GPR101-related pituitary adenoma 2

Genetic Pathograph 12 pituitary gland adenoma

GPR101-related pituitary adenoma 2 is a growth hormone excess pituitary adenoma or hyperplasia syndrome primarily driven by GPR101 copy-number gain. A reported recurrent GPR101 p.E308D variant is kept as a provisional extension rather than the main causal model. The mechanism is distinct from AIP two-hit tumor suppression: GPR101 acts as a dosage-driven GPCR entry point into the somatotroph cAMP/PKA overactivation module.

Ask OpenScientist

Ask a research question about GPR101-related pituitary adenoma 2. OpenScientist will conduct autonomous deep research using the Disorder Mechanisms Knowledge Base and PubMed literature (typically 10-30 minutes).

Submitting...

Do not include personal health information in your question. Questions and results are cached in your browser's local storage.

1
Mappings
1
Inheritance
6
Pathophys.
4
Phenotypes
1
Gaps
12
Pathograph
1
Genes
3
Medical Actions
5
References
1
Deep Research
🔗

Mappings

MONDO
MONDO:0006373 pituitary gland adenoma Not Yet Curated
skos:closeMatch MONDO
Closest available MONDO grouping term for the GPR101-related pituitary adenoma/acrogigantism spectrum; a gene-specific PITA2 term is not represented in the local ontology snapshot.
👪

Inheritance

1
X-linked dominant HP:0001423
Familial X-LAG/PITA2 follows dominant X-linked transmission through affected female carriers, while simplex cases can be de novo or somatic mosaic.
X-linked dominant inheritance
Show evidence (2 references)
PMID:25712922 SUPPORT Human Clinical
"All sporadic cases had unique duplications and the inheritance pattern in two families was dominant, with all Xq26.3 duplication carriers being affected."
This supports dominant inheritance of the Xq26.3 duplication in reported familial X-LAG kindreds.
PMID:38696651 SUPPORT Human Clinical
"X-LAG has been seen in 3 families due to transmission of the duplication from affected mothers to sons."
This supports the X-linked maternal transmission pattern for familial cases.
?

Discussions and Knowledge Gaps

1
Does the reported GPR101 p.E308D missense variant causally drive acromegaly in any patient subset, or was the original enrichment not reproducible?
KNOWLEDGE GAP OPEN gap_gpr101_pE308D_causality
Attached to
pathophysiology#Reported GPR101 p.E308D variant association pathophysiology#GPR101-driven adenylate cyclase-activating GPCR signaling
GPR101 duplication is sufficient for X-linked acrogigantism and is the core PITA2 mechanism. The p.E308D variant has in vitro activity and was reported in acromegaly, but a later cohort did not find increased prevalence versus public databases, so the point-variant branch should stay provisional.
Show evidence (1 reference)
PMID:27245663 SUPPORT Human Clinical
"did not have an increased prevalence of the c.924G > C (p.E308D) GPR101 variant compared to public databases."
This motivates keeping p.E308D causality as a knowledge gap rather than folding it into the established duplication mechanism.
⚙

Pathophysiology

6
GPR101 copy-number gain
GPR101 is the explicit gene-level entry point for PITA2. Germline or post-zygotic Xq26.3 copy-number gain increases GPR101 dosage and is the established causal route for X-linked acrogigantism.
GPR101 hgnc:14963 ↑ INCREASED
Genetic context GPR101 hgnc:14963 variant_origin: GERMLINE_AND_SOMATIC allelic_event: COPY_NUMBER_GAIN functional_impact_category: GAIN_OF_FUNCTION
GPR101 is affected by germline or somatic dosage gain in X-linked acrogigantism.
pituitary gland UBERON:0000007
Downstream
GPR101-driven adenylate cyclase-activating GPCR signaling Increased GPR101 dosage or activity increases GPCR signaling capacity upstream of cAMP production.
Show evidence (3 references)
PMID:25470569 SUPPORT Human Clinical
"We observed microduplication on chromosome Xq26.3 in samples from 13 patients with gigantism; of these samples, 4 were obtained from members of two unrelated kindreds, and 9 were from patients with sporadic cases."
This supports Xq26.3 duplication as the recurrent genomic event in childhood-onset GPR101-related disease.
PMID:27245663 SUPPORT Human Clinical
"In conclusion, XLAG can result from germline or somatic duplication of GPR101."
This replication/extension cohort supports both inherited and somatic GPR101 duplication as the causal genetic context for XLAG.
PMID:27245663 SUPPORT Human Clinical
"Duplication of GPR101 alone is sufficient for the development of XLAG, implicating it as the causative gene within the Xq26.3 region."
This directly supports GPR101 copy-number gain, not the broader duplicated interval, as sufficient for XLAG.
Reported GPR101 p.E308D variant association
The GPR101 p.E308D missense variant was reported in a subset of acromegaly cases and showed activity in GH3 cell assays, but a later cohort did not find increased prevalence in acromegaly. It is therefore retained as a provisional association rather than used as the main PITA2 causal entry point.
GPR101 hgnc:14963
Genetic context GPR101 hgnc:14963 variant_origin: GERMLINE_AND_SOMATIC allelic_event: MISSENSE_VARIANT functional_impact_category: UNKNOWN
Reported p.E308D observations include tumor and constitutive DNA contexts, but population enrichment and clinical causality remain unresolved.
Show evidence (2 references)
PMID:25470569 SUPPORT Human Clinical
"We identified a recurrent GPR101 mutation (p.E308D) in 11 of 248 patients with acromegaly, with the mutation found mostly in tumors."
This supports the original report of a recurrent p.E308D observation in acromegaly, mostly in tumor DNA.
PMID:27245663 REFUTE Human Clinical
"did not have an increased prevalence of the c.924G > C (p.E308D) GPR101 variant compared to public databases."
This later cohort argues against p.E308D being a common or clearly enriched acromegaly driver.
GPR101-driven adenylate cyclase-activating GPCR signaling
GPR101 encodes a GPCR that can couple to stimulatory G protein signaling, providing a gene-explicit route into adenylate cyclase activation and cAMP pathway overactivation.
somatotroph CL:0002312 mammotroph CL:0002311
GPR101 hgnc:14963 ↑ INCREASED
adenylate cyclase-activating GPCR signaling GO:0007189 ↑ INCREASED
GPR101 G protein-coupled receptor activity GO:0004930 ↑ INCREASED adenylate cyclase activator activity GO:0010856 ↑ INCREASED
Downstream
Increased cAMP/PKA signaling in somatotrophs Adenylate cyclase-activating GPCR signaling increases cAMP availability and PKA signaling in somatotroph-lineage cells.
Show evidence (2 references)
PMID:25470569 SUPPORT Human Clinical
"Only one of these genes, GPR101, which encodes a G-protein-coupled receptor, was overexpressed in patients' pituitary lesions."
This explicitly identifies GPR101 as the overexpressed GPCR in affected pituitary lesions.
PMID:25470569 SUPPORT In Vitro
"Moreover, we showed that GPR101 can strongly activate the cAMP pathway, for which the mitogenic effects in pituitary somatotropes are well established."
This connects GPR101 activity to cAMP pathway activation in the somatotroph tumor context.
Increased cAMP/PKA signaling in somatotrophs
GPR101 activation converges on the shared somatotroph cAMP/PKA signaling module, matching the downstream segment also reached by GNAS activation and AIP loss through different entry points.
somatotroph CL:0002312
cAMP/PKA signal transduction GO:0141156 ↑ INCREASED
Downstream
Increased growth hormone secretion Increased cAMP/PKA signaling increases secretory drive in somatotroph-lineage pituitary cells.
Somatotroph/lactotroph pituitary hyperplasia or adenoma Increased cAMP/PKA signaling supports proliferation and adenoma or hyperplasia formation in GH/PRL-lineage pituitary tissue.
Show evidence (1 reference)
PMID:25470569 SUPPORT In Vitro
"As in the construct containing the nonmutant receptor, the two mutant constructs resulted in increased cAMP signaling in GH3 cells in an in vitro reporter assay, both at baseline and in the presence of 10 μM forskolin, a direct stimulator of adenylyl cyclase (Fig. 4F)."
This supports increased cAMP signaling downstream of activating GPR101 variants in pituitary GH3 cells.
Increased growth hormone secretion
Somatotroph-lineage cells release excess growth hormone downstream of GPR101-driven cAMP/PKA pathway activation.
somatotroph CL:0002312
growth hormone secretion GO:0030252 ↑ INCREASED
Show evidence (1 reference)
PMID:25470569 SUPPORT In Vitro
"When the mutation was transfected into rat GH3 cells, it led to increased release of growth hormone and proliferation of growth hormone-producing cells."
This directly supports increased GH release downstream of activating GPR101 in a pituitary cell model.
Somatotroph/lactotroph pituitary hyperplasia or adenoma
GPR101-related disease produces pituitary macroadenomas or pituitary hyperplasia, often with somatotroph and mammotroph lineage features.
somatotroph CL:0002312 mammotroph CL:0002311
cell population proliferation GO:0008283 ↑ INCREASED
pituitary gland UBERON:0000007
Show evidence (1 reference)
PMID:25470569 SUPPORT Human Clinical
"Of the 13 patients who underwent surgery, 10 had pituitary macroadenomas alone (median maximum diameter, 16 mm), and 3 patients had pituitary hyperplasia, with or without an identified adenoma (Fig. 3H)."
This anchors the downstream proliferative outcome to the pituitary lesions observed in Xq26.3/GPR101 duplication patients.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for GPR101-related pituitary adenoma 2 Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
●

Phenotypes

4
Growth hormone excess HP:0000845
Show evidence (1 reference)
PMID:25470569 SUPPORT Human Clinical
"Increased secretion of growth hormone leads to gigantism in children and acromegaly in adults; the genetic causes of gigantism and acromegaly are poorly understood."
This frames the clinical syndrome as GH excess causing gigantism or acromegaly.
Hyperprolactinemia HP:0000870
Show evidence (1 reference)
PMID:25470569 SUPPORT Human Clinical
"As compared with patients who did not have an Xq26.3 microduplication, those with the microduplication had an earlier median age at the onset of abnormal growth (12 months vs. 16 years), an increased acceleration in height, and elevated levels of insulin-like growth factor 1 and prolactin (Table 1)."
This supports prolactin elevation as part of the Xq26.3/GPR101 duplication phenotype.
Pituitary macroadenoma or hyperplasia HP:0025693
Show evidence (1 reference)
PMID:25470569 SUPPORT Human Clinical
"Of the 13 patients who underwent surgery, 10 had pituitary macroadenomas alone (median maximum diameter, 16 mm), and 3 patients had pituitary hyperplasia, with or without an identified adenoma (Fig. 3H)."
This supports large pituitary adenoma or hyperplasia as a common structural outcome in GPR101-related X-LAG.
Acral overgrowth and coarse facial features HP:0033794
Show evidence (1 reference)
PMID:25712922 SUPPORT Human Clinical
"Apart from the increased overall body size, the children had acromegalic symptoms including acral enlargement and facial coarsening."
This adds the acromegalic tissue-overgrowth phenotype beyond biochemical GH excess.
🧬

