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Pathophys.

◆

Subtypes

Cowden Syndrome 1 (PTEN)

Classic Cowden syndrome caused by germline loss-of-function mutations in PTEN on chromosome 10q22-23, accounting for approximately 80% of cases meeting strict clinical diagnostic criteria. Mutations include nonsense, frameshift, missense, splice-site variants, and large deletions.

Show evidence (1 reference)

PMID:24136893 SUPPORT Human Clinical

"Although it was initially reported that approximately 80% of patients with Cowden syndrome had an identifiable germline PTEN mutation, more recent work has shown these diagnostic criteria to be far less specific."

Establishes PTEN mutation as the predominant genetic cause in Cowden syndrome 1, noting that original ~80% frequency estimates derived from clinically ascertained cohorts.

Cowden Syndrome 2 (KLLN)

Cowden syndrome caused by germline epigenetic silencing (promoter hypermethylation) of KILLIN (KLLN), a p53-co-regulated tumor suppressor transcribed from the same bidirectional promoter as PTEN. KLLN methylation down-regulates KILLIN expression and is associated with increased breast and renal cancer risk.

Show evidence (1 reference)

PMID:21177507 SUPPORT Human Clinical

"Germline KILLIN methylation is common among patients with Cowden syndrome or Cowden-like syndrome and is associated with increased risks of breast and renal cancer over PTEN mutation-positive individuals."

Defines KLLN germline epigenetic silencing as the second major cause of Cowden/Cowden-like syndrome, conferring higher breast and kidney cancer risk than PTEN mutation alone.

Cowden Syndrome 3 (PIK3CA)

Historical Cowden syndrome 3 designation for PTEN-negative Cowden-like syndrome associated with activating germline variants in PIK3CA, the catalytic subunit of PI3-kinase. These variants are better framed as Cowden-like susceptibility genes rather than classic PTEN-defined Cowden syndrome causes. Reported variants result in elevated PIP3 and activated AKT, mimicking PTEN loss at the pathway level.

Show evidence (1 reference)

PMID:23246288 SUPPORT Human Clinical

"Our observations suggest that PIK3CA and AKT1 are CS susceptibility genes."

Identifies PIK3CA germline mutations as a causative alternative to PTEN in Cowden syndrome 3, acting through the same PI3K/AKT signaling axis.

Cowden Syndrome 4 (SDHB)

Historical Cowden syndrome 4 designation for PTEN-negative Cowden-like syndrome associated with germline mutations in succinate dehydrogenase subunit B (SDHB). These variants are better framed as Cowden-like susceptibility genes rather than classic PTEN-defined Cowden syndrome causes. SDH mutations alter mitochondrial metabolism, stabilize HIF-1alpha through pseudohypoxia, and activate downstream PI3K/AKT/MAPK signaling in the absence of PTEN mutation.

Show evidence (1 reference)

PMID:18678321 SUPPORT Human Clinical

"Germline SDH mutations/variants occur in a subset of PTEN mutation-negative CS/CS-like individuals and are associated with increased frequencies of breast, thyroid, and renal cancers beyond those conferred by germline PTEN mutations."

Establishes SDHB germline mutations as a causative factor in Cowden/Cowden-like syndrome in PTEN-mutation-negative individuals with elevated cancer risk.

⚙

Pathophysiology

PTEN Loss and PI3K/AKT/mTOR Pathway Activation

PTEN (phosphatase and tensin homolog) is a tumor suppressor that dephosphorylates phosphatidylinositol-3,4,5-trisphosphate (PIP3) to PIP2, thereby inhibiting the PI3K/AKT/mTOR signaling axis. Germline loss-of-function mutations in PTEN lead to constitutive accumulation of PIP3 and unopposed activation of AKT and downstream mTOR complex 1 (mTORC1), resulting in excessive cell proliferation, survival, and growth that underlies hamartoma formation and elevated cancer risk across multiple organ systems.

Epithelial cell CL:0000066 Fibroblast CL:0000057

PI3K/AKT signaling GO:0043491 ↑ INCREASED TOR signaling GO:0031929 ↑ INCREASED Cell proliferation GO:0008283 ↑ INCREASED Negative regulation of apoptosis GO:0043066 ↑ INCREASED

Downstream

Hamartoma Formation

Increased Cancer Risk

Neurodevelopmental Cortical Dysfunction

Show evidence (2 references)

PMID:18781191 SUPPORT Human Clinical

"PTEN is located on chromosome 10q22-23 and negatively regulates the prosurvival PI3K/Akt/mTOR pathway through its lipid phosphatase activity. Loss of PTEN activates this pathway and leads to increased cellular growth, migration, proliferation, and survival."

Directly establishes that PTEN loss leads to PI3K/AKT/mTOR hyperactivation driving cellular overgrowth, the central molecular mechanism of Cowden syndrome.

PMID:30614812 SUPPORT Human Clinical

"The tumor suppressor phosphatase and tensin homolog (PTEN) classically counteracts the PI3K/AKT/mTOR signaling cascade. Germline pathogenic PTEN mutations cause PTEN hamartoma tumor syndrome (PHTS), featuring various benign and malignant tumors, as well as neurodevelopmental disorders such as..."

Confirms PTEN's role as a counterbalance to PI3K/AKT/mTOR and links germline PTEN mutations to the full PHTS spectrum including Cowden syndrome.

Hamartoma Formation

Constitutive activation of PI3K/AKT/mTOR signaling in multiple cell lineages drives the abnormal but organized proliferation of tissue elements native to the affected site, producing hamartomas. In Cowden syndrome these manifest as mucocutaneous trichilemmomas, papillomatous papules, acral keratoses, gastrointestinal hamartomatous polyps, and thyroid adenomas. The hamartomas are histologically benign but serve as a marker of systemic PTEN dysfunction and elevated cancer predisposition.

Keratinocyte CL:0000312 Thyroid follicular cell CL:0002258

Hamartomatous cell proliferation GO:0008283 ↑ INCREASED

Downstream

Increased Cancer Risk

Show evidence (1 reference)

PMID:18781191 SUPPORT Human Clinical

"The PTEN hamartoma tumor syndromes (PHTS) are a collection of rare clinical syndromes characterized by germline mutations of the tumor suppressor PTEN. These syndromes are driven by cellular overgrowth, leading to benign hamartomas in virtually any organ."

Confirms that PTEN loss drives cellular overgrowth leading to hamartomas across organ systems, which is the hallmark of Cowden syndrome pathology.

Increased Cancer Risk

The same PI3K/AKT/mTOR over-activation that drives benign hamartoma formation also confers markedly elevated lifetime risks for malignancies. The cumulative lifetime risk in PTEN mutation carriers includes breast cancer (~77-85%), follicular/papillary thyroid cancer (~35-38%), endometrial cancer (~28%), renal cell carcinoma (~34%), and colorectal cancer (~9-16%). Second-hit somatic mutations or epigenetic silencing of the remaining wild-type PTEN allele accelerate neoplastic progression.

Cell proliferation GO:0008283 ↑ INCREASED

Show evidence (4 references)

PMID:23335809 SUPPORT Human Clinical

"Cumulative cancer risks at age 70 were 85% (95% CI 70% to 95%) for any cancer, 77% (95% CI 59% to 91%) for female breast cancer, and 38% (95% CI 25% to 56%) for thyroid cancer."

Quantifies the markedly elevated cumulative cancer risks in PTEN mutation carriers, establishing the clinical significance of increased cancer risk in PHTS/Cowden syndrome.

PMID:32533092 SUPPORT Human Clinical

"The projected estimated lifetime risks of cancer in individuals with PHTS range from 85 to 89% for any cancer, 67 to 85% for female breast cancer, 6 to 38% for thyroid cancer, 2 to 28% for endometrial cancer, 2 to 34% for renal cancer, 9 to 20% for colorectal cancer and 0 to 6% for melanoma."

Provides European expert consensus estimates for organ-specific lifetime cancer risks in PHTS/Cowden syndrome, supporting the multi-organ cancer predisposition mechanism.

PMID:36634299 SUPPORT Human Clinical

"We demonstrate that PTEN PVs are associated with significantly increased risk for a range of cancers."

Large multigene panel-testing cohort (727,091 individuals) provides genotype-anchored risk estimates for major PTEN-associated cancers, complementing older clinic-ascertained CLTRs with less ascertainment-biased data.

+ 1 more reference

PTEN Genome Integrity Defect

Beyond its well-known role as a lipid phosphatase, PTEN performs nuclear functions in maintaining genome integrity, including DNA double-strand break repair and chromosomal stability. Quantitative DNA damage response (DDR) modeling of PHTS patient-derived lymphoblastoid cell lines (n=43) shows that PTEN nonsense variants have less efficient DNA repair (higher residual gamma-H2AX foci 24 h after irradiation) than missense variants, and that DDR dynamics differ between PHTS-ASD/DD and PHTS-cancer phenotypic subgroups. This second molecular axis (genome instability) likely contributes to the pleiotropy of PHTS — explaining why cancer and neurodevelopmental phenotypes can both arise from germline PTEN loss without simply scaling with PI3K/AKT/mTOR over-activation.

Lymphoblastoid cell line (B lymphocyte) CL:0000236

Double-strand break repair GO:0006302 ↓ DECREASED Maintenance of genome integrity GO:0006281 ↓ DECREASED

Downstream

Increased Cancer Risk

Neurodevelopmental Cortical Dysfunction

Show evidence (2 references)

PMID:39356721 SUPPORT In Vitro

"Maintenance of genome integrity is one of the key biological functions of PTEN, but no integrative studies have been conducted to quantify the DNA damage response (DDR) in individuals with PHTS"

Establishes PTEN's nuclear genome-integrity role as a mechanistically distinct contributor to PHTS pathology beyond cytoplasmic PI3K/AKT signaling.

PMID:39356721 SUPPORT In Vitro

"We found that PTEN nonsense variants are associated with less efficient DNA damage repair ability resulting in higher DNA damage levels at 24 hours after irradiation compared to PTEN missense variants."

Provides quantitative DDR phenotyping in PHTS patient-derived LCLs, demonstrating that PTEN variant class is associated with measurable differences in DNA repair capacity, supporting genome instability as a contributor to PHTS pleiotropy.

Neurodevelopmental Cortical Dysfunction

In addition to its cell-autonomous role in restraining cell growth, PTEN regulates neuronal differentiation, dendritic arborisation, and synaptic homeostasis. Germline PTEN loss causes early-stage neuroectoderm and forebrain organoid abnormalities (disrupted neuronal differentiation, radial glia mispositioning, and altered cortical layering) and contributes to macrocephaly and autism-spectrum neurobehavioral phenotypes through PI3K/AKT/mTOR over-activation in cortical progenitors and neurons. PTEN germline mutations account for ~0.2-1% of all autism spectrum disorder (ASD) cases, ~17% of ASD with macrocephaly, and ~20-23% of PHTS individuals are diagnosed with ASD.

Neuron CL:0000540 Radial glial cell CL:0000681 Neural progenitor cell CL:0011020

Neurogenesis GO:0022008 ⚠ ABNORMAL Neuron differentiation GO:0030182 ⚠ ABNORMAL Cortical layering GO:0021799 ⚠ ABNORMAL

Downstream

Increased Cancer Risk

Show evidence (3 references)

PMID:38030818 SUPPORT In Vitro

"PTEN germline mutations account for ~0.2-1% of all autism spectrum disorder (ASD) cases, as well as ~17% of ASD patients with macrocephaly, making it one of the top ASD-associated risk genes."

Quantifies PTEN's contribution to ASD risk and establishes germline PTEN loss as a top ASD-associated gene, motivating a dedicated neurodevelopmental pathophysiology node.

PMID:38030818 SUPPORT In Vitro

"we observed disrupted neuronal differentiation, radial glia positioning, and cortical layering in both PTEN-mutant organoids at the later stage of 72+ days of development."

Direct iPSC-derived forebrain-organoid evidence that germline PTEN mutations disrupt neuronal differentiation, radial glial positioning, and cortical layering — the cellular substrates of macrocephaly and ASD in PHTS/Cowden syndrome.

PMID:33509259 SUPPORT Human Clinical

"PTEN is a well-established risk gene for autism spectrum disorder (ASD)."

Independent confirmation in a multi-center prospective human cohort that germline PTEN mutations confer ASD risk, complementing the organoid mechanistic data.

⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

●

Phenotypes

Breast 1

Breast Cancer Risk Breast carcinoma HP:0003002

Show evidence (1 reference)

PMID:23335809 SUPPORT Human Clinical

"Elevated SIRs were found mainly for female breast cancer (39.1, 95% CI 24.8 to 58.6), thyroid cancer in women (43.2, 95% CI 19.7 to 82.1) and in men (199.5, 95% CI 106.39 to 342.03), melanoma in women (28.3, 95% CI 7.6 to 35.4) and in men (39.4, 95% CI 10.6 to 100.9), and endometrial cancer..."

Demonstrates markedly elevated standardized incidence ratios (SIR 39.1) for breast cancer in female PTEN mutation carriers, confirming the substantially increased breast cancer risk in Cowden syndrome.

Cardiovascular 1

Vascular Anomalies Arteriovenous malformation HP:0100026

Show evidence (2 references)

PMID:39048366 SUPPORT Human Clinical

"Vascular malformations are common in CS, particularly in the extremities."

Direct clinical statement that vascular malformations are common in Cowden syndrome, with case-level evidence of spinal dural arteriovenous fistulas associated with a truncating PTEN mutation.

PMID:40120468 SUPPORT Human Clinical

"predisposes patients to hamartomas, lipomas, vascular tumors/malformations, and potential malignancies."

Independent statement of vascular tumors/malformations as a defining PHTS phenotype.

Digestive 2

Gastrointestinal Hamartomatous Polyps Hamartomatous polyposis HP:0004390

Show evidence (1 reference)

PMID:32533092 SUPPORT Human Clinical

"Polyps are common in PHTS, and these are typically hamartomas, although other types can also occur."

Confirms hamartomatous GI polyps as a common feature of PTEN hamartoma tumor syndrome/Cowden syndrome.

Colorectal Cancer Colon cancer HP:0003003

Show evidence (1 reference)

PMID:32533092 SUPPORT Human Clinical

"9 to 20% for colorectal cancer"

European expert consensus quantifies the elevated colorectal cancer risk (9-20% lifetime) that motivates including colorectal carcinoma as a recognised PHTS/Cowden phenotype.

Endocrine 1

Thyroid Abnormalities Thyroid carcinoma HP:0002890

Show evidence (1 reference)

PMID:32533092 SUPPORT Human Clinical

"There is strong evidence of an increased risk of thyroid carcinoma in PHTS with evidence that this can arise at relatively young ages."

Confirms strong clinical evidence for increased thyroid carcinoma risk in PTEN hamartoma tumor syndrome/Cowden syndrome.

Genitourinary 1

Uterine Cancer Risk Endometrial carcinoma HP:0012114

Show evidence (1 reference)

PMID:23335809 SUPPORT Human Clinical

Documents a substantially elevated standardized incidence ratio (SIR 48.7) for endometrial cancer in PHTS, confirming uterine cancer as a major cancer risk in Cowden syndrome.

Head and Neck 1

Macrocephaly Macrocephaly HP:0000256

Show evidence (1 reference)

PMID:17526800 SUPPORT Human Clinical

"Bannayan-Riley-Ruvalcaba syndrome (BRRS), with childhood onset, macrocephaly, lipomas and developmental delay, and Cowden Syndrome (CS), an adult-onset condition recognised by mucocutaneous signs, with a risk of cancers, in particular those of the thyroid and breast."

Documents macrocephaly as a characteristic feature across the PTEN mutation phenotypic spectrum, particularly in the childhood-onset BRRS form.

Musculoskeletal 1

Lipoma Lipoma HP:0012032

Show evidence (2 references)

PMID:18781191 SUPPORT Human Clinical

"Bannayan-Riley-Ruvalcaba syndrome (BRRS), characterized by the developmental delay, macrocephaly, lipomas, hemangiomas, and speckled penis in males, is associated with PTEN mutations in approximately 60% of cases."

Establishes lipomas as a defining clinical feature of the BRRS end of the PHTS spectrum; CS and BRRS are now recognised as one PHTS condition with variable expression, so lipomas are a Cowden-spectrum phenotype.

PMID:40120468 SUPPORT Human Clinical

"Phosphatase and tensin homolog hamartoma tumor syndrome (PTEN Syndrome), an autosomal dominant group of disorders caused by PTEN dysregulation, predisposes patients to hamartomas, lipomas, vascular tumors/malformations, and potential malignancies."

Independent confirmation of lipomas as a recognised feature of the PTEN syndrome spectrum, including Cowden syndrome.

Nervous System 3

Lhermitte-Duclos Disease Dysplastic gangliocytoma of the cerebellum HP:0500009

Show evidence (1 reference)

PMID:37810307 SUPPORT Human Clinical

"Lhermitte-Duclos disease (LDD) is a rare tumor, with only about 300 reported cases. It often shows comorbidity with Cowden syndrome (CS); however, it can occur by itself."

Confirms the well-established association between Lhermitte-Duclos disease and Cowden syndrome in a systematic review of 302 cases, with 32.8% of LDD showing CS comorbidity.

Autism Spectrum Disorder Autism HP:0000717

Show evidence (2 references)

PMID:38030818 SUPPORT In Vitro

"Individuals with germline PTEN mutations receive the molecular diagnosis of PTEN Hamartoma Tumor Syndrome (PHTS), an inherited cancer predisposition syndrome, about 20-23% of whom are diagnosed with ASD."

iPSC-derived forebrain organoid study (IN_VITRO) reports the 20-23% PHTS-ASD frequency in its background, citing prior human-clinical literature; classified by the publication's primary evidence type. Human-cohort confirmation is provided separately by PMID:33509259.

PMID:33509259 SUPPORT Human Clinical

"PTEN is a well-established risk gene for autism spectrum disorder (ASD)."

Multi-center prospective patient cohort confirms PTEN as an established ASD risk gene, supporting ASD as a Cowden/PHTS clinical phenotype.

