoma Tumor Syndrome. NCBI Bookshelf NBK1488. (PMID:20301661)

Sources:

Ask OpenScientist

OpenScientist Report

Inheritance

Subtypes

Mechanistic Hypotheses

Discussions and Knowledge Gaps

Pathophysiology

Histopathology

Pathograph

Phenotypes

Genetic Associations

Variants

Medical Actions

Diagnosis

Prevalence

Differential Diagnoses

Related Datasets

Clinical Trials

Experimental Models

Animal Models

Source YAML

References & Deep Research

References

Deep Research

Bannayan–Riley–Ruvalcaba Syndrome (BRRS) — Comprehensive Research Report

⚠️ Curator preflight — read this before you copy anything into YAML

1. Disease Information

Overview

Identifiers

Synonyms and alternative names

Nature of the evidence base

2. Etiology

Primary cause

Genetic risk factors beyond PTEN

Environmental risk factors

Protective factors

Gene–environment interactions

3. Phenotypes

BRRS-specific frequencies (best available source)

Additional features (established in the older literature, frequencies less firm)

Phenotype characteristics

Neurodevelopmental detail

4. Genetic / Molecular Information

Causal gene

Variant spectrum

Genotype–phenotype correlations

Modifier genes

Epigenetics

Chromosomal abnormalities

5. Environmental Information

6. Mechanism / Pathophysiology

The causal chain, upstream → downstream

Parallel / non-canonical arms worth separate nodes

Cellular processes, cell types, and compartments

Metabolic, immune, and tissue-damage dimensions

Molecular profiling

7. Anatomical Structures Affected

Organ level

Tissue, cell, and subcellular level

8. Temporal Development

9. Inheritance and Population

Epidemiology

Inheritance

Population demographics

10. Diagnostics

Clinical evaluation

Imaging and functional testing

Biopsy and pathology

Genetic testing (the definitive test)

Omics-based diagnostics

Clinical criteria and differential diagnosis

Screening of asymptomatic individuals

11. Outcome / Prognosis

12. Treatment

Surgical / interventional (the mainstay)

Pharmacotherapy — mTOR inhibitors

Targeted / advanced therapeutics

Pharmacogenomics

Supportive, rehabilitative, and counseling

Treatment strategy

Mouse (`NCBITaxon:10090`) — the workhorse

Appendix A — Suggested `mechanistic_hypotheses` and `discussions`

Appendix B — Suggested `conforms_to` module targets