Genetic Associations

1
GPR101 (Xq26.3 copy-number gain including GPR101 causes X-linked acrogigantism. Recurrent GPR101 p.E308D variants were reported in acromegaly, but later cohort data did not support increased prevalence, so point-variant causality is modeled as provisional rather than as the core PITA2 mechanism.)
Gene: GPR101 hgnc:14963 relationship_type: CAUSATIVE variant_origin: GERMLINE_AND_SOMATIC
Show evidence (1 reference)
PMID:25470569 SUPPORT Human Clinical
"Duplication of GPR101 probably causes X-LAG."
The discovery paper identifies GPR101 dosage as the likely causal gene in the Xq26.3 duplication syndrome.
💊

Medical Actions

3
Extensive pituitary surgery for local control
Action: surgical procedure MAXO:0000004
X-LAG frequently requires surgery for pituitary macroadenoma or hyperplasia, but extensive resection can produce permanent hypopituitarism.
Mechanism Target:
MODULATES Somatotroph/lactotroph pituitary hyperplasia or adenoma — Surgery reduces the proliferative pituitary lesion that produces GH/PRL excess.
Target Phenotypes: Pituitary macroadenoma HP:0025693
Show evidence (1 reference)
PMID:25712922 SUPPORT Human Clinical
"Primary neurosurgical control was achieved with extensive anterior pituitary resection, but postoperative hypopituitarism was frequent."
This supports neurosurgical control and the associated morbidity in X-LAG.
Somatostatin analog therapy with limited control
Action: pharmacotherapy MAXO:0000058
Somatostatin analogs may be used for GH excess but are often insufficient as sole therapy in X-LAG, despite SSTR2 expression.
Mechanism Target:
MODULATES Increased growth hormone secretion — Somatostatin analogs attempt to suppress GH secretion downstream of the GPR101-driven cAMP/PKA state.
Target Phenotypes: Growth hormone excess HP:0000845
Show evidence (1 reference)
PMID:25712922 SUPPORT Human Clinical
"Control with somatostatin analogs was not readily achieved despite moderate to high levels of expression of somatostatin receptor subtype-2 in tumor tissue."
This supports limited somatostatin analog control as a treatment-relevant X-LAG feature.
Pegvisomant-based GH receptor blockade
Action: pharmacotherapy MAXO:0000058
Pegvisomant can control IGF1/GH action in X-LAG when surgery and somatostatin analogs are insufficient, often as part of combination therapy.
Target Phenotypes: Growth hormone excess HP:0000845
Show evidence (2 references)
PMID:25712922 SUPPORT Human Clinical
"Postoperative use of adjuvant pegvisomant resulted in control of IGF1 in all five cases where it was employed."
This supports pegvisomant as an effective adjuvant in reported X-LAG cases.
PMID:38696651 SUPPORT Human Clinical
"Treatment of X-LAG is challenging due to the young patient population and resistance to somatostatin analogs; the GH receptor antagonist pegvisomant is often an effective option."
This recent review supports pegvisomant as a common effective option in the resistant X-LAG treatment context.
{ }

Source YAML

click to show 
name: GPR101-related pituitary adenoma 2
creation_date: "2026-06-03T00:00:00Z"
category: Genetic
categories:
- Endocrine Neoplasia
- Genomic Disorder
parents:
- pituitary gland adenoma
disease_term:
  preferred_term: GPR101-related pituitary adenoma 2
synonyms:
- Pituitary adenoma 2
- X-linked acrogigantism
- X-LAG
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0006373
      label: pituitary gland adenoma
    mapping_predicate: skos:closeMatch
    mapping_source: MONDO
    mapping_justification: >-
      Closest available MONDO grouping term for the GPR101-related pituitary
      adenoma/acrogigantism spectrum; a gene-specific PITA2 term is not
      represented in the local ontology snapshot.
description: >-
  GPR101-related pituitary adenoma 2 is a growth hormone excess pituitary
  adenoma or hyperplasia syndrome primarily driven by GPR101 copy-number gain.
  A reported recurrent GPR101 p.E308D variant is kept as a provisional extension
  rather than the main causal model. The mechanism is distinct from AIP two-hit
  tumor suppression: GPR101 acts as a dosage-driven GPCR entry point into the
  somatotroph cAMP/PKA overactivation module.
references:
- reference: PMID:25470569
  title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
  findings:
  - statement: >-
      Xq26.3 microduplication and GPR101 overexpression are associated with
      early-childhood growth hormone excess, pituitary macroadenoma or
      hyperplasia, and X-linked acrogigantism.
  - statement: >-
      Recurrent GPR101 p.E308D variants were reported mostly in acromegaly
      tumor tissue, and mutant GPR101 increased cAMP signaling, growth hormone
      release, and proliferation in GH3 pituitary cells.
- reference: PMID:27245663
  title: "Germline or somatic GPR101 duplication leads to X-linked acrogigantism: a clinico-pathological and genetic study."
  findings:
  - statement: >-
      Germline or somatic GPR101 duplication is sufficient for X-linked
      acrogigantism and implicates GPR101 as the causative gene within Xq26.3.
  - statement: >-
      Acromegaly patients did not show increased prevalence of the c.924G>C
      (p.E308D) GPR101 variant compared with public databases.
- reference: PMID:25712922
  title: "X-linked acrogigantism syndrome: clinical profile and therapeutic responses."
  findings:
  - statement: >-
      X-LAG begins in infancy, shows GH/IGF1 and usually prolactin
      hypersecretion from pituitary macroadenoma or hyperplasia, and is
      difficult to control with somatostatin analogs alone.
- reference: PMID:26982009
  title: "Somatic GPR101 Duplication Causing X-Linked Acrogigantism (XLAG)-Diagnosis and Management."
  findings:
  - statement: >-
      Somatic mosaic GPR101 duplication can cause a typical XLAG phenotype even
      when peripheral blood testing is negative.
- reference: PMID:38696651
  title: "The Genetic Pathophysiology and Clinical Management of the TADopathy, X-Linked Acrogigantism."
  findings:
  - statement: >-
      X-LAG can be transmitted from affected mothers to sons, is resistant to
      somatostatin analogs, and often responds to pegvisomant.
inheritance:
- name: X-linked dominant
  inheritance_term:
    preferred_term: X-linked dominant inheritance
    term:
      id: HP:0001423
      label: X-linked dominant inheritance
  description: >-
    Familial X-LAG/PITA2 follows dominant X-linked transmission through affected
    female carriers, while simplex cases can be de novo or somatic mosaic.
  evidence:
  - reference: PMID:25712922
    reference_title: "X-linked acrogigantism syndrome: clinical profile and therapeutic responses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      All sporadic cases had unique duplications and the inheritance pattern in
      two families was dominant, with all Xq26.3 duplication carriers being
      affected.
    explanation: >-
      This supports dominant inheritance of the Xq26.3 duplication in reported
      familial X-LAG kindreds.
  - reference: PMID:38696651
    reference_title: "The Genetic Pathophysiology and Clinical Management of the TADopathy, X-Linked Acrogigantism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      X-LAG has been seen in 3 families due to transmission of the duplication
      from affected mothers to sons.
    explanation: >-
      This supports the X-linked maternal transmission pattern for familial
      cases.
progression:
- phase: Early childhood growth hormone excess phase
  age_range: infancy to early childhood
  notes: >-
    Xq26.3 microduplication carriers in the discovery cohort had disease onset
    during early childhood, often with rapid growth during infancy before
    detection of pituitary hyperplasia or adenoma.
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      All the patients had disease onset during early childhood.
    explanation: >-
      This supports early childhood onset as a characteristic timing for the
      X-LAG/GPR101 duplication presentation.
genetic:
- name: GPR101
  gene_term:
    preferred_term: GPR101
    term:
      id: hgnc:14963
      label: GPR101
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE_AND_SOMATIC
  association: >-
    Xq26.3 copy-number gain including GPR101 causes X-linked acrogigantism.
    Recurrent GPR101 p.E308D variants were reported in acromegaly, but later
    cohort data did not support increased prevalence, so point-variant
    causality is modeled as provisional rather than as the core PITA2 mechanism.
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Duplication of GPR101 probably causes X-LAG.
    explanation: >-
      The discovery paper identifies GPR101 dosage as the likely causal gene in
      the Xq26.3 duplication syndrome.
pathophysiology:
- name: GPR101 copy-number gain
  description: >-
    GPR101 is the explicit gene-level entry point for PITA2. Germline or
    post-zygotic Xq26.3 copy-number gain increases GPR101 dosage and is the
    established causal route for X-linked acrogigantism.
  role: trigger
  gene:
    preferred_term: GPR101
    modifier: INCREASED
    term:
      id: hgnc:14963
      label: GPR101
  genetic_context:
    gene:
      preferred_term: GPR101
      term:
        id: hgnc:14963
        label: GPR101
    variant_origin: GERMLINE_AND_SOMATIC
    allelic_events:
    - COPY_NUMBER_GAIN
    functional_impact_category: GAIN_OF_FUNCTION
    description: >-
      GPR101 is affected by germline or somatic dosage gain in X-linked
      acrogigantism.
  locations:
  - preferred_term: pituitary gland
    term:
      id: UBERON:0000007
      label: pituitary gland
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We observed microduplication on chromosome Xq26.3 in samples from 13
      patients with gigantism; of these samples, 4 were obtained from members
      of two unrelated kindreds, and 9 were from patients with sporadic cases.
    explanation: >-
      This supports Xq26.3 duplication as the recurrent genomic event in
      childhood-onset GPR101-related disease.
  - reference: PMID:27245663
    reference_title: "Germline or somatic GPR101 duplication leads to X-linked acrogigantism: a clinico-pathological and genetic study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In conclusion, XLAG can result from germline or somatic duplication of
      GPR101.
    explanation: >-
      This replication/extension cohort supports both inherited and somatic
      GPR101 duplication as the causal genetic context for XLAG.
  - reference: PMID:27245663
    reference_title: "Germline or somatic GPR101 duplication leads to X-linked acrogigantism: a clinico-pathological and genetic study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Duplication of GPR101 alone is sufficient for the development of XLAG,
      implicating it as the causative gene within the Xq26.3 region.
    explanation: >-
      This directly supports GPR101 copy-number gain, not the broader duplicated
      interval, as sufficient for XLAG.
  downstream:
  - target: GPR101-driven adenylate cyclase-activating GPCR signaling
    description: >-
      Increased GPR101 dosage or activity increases GPCR signaling capacity
      upstream of cAMP production.
    causal_link_type: DIRECT