Developmental Delay and Intellectual Disability Global developmental delay HP:0001263

Show evidence (2 references)

PMID:17526800 SUPPORT Human Clinical

"Bannayan-Riley-Ruvalcaba syndrome (BRRS), with childhood onset, macrocephaly, lipomas and developmental delay"

Establishes developmental delay as a defining clinical feature of the BRRS end of the PHTS spectrum (CS and BRRS are now recognised as a single PHTS condition with variable expression).

PMID:33509259 SUPPORT Human Clinical

"impairments in general cognitive ability are only common in PTEN-ASD. For most neurobehavioral measures, variability within and across patient groups was very large, with some patients functioning in the average or above average range in most neurocognitive domains and other patients showing..."

Multi-center prospective PHTS cohort documents the spectrum of cognitive impairment, supporting global developmental delay / intellectual disability as a distinct clinical phenotype distinguishable from ASD diagnosis itself.

Neoplasm 1

Mucocutaneous Lesions Hamartoma HP:0010566

Show evidence (1 reference)

PMID:17526800 SUPPORT Human Clinical

"Cowden Syndrome (CS), an adult-onset condition recognised by mucocutaneous signs, with a risk of cancers, in particular those of the thyroid and breast."

Establishes mucocutaneous signs as the defining clinical feature of Cowden syndrome in PTEN mutation carriers.

Other 1

Renal Cell Carcinoma Renal cell carcinoma HP:0005584

Show evidence (2 references)

PMID:32533092 SUPPORT Human Clinical

European expert consensus places lifetime renal cancer risk at 2-34%, motivating renal cell carcinoma as a distinct PHTS/Cowden phenotype with surveillance recommendations.

PMID:21177507 SUPPORT Human Clinical

Identifies KLLN-methylation Cowden syndrome 2 as conferring particularly elevated renal cancer risk relative to classical PTEN-mutation cases.

🧬

Genetic Associations

PTEN (Causative)

Gene: PTEN hgnc:9588

Autosomal dominant

Show evidence (1 reference)

PMID:21194675 SUPPORT Human Clinical

"Cowden syndrome (CS) and Bannayan-Riley-Ruvalcaba syndrome are allelic, defined by germline PTEN mutations, and collectively referred to as PTEN hamartoma tumor syndrome."

Establishes PTEN germline mutations as the defining genetic cause of Cowden syndrome in a large prospective cohort of 3042 probands.

KLLN (Causative)

Gene: KLLN hgnc:37212

Autosomal dominant

Show evidence (1 reference)

PMID:21177507 SUPPORT Human Clinical

Establishes KLLN germline methylation as a distinct molecular subtype of Cowden syndrome with measurably elevated cancer risks.

PIK3CA (Susceptibility in PTEN-negative Cowden-like syndrome)

Gene: PIK3CA hgnc:8975 relationship_type: SUSCEPTIBILITY

Autosomal dominant

Show evidence (1 reference)

PMID:23246288 SUPPORT Human Clinical

"We report that 8 of 91 (8.8%) unrelated CS individuals without germline PTEN mutations carried 10 germline PIK3CA mutations (7 missense, 1 nonsense, and 2 indels) and 2 (2.2%) AKT1 mutations. These mutations result in significantly increased P-Thr308-AKT and increased cellular PIP3."

Directly identifies PIK3CA germline mutations in Cowden syndrome patients lacking PTEN mutations, confirming PIK3CA as a causative gene in Cowden syndrome 3.

SDHB (Susceptibility in PTEN-negative Cowden-like syndrome)

Gene: SDHB hgnc:10681 relationship_type: SUSCEPTIBILITY

Autosomal dominant

Show evidence (1 reference)

PMID:18678321 SUPPORT Human Clinical

Establishes SDHB germline mutations as a causative factor in Cowden syndrome 4, found in PTEN-mutation-negative individuals with elevated cancer risk.

💊

Medical Actions

Enhanced Cancer Surveillance

Action: cancer surveillance Ontology label: cancer screening MAXO:0000126

PTEN mutation carriers require life-long intensified surveillance protocols. GeneReviews and ERN GENTURIS support organ-specific surveillance that includes breast awareness and clinical examination, annual breast MRI beginning around age 30 with mammography incorporated by age 40, yearly thyroid ultrasound, dermatologic evaluation, baseline colonoscopy at age 35-40 with intervals based on findings, renal imaging from age 40, and earlier screening 5-10 years before the youngest cancer in a family when family history indicates. Endometrial surveillance should be framed as consideration rather than universal screening: GeneReviews recommends considering screening by age 35 with endometrial biopsy every 1-2 years and/or postmenopausal transvaginal ultrasound at clinician discretion, while ERN GENTURIS notes weak evidence and recommends symptom education or clinical-trial-based screening.

Show evidence (5 references)

PMID:32533092 SUPPORT Human Clinical

"Recommendations were put forward for surveillance for breast, thyroid and renal cancers. Limited recommendations were developed for other sites including endometrial, colon and skin."

Provides evidence-based surveillance recommendations for PHTS/Cowden syndrome from the European Reference Network for Genetic Tumour Risk Syndromes.

PMID:20301661 SUPPORT Human Clinical

"Women beginning at age 30 years. Monthly breast self-examination; annual breast screening (at minimum mammogram; MRI may also be incorporated). Starting by age 35 years, consider transvaginal ultrasound or endometrial biopsy."

GeneReviews supports breast screening from age 30 and consideration of endometrial screening from age 35.

PMID:20301661 SUPPORT Human Clinical

"Men and women. Colonoscopy beginning at age 35 years with frequency dependent on degree of polyposis identified or family history of early-onset colon cancer (before age 40); biennial (every 2 years) renal imaging (CT or MRI preferred) beginning at age 40 years."

GeneReviews supports colorectal and renal surveillance age/interval guidance.

+ 2 more references

Prophylactic Mastectomy

Action: prophylactic mastectomy Ontology label: surgical procedure MAXO:0000004

Risk-reducing bilateral mastectomy reduces breast cancer risk by more than 90% in PTEN mutation carriers with high personal or family risk. It is offered as an option after careful counseling regarding elevated lifetime risk, using the same approach as for BRCA1/BRCA2 carriers.

Show evidence (1 reference)

PMID:32533092 SUPPORT Human Clinical

"Risk reduction surgery should be offered using the same considerations as for women with germline BRCA1/BRCA2 pathogenic variants"

Supports offering prophylactic mastectomy in PTEN mutation carriers following the same approach as for BRCA1/BRCA2, given comparable breast cancer risk levels.

mTOR Inhibitor Therapy

Action: mTOR inhibitor pharmacotherapy Ontology label: pharmacotherapy MAXO:0000058

Agent: everolimus CHEBI:68478

Everolimus (RAD001), an mTORC1 inhibitor, targets the hyperactivated PI3K/AKT/mTOR pathway in Cowden syndrome. The mechanistic rationale stems directly from PTEN loss driving constitutive mTOR activation. A 6-month phase II placebo-controlled randomised trial of everolimus in 46 PHTS individuals (5-45 years) demonstrated that the drug is well tolerated; the primary neurocognitive endpoint was not met but several secondary neurobehavioral measures and EEG biomarkers showed signals of improvement, supporting continued investigation rather than routine clinical use.

Show evidence (3 references)

PMID:35594551 PARTIAL Human Clinical

"PTEN hamartoma tumor syndrome (PHTS) is a complex neurodevelopmental disorder characterized by mechanistic target of rapamycin (mTOR) overactivity. Limited data suggest that mTOR inhibitors may be therapeutic."

Establishes the mechanistic rationale (mTOR overactivity) and motivates the placebo-controlled trial of everolimus in PHTS that this paper reports.

PMID:35594551 PARTIAL Human Clinical

"Everolimus is well tolerated in PHTS; adverse events were similar to previous reports. The primary efficacy endpoint did not reveal improvement."

Phase II RCT (n=46) shows everolimus is well tolerated in PHTS but did not meet its primary neurocognitive endpoint. Supports `PARTIAL`: pharmacology supports the mTOR-inhibition rationale, but no confirmed cognitive benefit yet — clinical use remains investigational.

PMID:18781191 SUPPORT Other

"Concomitant with improved understanding of the biology of PTEN and the PI3K/Akt/mTOR pathway, inhibitors of this pathway are being developed as anticancer agents. These medications could have applications for patients with PHTS, for whom no medical options currently exist."

Originally established the rationale for mTOR/PI3K inhibitor therapy in PHTS based on the underlying molecular mechanism (expert review, predates clinical trial data).

Genetic Counseling

Action: genetic counseling MAXO:0000079

Genetic counseling is recommended for all patients with suspected or confirmed Cowden syndrome and their at-risk family members, informing testing decisions, cancer risks, and surveillance strategies.

Show evidence (1 reference)

PMID:31433956 SUPPORT Human Clinical

"Timely diagnosis and understanding the natural history of PHTS are vital because early recognition enables gene-informed management, particularly as related to high-risk cancer surveillance and addressing the neurodevelopmental symptoms."

Highlights the importance of genetic diagnosis enabling gene-informed counseling and management in PHTS/Cowden syndrome.

🔬

Clinical Trials

NCT02991807 PHASE_II COMPLETED

A six-month randomized, double-blind, placebo-controlled phase II trial of everolimus (RAD001) in 46 individuals (5-45 years) with PTEN mutations, examining safety and efficacy on neurocognitive and behavioral outcomes in PHTS. Reported in Srivastava et al. 2022 (PMID:35594551). The primary neurocognitive endpoint was not met; everolimus was well tolerated and several secondary measures and EEG biomarkers showed signals of improvement.

Target Phenotypes: Autism HP:0000717 Global developmental delay HP:0001263

Show evidence (1 reference)

clinicaltrials:NCT02991807 SUPPORT 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."

ClinicalTrials.gov record for the everolimus phase II RCT in PHTS — formal registry capture of the study reported as PMID:35594551 in the mTOR Inhibitor Therapy treatment entry.