- name: Reported GPR101 p.E308D variant association
  description: >-
    The GPR101 p.E308D missense variant was reported in a subset of acromegaly
    cases and showed activity in GH3 cell assays, but a later cohort did not
    find increased prevalence in acromegaly. It is therefore retained as a
    provisional association rather than used as the main PITA2 causal entry
    point.
  role: provisional_trigger
  mechanism_confidence: PROVISIONAL
  gene:
    preferred_term: GPR101
    term:
      id: hgnc:14963
      label: GPR101
  genetic_context:
    gene:
      preferred_term: GPR101
      term:
        id: hgnc:14963
        label: GPR101
    variant_origin: GERMLINE_AND_SOMATIC
    allelic_events:
    - MISSENSE_VARIANT
    functional_impact_category: UNKNOWN
    description: >-
      Reported p.E308D observations include tumor and constitutive DNA contexts,
      but population enrichment and clinical causality remain unresolved.
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We identified a recurrent GPR101 mutation (p.E308D) in 11 of 248
      patients with acromegaly, with the mutation found mostly in tumors.
    explanation: >-
      This supports the original report of a recurrent p.E308D observation in
      acromegaly, mostly in tumor DNA.
  - reference: PMID:27245663
    reference_title: "Germline or somatic GPR101 duplication leads to X-linked acrogigantism: a clinico-pathological and genetic study."
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      did not have an increased prevalence of the c.924G > C (p.E308D) GPR101
      variant compared to public databases.
    explanation: >-
      This later cohort argues against p.E308D being a common or clearly
      enriched acromegaly driver.

- name: GPR101-driven adenylate cyclase-activating GPCR signaling
  description: >-
    GPR101 encodes a GPCR that can couple to stimulatory G protein signaling,
    providing a gene-explicit route into adenylate cyclase activation and cAMP
    pathway overactivation.
  role: upstream_effector
  cell_types:
  - preferred_term: somatotroph
    term:
      id: CL:0002312
      label: somatotroph
  - preferred_term: mammotroph
    term:
      id: CL:0002311
      label: mammotroph
  gene:
    preferred_term: GPR101
    modifier: INCREASED
    term:
      id: hgnc:14963
      label: GPR101
  molecular_functions:
  - preferred_term: GPR101 G protein-coupled receptor activity
    modifier: INCREASED
    term:
      id: GO:0004930
      label: G protein-coupled receptor activity
  - preferred_term: adenylate cyclase activator activity
    modifier: INCREASED
    term:
      id: GO:0010856
      label: adenylate cyclase activator activity
  biological_processes:
  - preferred_term: adenylate cyclase-activating GPCR signaling
    modifier: INCREASED
    term:
      id: GO:0007189
      label: adenylate cyclase-activating G protein-coupled receptor signaling pathway
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Only one of these genes, GPR101, which encodes a G-protein-coupled
      receptor, was overexpressed in patients' pituitary lesions.
    explanation: >-
      This explicitly identifies GPR101 as the overexpressed GPCR in affected
      pituitary lesions.
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Moreover, we showed that GPR101 can strongly activate the cAMP pathway,
      for which the mitogenic effects in pituitary somatotropes are well
      established.
    explanation: >-
      This connects GPR101 activity to cAMP pathway activation in the
      somatotroph tumor context.
  downstream:
  - target: Increased cAMP/PKA signaling in somatotrophs
    description: >-
      Adenylate cyclase-activating GPCR signaling increases cAMP availability
      and PKA signaling in somatotroph-lineage cells.
    causal_link_type: DIRECT

- name: Increased cAMP/PKA signaling in somatotrophs
  conforms_to: somatotroph_camp_pka_overactivation#Increased cAMP/PKA signaling in somatotrophs
  description: >-
    GPR101 activation converges on the shared somatotroph cAMP/PKA signaling
    module, matching the downstream segment also reached by GNAS activation and
    AIP loss through different entry points.
  role: central_effector
  cell_types:
  - preferred_term: somatotroph
    term:
      id: CL:0002312
      label: somatotroph
  biological_processes:
  - preferred_term: cAMP/PKA signal transduction
    modifier: INCREASED
    term:
      id: GO:0141156
      label: cAMP/PKA signal transduction
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      As in the construct containing the nonmutant receptor, the two mutant
      constructs resulted in increased cAMP signaling in GH3 cells in an in
      vitro reporter assay, both at baseline and in the presence of 10 μM
      forskolin, a direct stimulator of adenylyl cyclase (Fig. 4F).
    explanation: >-
      This supports increased cAMP signaling downstream of activating GPR101
      variants in pituitary GH3 cells.
  downstream:
  - target: Increased growth hormone secretion
    description: >-
      Increased cAMP/PKA signaling increases secretory drive in
      somatotroph-lineage pituitary cells.
    causal_link_type: DIRECT
  - target: Somatotroph/lactotroph pituitary hyperplasia or adenoma
    description: >-
      Increased cAMP/PKA signaling supports proliferation and adenoma or
      hyperplasia formation in GH/PRL-lineage pituitary tissue.
    causal_link_type: DIRECT

- name: Increased growth hormone secretion
  conforms_to: somatotroph_camp_pka_overactivation#Increased growth hormone secretion
  description: >-
    Somatotroph-lineage cells release excess growth hormone downstream of
    GPR101-driven cAMP/PKA pathway activation.
  role: consequence
  cell_types:
  - preferred_term: somatotroph
    term:
      id: CL:0002312
      label: somatotroph
  biological_processes:
  - preferred_term: growth hormone secretion
    modifier: INCREASED
    term:
      id: GO:0030252
      label: growth hormone secretion
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      When the mutation was transfected into rat GH3 cells, it led to increased
      release of growth hormone and proliferation of growth hormone-producing
      cells.
    explanation: >-
      This directly supports increased GH release downstream of activating
      GPR101 in a pituitary cell model.

- name: Somatotroph/lactotroph pituitary hyperplasia or adenoma
  conforms_to: somatotroph_camp_pka_overactivation#Somatotroph proliferation and adenoma growth
  description: >-
    GPR101-related disease produces pituitary macroadenomas or pituitary
    hyperplasia, often with somatotroph and mammotroph lineage features.
  role: consequence
  cell_types:
  - preferred_term: somatotroph
    term:
      id: CL:0002312
      label: somatotroph
  - preferred_term: mammotroph
    term:
      id: CL:0002311
      label: mammotroph
  locations:
  - preferred_term: pituitary gland
    term:
      id: UBERON:0000007
      label: pituitary gland
  biological_processes:
  - preferred_term: cell population proliferation
    modifier: INCREASED
    term:
      id: GO:0008283
      label: cell population proliferation
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Of the 13 patients who underwent surgery, 10 had pituitary macroadenomas
      alone (median maximum diameter, 16 mm), and 3 patients had pituitary
      hyperplasia, with or without an identified adenoma (Fig. 3H).
    explanation: >-
      This anchors the downstream proliferative outcome to the pituitary
      lesions observed in Xq26.3/GPR101 duplication patients.
phenotypes:
- name: Growth hormone excess
  phenotype_term:
    preferred_term: Elevated circulating growth hormone concentration
    term:
      id: HP:0000845
      label: Elevated circulating growth hormone concentration
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Increased secretion of growth hormone leads to gigantism in children and
      acromegaly in adults; the genetic causes of gigantism and acromegaly are
      poorly understood.
    explanation: >-
      This frames the clinical syndrome as GH excess causing gigantism or
      acromegaly.
- name: Hyperprolactinemia
  phenotype_term:
    preferred_term: Increased circulating prolactin concentration
    term:
      id: HP:0000870
      label: Increased circulating prolactin concentration
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      As compared with patients who did not have an Xq26.3 microduplication,
      those with the microduplication had an earlier median age at the onset of
      abnormal growth (12 months vs. 16 years), an increased acceleration in
      height, and elevated levels of insulin-like growth factor 1 and prolactin
      (Table 1).
    explanation: >-
      This supports prolactin elevation as part of the Xq26.3/GPR101 duplication
      phenotype.
- name: Pituitary macroadenoma or hyperplasia
  phenotype_term:
    preferred_term: Pituitary macroadenoma
    term:
      id: HP:0025693
      label: Pituitary macroadenoma
  evidence:
  - reference: PMID:25470569
    reference_title: "Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Of the 13 patients who underwent surgery, 10 had pituitary macroadenomas
      alone (median maximum diameter, 16 mm), and 3 patients had pituitary
      hyperplasia, with or without an identified adenoma (Fig. 3H).
    explanation: >-
      This supports large pituitary adenoma or hyperplasia as a common structural
      outcome in GPR101-related X-LAG.
- name: Acral overgrowth and coarse facial features
  phenotype_term:
    preferred_term: Acral overgrowth
    term:
      id: HP:0033794
      label: Acral overgrowth
  evidence:
  - reference: PMID:25712922
    reference_title: "X-linked acrogigantism syndrome: clinical profile and therapeutic responses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Apart from the increased overall body size, the children had acromegalic
      symptoms including acral enlargement and facial coarsening.
    explanation: >-
      This adds the acromegalic tissue-overgrowth phenotype beyond biochemical
      GH excess.
diagnosis:
- name: Xq26.3/GPR101 copy-number testing
  diagnosis_term:
    preferred_term: molecular genetic testing
    term:
      id: MAXO:0000533
      label: molecular genetic testing
    qualifiers:
    - predicate:
        preferred_term: has participant
        term:
          id: RO:0000057
          label: has participant
      value:
        preferred_term: GPR101
        term:
          id: hgnc:14963
          label: GPR101
  description: >-
    Early-onset pituitary gigantism should prompt copy-number testing for
    Xq26.3/GPR101 duplication; suspected mosaic cases may require tissue beyond
    peripheral blood.
  results: >-
    Detection of germline or mosaic GPR101 duplication supports the molecular
    diagnosis.
  evidence:
  - reference: PMID:27245663
    reference_title: "Germline or somatic GPR101 duplication leads to X-linked acrogigantism: a clinico-pathological and genetic study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The pathological features of XLAG-associated pituitary adenomas are
      typical and, together with the clinical phenotype, should prompt genetic
      testing.
    explanation: >-
      This supports using the XLAG phenotype and pathology to trigger GPR101
      duplication testing.
  - reference: PMID:26982009
    reference_title: "Somatic GPR101 Duplication Causing X-Linked Acrogigantism (XLAG)-Diagnosis and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      a negative test for Xq26.3 microduplication or GPR101 duplication on
      peripheral blood DNA does not exclude the diagnosis of XLAG because it can
      result from a mosaic mutation affecting the pituitary.
    explanation: >-
      This supports tissue-aware copy-number testing when clinical suspicion
      persists despite negative blood testing.
treatments:
- name: Extensive pituitary surgery for local control
  description: >-
    X-LAG frequently requires surgery for pituitary macroadenoma or hyperplasia,
    but extensive resection can produce permanent hypopituitarism.
  treatment_term:
    preferred_term: surgical procedure
    term:
      id: MAXO:0000004
      label: surgical procedure
  target_phenotypes:
  - preferred_term: Pituitary macroadenoma
    term:
      id: HP:0025693
      label: Pituitary macroadenoma
  target_mechanisms:
  - target: Somatotroph/lactotroph pituitary hyperplasia or adenoma
    treatment_effect: MODULATES
    description: >-
      Surgery reduces the proliferative pituitary lesion that produces GH/PRL
      excess.
  evidence:
  - reference: PMID:25712922
    reference_title: "X-linked acrogigantism syndrome: clinical profile and therapeutic responses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Primary neurosurgical control was achieved with extensive anterior
      pituitary resection, but postoperative hypopituitarism was frequent.
    explanation: >-
      This supports neurosurgical control and the associated morbidity in X-LAG.
- name: Somatostatin analog therapy with limited control
  description: >-
    Somatostatin analogs may be used for GH excess but are often insufficient as
    sole therapy in X-LAG, despite SSTR2 expression.
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
  target_phenotypes:
  - preferred_term: Growth hormone excess
    term:
      id: HP:0000845
      label: Elevated circulating growth hormone concentration
  target_mechanisms:
  - target: Increased growth hormone secretion
    treatment_effect: MODULATES
    description: >-
      Somatostatin analogs attempt to suppress GH secretion downstream of the
      GPR101-driven cAMP/PKA state.
  evidence:
  - reference: PMID:25712922
    reference_title: "X-linked acrogigantism syndrome: clinical profile and therapeutic responses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Control with somatostatin analogs was not readily achieved despite
      moderate to high levels of expression of somatostatin receptor subtype-2
      in tumor tissue.
    explanation: >-
      This supports limited somatostatin analog control as a treatment-relevant
      X-LAG feature.
- name: Pegvisomant-based GH receptor blockade
  description: >-
    Pegvisomant can control IGF1/GH action in X-LAG when surgery and
    somatostatin analogs are insufficient, often as part of combination therapy.
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
  target_phenotypes:
  - preferred_term: Growth hormone excess
    term:
      id: HP:0000845
      label: Elevated circulating growth hormone concentration
  evidence:
  - reference: PMID:25712922
    reference_title: "X-linked acrogigantism syndrome: clinical profile and therapeutic responses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Postoperative use of adjuvant pegvisomant resulted in control of IGF1 in
      all five cases where it was employed.
    explanation: >-
      This supports pegvisomant as an effective adjuvant in reported X-LAG
      cases.
  - reference: PMID:38696651
    reference_title: "The Genetic Pathophysiology and Clinical Management of the TADopathy, X-Linked Acrogigantism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Treatment of X-LAG is challenging due to the young patient population and
      resistance to somatostatin analogs; the GH receptor antagonist pegvisomant
      is often an effective option.
    explanation: >-
      This recent review supports pegvisomant as a common effective option in
      the resistant X-LAG treatment context.
discussions:
- discussion_id: gap_gpr101_pE308D_causality
  prompt: >-
    Does the reported GPR101 p.E308D missense variant causally drive acromegaly
    in any patient subset, or was the original enrichment not reproducible?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Reported GPR101 p.E308D variant association
  - pathophysiology#GPR101-driven adenylate cyclase-activating GPCR signaling
  rationale: >-
    GPR101 duplication is sufficient for X-linked acrogigantism and is the core
    PITA2 mechanism. The p.E308D variant has in vitro activity and was reported
    in acromegaly, but a later cohort did not find increased prevalence versus
    public databases, so the point-variant branch should stay provisional.
  evidence:
  - reference: PMID:27245663
    reference_title: "Germline or somatic GPR101 duplication leads to X-linked acrogigantism: a clinico-pathological and genetic study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      did not have an increased prevalence of the c.924G > C (p.E308D) GPR101
      variant compared to public databases.
    explanation: >-
      This motivates keeping p.E308D causality as a knowledge gap rather than
      folding it into the established duplication mechanism.
📚

References & Deep Research

References

5
PMID:25470569
Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation.
2 findings
Xq26.3 microduplication and GPR101 overexpression are associated with early-childhood growth hormone excess, pituitary macroadenoma or hyperplasia, and X-linked acrogigantism.
Recurrent GPR101 p.E308D variants were reported mostly in acromegaly tumor tissue, and mutant GPR101 increased cAMP signaling, growth hormone release, and proliferation in GH3 pituitary cells.
PMID:27245663
Germline or somatic GPR101 duplication leads to X-linked acrogigantism: a clinico-pathological and genetic study.
2 findings
Germline or somatic GPR101 duplication is sufficient for X-linked acrogigantism and implicates GPR101 as the causative gene within Xq26.3.
Acromegaly patients did not show increased prevalence of the c.924G>C (p.E308D) GPR101 variant compared with public databases.
PMID:25712922
X-linked acrogigantism syndrome: clinical profile and therapeutic responses.
1 finding
X-LAG begins in infancy, shows GH/IGF1 and usually prolactin hypersecretion from pituitary macroadenoma or hyperplasia, and is difficult to control with somatostatin analogs alone.
PMID:26982009
Somatic GPR101 Duplication Causing X-Linked Acrogigantism (XLAG)-Diagnosis and Management.
1 finding
Somatic mosaic GPR101 duplication can cause a typical XLAG phenotype even when peripheral blood testing is negative.
PMID:38696651
The Genetic Pathophysiology and Clinical Management of the TADopathy, X-Linked Acrogigantism.
1 finding
X-LAG can be transmitted from affected mothers to sons, is resistant to somatostatin analogs, and often responds to pegvisomant.

Deep Research

1
Falcon ▸
1. Disease Information
Edison Scientific Literature 39 citations 2026-06-03T15:51:19.863593

1. Disease Information

1.1 Definition and overview

X‑linked acrogigantism (X‑LAG) is a rare genetic form of pituitary gigantism in which growth hormone (GH) excess begins before epiphyseal fusion, usually during infancy, and is driven by GPR101 overexpression in pituitary tissue due to Xq26.3 duplications. It commonly presents with mixed GH–prolactin pituitary neuroendocrine tumors (PitNETs; historically “adenomas”) and/or pituitary hyperplasia, resulting in rapid linear growth and markedly elevated GH/IGF‑1 (often with hyperprolactinemia). (daly2024thegeneticpathophysiology pages 1-1, daly2024thegeneticpathophysiology pages 1-2)

Key abstract quote (expert review, 2024): “X-LAG is caused by constitutive or sporadic mosaic duplications at chromosome Xq26.3… around… GPR101…” and “GPR101 is a constitutively active receptor… to promote GH/prolactin hypersecretion.” (daly2024thegeneticpathophysiology pages 1-1)

1.2 Key identifiers (best available from retrieved sources)

  • OMIM (MIM): X‑linked acrogigantism MIM: 300942 (daly2024chromatinconformationcapture pages 7-9)
  • Gene: GPR101 (ENSG00000165370) (OpenTargets Search: pituitary adenoma,gigantism,acromegaly-GPR101)
  • Pituitary tumor class: Pituitary adenoma / Pituitary neuroendocrine tumor (PitNET) (caruso2024casereportmanagement pages 2-4, daly2024thegeneticpathophysiology pages 1-2)

Not retrieved in current tool context: MONDO, Orphanet, ICD-10/ICD-11, MeSH identifiers.

1.3 Synonyms / alternative names

  • X-linked acrogigantism (X‑LAG) (daly2024thegeneticpathophysiology pages 1-1)
  • GPR101 duplication–associated pituitary gigantism (iacovazzo2016germlineorsomatic pages 1-2)
  • Xq26.3 microduplication gigantism (iacovazzo2016germlineorsomatic pages 2-5)

1.4 Evidence sources

Most evidence comes from aggregated disease-level resources (reviews and cohorts) plus individual case reports with molecular and pathological detail. (daly2024thegeneticpathophysiology pages 1-1, iacovazzo2016germlineorsomatic pages 2-5, caruso2024casereportmanagement pages 2-4)

2. Etiology

2.1 Primary causal factors

Causal lesion: tandem duplications at Xq26.3 involving GPR101 that lead to marked pituitary overexpression of GPR101. (daly2024thegeneticpathophysiology pages 1-2, iacovazzo2016germlineorsomatic pages 2-5)

Dosage sufficiency (primary cohort evidence): a smallest-region case demonstrated that duplication of GPR101 alone is sufficient to cause the disease phenotype. (iacovazzo2016germlineorsomatic pages 2-5, iacovazzo2016germlineorsomatic pages 1-2)

2.2 Risk factors

  • Genetic risk factor: presence of a pathogenic Xq26.3 duplication producing neo‑TAD formation and ectopic enhancer adoption leading to pituitary GPR101 misexpression (mechanistic risk). (daly2024chromatinconformationcapture pages 1-2, daly2024chromatinconformationcapture pages 6-7)
  • Sex/biological context: strong female predominance in reported cohorts; sporadic males often have somatic mosaicism, affecting detection and possibly apparent frequency. (daly2024thegeneticpathophysiology pages 8-9, daly2024thegeneticpathophysiology pages 3-3)

No credible environmental/lifestyle risk factors were identified in the retrieved evidence.

2.3 Protective factors

No genetic or environmental protective factors were identified in the retrieved evidence.

2.4 Gene–environment interactions

No gene–environment interactions were identified in the retrieved evidence.