{ }

Source YAML

click to show

name: Cowden Syndrome
creation_date: "2026-03-19T00:00:00Z"
updated_date: "2026-04-25T17:45:00Z"
category: Mendelian
disease_term:
  preferred_term: Cowden syndrome
  term:
    id: MONDO:0016063
    label: Cowden disease
synonyms:
- Cowden disease
- Multiple hamartoma syndrome
parents:
- Autosomal dominant hereditary syndrome
- Hereditary cancer syndrome
- PTEN hamartoma tumor syndrome
prevalence:
- population: Global clinically recognized populations
  percentage: 1 in 200,000
  notes: >-
    Cowden syndrome is typically reported as affecting about 1 in 200,000
    individuals or live births in clinically recognized populations, although
    this likely underestimates true PTEN-hamartoma-spectrum burden because
    phenotypic expression is variable.
  evidence:
  - reference: PMID:21177507
    reference_title: Germline epigenetic regulation of KILLIN in Cowden and Cowden-like syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Germline loss-of-function phosphatase and tensin homolog gene (PTEN) mutations cause 80% of Cowden syndrome, a rare autosomal-dominant disorder (1 in 200,000 live births)"
    explanation: This JAMA study explicitly states the standard prevalence estimate for Cowden syndrome.
  - reference: PMID:29469739
    reference_title: "Cowden syndrome: clinical case and a brief review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cowden syndrome affects 1:200,000 individuals."
    explanation: This review-style clinical report independently gives the same population estimate.
has_subtypes:
- name: Cowden Syndrome 1 (PTEN)
  description: >
    Classic Cowden syndrome caused by germline loss-of-function mutations in PTEN on
    chromosome 10q22-23, accounting for approximately 80% of cases meeting strict
    clinical diagnostic criteria. Mutations include nonsense, frameshift, missense,
    splice-site variants, and large deletions.
  evidence:
  - reference: PMID:24136893
    reference_title: "Cowden syndrome and the PTEN hamartoma tumor syndrome: systematic review and revised diagnostic criteria."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Although it was initially reported that approximately 80% of patients with Cowden syndrome had an identifiable germline PTEN mutation, more recent work has shown these diagnostic criteria to be far less specific."
    explanation: "Establishes PTEN mutation as the predominant genetic cause in Cowden syndrome 1, noting that original ~80% frequency estimates derived from clinically ascertained cohorts."
- name: Cowden Syndrome 2 (KLLN)
  description: >
    Cowden syndrome caused by germline epigenetic silencing (promoter hypermethylation)
    of KILLIN (KLLN), a p53-co-regulated tumor suppressor transcribed from the same
    bidirectional promoter as PTEN. KLLN methylation down-regulates KILLIN expression
    and is associated with increased breast and renal cancer risk.
  evidence:
  - reference: PMID:21177507
    reference_title: Germline epigenetic regulation of KILLIN in Cowden and Cowden-like syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Germline KILLIN methylation is common among patients with Cowden syndrome or Cowden-like syndrome and is associated with increased risks of breast and renal cancer over PTEN mutation-positive individuals."
    explanation: "Defines KLLN germline epigenetic silencing as the second major cause of Cowden/Cowden-like syndrome, conferring higher breast and kidney cancer risk than PTEN mutation alone."
- name: Cowden Syndrome 3 (PIK3CA)
  description: >
    Historical Cowden syndrome 3 designation for PTEN-negative Cowden-like syndrome
    associated with activating germline variants in PIK3CA, the catalytic subunit of
    PI3-kinase. These variants are better framed as Cowden-like susceptibility genes
    rather than classic PTEN-defined Cowden syndrome causes. Reported variants result
    in elevated PIP3 and activated AKT, mimicking PTEN loss at the pathway level.
  evidence:
  - reference: PMID:23246288
    reference_title: Germline PIK3CA and AKT1 mutations in Cowden and Cowden-like syndromes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Our observations suggest that PIK3CA and AKT1 are CS susceptibility genes."
    explanation: "Identifies PIK3CA germline mutations as a causative alternative to PTEN in Cowden syndrome 3, acting through the same PI3K/AKT signaling axis."
- name: Cowden Syndrome 4 (SDHB)
  description: >
    Historical Cowden syndrome 4 designation for PTEN-negative Cowden-like syndrome
    associated with germline mutations in succinate dehydrogenase subunit B (SDHB).
    These variants are better framed as Cowden-like susceptibility genes rather than
    classic PTEN-defined Cowden syndrome causes. SDH mutations alter mitochondrial
    metabolism, stabilize HIF-1alpha through pseudohypoxia, and activate downstream
    PI3K/AKT/MAPK signaling in the absence of PTEN mutation.
  evidence:
  - reference: PMID:18678321
    reference_title: Germline mutations and variants in the succinate dehydrogenase genes in Cowden and Cowden-like syndromes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Germline SDH mutations/variants occur in a subset of PTEN mutation-negative CS/CS-like individuals and are associated with increased frequencies of breast, thyroid, and renal cancers beyond those conferred by germline PTEN mutations."
    explanation: "Establishes SDHB germline mutations as a causative factor in Cowden/Cowden-like syndrome in PTEN-mutation-negative individuals with elevated cancer risk."
pathophysiology:
- name: PTEN Loss and PI3K/AKT/mTOR Pathway Activation
  description: >
    PTEN (phosphatase and tensin homolog) is a tumor suppressor that dephosphorylates
    phosphatidylinositol-3,4,5-trisphosphate (PIP3) to PIP2, thereby inhibiting the
    PI3K/AKT/mTOR signaling axis. Germline loss-of-function mutations in PTEN lead to
    constitutive accumulation of PIP3 and unopposed activation of AKT and downstream
    mTOR complex 1 (mTORC1), resulting in excessive cell proliferation, survival, and
    growth that underlies hamartoma formation and elevated cancer risk across multiple
    organ systems.
  cell_types:
  - preferred_term: Epithelial cell
    term:
      id: CL:0000066
      label: epithelial cell
  - preferred_term: Fibroblast
    term:
      id: CL:0000057
      label: fibroblast
  biological_processes:
  - preferred_term: PI3K/AKT signaling
    term:
      id: GO:0043491
      label: phosphatidylinositol 3-kinase/protein kinase B signal transduction
    modifier: INCREASED
  - preferred_term: TOR signaling
    term:
      id: GO:0031929
      label: TOR signaling
    modifier: INCREASED
  - preferred_term: Cell proliferation
    term:
      id: GO:0008283
      label: cell population proliferation
    modifier: INCREASED
  - preferred_term: Negative regulation of apoptosis
    term:
      id: GO:0043066
      label: negative regulation of apoptotic process
    modifier: INCREASED
  evidence:
  - reference: PMID:18781191
    reference_title: PTEN hamartoma tumor syndromes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "PTEN is located on chromosome 10q22-23 and negatively regulates the prosurvival PI3K/Akt/mTOR pathway through its lipid phosphatase activity. Loss of PTEN activates this pathway and leads to increased cellular growth, migration, proliferation, and survival."
    explanation: "Directly establishes that PTEN loss leads to PI3K/AKT/mTOR hyperactivation driving cellular overgrowth, the central molecular mechanism of Cowden syndrome."
  - reference: PMID:30614812
    reference_title: "PTEN-opathies: from biological insights to evidence-based precision medicine."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The tumor suppressor phosphatase and tensin homolog (PTEN) classically counteracts the PI3K/AKT/mTOR signaling cascade. Germline pathogenic PTEN mutations cause PTEN hamartoma tumor syndrome (PHTS), featuring various benign and malignant tumors, as well as neurodevelopmental disorders such as autism spectrum disorder."
    explanation: "Confirms PTEN's role as a counterbalance to PI3K/AKT/mTOR and links germline PTEN mutations to the full PHTS spectrum including Cowden syndrome."
  downstream:
  - target: Hamartoma Formation
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:18781191
      reference_title: PTEN hamartoma tumor syndromes.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "These syndromes are driven by cellular overgrowth, leading to benign hamartomas in virtually any organ."
      explanation: "Direct causal link from PTEN-driven PI3K/AKT/mTOR pathway hyperactivation to multi-organ hamartoma formation."
  - target: Increased Cancer Risk
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:30614812
      reference_title: "PTEN-opathies: from biological insights to evidence-based precision medicine."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The tumor suppressor phosphatase and tensin homolog (PTEN) classically counteracts the PI3K/AKT/mTOR signaling cascade. Germline pathogenic PTEN mutations cause PTEN hamartoma tumor syndrome (PHTS), featuring various benign and malignant tumors"
      explanation: "Indirect causal link: PTEN-driven PI3K/AKT/mTOR hyperactivation predisposes to multiple malignant tumors through downstream proliferation and survival programs."
  - target: Neurodevelopmental Cortical Dysfunction
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:30614812
      reference_title: "PTEN-opathies: from biological insights to evidence-based precision medicine."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Germline pathogenic PTEN mutations cause PTEN hamartoma tumor syndrome (PHTS), featuring various benign and malignant tumors, as well as neurodevelopmental disorders such as autism spectrum disorder."
      explanation: "Direct causal link from germline PTEN loss / pathway over-activation to cortical neurodevelopmental phenotypes including autism spectrum disorder."
- name: Hamartoma Formation
  description: >
    Constitutive activation of PI3K/AKT/mTOR signaling in multiple cell lineages drives
    the abnormal but organized proliferation of tissue elements native to the affected
    site, producing hamartomas. In Cowden syndrome these manifest as mucocutaneous
    trichilemmomas, papillomatous papules, acral keratoses, gastrointestinal hamartomatous
    polyps, and thyroid adenomas. The hamartomas are histologically benign but serve as
    a marker of systemic PTEN dysfunction and elevated cancer predisposition.
  cell_types:
  - preferred_term: Keratinocyte
    term:
      id: CL:0000312
      label: keratinocyte
  - preferred_term: Thyroid follicular cell
    term:
      id: CL:0002258
      label: thyroid follicular cell
  biological_processes:
  - preferred_term: Hamartomatous cell proliferation
    term:
      id: GO:0008283
      label: cell population proliferation
    modifier: INCREASED
  evidence:
  - reference: PMID:18781191
    reference_title: PTEN hamartoma tumor syndromes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The PTEN hamartoma tumor syndromes (PHTS) are a collection of rare clinical syndromes characterized by germline mutations of the tumor suppressor PTEN. These syndromes are driven by cellular overgrowth, leading to benign hamartomas in virtually any organ."
    explanation: "Confirms that PTEN loss drives cellular overgrowth leading to hamartomas across organ systems, which is the hallmark of Cowden syndrome pathology."
  downstream:
  - target: Increased Cancer Risk
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:24136893
      reference_title: "Cowden syndrome and the PTEN hamartoma tumor syndrome: systematic review and revised diagnostic criteria."
      supports: PARTIAL
      evidence_source: HUMAN_CLINICAL
      snippet: "Although it was initially reported that approximately 80% of patients with Cowden syndrome had an identifiable germline PTEN mutation, more recent work has shown these diagnostic criteria to be far less specific."
      explanation: "Hamartomas serve as a clinical marker of underlying PTEN dysfunction; the same molecular state that produces hamartomas also drives the elevated multi-organ cancer risk, hence indirect causal contribution rather than a strict tumor-progression sequence from individual hamartomas to malignancy."
- name: Increased Cancer Risk
  description: >
    The same PI3K/AKT/mTOR over-activation that drives benign hamartoma formation also
    confers markedly elevated lifetime risks for malignancies. The cumulative lifetime
    risk in PTEN mutation carriers includes breast cancer (~77-85%), follicular/papillary
    thyroid cancer (~35-38%), endometrial cancer (~28%), renal cell carcinoma (~34%),
    and colorectal cancer (~9-16%). Second-hit somatic mutations or epigenetic silencing
    of the remaining wild-type PTEN allele accelerate neoplastic progression.
  biological_processes:
  - preferred_term: Cell proliferation
    term:
      id: GO:0008283
      label: cell population proliferation
    modifier: INCREASED
  evidence:
  - reference: PMID:23335809
    reference_title: High cumulative risks of cancer in patients with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cumulative cancer risks at age 70 were 85% (95% CI 70% to 95%) for any cancer, 77% (95% CI 59% to 91%) for female breast cancer, and 38% (95% CI 25% to 56%) for thyroid cancer."
    explanation: "Quantifies the markedly elevated cumulative cancer risks in PTEN mutation carriers, establishing the clinical significance of increased cancer risk in PHTS/Cowden syndrome."
  - reference: PMID:32533092
    reference_title: Cancer Surveillance Guideline for individuals with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The projected estimated lifetime risks of cancer in individuals with PHTS range from 85 to 89% for any cancer, 67 to 85% for female breast cancer, 6 to 38% for thyroid cancer, 2 to 28% for endometrial cancer, 2 to 34% for renal cancer, 9 to 20% for colorectal cancer and 0 to 6% for melanoma."
    explanation: "Provides European expert consensus estimates for organ-specific lifetime cancer risks in PHTS/Cowden syndrome, supporting the multi-organ cancer predisposition mechanism."
  - reference: PMID:36634299
    reference_title: Cancer Risk Associated With PTEN Pathogenic Variants Identified Using Multigene Hereditary Cancer Panel Testing.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We demonstrate that PTEN PVs are associated with significantly increased risk for a range of cancers."
    explanation: "Large multigene panel-testing cohort (727,091 individuals) provides genotype-anchored risk estimates for major PTEN-associated cancers, complementing older clinic-ascertained CLTRs with less ascertainment-biased data."
  - reference: PMID:33140411
    reference_title: A review on age-related cancer risks in PTEN hamartoma tumor syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Reported CLTRs for any cancer varied from 81% to 90%."
    explanation: "Independent meta-review of nine PHTS cohorts confirms the multi-organ lifetime cancer risk profile and the median diagnosis age of ~36 years used to motivate early surveillance."
- name: PTEN Genome Integrity Defect
  description: >
    Beyond its well-known role as a lipid phosphatase, PTEN performs nuclear functions
    in maintaining genome integrity, including DNA double-strand break repair and
    chromosomal stability. Quantitative DNA damage response (DDR) modeling of PHTS
    patient-derived lymphoblastoid cell lines (n=43) shows that PTEN nonsense variants
    have less efficient DNA repair (higher residual gamma-H2AX foci 24 h after
    irradiation) than missense variants, and that DDR dynamics differ between
    PHTS-ASD/DD and PHTS-cancer phenotypic subgroups. This second molecular axis (genome
    instability) likely contributes to the pleiotropy of PHTS — explaining why cancer
    and neurodevelopmental phenotypes can both arise from germline PTEN loss without
    simply scaling with PI3K/AKT/mTOR over-activation.
  cell_types:
  - preferred_term: Lymphoblastoid cell line (B lymphocyte)
    term:
      id: CL:0000236
      label: B cell
  biological_processes:
  - preferred_term: Double-strand break repair
    term:
      id: GO:0006302
      label: double-strand break repair
    modifier: DECREASED
  - preferred_term: Maintenance of genome integrity
    term:
      id: GO:0006281
      label: DNA repair
    modifier: DECREASED
  evidence:
  - reference: PMID:39356721
    reference_title: Quantitative evaluation of DNA damage repair dynamics to elucidate predictors of autism vs. cancer in individuals with germline PTEN variants.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Maintenance of genome integrity is one of the key biological functions of PTEN, but no integrative studies have been conducted to quantify the DNA damage response (DDR) in individuals with PHTS"
    explanation: "Establishes PTEN's nuclear genome-integrity role as a mechanistically distinct contributor to PHTS pathology beyond cytoplasmic PI3K/AKT signaling."
  - reference: PMID:39356721
    reference_title: Quantitative evaluation of DNA damage repair dynamics to elucidate predictors of autism vs. cancer in individuals with germline PTEN variants.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We found that PTEN nonsense variants are associated with less efficient DNA damage repair ability resulting in higher DNA damage levels at 24 hours after irradiation compared to PTEN missense variants."
    explanation: "Provides quantitative DDR phenotyping in PHTS patient-derived LCLs, demonstrating that PTEN variant class is associated with measurable differences in DNA repair capacity, supporting genome instability as a contributor to PHTS pleiotropy."
  downstream:
  - target: Increased Cancer Risk
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:39356721
      reference_title: Quantitative evaluation of DNA damage repair dynamics to elucidate predictors of autism vs. cancer in individuals with germline PTEN variants.
      supports: PARTIAL
      evidence_source: IN_VITRO
      snippet: "PHTS confers high risks of specific malignancies, and up to 23% of the patients are diagnosed with autism spectrum disorder (ASD) and/or developmental delay (DD)."
      explanation: "Genome-integrity loss is mechanistically expected to contribute directly to malignant transformation; the DDR phenotyping data support this axis as part of the cancer-predisposition explanation alongside PI3K/AKT/mTOR over-activation."
  - target: Neurodevelopmental Cortical Dysfunction
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39356721
      reference_title: Quantitative evaluation of DNA damage repair dynamics to elucidate predictors of autism vs. cancer in individuals with germline PTEN variants.
      supports: PARTIAL
      evidence_source: IN_VITRO
      snippet: "LCLs from PHTS individuals with ASD/DD showed faster DNA damage repairing rate than those from patients without ASD/DD or cancer."
      explanation: "DDR dynamics differ between PHTS-ASD/DD and PHTS-cancer phenotypic subgroups, suggesting genome-integrity differences contribute through unknown intermediates to neurodevelopmental versus oncologic phenotypic divergence."
- name: Neurodevelopmental Cortical Dysfunction
  description: >
    In addition to its cell-autonomous role in restraining cell growth, PTEN regulates
    neuronal differentiation, dendritic arborisation, and synaptic homeostasis. Germline
    PTEN loss causes early-stage neuroectoderm and forebrain organoid abnormalities
    (disrupted neuronal differentiation, radial glia mispositioning, and altered cortical
    layering) and contributes to macrocephaly and autism-spectrum neurobehavioral
    phenotypes through PI3K/AKT/mTOR over-activation in cortical progenitors and neurons.
    PTEN germline mutations account for ~0.2-1% of all autism spectrum disorder (ASD)
    cases, ~17% of ASD with macrocephaly, and ~20-23% of PHTS individuals are diagnosed
    with ASD.
  cell_types:
  - preferred_term: Neuron
    term:
      id: CL:0000540
      label: neuron
  - preferred_term: Radial glial cell
    term:
      id: CL:0000681
      label: radial glial cell
  - preferred_term: Neural progenitor cell
    term:
      id: CL:0011020
      label: neural progenitor cell
  biological_processes:
  - preferred_term: Neurogenesis
    term:
      id: GO:0022008
      label: neurogenesis
    modifier: ABNORMAL
  - preferred_term: Neuron differentiation
    term:
      id: GO:0030182
      label: neuron differentiation
    modifier: ABNORMAL
  - preferred_term: Cortical layering
    term:
      id: GO:0021799
      label: cerebral cortex radially oriented cell migration
    modifier: ABNORMAL
  evidence:
  - reference: PMID:38030818
    reference_title: Germline PTEN genotype-dependent phenotypic divergence during the early neural developmental process of forebrain organoids.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "PTEN germline mutations account for ~0.2-1% of all autism spectrum disorder (ASD) cases, as well as ~17% of ASD patients with macrocephaly, making it one of the top ASD-associated risk genes."
    explanation: "Quantifies PTEN's contribution to ASD risk and establishes germline PTEN loss as a top ASD-associated gene, motivating a dedicated neurodevelopmental pathophysiology node."
  - reference: PMID:38030818
    reference_title: Germline PTEN genotype-dependent phenotypic divergence during the early neural developmental process of forebrain organoids.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "we observed disrupted neuronal differentiation, radial glia positioning, and cortical layering in both PTEN-mutant organoids at the later stage of 72+ days of development."
    explanation: "Direct iPSC-derived forebrain-organoid evidence that germline PTEN mutations disrupt neuronal differentiation, radial glial positioning, and cortical layering — the cellular substrates of macrocephaly and ASD in PHTS/Cowden syndrome."
  - reference: PMID:33509259
    reference_title: Cross-level analysis of molecular and neurobehavioral function in a prospective series of patients with germline heterozygous PTEN mutations with and without autism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "PTEN is a well-established risk gene for autism spectrum disorder (ASD)."
    explanation: "Independent confirmation in a multi-center prospective human cohort that germline PTEN mutations confer ASD risk, complementing the organoid mechanistic data."
  downstream:
  - target: Increased Cancer Risk
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:38030818
      reference_title: Germline PTEN genotype-dependent phenotypic divergence during the early neural developmental process of forebrain organoids.
      supports: PARTIAL
      evidence_source: IN_VITRO
      snippet: "Individuals with germline PTEN mutations receive the molecular diagnosis of PTEN Hamartoma Tumor Syndrome (PHTS), an inherited cancer predisposition syndrome, about 20-23% of whom are diagnosed with ASD."
      explanation: "Same upstream PTEN/PI3K/AKT pathway underlies both ASD-relevant cortical phenotypes and PHTS cancer predisposition; the cancer risk arises through cell-type-specific (non-CNS) intermediates rather than a direct CNS→cancer cascade."