3. Phenotypes (clinical features)

3.1 Core phenotype domain and onset

  • Primary phenotype: pituitary gigantism due to GH excess beginning in infancy (median onset ~18 months; diagnosis ~4 years). (daly2024thegeneticpathophysiology pages 1-2, daly2024thegeneticpathophysiology pages 8-9)
  • In a large gigantism cohort, onset can be as early as 7 months. (iacovazzo2016germlineorsomatic pages 2-5)

3.2 Endocrine laboratory abnormalities

  • GH: basal GH elevated in all patients in a 12‑patient X‑LAG cohort. (iacovazzo2016germlineorsomatic pages 2-5)
  • IGF‑1: median ~2.9× ULN in the 2016 cohort; 2024 synthesis reports median 3.1× ULN with values up to 15.9× ULN. (iacovazzo2016germlineorsomatic pages 2-5, daly2024thegeneticpathophysiology pages 9-10)
  • Prolactin: hyperprolactinemia common—10/12 (83.3%) in one cohort; 31/39 (79.5%) in a review cohort. (iacovazzo2016germlineorsomatic pages 7-9, daly2024thegeneticpathophysiology pages 9-10)

Representative pediatric case values: random GH 62 ng/mL, IGF‑1 752.1 ng/mL, prolactin 2,656 mIU/L with a pituitary mass 17×12 mm. (caruso2024casereportmanagement pages 2-4)

3.3 Imaging (pituitary MRI)

  • Macroadenoma predominance: 75% macroadenomas in the 2016 cohort; 2024 review reports 82.1% macroadenomas and only 2.6% microadenomas; suprasellar extension typical, carotid sinus invasion infrequent. (iacovazzo2016germlineorsomatic pages 2-5, daly2024thegeneticpathophysiology pages 10-11)
  • Pituitary hyperplasia: ~25% in the 2016 cohort; 2024 synthesis reports hyperplasia alone in 10.3% and adenoma+hyperplasia in 7.7%. (iacovazzo2016germlineorsomatic pages 2-5, daly2024thegeneticpathophysiology pages 13-14)

3.4 Pathology/histology and immunophenotype

Common findings include a mixed somatotroph–lactotroph lesion with sinusoidal/lobular architecture and low proliferative indices in most sporadic cases. (iacovazzo2016germlineorsomatic pages 5-7, caruso2024casereportmanagement pages 4-6)

  • Lineage/TF: PIT‑1 positive in >90% tumor cells in a cohort; Pit‑1 positivity is described as 90–100% in synthesis. (iacovazzo2016germlineorsomatic pages 5-7, daly2024thegeneticpathophysiology pages 11-12)
  • Ki‑67: typically <3% in cohort tumors; familial mother–infant pair had higher indices (5.6% and 8.5%). (iacovazzo2016germlineorsomatic pages 5-7, wiseoringer2019familialxlinkedacrogigantism pages 1-2)
  • SSTR2/5: variable SSTR2a/SSTR5 staining reported in cohort tumors; a severe case showed strong SSTR2/5 expression. (iacovazzo2016germlineorsomatic pages 5-7, naves2016aggressivetumorgrowth pages 2-5)
  • Other features: follicle-like structures, calcifications, fibrous bodies (CAM5.2). (iacovazzo2016germlineorsomatic pages 5-7, caruso2024casereportmanagement pages 4-6)

3.5 Quality of life impact

Direct QoL outcome data specific to X‑LAG were not retrieved; however, trials in acromegaly and GH excess commonly assess QoL and symptoms, and pediatric GH excess trials include symptom and QoL measures as endpoints. (NCT03882034 chunk 1, NCT02354508 chunk 2)

3.6 Suggested HPO terms (non-exhaustive)

  • Excessive growth / gigantism: Abnormality of body height (HP:0000002), Tall stature (HP:0000098)
  • Endocrine labs: Increased circulating growth hormone level (HP:0000848), Increased circulating insulin-like growth factor 1 level (HP:0030305), Hyperprolactinemia (HP:0000871)
  • Tumor/anatomy: Pituitary adenoma (HP:0002893), Pituitary hyperplasia (HPO term availability varies)
  • Hypopituitarism as treatment consequence: Hypopituitarism (HP:0000871 is prolactin; hypopituitarism is HP:0000863)

4. Genetic / Molecular Information

4.1 Causal gene

  • GPR101 (G protein-coupled receptor 101), orphan GPCR implicated through dosage increase from duplications. (daly2024thegeneticpathophysiology pages 1-1, iacovazzo2016germlineorsomatic pages 2-5)

4.2 Pathogenic variant class and origin

  • Primary pathogenic mechanism: copy-number gain (duplication) at Xq26.3 that is functionally pathogenic when it disrupts local TAD architecture (a “TADopathy”), enabling ectopic enhancer–promoter contacts and GPR101 misexpression. (daly2024chromatinconformationcapture pages 1-2, daly2024chromatinconformationcapture pages 6-7)
  • Germline vs somatic: in a cohort of 12 X‑LAG patients, females had germline duplications while males had mosaic duplications. (iacovazzo2016germlineorsomatic pages 2-5)

4.3 Functional consequence

GPR101 is described as constitutively active and capable of stimulating GH (and often prolactin) hypersecretion. (daly2024thegeneticpathophysiology pages 1-1, daly2024thegeneticpathophysiology pages 5-6)

4.4 Modifier genes / epigenetics / chromosomal abnormalities

No validated modifier genes or epigenetic signatures specific to X‑LAG were identified in the retrieved evidence.

5. Environmental Information

No specific environmental, lifestyle, or infectious contributors were identified in the retrieved evidence; the condition is primarily a structural-variant driven genetic endocrine tumor syndrome. (daly2024thegeneticpathophysiology pages 1-1, iacovazzo2016germlineorsomatic pages 2-5)

6. Mechanism / Pathophysiology

6.1 Causal chain (gene → molecular → cellular → clinical)

1) Xq26.3 duplication reorganizes chromatin and can create a neo‑TAD that places the GPR101 promoter under the influence of ectopic pituitary enhancers, causing massive pituitary GPR101 overexpression. (daly2024chromatinconformationcapture pages 1-2, daly2024chromatinconformationcapture pages 6-7) 2) GPR101 constitutive activity signals through multiple G proteins including Gs and Gq/11, increasing cAMP/PKA and PLCβ/PKC pathway activity, which increases GH secretion (and often PRL). (abboud2020gpr101drivesgrowth pages 8-8, daly2024thegeneticpathophysiology pages 5-6) 3) Resulting chronic GH/IGF‑1 excess in infancy causes rapid linear growth and pituitary adenoma/hyperplasia phenotypes in humans. (daly2024thegeneticpathophysiology pages 1-2, daly2024thegeneticpathophysiology pages 9-10)

6.2 Upstream vs downstream

  • Upstream: 3D genome/TAD disruption (structural variant effect) and GPR101 overexpression (daly2024chromatinconformationcapture pages 6-7)
  • Downstream: PKA/PKC signaling, GH secretion, systemic IGF‑1 elevation, somatic overgrowth (abboud2020gpr101drivesgrowth pages 8-8, abboud2020gpr101drivesgrowth pages 2-3)

6.3 Cell types and tissues

  • Primary tissue: anterior pituitary (adenohypophysis), particularly somatotroph and lactotroph lineages (Pit‑1 lineage). (iacovazzo2016germlineorsomatic pages 5-7, daly2024thegeneticpathophysiology pages 11-12)

Suggested Cell Ontology (CL) terms: - Somatotroph (CL:0002395) - Lactotroph (CL:0002400)

Suggested UBERON terms: - Pituitary gland (UBERON:0000007) - Anterior pituitary gland (UBERON:0002196)

6.4 Pathway and ontology suggestions

Suggested GO Biological Process terms (examples): - Regulation of hormone secretion - Growth hormone secretion - cAMP-mediated signaling - Protein kinase C-activating signaling pathway

Molecular pathway concepts: Gs/adenylyl cyclase/cAMP/PKA and Gq/PLCβ/PKC axes in pituitary secretory control (abboud2020gpr101drivesgrowth pages 8-8, abboud2020gpr101drivesgrowth pages 2-3)

6.5 Model-organism evidence

  • Mouse: pituitary-targeted Gpr101 overexpression causes elevated GH/IGF‑1/PRL and overgrowth without pituitary adenoma or hyperplasia, implying GPR101 is strongly secretagogue but not sufficient for tumorigenesis in that model. (abboud2020gpr101drivesgrowth pages 2-3, abboud2020gpr101drivesgrowth pages 10-11)

7. Anatomical Structures Affected

  • Primary organ: pituitary gland (macroadenoma/hyperplasia). (daly2024thegeneticpathophysiology pages 10-11)
  • Secondary structures: suprasellar region/optic chiasm risk due to extension; cavernous sinus invasion can occur in severe cases. (naves2016aggressivetumorgrowth pages 2-5)

8. Temporal Development

  • Onset: typically infancy, with clinical overgrowth apparent in the first 1–3 years; median onset ~18 months. (daly2024thegeneticpathophysiology pages 8-9, daly2024thegeneticpathophysiology pages 1-2)
  • Course: progressive overgrowth until GH/IGF‑1 controlled; diagnostic delay of ~2–3 years is described. (daly2024thegeneticpathophysiology pages 10-11)

9. Inheritance and Population

9.1 Epidemiology (best available)

  • X‑LAG accounts for ~10% of pituitary gigantism cases in reviews. (daly2024thegeneticpathophysiology pages 1-1, daly2024thegeneticpathophysiology pages 3-3)
  • In a 153‑patient pituitary gigantism cohort, X‑LAG was 7.8% overall. (iacovazzo2016germlineorsomatic pages 1-2)
  • Case counts: ~39–40 reported cases in the first decade after discovery (as of 2024 reviews). (daly2024thegeneticpathophysiology pages 1-1, daly2024thegeneticpathophysiology pages 8-9)

Population-level incidence/prevalence per 100,000 were not retrieved.

9.2 Inheritance pattern and penetrance

  • X-linked dominant; familial transmission observed from affected mothers to sons (daly2024thegeneticpathophysiology pages 1-1, daly2024thegeneticpathophysiology pages 3-3)
  • Penetrance: full penetrance described in familial cases in synthesis literature. (nadhamuni2020novelinsightsinto pages 10-11)

9.3 Sex ratio and mosaicism

  • Female predominance (~77% female in a 39-patient compilation). (daly2024thegeneticpathophysiology pages 8-9)
  • Sporadic males often have somatic mosaic duplication, complicating detection from blood. (daly2024thegeneticpathophysiology pages 3-3)

10. Diagnostics

10.1 Clinical tests

  • Biochemical: GH suppression testing after oral glucose load (OGTT) and IGF‑1 vs age/sex norms are emphasized for suspected pituitary gigantism. (daly2024thegeneticpathophysiology pages 3-3)
  • Imaging: low threshold for pituitary MRI when IGF‑1 is elevated or GH is not suppressed. (daly2024thegeneticpathophysiology pages 3-3)

10.2 Pathology

IHC/histology supportive features include GH/PRL expression patterns, Pit‑1 lineage, variable SSTR2/5, and typical low Ki‑67 in most cases. (iacovazzo2016germlineorsomatic pages 5-7)

10.3 Genetic testing strategy and mosaicism considerations

  • First-line CNV detection: array/HD‑aCGH/CMA; ddPCR CNV assays can improve sensitivity. (daly2024thegeneticpathophysiology pages 3-3, iacovazzo2016germlineorsomatic pages 1-2)
  • Mosaicism: blood/saliva/buccal arrays can be negative in mosaic males; ddPCR and testing other tissues (skin, pituitary tumor) can be required. (daly2024thegeneticpathophysiology pages 3-3, iacovazzo2016germlineorsomatic pages 1-2)
  • Breakpoint/TAD interpretation: 4C‑seq/Hi‑C can classify duplications as pathogenic vs neutral based on whether they create a neo‑TAD and adopt ectopic enhancers. (daly2024chromatinconformationcapture pages 1-2, daly2024chromatinconformationcapture pages 7-9)

10.4 Differential diagnosis (key items)

  • AIP-related pituitary gigantism
  • McCune–Albright syndrome (postzygotic GNAS)
  • MEN1 and Carney complex (excluded in a cohort via clinical/genetic data) (iacovazzo2016germlineorsomatic pages 1-2)

11. Outcome / Prognosis

11.1 Disease control and long-term outcomes

In a 39-patient compilation, hormonal control at last follow-up was reported in 31/39 (79.5%), but control often requires multiple modalities and comes with high endocrine morbidity. (daly2024thegeneticpathophysiology pages 13-13)

11.2 Treatment-related morbidity

  • Hypopituitarism: any axis in 26/39 (66.7%); only 8/39 (20.5%) achieved control without hypopituitarism. (daly2024thegeneticpathophysiology pages 13-14)
  • Radiotherapy use: 15/39 (38.5%). (daly2024thegeneticpathophysiology pages 13-14)

11.3 Aggressiveness spectrum

Although carotid sinus invasion is described as infrequent in synthesis cohorts, severe aggressive cases with cavernous sinus invasion and hydrocephalus have been reported. (daly2024thegeneticpathophysiology pages 11-12, naves2016aggressivetumorgrowth pages 2-5)

12. Treatment

12.1 Real-world treatment strategy (current understanding)

X‑LAG often requires multimodal therapy because of early age at presentation, high secretory burden, and relative resistance to first-generation somatostatin analogs. (daly2024thegeneticpathophysiology pages 13-13, daly2024thegeneticpathophysiology pages 12-13)

  • Surgery (MAXO suggestion): transsphenoidal pituitary tumor resection / debulking; performed in 35/39 (89.7%) in a compilation. (daly2024thegeneticpathophysiology pages 13-13)
  • Somatostatin analogs (MAXO): often inadequate for GH/IGF‑1 control; postoperative responsiveness may improve after debulking in some cases. (daly2024thegeneticpathophysiology pages 12-13)
  • Dopamine agonists (MAXO): may help prolactin but little GH impact. (daly2024thegeneticpathophysiology pages 12-13)
  • Pegvisomant (GH receptor antagonist; MAXO): highlighted as effective for IGF‑1 control in X‑LAG management. (daly2024thegeneticpathophysiology pages 13-14, daly2024thegeneticpathophysiology pages 12-13)
  • Radiotherapy (MAXO): used in a subset (38.5%). (daly2024thegeneticpathophysiology pages 13-14)

Real-world implementation example: in a 2024 pediatric case, somatostatin analogs and cabergoline did not normalize GH/IGF‑1; pegvisomant reduced IGF‑1 but was complicated by inconsistent control and lipohypertrophy at injection sites. (caruso2024casereportmanagement pages 2-4)

12.2 Clinical trials (selected)

  • Pegvisomant in pediatric GH excess: NCT03882034 (ClinicalTrials.gov, 2019) Phase 3, open-label single group, n=12, ages 2–<18; primary endpoint is % change in IGF‑1 z‑score at 12 months with efficacy target >50% decrease. URL: https://clinicaltrials.gov/study/NCT03882034 (NCT03882034 chunk 1, NCT03882034 chunk 2)

(Trials are not X‑LAG-specific but relevant to pediatric GH excess management.)

13. Prevention

No established primary prevention exists because the disorder is driven by structural variants. Prevention is primarily secondary/tertiary: - Secondary prevention: early recognition of accelerated growth in infancy/toddlerhood and rapid biochemical/MRI evaluation. (daly2024thegeneticpathophysiology pages 3-3) - Genetic counseling/prenatal context: incidentally detected GPR101 duplications require careful interpretation; 4C/Hi‑C (or validated predictors) can distinguish neutral vs pathogenic duplications to prevent unnecessary surveillance and anxiety. (daly2024chromatinconformationcapture pages 1-2, daly2024chromatinconformationcapture pages 7-9)

14. Other species / natural disease

No naturally occurring veterinary disease associations were retrieved.

15. Model organisms

  • Mouse model: pituitary somatotroph-targeted Gpr101 overexpression causes GH/IGF‑1/PRL excess and overgrowth without adenoma/hyperplasia—useful for studying secretion/signaling but limited for tumorigenesis modeling. (abboud2020gpr101drivesgrowth pages 2-3, abboud2020gpr101drivesgrowth pages 10-11)

2023–2024 highlights (recent developments and expert analysis)

1) X‑LAG reframed as a “TADopathy”: 2024 Endocrine Reviews synthesizes 10 years of X‑LAG research, emphasizing chromatin architecture disruption and management challenges. Publication date: May 2024. URL: https://doi.org/10.1210/endrev/bnae014 (daly2024thegeneticpathophysiology pages 1-1) 2) Clinical chromatin conformation capture for CNV interpretation: 2024 Genome Medicine demonstrates 4C‑seq/Hi‑C can distinguish pathogenic vs neutral GPR101 duplications for counseling and prenatal interpretation. Publication date: Sep 2024. URL: https://doi.org/10.1186/s13073-024-01378-5 (daly2024chromatinconformationcapture pages 1-2, daly2024chromatinconformationcapture pages 7-9) 3) Detailed pediatric management pathway: 2024 Frontiers in Endocrinology case report provides end-to-end diagnostic and multimodal management, including 4C‑seq evidence of neo‑TAD and medical therapy challenges. Publication date: Feb 2024. URL: https://doi.org/10.3389/fendo.2024.1345363 (caruso2024casereportmanagement pages 2-4)

Data tables and visual evidence

A quantitative summary table is provided below.