phenotypes:
- category: Clinical
  name: Mucocutaneous Lesions
  description: >
    Pathognomonic mucocutaneous findings include multiple facial trichilemmomas
    (benign hamartomas of the hair follicle outer root sheath), acral and plantar
    keratoses, and papillomatous papules of the oral mucosa (cobblestone appearance).
    These lesions are present in more than 90% of adult Cowden syndrome patients and
    are the most distinctive clinical features of the syndrome.
  phenotype_term:
    preferred_term: Skin hamartoma
    term:
      id: HP:0010566
      label: Hamartoma
  evidence:
  - reference: PMID:17526800
    reference_title: "Cowden syndrome and Bannayan Riley Ruvalcaba syndrome represent one condition with variable expression and age-related penetrance: results of a clinical study of PTEN mutation carriers."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cowden Syndrome (CS), an adult-onset condition recognised by mucocutaneous signs, with a risk of cancers, in particular those of the thyroid and breast."
    explanation: "Establishes mucocutaneous signs as the defining clinical feature of Cowden syndrome in PTEN mutation carriers."
- category: Clinical
  name: Macrocephaly
  description: >
    Megalencephaly or macrocephaly (occipitofrontal circumference ≥ 97th percentile)
    is among the most prevalent features of PTEN-associated disorders, occurring in
    approximately 80% of affected individuals. It reflects PTEN's role in regulating
    neuronal cell size and cortical structure and is a prominent feature of
    Bannayan-Riley-Ruvalcaba syndrome, the childhood-onset form of PHTS.
  phenotype_term:
    preferred_term: Macrocephaly
    term:
      id: HP:0000256
      label: Macrocephaly
  evidence:
  - reference: PMID:17526800
    reference_title: "Cowden syndrome and Bannayan Riley Ruvalcaba syndrome represent one condition with variable expression and age-related penetrance: results of a clinical study of PTEN mutation carriers."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Bannayan-Riley-Ruvalcaba syndrome (BRRS), with childhood onset, macrocephaly, lipomas and developmental delay, and Cowden Syndrome (CS), an adult-onset condition recognised by mucocutaneous signs, with a risk of cancers, in particular those of the thyroid and breast."
    explanation: "Documents macrocephaly as a characteristic feature across the PTEN mutation phenotypic spectrum, particularly in the childhood-onset BRRS form."
- category: Clinical
  name: Breast Cancer Risk
  description: >
    PTEN mutation carriers face a lifetime breast cancer risk of approximately 77-85%,
    with both invasive carcinoma and benign fibrocystic changes being common. Risk
    management includes enhanced surveillance with annual MRI from age 30 and
    mammography from age 40, or prophylactic mastectomy.
  phenotype_term:
    preferred_term: Breast carcinoma
    term:
      id: HP:0003002
      label: Breast carcinoma
  evidence:
  - reference: PMID:23335809
    reference_title: High cumulative risks of cancer in patients with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Elevated SIRs were found mainly for female breast cancer (39.1, 95% CI 24.8 to 58.6), thyroid cancer in women (43.2, 95% CI 19.7 to 82.1) and in men (199.5, 95% CI 106.39 to 342.03), melanoma in women (28.3, 95% CI 7.6 to 35.4) and in men (39.4, 95% CI 10.6 to 100.9), and endometrial cancer (48.7, 95% CI 9.8 to 142.3)."
    explanation: "Demonstrates markedly elevated standardized incidence ratios (SIR 39.1) for breast cancer in female PTEN mutation carriers, confirming the substantially increased breast cancer risk in Cowden syndrome."
- category: Clinical
  name: Thyroid Abnormalities
  description: >
    Non-medullary thyroid cancer (follicular and papillary subtypes) occurs in
    approximately 35% of PTEN mutation carriers. Benign thyroid conditions including
    multinodular goiter, follicular adenoma, and Hashimoto thyroiditis are also
    common; up to 75% of individuals develop some thyroid disease.
  phenotype_term:
    preferred_term: Thyroid carcinoma
    term:
      id: HP:0002890
      label: Thyroid carcinoma
  evidence:
  - reference: PMID:32533092
    reference_title: Cancer Surveillance Guideline for individuals with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "There is strong evidence of an increased risk of thyroid carcinoma in PHTS with evidence that this can arise at relatively young ages."
    explanation: "Confirms strong clinical evidence for increased thyroid carcinoma risk in PTEN hamartoma tumor syndrome/Cowden syndrome."
- category: Clinical
  name: Uterine Cancer Risk
  description: >
    Germline PTEN mutations confer a lifetime risk of endometrial cancer of approximately
    28%, substantially higher than the general population risk (~3%). The endometrium
    is particularly sensitive to PTEN loss because somatic PTEN mutations are the most
    common alteration in sporadic endometrial cancers.
  phenotype_term:
    preferred_term: Endometrial carcinoma
    term:
      id: HP:0012114
      label: Endometrial carcinoma
  evidence:
  - reference: PMID:23335809
    reference_title: High cumulative risks of cancer in patients with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Elevated SIRs were found mainly for female breast cancer (39.1, 95% CI 24.8 to 58.6), thyroid cancer in women (43.2, 95% CI 19.7 to 82.1) and in men (199.5, 95% CI 106.39 to 342.03), melanoma in women (28.3, 95% CI 7.6 to 35.4) and in men (39.4, 95% CI 10.6 to 100.9), and endometrial cancer (48.7, 95% CI 9.8 to 142.3)."
    explanation: "Documents a substantially elevated standardized incidence ratio (SIR 48.7) for endometrial cancer in PHTS, confirming uterine cancer as a major cancer risk in Cowden syndrome."
- category: Clinical
  name: Lhermitte-Duclos Disease
  description: >
    Lhermitte-Duclos disease (LDD, dysplastic gangliocytoma of the cerebellum) is a
    pathognomonic central nervous system manifestation of Cowden syndrome, characterized
    by replacement of normal Purkinje cells with dysplastic ganglion cells. A systematic
    review of 302 LDD cases found that 32.8% were associated with Cowden syndrome and
    19.9% had confirmed PTEN mutation. Symptoms include headache (57.6%) and cerebellar
    ataxia (36.1%); the radiologic "tiger-stripe" appearance on MRI is pathognomonic.
  phenotype_term:
    preferred_term: Lhermitte-Duclos disease
    term:
      id: HP:0500009
      label: Dysplastic gangliocytoma of the cerebellum
  evidence:
  - reference: PMID:37810307
    reference_title: "Lhermitte-Duclos disease: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lhermitte-Duclos disease (LDD) is a rare tumor, with only about 300 reported cases. It often shows comorbidity with Cowden syndrome (CS); however, it can occur by itself."
    explanation: "Confirms the well-established association between Lhermitte-Duclos disease and Cowden syndrome in a systematic review of 302 cases, with 32.8% of LDD showing CS comorbidity."
- category: Clinical
  name: Gastrointestinal Hamartomatous Polyps
  description: >
    Hamartomatous polyps of the gastrointestinal tract occur throughout the GI tract
    in more than 90% of individuals with Cowden syndrome. They are typically benign
    but may cause bleeding or obstruction, and are associated with a modestly increased
    colorectal cancer risk (~9-16% lifetime).
  phenotype_term:
    preferred_term: Hamartomatous intestinal polyposis
    term:
      id: HP:0004390
      label: Hamartomatous polyposis
  evidence:
  - reference: PMID:32533092
    reference_title: Cancer Surveillance Guideline for individuals with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Polyps are common in PHTS, and these are typically hamartomas, although other types can also occur."
    explanation: "Confirms hamartomatous GI polyps as a common feature of PTEN hamartoma tumor syndrome/Cowden syndrome."
- category: Clinical
  name: Autism Spectrum Disorder
  description: >
    Autism spectrum disorder (ASD) is a recognised neurodevelopmental manifestation of
    PHTS/Cowden syndrome. Approximately 20-23% of PHTS individuals are diagnosed with ASD,
    and germline PTEN mutations account for ~0.2-1% of all ASD and ~17% of ASD with
    macrocephaly. ASD-associated PTEN mutations disrupt early neuroectoderm formation
    and downstream cortical layering through PI3K/AKT/mTOR over-activation in cortical
    progenitors.
  phenotype_term:
    preferred_term: Autism
    term:
      id: HP:0000717
      label: Autism
  evidence:
  - reference: PMID:38030818
    reference_title: Germline PTEN genotype-dependent phenotypic divergence during the early neural developmental process of forebrain organoids.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Individuals with germline PTEN mutations receive the molecular diagnosis of PTEN Hamartoma Tumor Syndrome (PHTS), an inherited cancer predisposition syndrome, about 20-23% of whom are diagnosed with ASD."
    explanation: "iPSC-derived forebrain organoid study (IN_VITRO) reports the 20-23% PHTS-ASD frequency in its background, citing prior human-clinical literature; classified by the publication's primary evidence type. Human-cohort confirmation is provided separately by PMID:33509259."
  - reference: PMID:33509259
    reference_title: Cross-level analysis of molecular and neurobehavioral function in a prospective series of patients with germline heterozygous PTEN mutations with and without autism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "PTEN is a well-established risk gene for autism spectrum disorder (ASD)."
    explanation: "Multi-center prospective patient cohort confirms PTEN as an established ASD risk gene, supporting ASD as a Cowden/PHTS clinical phenotype."
- category: Clinical
  name: Developmental Delay and Intellectual Disability
  description: >
    Global developmental delay and intellectual disability are common neurodevelopmental
    manifestations of PHTS/Cowden syndrome, particularly in the childhood-onset
    Bannayan-Riley-Ruvalcaba end of the spectrum. Pediatric PHTS cohorts report DD/ID in
    approximately 42% of patients (a higher frequency than autism spectrum disorder
    itself), often co-occurring with macrocephaly. Cognitive impairment in PTEN mutation
    carriers ranges from mild language delays to moderate-severe global cognitive
    dysfunction; impairments in general cognitive ability are most common in PTEN-ASD
    cases but neurobehavioral variability is high across the PHTS spectrum.
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:17526800
    reference_title: "Cowden syndrome and Bannayan Riley Ruvalcaba syndrome represent one condition with variable expression and age-related penetrance: results of a clinical study of PTEN mutation carriers."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Bannayan-Riley-Ruvalcaba syndrome (BRRS), with childhood onset, macrocephaly, lipomas and developmental delay"
    explanation: "Establishes developmental delay as a defining clinical feature of the BRRS end of the PHTS spectrum (CS and BRRS are now recognised as a single PHTS condition with variable expression)."
  - reference: PMID:33509259
    reference_title: Cross-level analysis of molecular and neurobehavioral function in a prospective series of patients with germline heterozygous PTEN mutations with and without autism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "impairments in general cognitive ability are only common in PTEN-ASD. For most neurobehavioral measures, variability within and across patient groups was very large, with some patients functioning in the average or above average range in most neurocognitive domains and other patients showing moderate to severe global cognitive dysfunction"
    explanation: "Multi-center prospective PHTS cohort documents the spectrum of cognitive impairment, supporting global developmental delay / intellectual disability as a distinct clinical phenotype distinguishable from ASD diagnosis itself."
- category: Clinical
  name: Lipoma
  description: >
    Subcutaneous and visceral lipomas are common in PHTS/Cowden syndrome and are part
    of the diagnostic criteria. Lipomas reflect adipocyte over-proliferation driven by
    PI3K/AKT pathway hyperactivation in PTEN-haploinsufficient mesenchymal cells. They
    are particularly characteristic of the Bannayan-Riley-Ruvalcaba (childhood-onset)
    end of the PHTS spectrum but also occur in adult Cowden syndrome.
  phenotype_term:
    preferred_term: Lipoma
    term:
      id: HP:0012032
      label: Lipoma
  evidence:
  - reference: PMID:18781191
    reference_title: PTEN hamartoma tumor syndromes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Bannayan-Riley-Ruvalcaba syndrome (BRRS), characterized by the developmental delay, macrocephaly, lipomas, hemangiomas, and speckled penis in males, is associated with PTEN mutations in approximately 60% of cases."
    explanation: "Establishes lipomas as a defining clinical feature of the BRRS end of the PHTS spectrum; CS and BRRS are now recognised as one PHTS condition with variable expression, so lipomas are a Cowden-spectrum phenotype."
  - reference: PMID:40120468
    reference_title: "Spontaneous tonsillar hemorrhage in a patient with PTEN mutation: A case report and systematic literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Phosphatase and tensin homolog hamartoma tumor syndrome (PTEN Syndrome), an autosomal dominant group of disorders caused by PTEN dysregulation, predisposes patients to hamartomas, lipomas, vascular tumors/malformations, and potential malignancies."
    explanation: "Independent confirmation of lipomas as a recognised feature of the PTEN syndrome spectrum, including Cowden syndrome."
- category: Clinical
  name: Vascular Anomalies
  description: >
    Vascular anomalies — including arteriovenous malformations (AVMs), arteriovenous
    fistulas, hemangiomas, and venous malformations — are recognised features of
    PHTS/Cowden syndrome, particularly affecting the extremities and central nervous
    system. They are thought to arise from PTEN-deficient endothelial proliferation and
    PI3K/AKT pathway dysregulation in the vascular bed. Spinal and intracranial AVMs
    have been reported and may produce neurological signs. The descriptor binds to AVM
    as the most consistently reported vascular lesion in CS case series; venous
    malformations and hemangiomas are also reported but lack a single covering term.
  phenotype_term:
    preferred_term: Arteriovenous malformation
    term:
      id: HP:0100026
      label: Arteriovenous malformation
  evidence:
  - reference: PMID:39048366
    reference_title: Spinal Dural Arteriovenous Fistulas in a Patient with Cowden Syndrome and a Phosphatase and Tensin Homolog Mutation.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Vascular malformations are common in CS, particularly in the extremities."
    explanation: "Direct clinical statement that vascular malformations are common in Cowden syndrome, with case-level evidence of spinal dural arteriovenous fistulas associated with a truncating PTEN mutation."
  - reference: PMID:40120468
    reference_title: "Spontaneous tonsillar hemorrhage in a patient with PTEN mutation: A case report and systematic literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "predisposes patients to hamartomas, lipomas, vascular tumors/malformations, and potential malignancies."
    explanation: "Independent statement of vascular tumors/malformations as a defining PHTS phenotype."
- category: Clinical
  name: Renal Cell Carcinoma
  description: >
    PTEN mutation carriers face a markedly elevated lifetime risk of renal cell carcinoma
    (estimated 2-34% across PHTS cohorts and surveillance guideline projections, vs.
    ~1.6% general population). KLLN-methylation (Cowden syndrome 2) carriers may have
    higher renal cancer risk than PTEN-mutation-positive patients alone. Screening renal
    ultrasound is recommended every 2 years from age 40.
  phenotype_term:
    preferred_term: Renal cell carcinoma
    term:
      id: HP:0005584
      label: Renal cell carcinoma
  evidence:
  - reference: PMID:32533092
    reference_title: Cancer Surveillance Guideline for individuals with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The projected estimated lifetime risks of cancer in individuals with PHTS range from 85 to 89% for any cancer, 67 to 85% for female breast cancer, 6 to 38% for thyroid cancer, 2 to 28% for endometrial cancer, 2 to 34% for renal cancer, 9 to 20% for colorectal cancer and 0 to 6% for melanoma."
    explanation: "European expert consensus places lifetime renal cancer risk at 2-34%, motivating renal cell carcinoma as a distinct PHTS/Cowden phenotype with surveillance recommendations."
  - reference: PMID:21177507
    reference_title: Germline epigenetic regulation of KILLIN in Cowden and Cowden-like syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Germline KILLIN methylation is common among patients with Cowden syndrome or Cowden-like syndrome and is associated with increased risks of breast and renal cancer over PTEN mutation-positive individuals."
    explanation: "Identifies KLLN-methylation Cowden syndrome 2 as conferring particularly elevated renal cancer risk relative to classical PTEN-mutation cases."
- category: Clinical
  name: Colorectal Cancer
  description: >
    Lifetime colorectal cancer risk in PHTS is estimated at ~9-20%, substantially higher
    than the general-population background (~4%). Hamartomatous colon polyps are nearly
    universal in adult Cowden syndrome and may, in a subset, transform to adenomatous
    lesions and carcinoma. Baseline colonoscopy at age 35-40 with surveillance intervals
    based on findings is recommended.
  phenotype_term:
    preferred_term: Colon cancer
    term:
      id: HP:0003003
      label: Colon cancer
  evidence:
  - reference: PMID:32533092
    reference_title: Cancer Surveillance Guideline for individuals with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "9 to 20% for colorectal cancer"
    explanation: "European expert consensus quantifies the elevated colorectal cancer risk (9-20% lifetime) that motivates including colorectal carcinoma as a recognised PHTS/Cowden phenotype."

genetic:
- name: PTEN
  gene_term:
    preferred_term: PTEN
    term:
      id: hgnc:9588
      label: PTEN
  association: Causative
  inheritance:
  - name: Autosomal dominant
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
    evidence:
    - reference: PMID:21194675
      reference_title: A clinical scoring system for selection of patients for PTEN mutation testing is proposed on the basis of a prospective study of 3042 probands.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Cowden syndrome (CS) and Bannayan-Riley-Ruvalcaba syndrome are allelic, defined by germline PTEN mutations, and collectively referred to as PTEN hamartoma tumor syndrome."
      explanation: "Establishes autosomal dominant germline PTEN mutations as the cause of Cowden syndrome: each affected generation inherits one pathogenic allele."
  notes: >
    Germline loss-of-function mutations in PTEN (MIM 601728) on chromosome 10q22-23
    are identified in approximately 80% of patients meeting strict clinical diagnostic
    criteria for Cowden syndrome. Mutations include nonsense, frameshift, missense,
    splice-site variants, and large deletions.
  evidence:
  - reference: PMID:21194675
    reference_title: A clinical scoring system for selection of patients for PTEN mutation testing is proposed on the basis of a prospective study of 3042 probands.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cowden syndrome (CS) and Bannayan-Riley-Ruvalcaba syndrome are allelic, defined by germline PTEN mutations, and collectively referred to as PTEN hamartoma tumor syndrome."
    explanation: "Establishes PTEN germline mutations as the defining genetic cause of Cowden syndrome in a large prospective cohort of 3042 probands."
- name: KLLN
  gene_term:
    preferred_term: KLLN
    term:
      id: hgnc:37212
      label: KLLN
  association: Causative
  inheritance:
  - name: Autosomal dominant
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
    evidence:
    - reference: PMID:21177507
      reference_title: Germline epigenetic regulation of KILLIN in Cowden and Cowden-like syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Germline KILLIN methylation is common among patients with Cowden syndrome or Cowden-like syndrome and is associated with increased risks of breast and renal cancer over PTEN mutation-positive individuals."
      explanation: "Confirms KLLN/KILLIN germline epigenetic silencing as a heritable mechanism in Cowden syndrome 2, transmitted in an autosomal dominant pattern through the PTEN-KLLN bidirectional promoter locus."
  notes: >
    Promoter hypermethylation (epimutation) or deletion of KILLIN (KLLN), a p53
    co-regulated tumor suppressor transcribed in the opposite direction from the same
    PTEN promoter, is found in approximately 37% of Cowden/Cowden-like syndrome patients
    lacking PTEN coding mutations. KLLN down-regulation by 250-fold leads to loss of
    p53-activated DNA synthesis inhibition and apoptosis, conferring higher breast and
    kidney cancer risk than PTEN mutation alone.
  evidence:
  - reference: PMID:21177507
    reference_title: Germline epigenetic regulation of KILLIN in Cowden and Cowden-like syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Germline KILLIN methylation is common among patients with Cowden syndrome or Cowden-like syndrome and is associated with increased risks of breast and renal cancer over PTEN mutation-positive individuals."
    explanation: "Establishes KLLN germline methylation as a distinct molecular subtype of Cowden syndrome with measurably elevated cancer risks."
- name: PIK3CA
  gene_term:
    preferred_term: PIK3CA
    term:
      id: hgnc:8975
      label: PIK3CA
  association: Susceptibility in PTEN-negative Cowden-like syndrome
  relationship_type: SUSCEPTIBILITY
  inheritance:
  - name: Autosomal dominant
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
    evidence:
    - reference: PMID:23246288
      reference_title: Germline PIK3CA and AKT1 mutations in Cowden and Cowden-like syndromes.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Our observations suggest that PIK3CA and AKT1 are CS susceptibility genes."
      explanation: "Establishes PIK3CA germline mutations as a cause of Cowden syndrome 3 through direct activation of the PI3K/AKT pathway, with autosomal dominant inheritance."
  notes: >
    Activating germline mutations in PIK3CA (the catalytic p110alpha subunit of PI3-kinase)
    are identified in approximately 8.8% of PTEN mutation-negative Cowden/Cowden-like
    syndrome individuals and result in significantly increased phospho-AKT and cellular
    PIP3. Current nosology should treat this as PTEN-negative Cowden-like susceptibility,
    not as classic PTEN-defined Cowden syndrome. This directly activates the same
    downstream pathway affected by PTEN loss.
  evidence:
  - reference: PMID:23246288
    reference_title: Germline PIK3CA and AKT1 mutations in Cowden and Cowden-like syndromes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report that 8 of 91 (8.8%) unrelated CS individuals without germline PTEN mutations carried 10 germline PIK3CA mutations (7 missense, 1 nonsense, and 2 indels) and 2 (2.2%) AKT1 mutations. These mutations result in significantly increased P-Thr308-AKT and increased cellular PIP3."
    explanation: "Directly identifies PIK3CA germline mutations in Cowden syndrome patients lacking PTEN mutations, confirming PIK3CA as a causative gene in Cowden syndrome 3."
- name: SDHB
  gene_term:
    preferred_term: SDHB
    term:
      id: hgnc:10681
      label: SDHB
  association: Susceptibility in PTEN-negative Cowden-like syndrome
  relationship_type: SUSCEPTIBILITY
  inheritance:
  - name: Autosomal dominant
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
    evidence:
    - reference: PMID:18678321
      reference_title: Germline mutations and variants in the succinate dehydrogenase genes in Cowden and Cowden-like syndromes.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Germline SDH mutations/variants occur in a subset of PTEN mutation-negative CS/CS-like individuals and are associated with increased frequencies of breast, thyroid, and renal cancers beyond those conferred by germline PTEN mutations."
      explanation: "Establishes SDHB/SDHD germline mutations as heritable CS4/CS5 causes via autosomal dominant inheritance, manifesting increased breast, thyroid, and renal cancer risk."
  notes: >
    Germline mutations in SDHB (succinate dehydrogenase subunit B) occur in approximately
    13.5% of Cowden/Cowden-like individuals with mitochondrial dysfunction markers and no
    PTEN alteration (10/74 SDH-variants in 375 PTEN-negative CS/CS-like individuals).
    Current nosology should treat this as PTEN-negative Cowden-like susceptibility, not
    as classic PTEN-defined Cowden syndrome. SDH mutations cause mitochondrial
    dysfunction, pseudohypoxia via HIF-1alpha stabilization, and activation of AKT/MAPK
    signaling downstream of PTEN.
  evidence:
  - reference: PMID:18678321
    reference_title: Germline mutations and variants in the succinate dehydrogenase genes in Cowden and Cowden-like syndromes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Germline SDH mutations/variants occur in a subset of PTEN mutation-negative CS/CS-like individuals and are associated with increased frequencies of breast, thyroid, and renal cancers beyond those conferred by germline PTEN mutations."
    explanation: "Establishes SDHB germline mutations as a causative factor in Cowden syndrome 4, found in PTEN-mutation-negative individuals with elevated cancer risk."