Topic Specific data point Value(s) with units or percentages Source (first author year, journal) PMID if known URL Evidence type
Genetics/Epidemiology Proportion of pituitary gigantism cohort with GPR101 duplication/X-LAG 12/153 patients = 7.8%; females 10/58 = 17.2% of female gigantism cases Iacovazzo 2016, Acta Neuropathologica Communications (iacovazzo2016germlineorsomatic pages 2-5, iacovazzo2016germlineorsomatic pages 1-2) https://doi.org/10.1186/s40478-016-0328-1 Human cohort
Epidemiology Share of pituitary gigantism attributable to X-LAG ~10% of pituitary gigantism cases Daly 2024, Endocrine Reviews (daly2024thegeneticpathophysiology pages 1-1, daly2024thegeneticpathophysiology pages 3-3) https://doi.org/10.1210/endrev/bnae014 Review of human cohorts
Epidemiology Total reported X-LAG cases in review cohort 39 reported patients; ~40 cases over first 10 years since discovery Daly 2024, Endocrine Reviews (daly2024thegeneticpathophysiology pages 1-1, daly2024thegeneticpathophysiology pages 8-9) https://doi.org/10.1210/endrev/bnae014 Review of human cohorts
Epidemiology Sex distribution Female 30/39 (76.9%); male 9/39 (23.1%) Daly 2024, Endocrine Reviews (daly2024thegeneticpathophysiology pages 8-9, daly2024thegeneticpathophysiology pages 1-2, daly2024thegeneticpathophysiology media 4af4c0f4) https://doi.org/10.1210/endrev/bnae014 Review of human cohorts
Genetics Germline vs mosaic pattern Females: germline duplications; sporadic males: often somatic mosaic duplications; familial maternal transmission reported Iacovazzo 2016, Acta Neuropathologica Communications; Daly 2016, Endocrine-Related Cancer; Daly 2024, Endocrine Reviews (iacovazzo2016germlineorsomatic pages 2-5, daly2024thegeneticpathophysiology pages 3-3) https://doi.org/10.1186/s40478-016-0328-1 Human cohort
Genetics Inheritance/penetrance summary X-linked dominant; familial cases reported; full penetrance reported in familial X-LAG Daly 2024, Endocrine Reviews; Nadhamuni 2020, Endocrine Reviews (daly2024thegeneticpathophysiology pages 13-14, nadhamuni2020novelinsightsinto pages 10-11) https://doi.org/10.1210/endrev/bnae014 Review of human cohorts
Phenotype Median age at onset 18 months in review cohort; 1.9 years in 2016 cohort Daly 2024, Endocrine Reviews; Iacovazzo 2016, Acta Neuropathologica Communications (daly2024thegeneticpathophysiology pages 8-9, iacovazzo2016germlineorsomatic pages 2-5) https://doi.org/10.1210/endrev/bnae014 Human cohort/review
Phenotype Median age at diagnosis ~4 years in review cohort; 4.4 years in 2016 cohort Daly 2024, Endocrine Reviews; Iacovazzo 2016, Acta Neuropathologica Communications (daly2024thegeneticpathophysiology pages 1-2, iacovazzo2016germlineorsomatic pages 2-5) https://doi.org/10.1210/endrev/bnae014 Human cohort/review
Phenotype Height excess at presentation Median height SDS +5.4 in XLAG cohort Iacovazzo 2016, Acta Neuropathologica Communications (iacovazzo2016germlineorsomatic pages 2-5) https://doi.org/10.1186/s40478-016-0328-1 Human cohort
Phenotype GH/IGF-1 excess Basal GH elevated in all patients; median IGF-1 ~2.9× upper limit of normal Iacovazzo 2016, Acta Neuropathologica Communications (iacovazzo2016germlineorsomatic pages 2-5) https://doi.org/10.1186/s40478-016-0328-1 Human cohort
Tumor pathology Macroadenoma frequency 9/12 = 75% macroadenomas in 2016 cohort; 82.1% macroadenomas in 2024 review cohort Iacovazzo 2016, Acta Neuropathologica Communications; Daly 2024, Endocrine Reviews (iacovazzo2016germlineorsomatic pages 2-5, daly2024thegeneticpathophysiology pages 10-11) https://doi.org/10.1186/s40478-016-0328-1 Human cohort/review
Tumor pathology Hyperplasia frequency 3/12 = 25% diffuse pituitary hyperplasia in 2016 cohort; 10.3% hyperplasia and 7.7% adenoma + hyperplasia in 2024 review table Iacovazzo 2016, Acta Neuropathologica Communications; Daly 2024, Endocrine Reviews (iacovazzo2016germlineorsomatic pages 2-5, daly2024thegeneticpathophysiology pages 13-14, daly2024thegeneticpathophysiology media 4af4c0f4) https://doi.org/10.1186/s40478-016-0328-1 Human cohort/review
Tumor pathology Typical tumor lineage Mixed GH–prolactin adenoma common; mixed GH/PRL lesions 72% in review table Daly 2024, Endocrine Reviews (daly2024thegeneticpathophysiology pages 13-14, daly2024thegeneticpathophysiology media 4af4c0f4) https://doi.org/10.1210/endrev/bnae014 Review of human cohorts
Tumor pathology Prolactin co-secretion / hyperprolactinemia PRL elevated in 10/12 patients (83.3%) in 2016 cohort; prolactin co-secretion 77% in 2024 review Iacovazzo 2016, Acta Neuropathologica Communications; Daly 2024, Endocrine Reviews (iacovazzo2016germlineorsomatic pages 2-5, daly2024thegeneticpathophysiology pages 13-14, iacovazzo2016germlineorsomatic pages 7-9) https://doi.org/10.1186/s40478-016-0328-1 Human cohort/review
Tumor pathology Histologic architecture Sinusoidal/lobular architecture; mixed densely granulated somatotrophs and lactotrophs; Ki-67 usually <3% in cohort cases Iacovazzo 2016, Acta Neuropathologica Communications (iacovazzo2016germlineorsomatic pages 5-7, iacovazzo2016germlineorsomatic pages 7-9) https://doi.org/10.1186/s40478-016-0328-1 Human pathology cohort
Treatment outcomes Any pituitary axis hypopituitarism after treatment 26/39 = 66.7% had hypopituitarism affecting any axis Daly 2024, Endocrine Reviews (daly2024thegeneticpathophysiology pages 13-14, daly2024thegeneticpathophysiology media 4af4c0f4) https://doi.org/10.1210/endrev/bnae014 Review of human cohorts
Treatment outcomes Radiotherapy use 15/39 = 38.5% received radiotherapy Daly 2024, Endocrine Reviews (daly2024thegeneticpathophysiology pages 13-14, daly2024thegeneticpathophysiology media 4af4c0f4) https://doi.org/10.1210/endrev/bnae014 Review of human cohorts
Treatment outcomes Control without hypopituitarism 8/39 = 20.5% achieved control without hypopituitarism Daly 2024, Endocrine Reviews (daly2024thegeneticpathophysiology pages 13-14, daly2024thegeneticpathophysiology media 4af4c0f4) https://doi.org/10.1210/endrev/bnae014 Review of human cohorts
Treatment outcomes General medical therapy response First-generation SSA resistance common; pegvisomant often effective for IGF-1 control Daly 2024, Endocrine Reviews (daly2024thegeneticpathophysiology pages 13-14, daly2024thegeneticpathophysiology pages 1-2) https://doi.org/10.1210/endrev/bnae014 Review/expert analysis
Treatment outcomes Example of real-world pediatric case Octreotide/lanreotide and cabergoline did not normalize GH/IGF-1; pegvisomant lowered IGF-1 but control remained inconsistent and lipohypertrophy occurred Caruso 2024, Frontiers in Endocrinology (caruso2024casereportmanagement pages 2-4) https://doi.org/10.3389/fendo.2024.1345363 Human case report
Diagnostics Example baseline pediatric biochemical values Random GH 62 ng/mL; IGF-1 752.1 ng/mL; prolactin 2,656 mIU/L; pituitary mass 17 × 12 mm Caruso 2024, Frontiers in Endocrinology (caruso2024casereportmanagement pages 2-4) https://doi.org/10.3389/fendo.2024.1345363 Human case report
Diagnostics Pathogenic structural criterion at GPR101 locus Pathogenic duplications disrupt the invariant centromeric TAD boundary and create a neo-TAD enabling ectopic enhancer adoption; duplications preserving the boundary are neutral/non-pathogenic Daly 2024, Genome Medicine (daly2024chromatinconformationcapture pages 7-9, daly2024chromatinconformationcapture pages 1-2, daly2024chromatinconformationcapture pages 6-7, daly2024chromatinconformationcapture pages 9-10) https://doi.org/10.1186/s13073-024-01378-5 Human genomic mechanism/clinical translational study
Diagnostics Clinical utility of 4C-seq/Hi-C 4C-seq/Hi-C used to reclassify suspected X-LAG CNVs and discontinue unnecessary endocrine surveillance in neutral cases Daly 2024, Genome Medicine (daly2024chromatinconformationcapture pages 7-9, daly2024chromatinconformationcapture pages 4-6) https://doi.org/10.1186/s13073-024-01378-5 Human translational diagnostics study
Mechanism Primary molecular lesion Xq26.3 tandem duplication involving GPR101 with topological domain disruption and pituitary GPR101 misexpression (>1000-fold overexpression reported) Daly 2024, Endocrine Reviews; Daly 2024, Genome Medicine (daly2024thegeneticpathophysiology pages 8-9, daly2024chromatinconformationcapture pages 1-2) https://doi.org/10.1210/endrev/bnae014 Human molecular/review
Mechanism Receptor signaling partners Constitutive coupling to Gs, Gq/11, and G12/13; increases cAMP, IP1/IP3, and Rho signaling Abboud 2020, Nature Communications; Daly 2024, Endocrine Reviews (abboud2020gpr101drivesgrowth pages 10-11, abboud2020gpr101drivesgrowth pages 1-2, daly2024thegeneticpathophysiology pages 5-6) https://doi.org/10.1038/s41467-020-18500-x Animal model/in vitro
Mechanism Downstream pathways PKA and PKC activation drive GH secretion; phospho-PKC increased in mouse pituitary and human tumors with high GPR101 expression Abboud 2020, Nature Communications (abboud2020gpr101drivesgrowth pages 10-11, abboud2020gpr101drivesgrowth pages 8-8, abboud2020gpr101drivesgrowth pages 8-9, abboud2020gpr101drivesgrowth pages 2-3) https://doi.org/10.1038/s41467-020-18500-x Animal model/in vitro/human tumor validation
Mechanism Secretory vs proliferative effect in model Ghrhr-Gpr101 transgenic mice developed elevated GH, IGF-1, PRL and gigantism but no pituitary adenoma or hyperplasia Abboud 2020, Nature Communications (abboud2020gpr101drivesgrowth pages 10-11, abboud2020gpr101drivesgrowth pages 1-2, abboud2020gpr101drivesgrowth pages 2-3) https://doi.org/10.1038/s41467-020-18500-x Animal model
Clinical trial Pediatric pegvisomant trial design NCT03882034; Phase 3; open-label single-group; n=12; ages 2 to <18 years; 10 mg SC daily with dose adjustment ClinicalTrials.gov/NICHD 2019 (NCT03882034 chunk 1, NCT03882034 chunk 2) https://clinicaltrials.gov/study/NCT03882034 Clinical trial
Clinical trial Pediatric pegvisomant primary endpoints Percent change in IGF-1 z-score from baseline to 12 months; efficacy target: >50% decrease in IGF-1 z-score; safety/tolerability co-primary ClinicalTrials.gov/NICHD 2019 (NCT03882034 chunk 1, NCT03882034 chunk 2) https://clinicaltrials.gov/study/NCT03882034 Clinical trial
Clinical trial Pediatric pegvisomant secondary endpoints Normalization of age/sex-adjusted IGF-1, change in growth velocity, symptom/QoL measures, cardiac structure/function, PK studies ClinicalTrials.gov/NICHD 2019 (NCT03882034 chunk 1, NCT03882034 chunk 2) https://clinicaltrials.gov/study/NCT03882034 Clinical trial

Table: This table summarizes key quantitative and mechanistic findings for GPR101/X-linked acrogigantism, used here as the closest evidence base for GPR101-related pituitary adenoma 2. It consolidates cohort statistics, pathology, mechanism, diagnostic interpretation, and relevant pediatric trial endpoints into a structured format for downstream knowledge-base use.

Cohort summary table from Daly & Beckers 2024 (Endocrine Reviews) was retrieved as an image (Table 1). (daly2024thegeneticpathophysiology media 4af4c0f4)

Key limitations of this report

  • MONDO/Orphanet/ICD/MeSH identifiers were not retrieved in the current tool context; filling those would require dedicated ontology database queries.
  • Some requested elements (environmental factors, QoL instruments specifically in X‑LAG, population prevalence/incidence rates) are not well established or not present in the retrieved evidence.

References

  1. (daly2024thegeneticpathophysiology pages 1-1): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  2. (iacovazzo2016germlineorsomatic pages 1-2): Donato Iacovazzo, Richard Caswell, Benjamin Bunce, Sian Jose, Bo Yuan, Laura C. Hernández-Ramírez, Sonal Kapur, Francisca Caimari, Jane Evanson, Francesco Ferraù, Mary N. Dang, Plamena Gabrovska, Sarah J. Larkin, Olaf Ansorge, Celia Rodd, Mary L. Vance, Claudia Ramírez-Renteria, Moisés Mercado, Anthony P. Goldstone, Michael Buchfelder, Christine P. Burren, Alper Gurlek, Pinaki Dutta, Catherine S. Choong, Timothy Cheetham, Giampaolo Trivellin, Constantine A. Stratakis, Maria-Beatriz Lopes, Ashley B. Grossman, Jacqueline Trouillas, James R. Lupski, Sian Ellard, Julian R. Sampson, Federico Roncaroli, and Márta Korbonits. Germline or somatic gpr101 duplication leads to x-linked acrogigantism: a clinico-pathological and genetic study. Acta Neuropathologica Communications, Jun 2016. URL: https://doi.org/10.1186/s40478-016-0328-1, doi:10.1186/s40478-016-0328-1. This article has 161 citations and is from a peer-reviewed journal.