diagnosis:
- name: Clinical Cowden syndrome diagnostic criteria
  description: >
    Clinical diagnosis should apply the Cowden syndrome pathognomonic, major, and
    minor criteria before or alongside molecular testing. Pathognomonic criteria
    include adult Lhermitte-Duclos disease and characteristic mucocutaneous lesions
    such as multiple facial trichilemmomas, oral mucosal papillomatosis with acral
    keratoses, or multiple palmoplantar keratoses. Major criteria include breast
    cancer, non-medullary thyroid cancer, macrocephaly, and endometrial carcinoma.
    Minor criteria include other thyroid lesions, intellectual disability,
    hamartomatous intestinal polyps, lipomas, fibromas, genitourinary tumors
    including renal cell carcinoma, genitourinary malformations, and uterine
    fibroids. A clinical diagnosis is met by a pathognomonic mucocutaneous pattern,
    two or more major criteria, one major plus at least three minor criteria, or
    four or more minor criteria.
  diagnosis_term:
    preferred_term: clinical assessment
    term:
      id: MAXO:0000487
      label: clinical assessment
  evidence:
  - 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: OTHER
    snippet: "Consensus clinical diagnostic criteria have been divided into three categories: pathognomonic, major, and minor."
    explanation: GeneReviews provides the pathognomonic/major/minor clinical criteria framework for Cowden syndrome.
  - 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: OTHER
    snippet: "A clinical diagnosis of CS</b> is established if an individual meets <b>any one</b> of the following criteria:"
    explanation: GeneReviews supports applying rule-based clinical diagnostic combinations before or alongside molecular confirmation.
- name: PTEN molecular genetic testing cascade
  description: >
    Molecular confirmation of classic PHTS/Cowden syndrome is by identifying a
    heterozygous germline pathogenic PTEN variant. Testing should start with PTEN
    sequence analysis, then deletion/duplication analysis if sequencing is negative,
    and PTEN promoter sequencing if no pathogenic variant is found. If the phenotype
    remains Cowden-like without a PTEN finding, consider Cowden-like susceptibility
    mechanisms such as KLLN epimutation, SDHx, PIK3CA, AKT1, SEC23B, and WWP1 rather
    than treating them as equivalent to classic PTEN Cowden syndrome.
  diagnosis_term:
    preferred_term: molecular genetic testing
    term:
      id: MAXO:0000533
      label: molecular genetic testing
  evidence:
  - 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 establishes heterozygous germline PTEN pathogenic variation as the molecular diagnostic basis for PHTS.
  - 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: OTHER
    snippet: "Sequence analysis of <i>PTEN</i> is performed first and followed by gene-targeted deletion/duplication analysis if no pathogenic variant is found."
    explanation: GeneReviews supports the PTEN sequence-first, deletion/duplication-second testing cascade.
  - 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: OTHER
    snippet: "Susceptibility genes in individuals with non-PHTS CS and CLS."
    explanation: GeneReviews separates non-PHTS Cowden/Cowden-like susceptibility genes from classic PTEN-defined PHTS.
- name: Testing and counseling of at-risk relatives
  description: >
    Once a familial PTEN pathogenic variant is identified, asymptomatic at-risk
    relatives should be offered molecular testing so that carriers can enter organ-
    specific surveillance and non-carriers can avoid unnecessary PHTS surveillance.
    Counseling should cover autosomal dominant inheritance, incomplete clinical
    recognition, cancer risks, reproductive options, and the need for surveillance
    beginning before many cancers develop.
  diagnosis_term:
    preferred_term: molecular genetic testing
    term:
      id: MAXO:0000533
      label: molecular genetic testing
  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 familial variant testing to determine which relatives need PHTS surveillance.
treatments:
- name: Enhanced Cancer Surveillance
  description: >
    PTEN mutation carriers require life-long intensified surveillance protocols.
    GeneReviews and ERN GENTURIS support organ-specific surveillance that includes
    breast awareness and clinical examination, annual breast MRI beginning around
    age 30 with mammography incorporated by age 40, yearly thyroid ultrasound,
    dermatologic evaluation, baseline colonoscopy at age 35-40 with intervals based
    on findings, renal imaging from age 40, and earlier screening 5-10 years before
    the youngest cancer in a family when family history indicates. Endometrial
    surveillance should be framed as consideration rather than universal screening:
    GeneReviews recommends considering screening by age 35 with endometrial biopsy
    every 1-2 years and/or postmenopausal transvaginal ultrasound at clinician
    discretion, while ERN GENTURIS notes weak evidence and recommends symptom
    education or clinical-trial-based screening.
  treatment_term:
    preferred_term: cancer surveillance
    term:
      id: MAXO:0000126
      label: cancer screening
  evidence:
  - reference: PMID:32533092
    reference_title: Cancer Surveillance Guideline for individuals with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Recommendations were put forward for surveillance for breast, thyroid and renal cancers. Limited recommendations were developed for other sites including endometrial, colon and skin."
    explanation: "Provides evidence-based surveillance recommendations for PHTS/Cowden syndrome from the European Reference Network for Genetic Tumour Risk Syndromes."
  - reference: PMID:20301661
    reference_title: "PTEN Hamartoma Tumor Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Women beginning at age 30 years. Monthly breast self-examination; annual breast screening (at minimum mammogram; MRI may also be incorporated). Starting by age 35 years, consider transvaginal ultrasound or endometrial biopsy."
    explanation: GeneReviews supports breast screening from age 30 and consideration of endometrial screening from age 35.
  - reference: PMID:20301661
    reference_title: "PTEN Hamartoma Tumor Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Men and women. Colonoscopy beginning at age 35 years with frequency dependent on degree of polyposis identified or family history of early-onset colon cancer (before age 40); biennial (every 2 years) renal imaging (CT or MRI preferred) beginning at age 40 years."
    explanation: GeneReviews supports colorectal and renal surveillance age/interval guidance.
  - reference: PMID:20301661
    reference_title: "PTEN Hamartoma Tumor Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Adults. Yearly thyroid ultrasound and dermatologic evaluation."
    explanation: GeneReviews supports yearly thyroid and dermatologic surveillance in adults.
  - reference: PMID:20301661
    reference_title: "PTEN Hamartoma Tumor Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Those with a family history of a particular cancer type at an early age. Consider initiating screening 5 to 10 years prior to the youngest age of diagnosis in the family."
    explanation: GeneReviews supports earlier family-history-driven surveillance starts.
- name: Prophylactic Mastectomy
  description: >
    Risk-reducing bilateral mastectomy reduces breast cancer risk by more than 90% in
    PTEN mutation carriers with high personal or family risk. It is offered as an option
    after careful counseling regarding elevated lifetime risk, using the same approach
    as for BRCA1/BRCA2 carriers.
  treatment_term:
    preferred_term: prophylactic mastectomy
    term:
      id: MAXO:0000004
      label: surgical procedure
  evidence:
  - reference: PMID:32533092
    reference_title: Cancer Surveillance Guideline for individuals with PTEN hamartoma tumour syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Risk reduction surgery should be offered using the same considerations as for women with germline BRCA1/BRCA2 pathogenic variants"
    explanation: "Supports offering prophylactic mastectomy in PTEN mutation carriers following the same approach as for BRCA1/BRCA2, given comparable breast cancer risk levels."
- name: mTOR Inhibitor Therapy
  description: >
    Everolimus (RAD001), an mTORC1 inhibitor, targets the hyperactivated PI3K/AKT/mTOR
    pathway in Cowden syndrome. The mechanistic rationale stems directly from PTEN loss
    driving constitutive mTOR activation. A 6-month phase II placebo-controlled randomised
    trial of everolimus in 46 PHTS individuals (5-45 years) demonstrated that the drug is
    well tolerated; the primary neurocognitive endpoint was not met but several secondary
    neurobehavioral measures and EEG biomarkers showed signals of improvement, supporting
    continued investigation rather than routine clinical use.
  treatment_term:
    preferred_term: mTOR inhibitor pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    therapeutic_agent:
    - preferred_term: everolimus
      term:
        id: CHEBI:68478
        label: everolimus
  evidence:
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "PTEN hamartoma tumor syndrome (PHTS) is a complex neurodevelopmental disorder characterized by mechanistic target of rapamycin (mTOR) overactivity. Limited data suggest that mTOR inhibitors may be therapeutic."
    explanation: "Establishes the mechanistic rationale (mTOR overactivity) and motivates the placebo-controlled trial of everolimus in PHTS that this paper reports."
  - reference: PMID:35594551
    reference_title: A randomized controlled trial of everolimus for neurocognitive symptoms in PTEN hamartoma tumor syndrome.
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "Everolimus is well tolerated in PHTS; adverse events were similar to previous reports. The primary efficacy endpoint did not reveal improvement."
    explanation: "Phase II RCT (n=46) shows everolimus is well tolerated in PHTS but did not meet its primary neurocognitive endpoint. Supports `PARTIAL`: pharmacology supports the mTOR-inhibition rationale, but no confirmed cognitive benefit yet — clinical use remains investigational."
  - reference: PMID:18781191
    reference_title: PTEN hamartoma tumor syndromes.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Concomitant with improved understanding of the biology of PTEN and the PI3K/Akt/mTOR pathway, inhibitors of this pathway are being developed as anticancer agents. These medications could have applications for patients with PHTS, for whom no medical options currently exist."
    explanation: "Originally established the rationale for mTOR/PI3K inhibitor therapy in PHTS based on the underlying molecular mechanism (expert review, predates clinical trial data)."
- name: Genetic Counseling
  description: >
    Genetic counseling is recommended for all patients with suspected or confirmed
    Cowden syndrome and their at-risk family members, informing testing decisions,
    cancer risks, and surveillance strategies.
  treatment_term:
    preferred_term: genetic counseling
    term:
      id: MAXO:0000079
      label: genetic counseling
  evidence:
  - reference: PMID:31433956
    reference_title: The Clinical Spectrum of PTEN Mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Timely diagnosis and understanding the natural history of PHTS are vital because early recognition enables gene-informed management, particularly as related to high-risk cancer surveillance and addressing the neurodevelopmental symptoms."
    explanation: "Highlights the importance of genetic diagnosis enabling gene-informed counseling and management in PHTS/Cowden syndrome."

clinical_trials:
- name: NCT02991807
  phase: PHASE_II
  status: COMPLETED
  description: >
    A six-month randomized, double-blind, placebo-controlled phase II trial of
    everolimus (RAD001) in 46 individuals (5-45 years) with PTEN mutations,
    examining safety and efficacy on neurocognitive and behavioral outcomes
    in PHTS. Reported in Srivastava et al. 2022 (PMID:35594551). The primary
    neurocognitive endpoint was not met; everolimus was well tolerated and
    several secondary measures and EEG biomarkers showed signals of improvement.
  target_phenotypes:
  - preferred_term: Autism
    term:
      id: HP:0000717
      label: Autism
  - preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  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
    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: "ClinicalTrials.gov record for the everolimus phase II RCT in PHTS — formal registry capture of the study reported as PMID:35594551 in the mTOR Inhibitor Therapy treatment entry."
references:
- reference: PMID:20301661
  title: "PTEN Hamartoma Tumor Syndrome."
  tags:
  - GeneReviews
  findings:
  - statement: GeneReviews supports Cowden syndrome/PHTS diagnostic testing, surveillance, inheritance, and family testing guidance used in this entry.
    supporting_text: PMID:20301661 for the GeneReviews clinical characteristics, diagnosis/testing, management, surveillance, and genetic counseling summary.
- reference: 'url:https://www.ncbi.nlm.nih.gov/books/NBK1488/?report=printable'
  title: "PTEN Hamartoma Tumor Syndrome - GeneReviews® - NCBI Bookshelf"
  tags:
  - GeneReviews
  findings:
  - statement: Full GeneReviews chapter supports the pathognomonic/major/minor diagnostic criteria, PTEN testing cascade, and non-PHTS Cowden-like gene-boundary nuance.
    supporting_text: Full GeneReviews chapter for detailed Cowden syndrome clinical diagnostic criteria and molecular testing approach.

📚

References & Deep Research

References

PMID:20301661

PTEN Hamartoma Tumor Syndrome.

1 finding

GeneReviews supports Cowden syndrome/PHTS diagnostic testing, surveillance, inheritance, and family testing guidance used in this entry.

"PMID:20301661 for the GeneReviews clinical characteristics, diagnosis/testing, management, surveillance, and genetic counseling summary."

url:https://www.ncbi.nlm.nih.gov/books/NBK1488/?report=printable

PTEN Hamartoma Tumor Syndrome - GeneReviews® - NCBI Bookshelf

1 finding

Full GeneReviews chapter supports the pathognomonic/major/minor diagnostic criteria, PTEN testing cascade, and non-PHTS Cowden-like gene-boundary nuance.

"Full GeneReviews chapter for detailed Cowden syndrome clinical diagnostic criteria and molecular testing approach."

Deep Research

Falcon ▸

Cowden Syndrome (PTEN Hamartoma Tumor Syndrome, PHTS): Disease Characteristics Research Report

Edison Scientific Literature 46 citations 2026-04-25T17:04:44.801252

Cowden Syndrome (PTEN Hamartoma Tumor Syndrome, PHTS): Disease Characteristics Research Report

1. Disease Information

1.1 Concise overview

Cowden syndrome (CS) is a multisystem hamartoma and cancer predisposition disorder within the broader PTEN hamartoma tumor syndrome (PHTS) spectrum, characterized by mucocutaneous lesions, macrocephaly, gastrointestinal hamartomatous polyps, and elevated risks of multiple malignancies (notably breast, thyroid, endometrial, colorectal, and renal cancers). It is typically caused by heterozygous germline pathogenic variants in PTEN, resulting in dysregulated growth control via PI3K/AKT/mTOR signaling. (pirlog2024insightsintoclinical pages 1-2, takayama2023clinicalguidelinesfor pages 2-4)

1.2 Key identifiers (as available from retrieved sources)

MONDO: Cowden syndrome 1 MONDO_0008021; Cowden disease MONDO_0016063 (cummings2023cancerriskassociated pages 1-2)
OMIM: Cowden syndrome 158350 (explicitly stated in a 2023 case review) (jurca2023anewframeshift pages 9-10)
Orphanet / ICD-10 / ICD-11 / MeSH: Not found in retrieved sources in this run (insufficient evidence in retrieved texts to cite).

1.3 Synonyms and alternative names

Cowden syndrome; Cowden disease; PTEN hamartoma tumor syndrome (umbrella term) (takayama2023clinicalguidelinesfor pages 2-4, pilarski2019ptenhamartomatumor pages 1-3)
Related phenotypes within the PHTS umbrella include Bannayan–Riley–Ruvalcaba syndrome (BRRS), Proteus syndrome, Proteus-like syndrome, and adult Lhermitte–Duclos disease (pilarski2019ptenhamartomatumor pages 1-3, pirlog2024insightsintoclinical pages 1-2).

1.4 Evidence provenance (individual-level vs aggregated resources)

Much of the evidence base for CS/PHTS includes (i) aggregated guideline and cohort estimates (e.g., lifetime cancer risk ranges across cohorts, surveillance guidelines) and (ii) clinic-ascertained cohorts with ascertainment bias concerns. For example, cancer risk estimates vary substantially across studies, and reviews emphasize cautious interpretation because cohorts often include index cases and prevalent cancers. (hendricks2021areviewon pages 1-4, pilarski2019ptenhamartomatumor pages 3-5)

2. Etiology

2.1 Disease causal factors

Primary cause: heterozygous germline pathogenic variants in the tumor suppressor PTEN (autosomal dominant), leading to loss of PTEN function and downstream pathway dysregulation. (pirlog2024insightsintoclinical pages 1-2, takayama2023clinicalguidelinesfor pages 2-4)

Pathway consequence: PTEN normally dephosphorylates PIP3 to PIP2, antagonizing PI3K signaling and limiting AKT/mTOR pathway activation. PTEN loss-of-function therefore permits increased PI3K/AKT/mTOR signaling that promotes overgrowth/hamartomas and cancer predisposition. (yehia2020ptenhamartomatumour pages 5-6, pirlog2024insightsintoclinical pages 1-2)

2.2 Risk factors

Genetic: Germline PTEN pathogenic variants drive disease and confer elevated risks of multiple cancers (breast, endometrium, thyroid, colon polyposis/cancer, renal). In a large hereditary cancer panel-testing cohort (727,091 individuals tested), PTEN PV carriers had increased risk (odds ratios) for female breast cancer (OR 7.88), endometrial cancer (OR 13.51), thyroid cancer (OR 4.88), and colon polyposis (OR 31.60), with modest evidence for ovarian cancer (OR 3.77). (cummings2023cancerriskassociated pages 1-2)
Phenotype-genotype heterogeneity: Clinical CS criteria and PTEN-variant status incompletely overlap: reviews note only ~30–35% of individuals meeting clinical CS diagnostic criteria have detectable PTEN variants, underscoring heterogeneity and the role of ascertainment. (pilarski2019ptenhamartomatumor pages 1-3, cummings2023cancerriskassociated pages 1-2)

2.3 Protective factors

No specific genetic or environmental protective factors were identified in retrieved sources.

2.4 Gene–environment interactions

No explicit gene–environment interaction evidence for CS/PHTS was identified in retrieved sources.

3. Phenotypes

The phenotype spectrum is broad and age-dependent, with pediatric presentations often dominated by macrocephaly and neurodevelopmental issues, and adult presentations more often demonstrating classic mucocutaneous lesions, polyposis, and malignancies. (martinvalbuena2024ptenhamartomatumor pages 1-2)

Phenotype	HPO term suggestion	Typical age / notes	Frequency / statistics from evidence	Key citations
Macrocephaly	HP:0000256 Macrocephaly	Often earliest and most consistent pediatric finding; may be the presenting sign in infancy/childhood; adult diagnostic thresholds noted as ≥58 cm in women and ≥60 cm in men	100% (11/11) in a 2024 pediatric cohort; 85.1% at presentation and 96.3% post-diagnosis in a pediatric cohort of 81; 80–100% in mutation carriers in review data; 98% (46/47) in one pediatric study cited by review (martinvalbuena2024ptenhamartomatumor pages 1-2, baran2021theclinicalspectrum pages 3-4, pilarski2019ptenhamartomatumor pages 5-7, takayama2023clinicalguidelinesfor pages 6-8)	(martinvalbuena2024ptenhamartomatumor pages 1-2, baran2021theclinicalspectrum pages 3-4, pilarski2019ptenhamartomatumor pages 5-7, takayama2023clinicalguidelinesfor pages 6-8)
Mucocutaneous lesions (trichilemmomas, oral papillomas/fibromas, acral keratoses)	HP:0010618 Trichilemmoma; HP:0009723 Skin papilloma; HP:0100767 Oral mucosal papillomatosis; HP:0007565 Multiple lipomas	Usually accumulate with age; more prominent in adults, but can occur in childhood; characteristic facial papules and multiple trichilemmomas are considered hallmark findings	Skin/oral lesions in 30.9% at presentation and 68.2% after diagnosis in a pediatric cohort; oral fibromas reported in 14–76% and trichilemmomas in 6–25% across reviewed series; pediatric cohort described thumb hamartoma/lipoma and other cutaneous findings but fewer classic lesions than adults (baran2021theclinicalspectrum pages 3-4, pilarski2019ptenhamartomatumor pages 5-7, takayama2023clinicalguidelinesfor pages 6-8, martinvalbuena2024ptenhamartomatumor pages 2-3)	(baran2021theclinicalspectrum pages 3-4, pilarski2019ptenhamartomatumor pages 5-7, takayama2023clinicalguidelinesfor pages 6-8, martinvalbuena2024ptenhamartomatumor pages 2-3)
Gastrointestinal polyps / GI manifestations	HP:0200063 Hamartomatous polyposis; HP:0002242 Constipation; HP:0011473 Feeding difficulties	Polyps may appear in childhood but burden increases with age; adults can have few to hundreds of polyps; symptomatic children may present with constipation/feeding issues	>90% of patients undergoing upper endoscopy/colonoscopy had GI polyps in guideline review; up to 95% of adults with PTEN variants who had colonoscopy had polyps; in 80 children, GI polyps occurred in 28% (22/80), constipation in 51% (41/80), feeding issues in 39% (31/80), eosinophilic GI disorders in 6% (5/80) (takayama2023clinicalguidelinesfor pages 6-8, pilarski2019ptenhamartomatumor pages 5-7, liu2024abiinstitutionalstudy pages 1-2)	(takayama2023clinicalguidelinesfor pages 6-8, pilarski2019ptenhamartomatumor pages 5-7, liu2024abiinstitutionalstudy pages 1-2)
Thyroid nodules / thyroid abnormalities / differentiated thyroid carcinoma	HP:0000821 Goiter; HP:0002664 Thyroid carcinoma; HP:0000857 Thyroid nodule; HP:0002716 Autoimmune thyroiditis	Thyroid disease can begin in childhood; some guidelines recommend ultrasound from diagnosis because cancer has been reported as early as age 7; pediatric cancers generally low-invasive	In 43 surveilled children: thyroid abnormalities 84%, nodular disease 74%, goiter 30%, autoimmune thyroiditis 12%, nodular growth 33%, thyroidectomy 16%, DTC 5% (2/43) at ages 12 and 17; prior pediatric estimates for DTC 4–12% with median age ~12 years (range 4–17); another pediatric cohort reported thyroid cancer in 7.4% (6/81), all >10 years old (bormans2024experienceina pages 1-2, baran2021theclinicalspectrum pages 3-4, takayama2023clinicalguidelinesfor pages 6-8)	(bormans2024experienceina pages 1-2, baran2021theclinicalspectrum pages 3-4, takayama2023clinicalguidelinesfor pages 6-8)
Neurodevelopmental delay / intellectual disability / autism spectrum disorder	HP:0001263 Developmental delay; HP:0001249 Intellectual disability; HP:0000729 Autism	Often prominent in childhood and can drive referral for testing; neurobehavioral phenotype appears relatively stable over time in longitudinal study	Developmental delay in 5/11 children in one cohort; in 81 children, DD/ID present in 42.0% and ASD in 27.2%; guideline review reports ASD in ~17% of PTEN variant carriers, PTEN variants in 10–20% of ASD with macrocephaly, and intellectual disability in 12–20%; review notes PTEN mutations found in 1–27% of ASD with macrocephaly (martinvalbuena2024ptenhamartomatumor pages 1-2, baran2021theclinicalspectrum pages 3-4, takayama2023clinicalguidelinesfor pages 6-8, pilarski2019ptenhamartomatumor pages 5-7)	(martinvalbuena2024ptenhamartomatumor pages 1-2, baran2021theclinicalspectrum pages 3-4, takayama2023clinicalguidelinesfor pages 6-8, pilarski2019ptenhamartomatumor pages 5-7)
Vascular malformations / vascular anomalies	HP:0005306 Vascular malformation	May occur in childhood or adulthood; often part of BRRS/PHTS overlap and may be under-recognized	Guideline review reports multiple vascular malformations in approximately half of patients; pediatric surveillance paper lists vascular malformations among recognized manifestations but does not quantify them in that cohort (takayama2023clinicalguidelinesfor pages 6-8, bormans2024experienceina pages 1-2)	(takayama2023clinicalguidelinesfor pages 6-8, bormans2024experienceina pages 1-2)
Lhermitte–Duclos disease (dysplastic cerebellar gangliocytoma)	HP:0006887 Dysplastic cerebellar gangliocytoma	Classically associated with adult disease, often diagnosed in 20s–30s, but cerebellar dysplasia/LDD-compatible imaging can be seen earlier	~6% prevalence in guideline review; overlap of LDD patients with Cowden syndrome reported at ~50%; one pediatric cohort had a patient with cortical cerebellar dysplasia compatible with LDD (takayama2023clinicalguidelinesfor pages 6-8, martinvalbuena2024ptenhamartomatumor pages 6-7, pilarski2019ptenhamartomatumor pages 3-5)	(takayama2023clinicalguidelinesfor pages 6-8, martinvalbuena2024ptenhamartomatumor pages 6-7, pilarski2019ptenhamartomatumor pages 3-5)

Table: This table summarizes major clinical phenotypes reported for Cowden syndrome/PTEN hamartoma tumor syndrome, with suggested HPO terms, timing, and quantitative frequencies from recent and key studies. It is useful for phenotype curation and knowledge base population.

Quality-of-life impact (selected)

Direct quality-of-life (EQ-5D/SF-36/PROMIS) statistics were not identified in retrieved sources. However, multiple phenotypes have substantial functional impacts: neurodevelopmental disorders (developmental delay, ASD), obstructive sleep apnea related to tonsillar pathology, and repeated cancer surveillance/surgery burden. (baran2021theclinicalspectrum pages 3-4, bormans2024experienceina pages 1-2)

4. Genetic / Molecular Information

4.1 Causal gene(s)

PTEN is the primary causal gene for Cowden syndrome/PHTS in the retrieved sources. (pirlog2024insightsintoclinical pages 1-2, takayama2023clinicalguidelinesfor pages 2-4)

4.2 Pathogenic variant classes and consequences (high-level)

PTEN pathogenic variants may be truncating (nonsense/frameshift), missense, splice-site, or structural; functionally, many act via loss of function leading to elevated PI3K pathway signaling and impaired genome-stability functions. (yehia2020ptenhamartomatumour pages 5-6, wei2024quantitativeevaluationof pages 1-2)
In patient-derived lymphoblastoid cell lines, PTEN nonsense variants were associated with less efficient DNA damage repair dynamics (higher residual damage at 24 hours after irradiation) compared with missense variants, supporting a genotype-linked difference in genome integrity phenotypes. (wei2024quantitativeevaluationof pages 1-2)

4.3 Non-PTEN genetic etiologies / phenocopies

When a patient has a PHTS/CS-like phenotype but lacks a germline PTEN variant, germline activating variants in PI3K-pathway genes (e.g., AKT1, PIK3CA) can phenocopy PTEN loss, with increased AKT phosphorylation and increased PIP3 levels observed in patient-derived cells—“mimicking effects of PTEN loss-of-function.” (yehia2020ptenhamartomatumour pages 8-9)

4.4 Modifier genes / genomic background

No definitive modifier genes were established from retrieved sources in this run (beyond pathway-related phenocopies above).

4.5 Epigenetic information

No epigenetic mechanisms (e.g., methylation signatures) were identified in retrieved sources.

4.6 Chromosomal abnormalities

No recurrent chromosomal abnormalities were identified in retrieved sources.

5. Environmental Information

5.1 Environmental and lifestyle factors

Direct environmental risk factors for CS/PHTS were not identified in retrieved sources. The disease is primarily genetic.

6. Mechanism / Pathophysiology

6.1 Core molecular pathway mechanism (upstream → downstream)

1) Trigger: germline PTEN loss-of-function (heterozygous) (pirlog2024insightsintoclinical pages 1-2) 2) Molecular effect: reduced dephosphorylation of PIP3 → increased PIP3 and increased AKT activation → increased downstream growth signaling including mTOR activity (yehia2020ptenhamartomatumour pages 5-6, pirlog2024insightsintoclinical pages 1-2) 3) Cellular consequences: increased proliferation/survival and disordered growth leading to hamartomas/overgrowth; tumor predisposition due to growth signaling plus PTEN roles in nuclear genome stability and DNA double-strand break repair (yehia2020ptenhamartomatumour pages 5-6) 4) Clinical outcomes: multisystem hamartomas (skin/oral mucosa, GI tract, thyroid, breast, etc.) and increased cancer risks with earlier onset (pirlog2024insightsintoclinical pages 1-2, cummings2023cancerriskassociated pages 1-2)

6.2 Genome integrity / DNA damage response as a contributor to pleiotropy

PTEN has non-canonical roles relevant to “maintenance of genome integrity,” and quantitative DNA damage response modeling in PTEN-variant patient cell lines showed variant-class and phenotype associations (e.g., less efficient repair in nonsense variants; different repair dynamics in ASD/DD vs cancer phenotypic subgroups), providing a mechanistic framework for pleiotropic outcomes. (wei2024quantitativeevaluationof pages 1-2)

6.3 Immune dysregulation (emerging/variable evidence)

Immune dysregulation is increasingly reported in PHTS. A 2024 case report links PTEN mutation and immune dysregulation in the context of systemic lupus erythematosus (SLE), emphasizing PTEN’s regulation of PI3K/AKT/mTOR signaling relevant to immune function. (drozdz2024severelupusnephritis pages 1-2)

Suggested ontology terms

GO Biological Process (examples): PI3K signaling (e.g., “phosphatidylinositol 3-kinase signaling”); regulation of cell proliferation; DNA repair / double-strand break repair; regulation of apoptosis (mechanistically supported by PTEN roles described in retrieved sources) (yehia2020ptenhamartomatumour pages 5-6, wei2024quantitativeevaluationof pages 1-2)
Cell types (CL suggestions, examples): epithelial cells (breast/thyroid/endometrium), colonic epithelial cells; endothelial cells (vascular malformations noted clinically); lymphocytes (immune dysregulation discussions) (takayama2023clinicalguidelinesfor pages 6-8, drozdz2024severelupusnephritis pages 1-2)

7. Anatomical Structures Affected

7.1 Organ-level involvement (primary)

Commonly involved organs/systems include: - Skin and mucous membranes (mucocutaneous lesions) (takayama2023clinicalguidelinesfor pages 2-4, pilarski2019ptenhamartomatumor pages 5-7) - Gastrointestinal tract (hamartomatous polyps; constipation/feeding issues in children) (takayama2023clinicalguidelinesfor pages 6-8, liu2024abiinstitutionalstudy pages 1-2) - Thyroid (nodules, goiter, autoimmune thyroiditis, differentiated thyroid carcinoma) (bormans2024experienceina pages 1-2) - Breast, endometrium, kidney, colon (cancer predisposition) (cummings2023cancerriskassociated pages 1-2, hendricks2021areviewon pages 1-4) - Central nervous system (macrocephaly; MRI abnormalities; Lhermitte–Duclos disease) (pilarski2019ptenhamartomatumor pages 5-7, takayama2023clinicalguidelinesfor pages 6-8)

7.2 Tissue/cell-level and subcellular notes

At a mechanistic level, PTEN functions at the plasma membrane (PIP3→PIP2 dephosphorylation) and in the nucleus (genomic stability/cell cycle regulation), providing plausible cross-tissue impact on growth and tumor suppression. (yehia2020ptenhamartomatumour pages 5-6)

7.3 UBERON term suggestions (examples)

Thyroid gland; breast; endometrium; colon; kidney; cerebellum; skin; oral mucosa; gastrointestinal tract (supported by multisystem involvement described in guidelines/reviews) (takayama2023clinicalguidelinesfor pages 2-4, takayama2023clinicalguidelinesfor pages 6-8)

8. Temporal Development

8.1 Onset and progression

Many individuals demonstrate early manifestations such as macrocephaly and neurodevelopmental concerns in childhood, whereas mucocutaneous lesions and some cancer manifestations often become more apparent in adolescence/adulthood. (martinvalbuena2024ptenhamartomatumor pages 1-2, baran2021theclinicalspectrum pages 3-4)
Median age at cancer diagnosis has been reported around 36 years in CS/PHTS cohorts summarized in reviews. (pirlog2024insightsintoclinical pages 1-2, hendricks2021areviewon pages 1-4)

9. Inheritance and Population

9.1 Inheritance

CS/PHTS is autosomal dominant due to heterozygous germline PTEN pathogenic variants. (pirlog2024insightsintoclinical pages 1-2, takayama2023clinicalguidelinesfor pages 2-4)

9.2 Penetrance and expressivity

CS/PHTS shows high penetrance with variable expressivity; one pediatric cohort report cites penetrance approaching ~100% by the fourth decade for pathogenic PTEN variants and reports de novo rates from ~10.7% to 47.6% (range across literature). (martinvalbuena2024ptenhamartomatumor pages 1-2)

9.3 Epidemiology

A commonly cited prevalence/incidence estimate for Cowden syndrome/PHTS in reviews is approximately 1 in 200,000, while multiple sources emphasize that true incidence is uncertain and likely under-recognized. (pirlog2024insightsintoclinical pages 1-2, hendricks2021areviewon pages 1-4)

9.4 Recent population-level genetic testing statistic

In a large hereditary cancer panel-testing cohort (testing 2013–2022), PTEN pathogenic variants were detected in 0.027% (193/727,091) of tested individuals. (cummings2023cancerriskassociated pages 1-2)

10. Diagnostics

10.1 Clinical criteria and diagnostic framework

Contemporary clinical diagnosis commonly uses frameworks aligned with NCCN criteria for CS/PHTS; the Japanese 2023 guideline explicitly adopted an NCCN-based framework (noting 8 major and 10 minor criteria) and provides a diagnostic flowchart. (takayama2023clinicalguidelinesfor pages 2-4)
Because clinical criteria and PTEN variant detection incompletely overlap (only a subset meeting CS criteria have PTEN variants), diagnosis may be made clinically even if genetic testing is negative/unavailable, but this complicates gene-informed risk assessment. (pilarski2019ptenhamartomatumor pages 1-3, yehia2020ptenhamartomatumour pages 8-9)

10.2 Genetic testing approach (current understanding)

Multigene cancer predisposition panels and targeted PTEN testing are used in clinical practice and can identify PTEN PVs even in individuals not previously recognized clinically as having CS. The panel-testing cohort study emphasizes that risk estimates derived purely from clinically diagnosed CS cohorts may be biased, motivating genotype-based risk modeling. (cummings2023cancerriskassociated pages 1-2)

10.3 Differential diagnosis (selected)

PTEN-wildtype CS-like phenotypes may be due to variants in PI3K-pathway genes (e.g., AKT1, PIK3CA), which can mimic PTEN loss, reinforcing the need for differential genetic evaluation in PTEN-negative cases. (yehia2020ptenhamartomatumour pages 8-9)

11. Outcome / Prognosis

11.1 Cancer risk burden (statistics from cohorts)

Aggregated cohort data summarized in a 2021 review report cumulative lifetime risk for any cancer of 81%–90% in PHTS, with wide ranges by cancer site (female breast 67%–85% by age 60–70; endometrium 19%–28%; thyroid 6%–38%; renal 2%–24%; colorectal 9%–32%; melanoma 0%–6%). (hendricks2021areviewon pages 1-4)

11.2 Surveillance yield (real-world implementation data)

In a PHTS expertise center cohort (children screened by thyroid ultrasound before 18 years), 2/43 (5%) had differentiated thyroid carcinoma (ages 12 and 17), and 84% had thyroid abnormalities (mostly benign), illustrating high surveillance burden and nontrivial detection yield. (bormans2024experienceina pages 1-2)

12. Treatment

12.1 Standard treatments

Cancers in CS/PHTS are generally treated according to standard organ-specific oncology/surgical care pathways; no PHTS-specific renal cancer treatment evidence was found in the retrieved guideline excerpt, which notes following sporadic RCC management. (takayama2023clinicalguidelinesfor pages 8-11)

12.2 Targeted/experimental therapeutics (mechanism-informed)

Guidelines and reviews note that PI3K/AKT/mTOR pathway inhibitors are being investigated clinically because PTEN inactivation converges on this pathway. (takayama2023clinicalguidelinesfor pages 8-11)

MAXO term suggestions (examples): cancer surveillance; breast MRI screening; thyroid ultrasound screening; colonoscopy; nephrologic imaging surveillance; prophylactic mastectomy (consideration) (tischkowitz2020cancersurveillanceguideline pages 2-4, takayama2023clinicalguidelinesfor pages 8-11)

13. Prevention

Because CS/PHTS is Mendelian, prevention focuses on secondary prevention (early cancer detection via surveillance) rather than primary prevention.

13.1 Surveillance (secondary prevention): key guideline recommendations

The ERN GENTURIS guideline provides organ-specific surveillance with evidence-strength grading.

Key schedule elements (also shown in the guideline’s table image): - Breast: annual MRI from age 30; mammography every 2 years from age 40 (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline media 2ffc24d6) - Thyroid: annual ultrasound from ~age 18 (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline media 2ffc24d6) - Renal: ultrasound every 2 years from age ~40 (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline media 2ffc24d6) - Colon: baseline colonoscopy at 35–40 to assess polyp load (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline media 2ffc24d6) - Endometrium: routine screening not recommended; consider within trials (tischkowitz2020cancersurveillanceguideline pages 2-4)

The Japanese guideline (NCCN-aligned) recommends earlier surveillance for some sites: - Breast: self-exam from 18; clinical exams from 25; annual mammography + contrast MRI from 30 (or 5–10 years earlier than the youngest family diagnosis) (takayama2023clinicalguidelinesfor pages 8-11) - Thyroid: annual ultrasound from diagnosis, including in children, motivated by pediatric thyroid cancer reports (earliest age 7; ~5% risk <20 years cited) (takayama2023clinicalguidelinesfor pages 11-12, takayama2023clinicalguidelinesfor pages 8-11)

Cancer site	Reported risk estimates	ERN GENTURIS / European guideline start age & modality	NCCN / Japanese guideline start age & modality	Evidence strength (if stated)	Notes / controversies
Breast	Female breast cancer CLTR 67%–85% by age 60–70 in prior cohorts; PTEN PVs associated with OR 7.88 (95% CI 5.57–11.16) in a panel-testing cohort (hendricks2021areviewon pages 1-4, cummings2023cancerriskassociated pages 1-2)	Annual breast MRI from age 30; mammography every 2 years from age 40; risk-reducing surgery may be offered (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5, tischkowitz2020cancersurveillanceguideline media 2ffc24d6)	Monthly self-exam from 18; clinical breast exam/interview from 25 or 5–10 years before youngest family cancer; annual mammography plus gadolinium-enhanced breast MRI from 30 or 5–10 years before youngest familial onset (takayama2023clinicalguidelinesfor pages 8-11)	MRI: Strong; mammography/risk-reducing surgery: Moderate (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5)	Lifetime risk estimates vary widely across cohorts because of ascertainment bias; Takayama notes no evidence that prophylactic mastectomy improves overall survival (hendricks2021areviewon pages 1-4, takayama2023clinicalguidelinesfor pages 8-11)
Thyroid	Thyroid cancer CLTR 6%–38% in review cohorts; historical/literature estimates often 10%–35%; PTEN PVs associated with OR 4.88 (95% CI 2.64–9.01); pediatric DTC estimates 4%–12%; in one pediatric surveillance cohort, 2/43 (5%) had DTC and 84% had thyroid abnormalities (hendricks2021areviewon pages 1-4, pilarski2019ptenhamartomatumor pages 3-5, cummings2023cancerriskassociated pages 1-2, bormans2024experienceina pages 1-2)	Annual thyroid ultrasound from about age 18 (table lists 18a) (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5, tischkowitz2020cancersurveillanceguideline media 2ffc24d6)	Annual thyroid ultrasonography at diagnosis, including childhood; rationale includes thyroid cancer reported at age 7 and ~5% risk in patients <20 years (takayama2023clinicalguidelinesfor pages 11-12, takayama2023clinicalguidelinesfor pages 8-11)	Strong (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5)	Major divergence between guidelines: ERN starts around 18, while NCCN/Japanese guidance starts in childhood/at diagnosis; pediatric series support earlier surveillance in expertise centers, sometimes from age 12 (pirlog2024insightsintoclinical pages 11-12, takayama2023clinicalguidelinesfor pages 11-12, bormans2024experienceina pages 1-2)
Endometrial	Endometrial cancer CLTR 19%–28%; PTEN PVs associated with OR 13.51 (95% CI 8.77–20.83) (hendricks2021areviewon pages 1-4, pilarski2019ptenhamartomatumor pages 3-5, cummings2023cancerriskassociated pages 1-2)	Routine screening not recommended; if surveillance is offered, guideline suggests this should preferably be in clinical trials, and if offered probably at least annually (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5)	Yearly transvaginal ultrasound or endometrial biopsy beginning at age 30 (Japanese guideline) (takayama2023clinicalguidelinesfor pages 11-12)	Weak (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5)	Substantial controversy: ERN does not recommend routine endometrial surveillance outside trials, whereas Japanese/NCCN-derived guidance is more proactive; evidence base remains limited (pirlog2024insightsintoclinical pages 11-12, takayama2023clinicalguidelinesfor pages 11-12)
Colorectal	Colorectal cancer CLTR 9%–32% in review cohorts; prevalence in cohorts often 9%–13%; one estimate 9% lifetime and another 16%; PTEN PVs strongly associated with colon polyposis OR 31.60 (95% CI 15.60–64.02) (hendricks2021areviewon pages 1-4, pilarski2019ptenhamartomatumor pages 3-5, cummings2023cancerriskassociated pages 1-2)	Baseline colonoscopy at age 35–40 to assess polyp load; if normal, follow general-population screening, with further surveillance as required (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5, tischkowitz2020cancersurveillanceguideline media 2ffc24d6)	Total colonoscopy 5–10 years before age 35 or before youngest family cancer onset; interval depends on degree of polyposis; adenomatous polyps ≥6 mm should be resected (takayama2023clinicalguidelinesfor pages 11-12)	Moderate for baseline colonoscopy (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5)	Risk may be lower than historically estimated; a surveillance cohort found no CRCs over 67 follow-up years, supporting personalized intervals rather than uniformly intensive screening (tischkowitz2020cancersurveillanceguideline pages 1-2, takayama2023clinicalguidelinesfor pages 11-12)
Renal	Renal cancer CLTR 2%–24% in review cohorts; some small studies projected up to ~34% lifetime risk, likely overestimated (hendricks2021areviewon pages 1-4, pilarski2019ptenhamartomatumor pages 3-5)	Renal ultrasound every 2 years starting about age 40 (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5, tischkowitz2020cancersurveillanceguideline media 2ffc24d6)	Annual renal ultrasonography from age 40; some sources mention CT or preferably MRI if needed (takayama2023clinicalguidelinesfor pages 11-12, jurca2023anewframeshift pages 9-10)	Moderate (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5)	ERN notes insufficient data to recommend renal MRI routinely; early-onset RCC case reports have prompted debate about lowering surveillance age, but this is not standardized (tischkowitz2020cancersurveillanceguideline pages 4-5, jurca2023anewframeshift pages 9-10)
Melanoma / skin	Melanoma CLTR 0%–6%; evidence for increased melanoma risk remains limited, with some cohorts showing ~1% prevalence and others projecting 6% lifetime (hendricks2021areviewon pages 1-4, pilarski2019ptenhamartomatumor pages 3-5)	Baseline skin examination around age 30; no strong recommendation for additional routine surveillance beyond this (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5, tischkowitz2020cancersurveillanceguideline media 2ffc24d6)	No explicit melanoma screening schedule retrieved in Takayama 2023; strong recommendation for dermatology referral to assess mucocutaneous lesions (takayama2023clinicalguidelinesfor pages 11-12)	Weak (tischkowitz2020cancersurveillanceguideline pages 2-4, tischkowitz2020cancersurveillanceguideline pages 4-5)	Skin surveillance is limited by uncertain melanoma risk, but dermatologic evaluation remains clinically valuable because mucocutaneous lesions are prominent and may support diagnosis (tischkowitz2020cancersurveillanceguideline pages 4-5, takayama2023clinicalguidelinesfor pages 11-12)

Table: This table summarizes site-specific cancer risk estimates and surveillance recommendations for Cowden syndrome/PTEN hamartoma tumor syndrome. It contrasts ERN GENTURIS and NCCN/Japanese approaches and highlights where evidence is strong versus where recommendations remain controversial.

14. Other Species / Natural Disease

No naturally occurring CS/PHTS analogs in non-human species were identified in retrieved sources in this run.

15. Model Organisms

Model organism evidence was not deeply extracted in this run; however, multiple reviews highlight that PTEN function and tumor suppression mechanisms are conserved across species and have been studied in zebrafish and Drosophila models (e.g., for tumorigenesis and variant functional assays), supporting mechanistic inference for PTEN loss. (yehia2020ptenhamartomatumour pages 5-6)

Recent developments and latest research (prioritizing 2023–2024)

2023–2024 high-value sources retrieved in this run

Japanese clinical guideline (2023-10-XX) providing English secondary publication and emphasizing NCCN-aligned diagnosis/management and the need for surveillance across breast/thyroid/endometrium/colon/kidney (Takayama et al., 2023; URL: https://doi.org/10.23922/jarc.2023-028). (takayama2023clinicalguidelinesfor pages 2-4, takayama2023clinicalguidelinesfor pages 8-11)
Large-scale panel-testing risk quantification (2023-01-XX) providing genotype-based ORs for major cancers and colon polyposis (Cummings et al., 2023; URL: https://doi.org/10.1200/po.22.00415). (cummings2023cancerriskassociated pages 1-2)
Pediatric GI/hepatic bi-institutional cohort (2024-01-XX) quantifying constipation, feeding issues, and pediatric polyp frequency in 80 children (Liu et al., 2024; URL: https://doi.org/10.1016/j.gastha.2023.10.012). (liu2024abiinstitutionalstudy pages 1-2)
Pediatric thyroid surveillance implementation study (2024-08-XX) describing high detection of benign thyroid abnormalities and DTC yield (Bormans et al., 2024; URL: https://doi.org/10.4274/jcrpe.galenos.2024.2024-3-14). (bormans2024experienceina pages 1-2)
Mechanistic DDR phenotyping + modeling (2024-10-XX) linking PTEN variant class to DNA repair dynamics and exploring phenotype prediction (Wei et al., 2024; URL: https://doi.org/10.1371/journal.pcbi.1012449). (wei2024quantitativeevaluationof pages 1-2)
Comprehensive CS clinical review (2024-05-XX) summarizing multisystem manifestations and describing inter-guideline differences (Pîrlog et al., 2024; URL: https://doi.org/10.3390/medicina60050767). (pirlog2024insightsintoclinical pages 2-4, pirlog2024insightsintoclinical pages 11-12)

Embedded summary artifacts

Concept	MONDO ID	OMIM	Key synonyms/related syndromes	Causal gene	Inheritance	Notes on ascertainment
Cowden syndrome	MONDO_0008021 (Cowden syndrome 1); MONDO_0016063 (Cowden disease)	158350	Cowden disease; Cowden syndrome (CS); related PTEN-spectrum entities include Bannayan–Riley–Ruvalcaba syndrome (BRRS), Proteus syndrome, Proteus-like syndrome, adult Lhermitte–Duclos disease	PTEN	Autosomal dominant	Clinical and molecular diagnosis do not fully overlap: only ~30–35% of individuals meeting clinical CS criteria have a detectable PTEN variant in cited reviews; diagnosis may be made clinically and/or by multigene panel testing (pilarski2019ptenhamartomatumor pages 1-3, pirlog2024insightsintoclinical pages 1-2, takayama2023clinicalguidelinesfor pages 2-4)
PTEN hamartoma tumor syndrome (PHTS) umbrella	Not found in retrieved sources	Not found in retrieved sources	PTEN hamartoma tumour/tumor syndrome; umbrella including Cowden syndrome, BRRS, Proteus syndrome, Proteus-like syndrome, and adult Lhermitte–Duclos disease; autism spectrum disorder with macrocephaly is also described within the PTEN-related spectrum	PTEN	Autosomal dominant	PHTS is an umbrella term for PTEN-related disorders; PTEN pathogenic variants were found in only a subset of clinically diagnosed phenotypes (e.g., ~30–35% of CS/CS-like and ~60% of BRRS in cited reviews), underscoring phenotype–genotype heterogeneity and ascertainment differences between clinically defined and genetically confirmed cohorts (cummings2023cancerriskassociated pages 1-2, pilarski2019ptenhamartomatumor pages 1-3, pirlog2024insightsintoclinical pages 1-2)

Table: This table summarizes the key identifiers, synonyms, causal gene, and inheritance for Cowden syndrome and the broader PTEN hamartoma tumor syndrome umbrella. It also highlights the important distinction between clinical diagnosis and genetically confirmed PTEN-associated disease.

Key guideline table image (visual evidence)

The extracted table image from the ERN GENTURIS surveillance guideline (European Journal of Human Genetics, 2020) summarizes screening start ages and modalities across organ sites. (tischkowitz2020cancersurveillanceguideline media 2ffc24d6)

Notes on evidence gaps (from retrieved sources in this run)

ICD-10/ICD-11, Orphanet, MeSH identifiers were not present in retrieved sources in this run; inclusion would require targeted retrieval from OMIM/Orphanet/WHO/NCBI MeSH.
Quality-of-life instruments, formal epidemiologic incidence, and long-term survival statistics were not directly retrieved.
Animal model and comparative disease sections were not fully supported by extracted evidence in this run; additional targeted model-organism papers could strengthen this component.

References

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(takayama2023clinicalguidelinesfor pages 2-4): Tetsuji Takayama, Naoki Muguruma, Masahiro Igarashi, Shozo Ohsumi, Shiro Oka, Fumihiko Kakuta, Yoshiaki Kubo, Hideki Kumagai, Mika Sasaki, Tamotsu Sugai, Kokichi Sugano, Yuko Takeda, Hisashi Doyama, Kouji Banno, Suguru Fukahori, Yoichi Furukawa, Takahiro Horimatsu, Hideki Ishikawa, Takeo Iwama, Yasushi Okazaki, Yutaka Saito, Nariaki Matsuura, Michihiro Mutoh, Naohiro Tomita, Takashi Akiyama, Toshiki Yamamoto, Hideyuki Ishida, and Yoshiko Nakayama. Clinical guidelines for diagnosis and management of cowden syndrome/pten hamartoma tumor syndrome in children and adults―secondary publication. Journal of the Anus, Rectum and Colon, 7:284-300, Oct 2023. URL: https://doi.org/10.23922/jarc.2023-028, doi:10.23922/jarc.2023-028. This article has 43 citations.
(cummings2023cancerriskassociated pages 1-2): Shelly Cummings, Andrew Alfonso, Elisha Hughes, Matt Kucera, Brent Mabey, Nanda Singh, and Charis Eng. Cancer risk associated with pten pathogenic variants identified using multigene hereditary cancer panel testing. JCO Precision Oncology, Jan 2023. URL: https://doi.org/10.1200/po.22.00415, doi:10.1200/po.22.00415. This article has 29 citations and is from a peer-reviewed journal.
(jurca2023anewframeshift pages 9-10): Claudia Maria Jurca, Ovidiu Frățilă, Tiberia Iliaș, Aurora Jurca, Andreea Cătana, Corina Moisa, and Alexandru Daniel Jurca. A new frameshift mutation of pten gene associated with cowden syndrome—case report and brief review of the literature. Genes, 14:1909, Oct 2023. URL: https://doi.org/10.3390/genes14101909, doi:10.3390/genes14101909. This article has 9 citations.
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(hendricks2021areviewon pages 1-4): Linda A.J. Hendricks, Nicoline Hoogerbrugge, Janneke H.M. Schuurs‐Hoeijmakers, and Janet R. Vos. A review on age‐related cancer risks in pten hamartoma tumor syndrome. Clinical Genetics, 99:219-225, Nov 2021. URL: https://doi.org/10.1111/cge.13875, doi:10.1111/cge.13875. This article has 93 citations and is from a peer-reviewed journal.
(pilarski2019ptenhamartomatumor pages 3-5): Robert Pilarski. Pten hamartoma tumor syndrome: a clinical overview. Cancers, 11:844, Jun 2019. URL: https://doi.org/10.3390/cancers11060844, doi:10.3390/cancers11060844. This article has 232 citations.
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(martinvalbuena2024ptenhamartomatumor pages 1-2): Jesús Martín-Valbuena, Nerea Gestoso-Uzal, María Justel-Rodríguez, María Isidoro-García, Elena Marcos-Vadillo, Sandra Milagros Lorenzo-Hernández, M. Carla Criado-Muriel, and Pablo Prieto-Matos. Pten hamartoma tumor syndrome: clinical and genetic characterization in pediatric patients. Child's Nervous System, 40:1689-1697, Feb 2024. URL: https://doi.org/10.1007/s00381-024-06301-2, doi:10.1007/s00381-024-06301-2. This article has 9 citations.
(baran2021theclinicalspectrum pages 3-4): Julia A. Baran, Steven D. Tsai, Amber Isaza, Garrett M. Brodeur, Suzanne P. MacFarland, Kristin Zelley, Denise M. Adams, Aime T. Franco, and Andrew J. Bauer. The clinical spectrum of pten hamartoma tumor syndrome: exploring the value of thyroid surveillance. Hormone Research in Paediatrics, 93:634-642, Apr 2021. URL: https://doi.org/10.1159/000515731, doi:10.1159/000515731. This article has 21 citations and is from a peer-reviewed journal.
(pilarski2019ptenhamartomatumor pages 5-7): Robert Pilarski. Pten hamartoma tumor syndrome: a clinical overview. Cancers, 11:844, Jun 2019. URL: https://doi.org/10.3390/cancers11060844, doi:10.3390/cancers11060844. This article has 232 citations.
(takayama2023clinicalguidelinesfor pages 6-8): Tetsuji Takayama, Naoki Muguruma, Masahiro Igarashi, Shozo Ohsumi, Shiro Oka, Fumihiko Kakuta, Yoshiaki Kubo, Hideki Kumagai, Mika Sasaki, Tamotsu Sugai, Kokichi Sugano, Yuko Takeda, Hisashi Doyama, Kouji Banno, Suguru Fukahori, Yoichi Furukawa, Takahiro Horimatsu, Hideki Ishikawa, Takeo Iwama, Yasushi Okazaki, Yutaka Saito, Nariaki Matsuura, Michihiro Mutoh, Naohiro Tomita, Takashi Akiyama, Toshiki Yamamoto, Hideyuki Ishida, and Yoshiko Nakayama. Clinical guidelines for diagnosis and management of cowden syndrome/pten hamartoma tumor syndrome in children and adults―secondary publication. Journal of the Anus, Rectum and Colon, 7:284-300, Oct 2023. URL: https://doi.org/10.23922/jarc.2023-028, doi:10.23922/jarc.2023-028. This article has 43 citations.
(martinvalbuena2024ptenhamartomatumor pages 2-3): Jesús Martín-Valbuena, Nerea Gestoso-Uzal, María Justel-Rodríguez, María Isidoro-García, Elena Marcos-Vadillo, Sandra Milagros Lorenzo-Hernández, M. Carla Criado-Muriel, and Pablo Prieto-Matos. Pten hamartoma tumor syndrome: clinical and genetic characterization in pediatric patients. Child's Nervous System, 40:1689-1697, Feb 2024. URL: https://doi.org/10.1007/s00381-024-06301-2, doi:10.1007/s00381-024-06301-2. This article has 9 citations.
(liu2024abiinstitutionalstudy pages 1-2): Darren Liu, Suzanne P. MacFarland, Lamis Yehia, Melani M. Duvall, Petar Mamula, Jacob A. Kurowski, Colleen S. Greene, Kadakkal Radhakrishnan, and Charis Eng. A bi-institutional study of gastrointestinal and hepatic manifestations in children with pten hamartoma tumor syndrome. Gastro Hep Advances, 3:250-259, Jan 2024. URL: https://doi.org/10.1016/j.gastha.2023.10.012, doi:10.1016/j.gastha.2023.10.012. This article has 4 citations and is from a peer-reviewed journal.
(bormans2024experienceina pages 1-2): Esther M.G. Bormans, Janneke H.M. Schuurs-Hoeijmakers, Petra van Setten, Linda A.J. Hendricks, Meggie M.C.M. Drissen, Martin Gotthardt, Hedi L. Claahsen-van der Grinten, Nicoline Hoogerbrugge, and Jolanda H. Schieving. Experience in a pten hamartoma tumor syndrome expertise centre: yield of thyroid ultrasound surveillance in children with pten hamartoma tumor syndrome. Journal of Clinical Research in Pediatric Endocrinology, 17:46-57, Aug 2024. URL: https://doi.org/10.4274/jcrpe.galenos.2024.2024-3-14, doi:10.4274/jcrpe.galenos.2024.2024-3-14. This article has 2 citations.
(martinvalbuena2024ptenhamartomatumor pages 6-7): Jesús Martín-Valbuena, Nerea Gestoso-Uzal, María Justel-Rodríguez, María Isidoro-García, Elena Marcos-Vadillo, Sandra Milagros Lorenzo-Hernández, M. Carla Criado-Muriel, and Pablo Prieto-Matos. Pten hamartoma tumor syndrome: clinical and genetic characterization in pediatric patients. Child's Nervous System, 40:1689-1697, Feb 2024. URL: https://doi.org/10.1007/s00381-024-06301-2, doi:10.1007/s00381-024-06301-2. This article has 9 citations.
(wei2024quantitativeevaluationof pages 1-2): Ruipeng Wei, Masahiro Hitomi, Tammy Sadler, Lamis Yehia, Daniela Calvetti, Jacob Scott, and Charis Eng. Quantitative evaluation of dna damage repair dynamics to elucidate predictors of autism vs. cancer in individuals with germline pten variants. PLOS Computational Biology, 20:e1012449, Oct 2024. URL: https://doi.org/10.1371/journal.pcbi.1012449, doi:10.1371/journal.pcbi.1012449. This article has 4 citations and is from a highest quality peer-reviewed journal.
(yehia2020ptenhamartomatumour pages 8-9): Lamis Yehia and Charis Eng. Pten hamartoma tumour syndrome: what happens when there is no pten germline mutation? Human molecular genetics, 29:R150-R157, Jun 2020. URL: https://doi.org/10.1093/hmg/ddaa127, doi:10.1093/hmg/ddaa127. This article has 23 citations and is from a domain leading peer-reviewed journal.
(drozdz2024severelupusnephritis pages 1-2): Wiktoria Drozdz, Daniel Joller, Philipp Grosse, and Thomas Fehr. Severe lupus nephritis in a young adult with pten hamartoma tumour syndrome. BMJ Case Reports, 17:e258400, Sep 2024. URL: https://doi.org/10.1136/bcr-2023-258400, doi:10.1136/bcr-2023-258400. This article has 2 citations and is from a peer-reviewed journal.
(takayama2023clinicalguidelinesfor pages 8-11): Tetsuji Takayama, Naoki Muguruma, Masahiro Igarashi, Shozo Ohsumi, Shiro Oka, Fumihiko Kakuta, Yoshiaki Kubo, Hideki Kumagai, Mika Sasaki, Tamotsu Sugai, Kokichi Sugano, Yuko Takeda, Hisashi Doyama, Kouji Banno, Suguru Fukahori, Yoichi Furukawa, Takahiro Horimatsu, Hideki Ishikawa, Takeo Iwama, Yasushi Okazaki, Yutaka Saito, Nariaki Matsuura, Michihiro Mutoh, Naohiro Tomita, Takashi Akiyama, Toshiki Yamamoto, Hideyuki Ishida, and Yoshiko Nakayama. Clinical guidelines for diagnosis and management of cowden syndrome/pten hamartoma tumor syndrome in children and adults―secondary publication. Journal of the Anus, Rectum and Colon, 7:284-300, Oct 2023. URL: https://doi.org/10.23922/jarc.2023-028, doi:10.23922/jarc.2023-028. This article has 43 citations.
(tischkowitz2020cancersurveillanceguideline pages 2-4): M. Tischkowitz, C. Colas, Sjaak Pouwels, N. Hoogerbrugge, Tanya Virginie Frederic Nathalie Chrystelle Sophie Marti Bisseling Bubien Caux Chabbert-Buffet Colas Da Mot, T. Bisseling, V. Bubien, F. Caux, N. Chabbert-Buffet, Sophie Da Mota Gomes, M. Gotthardt, M. Kets, K. Lachlan, T. Links, M. Longy, R. Mann, L. S. Kool, R. Semple, Ian Stock, M. Tischkowitz, J. Vos, Nicoline Marjolijn Rianne Rolf Gareth Emma Marc Eamonn Rosa Hoogerbrugge Ligtenberg Oostenbrink Sijmons Evans, M. Ligtenberg, R. Oostenbrink, R. Sijmons, G. Evans, E. Woodward, E. Maher, R. Ferner, S. Aretz, I. Spier, V. Steinke-Lange, E. Holinski-Feder, E. Schröck, T. Frebourg, C. Houdayer, P. Wolkenstein, V. Bours, E. Legius, B. Poppe, K. Claes, Robin de Putter, I. Guillermo, G. Capellá, J. B. Vidal, C. Lázaro, J. Balmaña, Héctor Salvador Hernández, Carla Oliveira, M. Teixeira, S. Bajalica-Lagercrantz, E. Tham, J. Lubiński, K. Ertmańska, B. Melegh, M. Krajc, A. Blatnik, S. Peltonen, and M. Hietala. Cancer surveillance guideline for individuals with pten hamartoma tumour syndrome. European Journal of Human Genetics, 28:1387-1393, Jun 2020. URL: https://doi.org/10.1038/s41431-020-0651-7, doi:10.1038/s41431-020-0651-7. This article has 146 citations and is from a domain leading peer-reviewed journal.
(tischkowitz2020cancersurveillanceguideline media 2ffc24d6): M. Tischkowitz, C. Colas, Sjaak Pouwels, N. Hoogerbrugge, Tanya Virginie Frederic Nathalie Chrystelle Sophie Marti Bisseling Bubien Caux Chabbert-Buffet Colas Da Mot, T. Bisseling, V. Bubien, F. Caux, N. Chabbert-Buffet, Sophie Da Mota Gomes, M. Gotthardt, M. Kets, K. Lachlan, T. Links, M. Longy, R. Mann, L. S. Kool, R. Semple, Ian Stock, M. Tischkowitz, J. Vos, Nicoline Marjolijn Rianne Rolf Gareth Emma Marc Eamonn Rosa Hoogerbrugge Ligtenberg Oostenbrink Sijmons Evans, M. Ligtenberg, R. Oostenbrink, R. Sijmons, G. Evans, E. Woodward, E. Maher, R. Ferner, S. Aretz, I. Spier, V. Steinke-Lange, E. Holinski-Feder, E. Schröck, T. Frebourg, C. Houdayer, P. Wolkenstein, V. Bours, E. Legius, B. Poppe, K. Claes, Robin de Putter, I. Guillermo, G. Capellá, J. B. Vidal, C. Lázaro, J. Balmaña, Héctor Salvador Hernández, Carla Oliveira, M. Teixeira, S. Bajalica-Lagercrantz, E. Tham, J. Lubiński, K. Ertmańska, B. Melegh, M. Krajc, A. Blatnik, S. Peltonen, and M. Hietala. Cancer surveillance guideline for individuals with pten hamartoma tumour syndrome. European Journal of Human Genetics, 28:1387-1393, Jun 2020. URL: https://doi.org/10.1038/s41431-020-0651-7, doi:10.1038/s41431-020-0651-7. This article has 146 citations and is from a domain leading peer-reviewed journal.
(takayama2023clinicalguidelinesfor pages 11-12): Tetsuji Takayama, Naoki Muguruma, Masahiro Igarashi, Shozo Ohsumi, Shiro Oka, Fumihiko Kakuta, Yoshiaki Kubo, Hideki Kumagai, Mika Sasaki, Tamotsu Sugai, Kokichi Sugano, Yuko Takeda, Hisashi Doyama, Kouji Banno, Suguru Fukahori, Yoichi Furukawa, Takahiro Horimatsu, Hideki Ishikawa, Takeo Iwama, Yasushi Okazaki, Yutaka Saito, Nariaki Matsuura, Michihiro Mutoh, Naohiro Tomita, Takashi Akiyama, Toshiki Yamamoto, Hideyuki Ishida, and Yoshiko Nakayama. Clinical guidelines for diagnosis and management of cowden syndrome/pten hamartoma tumor syndrome in children and adults―secondary publication. Journal of the Anus, Rectum and Colon, 7:284-300, Oct 2023. URL: https://doi.org/10.23922/jarc.2023-028, doi:10.23922/jarc.2023-028. This article has 43 citations.
(tischkowitz2020cancersurveillanceguideline pages 4-5): M. Tischkowitz, C. Colas, Sjaak Pouwels, N. Hoogerbrugge, Tanya Virginie Frederic Nathalie Chrystelle Sophie Marti Bisseling Bubien Caux Chabbert-Buffet Colas Da Mot, T. Bisseling, V. Bubien, F. Caux, N. Chabbert-Buffet, Sophie Da Mota Gomes, M. Gotthardt, M. Kets, K. Lachlan, T. Links, M. Longy, R. Mann, L. S. Kool, R. Semple, Ian Stock, M. Tischkowitz, J. Vos, Nicoline Marjolijn Rianne Rolf Gareth Emma Marc Eamonn Rosa Hoogerbrugge Ligtenberg Oostenbrink Sijmons Evans, M. Ligtenberg, R. Oostenbrink, R. Sijmons, G. Evans, E. Woodward, E. Maher, R. Ferner, S. Aretz, I. Spier, V. Steinke-Lange, E. Holinski-Feder, E. Schröck, T. Frebourg, C. Houdayer, P. Wolkenstein, V. Bours, E. Legius, B. Poppe, K. Claes, Robin de Putter, I. Guillermo, G. Capellá, J. B. Vidal, C. Lázaro, J. Balmaña, Héctor Salvador Hernández, Carla Oliveira, M. Teixeira, S. Bajalica-Lagercrantz, E. Tham, J. Lubiński, K. Ertmańska, B. Melegh, M. Krajc, A. Blatnik, S. Peltonen, and M. Hietala. Cancer surveillance guideline for individuals with pten hamartoma tumour syndrome. European Journal of Human Genetics, 28:1387-1393, Jun 2020. URL: https://doi.org/10.1038/s41431-020-0651-7, doi:10.1038/s41431-020-0651-7. This article has 146 citations and is from a domain leading peer-reviewed journal.
(pirlog2024insightsintoclinical pages 11-12): Lorin-Manuel Pîrlog, Andrada-Adelaida Pătrășcanu, Mariela Sanda Militaru, and Andreea Cătană. Insights into clinical disorders in cowden syndrome: a comprehensive review. Medicina, 60:767, May 2024. URL: https://doi.org/10.3390/medicina60050767, doi:10.3390/medicina60050767. This article has 10 citations.
(tischkowitz2020cancersurveillanceguideline pages 1-2): M. Tischkowitz, C. Colas, Sjaak Pouwels, N. Hoogerbrugge, Tanya Virginie Frederic Nathalie Chrystelle Sophie Marti Bisseling Bubien Caux Chabbert-Buffet Colas Da Mot, T. Bisseling, V. Bubien, F. Caux, N. Chabbert-Buffet, Sophie Da Mota Gomes, M. Gotthardt, M. Kets, K. Lachlan, T. Links, M. Longy, R. Mann, L. S. Kool, R. Semple, Ian Stock, M. Tischkowitz, J. Vos, Nicoline Marjolijn Rianne Rolf Gareth Emma Marc Eamonn Rosa Hoogerbrugge Ligtenberg Oostenbrink Sijmons Evans, M. Ligtenberg, R. Oostenbrink, R. Sijmons, G. Evans, E. Woodward, E. Maher, R. Ferner, S. Aretz, I. Spier, V. Steinke-Lange, E. Holinski-Feder, E. Schröck, T. Frebourg, C. Houdayer, P. Wolkenstein, V. Bours, E. Legius, B. Poppe, K. Claes, Robin de Putter, I. Guillermo, G. Capellá, J. B. Vidal, C. Lázaro, J. Balmaña, Héctor Salvador Hernández, Carla Oliveira, M. Teixeira, S. Bajalica-Lagercrantz, E. Tham, J. Lubiński, K. Ertmańska, B. Melegh, M. Krajc, A. Blatnik, S. Peltonen, and M. Hietala. Cancer surveillance guideline for individuals with pten hamartoma tumour syndrome. European Journal of Human Genetics, 28:1387-1393, Jun 2020. URL: https://doi.org/10.1038/s41431-020-0651-7, doi:10.1038/s41431-020-0651-7. This article has 146 citations and is from a domain leading peer-reviewed journal.
(pirlog2024insightsintoclinical pages 2-4): Lorin-Manuel Pîrlog, Andrada-Adelaida Pătrășcanu, Mariela Sanda Militaru, and Andreea Cătană. Insights into clinical disorders in cowden syndrome: a comprehensive review. Medicina, 60:767, May 2024. URL: https://doi.org/10.3390/medicina60050767, doi:10.3390/medicina60050767. This article has 10 citations.

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Subtypes

Pathophysiology

Pathograph

Phenotypes

Genetic Associations

Medical Actions

Clinical Trials

Source YAML

References & Deep Research

References

Deep Research

Cowden Syndrome (PTEN Hamartoma Tumor Syndrome, PHTS): Disease Characteristics Research Report

1. Disease Information

1.1 Concise overview

1.2 Key identifiers (as available from retrieved sources)

1.3 Synonyms and alternative names

1.4 Evidence provenance (individual-level vs aggregated resources)

2. Etiology

2.1 Disease causal factors

2.2 Risk factors

2.3 Protective factors

2.4 Gene–environment interactions

3. Phenotypes

Quality-of-life impact (selected)

4. Genetic / Molecular Information

4.1 Causal gene(s)

4.2 Pathogenic variant classes and consequences (high-level)

4.3 Non-PTEN genetic etiologies / phenocopies

4.4 Modifier genes / genomic background

4.5 Epigenetic information

4.6 Chromosomal abnormalities

5. Environmental Information

5.1 Environmental and lifestyle factors

6. Mechanism / Pathophysiology

6.1 Core molecular pathway mechanism (upstream → downstream)

6.2 Genome integrity / DNA damage response as a contributor to pleiotropy

6.3 Immune dysregulation (emerging/variable evidence)

Suggested ontology terms

7. Anatomical Structures Affected

7.1 Organ-level involvement (primary)

7.2 Tissue/cell-level and subcellular notes

7.3 UBERON term suggestions (examples)

8. Temporal Development

8.1 Onset and progression

9. Inheritance and Population

9.1 Inheritance

9.2 Penetrance and expressivity

9.3 Epidemiology

9.4 Recent population-level genetic testing statistic

10. Diagnostics

10.1 Clinical criteria and diagnostic framework

10.2 Genetic testing approach (current understanding)

10.3 Differential diagnosis (selected)

11. Outcome / Prognosis

11.1 Cancer risk burden (statistics from cohorts)

11.2 Surveillance yield (real-world implementation data)

12. Treatment

12.1 Standard treatments

12.2 Targeted/experimental therapeutics (mechanism-informed)

13. Prevention

13.1 Surveillance (secondary prevention): key guideline recommendations

14. Other Species / Natural Disease

15. Model Organisms

Recent developments and latest research (prioritizing 2023–2024)

2023–2024 high-value sources retrieved in this run

Embedded summary artifacts

Key guideline table image (visual evidence)

Notes on evidence gaps (from retrieved sources in this run)