  3. (daly2024thegeneticpathophysiology pages 1-2): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  4. (daly2024chromatinconformationcapture pages 7-9): Adrian F. Daly, Leslie A. Dunnington, David F. Rodriguez-Buritica, Erica Spiegel, Francesco Brancati, Giovanna Mantovani, Vandana M. Rawal, Fabio Rueda Faucz, Hadia Hijazi, Jean-Hubert Caberg, Anna Maria Nardone, Mario Bengala, Paola Fortugno, Giulia Del Sindaco, Marta Ragonese, Helen Gould, Salvatore Cannavò, Patrick Pétrossians, Andrea Lania, James R. Lupski, Albert Beckers, Constantine A. Stratakis, Brynn Levy, Giampaolo Trivellin, and Martin Franke. Chromatin conformation capture in the clinic: 4c-seq/hic distinguishes pathogenic from neutral duplications at the gpr101 locus. Genome Medicine, Sep 2024. URL: https://doi.org/10.1186/s13073-024-01378-5, doi:10.1186/s13073-024-01378-5. This article has 12 citations and is from a highest quality peer-reviewed journal.

  5. (OpenTargets Search: pituitary adenoma,gigantism,acromegaly-GPR101): Open Targets Query (pituitary adenoma,gigantism,acromegaly-GPR101, 3 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.

  6. (caruso2024casereportmanagement pages 2-4): Manuela Caruso, Diego Mazzatenta, Sofia Asioli, Giuseppe Costanza, Giampaolo Trivellin, Martin Franke, Dayana Abboud, Julien Hanson, Véronique Raverot, Patrick Pétrossians, Albert Beckers, Marco Cappa, and Adrian F. Daly. Case report: management of pediatric gigantism caused by the tadopathy, x-linked acrogigantism. Frontiers in Endocrinology, Feb 2024. URL: https://doi.org/10.3389/fendo.2024.1345363, doi:10.3389/fendo.2024.1345363. This article has 7 citations.

  7. (iacovazzo2016germlineorsomatic pages 2-5): Donato Iacovazzo, Richard Caswell, Benjamin Bunce, Sian Jose, Bo Yuan, Laura C. Hernández-Ramírez, Sonal Kapur, Francisca Caimari, Jane Evanson, Francesco Ferraù, Mary N. Dang, Plamena Gabrovska, Sarah J. Larkin, Olaf Ansorge, Celia Rodd, Mary L. Vance, Claudia Ramírez-Renteria, Moisés Mercado, Anthony P. Goldstone, Michael Buchfelder, Christine P. Burren, Alper Gurlek, Pinaki Dutta, Catherine S. Choong, Timothy Cheetham, Giampaolo Trivellin, Constantine A. Stratakis, Maria-Beatriz Lopes, Ashley B. Grossman, Jacqueline Trouillas, James R. Lupski, Sian Ellard, Julian R. Sampson, Federico Roncaroli, and Márta Korbonits. Germline or somatic gpr101 duplication leads to x-linked acrogigantism: a clinico-pathological and genetic study. Acta Neuropathologica Communications, Jun 2016. URL: https://doi.org/10.1186/s40478-016-0328-1, doi:10.1186/s40478-016-0328-1. This article has 161 citations and is from a peer-reviewed journal.

  8. (daly2024chromatinconformationcapture pages 1-2): Adrian F. Daly, Leslie A. Dunnington, David F. Rodriguez-Buritica, Erica Spiegel, Francesco Brancati, Giovanna Mantovani, Vandana M. Rawal, Fabio Rueda Faucz, Hadia Hijazi, Jean-Hubert Caberg, Anna Maria Nardone, Mario Bengala, Paola Fortugno, Giulia Del Sindaco, Marta Ragonese, Helen Gould, Salvatore Cannavò, Patrick Pétrossians, Andrea Lania, James R. Lupski, Albert Beckers, Constantine A. Stratakis, Brynn Levy, Giampaolo Trivellin, and Martin Franke. Chromatin conformation capture in the clinic: 4c-seq/hic distinguishes pathogenic from neutral duplications at the gpr101 locus. Genome Medicine, Sep 2024. URL: https://doi.org/10.1186/s13073-024-01378-5, doi:10.1186/s13073-024-01378-5. This article has 12 citations and is from a highest quality peer-reviewed journal.

  9. (daly2024chromatinconformationcapture pages 6-7): Adrian F. Daly, Leslie A. Dunnington, David F. Rodriguez-Buritica, Erica Spiegel, Francesco Brancati, Giovanna Mantovani, Vandana M. Rawal, Fabio Rueda Faucz, Hadia Hijazi, Jean-Hubert Caberg, Anna Maria Nardone, Mario Bengala, Paola Fortugno, Giulia Del Sindaco, Marta Ragonese, Helen Gould, Salvatore Cannavò, Patrick Pétrossians, Andrea Lania, James R. Lupski, Albert Beckers, Constantine A. Stratakis, Brynn Levy, Giampaolo Trivellin, and Martin Franke. Chromatin conformation capture in the clinic: 4c-seq/hic distinguishes pathogenic from neutral duplications at the gpr101 locus. Genome Medicine, Sep 2024. URL: https://doi.org/10.1186/s13073-024-01378-5, doi:10.1186/s13073-024-01378-5. This article has 12 citations and is from a highest quality peer-reviewed journal.

  10. (daly2024thegeneticpathophysiology pages 8-9): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  11. (daly2024thegeneticpathophysiology pages 3-3): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  12. (daly2024thegeneticpathophysiology pages 9-10): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  13. (iacovazzo2016germlineorsomatic pages 7-9): Donato Iacovazzo, Richard Caswell, Benjamin Bunce, Sian Jose, Bo Yuan, Laura C. Hernández-Ramírez, Sonal Kapur, Francisca Caimari, Jane Evanson, Francesco Ferraù, Mary N. Dang, Plamena Gabrovska, Sarah J. Larkin, Olaf Ansorge, Celia Rodd, Mary L. Vance, Claudia Ramírez-Renteria, Moisés Mercado, Anthony P. Goldstone, Michael Buchfelder, Christine P. Burren, Alper Gurlek, Pinaki Dutta, Catherine S. Choong, Timothy Cheetham, Giampaolo Trivellin, Constantine A. Stratakis, Maria-Beatriz Lopes, Ashley B. Grossman, Jacqueline Trouillas, James R. Lupski, Sian Ellard, Julian R. Sampson, Federico Roncaroli, and Márta Korbonits. Germline or somatic gpr101 duplication leads to x-linked acrogigantism: a clinico-pathological and genetic study. Acta Neuropathologica Communications, Jun 2016. URL: https://doi.org/10.1186/s40478-016-0328-1, doi:10.1186/s40478-016-0328-1. This article has 161 citations and is from a peer-reviewed journal.

  14. (daly2024thegeneticpathophysiology pages 10-11): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  15. (daly2024thegeneticpathophysiology pages 13-14): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  16. (iacovazzo2016germlineorsomatic pages 5-7): Donato Iacovazzo, Richard Caswell, Benjamin Bunce, Sian Jose, Bo Yuan, Laura C. Hernández-Ramírez, Sonal Kapur, Francisca Caimari, Jane Evanson, Francesco Ferraù, Mary N. Dang, Plamena Gabrovska, Sarah J. Larkin, Olaf Ansorge, Celia Rodd, Mary L. Vance, Claudia Ramírez-Renteria, Moisés Mercado, Anthony P. Goldstone, Michael Buchfelder, Christine P. Burren, Alper Gurlek, Pinaki Dutta, Catherine S. Choong, Timothy Cheetham, Giampaolo Trivellin, Constantine A. Stratakis, Maria-Beatriz Lopes, Ashley B. Grossman, Jacqueline Trouillas, James R. Lupski, Sian Ellard, Julian R. Sampson, Federico Roncaroli, and Márta Korbonits. Germline or somatic gpr101 duplication leads to x-linked acrogigantism: a clinico-pathological and genetic study. Acta Neuropathologica Communications, Jun 2016. URL: https://doi.org/10.1186/s40478-016-0328-1, doi:10.1186/s40478-016-0328-1. This article has 161 citations and is from a peer-reviewed journal.

  17. (caruso2024casereportmanagement pages 4-6): Manuela Caruso, Diego Mazzatenta, Sofia Asioli, Giuseppe Costanza, Giampaolo Trivellin, Martin Franke, Dayana Abboud, Julien Hanson, Véronique Raverot, Patrick Pétrossians, Albert Beckers, Marco Cappa, and Adrian F. Daly. Case report: management of pediatric gigantism caused by the tadopathy, x-linked acrogigantism. Frontiers in Endocrinology, Feb 2024. URL: https://doi.org/10.3389/fendo.2024.1345363, doi:10.3389/fendo.2024.1345363. This article has 7 citations.

  18. (daly2024thegeneticpathophysiology pages 11-12): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  19. (wiseoringer2019familialxlinkedacrogigantism pages 1-2): Brittany K Wise-Oringer, George J Zanazzi, Rebecca J Gordon, Sharon L Wardlaw, Christopher William, Kwame Anyane-Yeboa, Wendy K Chung, Brenda Kohn, Jeffrey H Wisoff, Raphael David, and Sharon E Oberfield. Familial x-linked acrogigantism: postnatal outcomes and tumor pathology in a prenatally diagnosed infant and his mother. The Journal of clinical endocrinology and metabolism, 104:4667-4675, Oct 2019. URL: https://doi.org/10.1210/jc.2019-00817, doi:10.1210/jc.2019-00817. This article has 31 citations.

  20. (naves2016aggressivetumorgrowth pages 2-5): Luciana A. Naves, Adrian F. Daly, Luiz Augusto Dias, Bo Yuan, Juliano Coelho Oliveira Zakir, Gustavo Barcellos Barra, Leonor Palmeira, Chiara Villa, Giampaolo Trivellin, Armindo Jreige Júnior, Florêncio Figueiredo Cavalcante Neto, Pengfei Liu, Natalia S. Pellegata, Constantine A. Stratakis, James R. Lupski, and Albert Beckers. Aggressive tumor growth and clinical evolution in a patient with x-linked acro-gigantism syndrome. Endocrine, 51:236-244, Feb 2016. URL: https://doi.org/10.1007/s12020-015-0804-6, doi:10.1007/s12020-015-0804-6. This article has 71 citations and is from a peer-reviewed journal.

  21. (NCT03882034 chunk 1): Safety and Efficacy of Pegvisomant in Children With Growth Hormone Excess. Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). 2019. ClinicalTrials.gov Identifier: NCT03882034

  22. (NCT02354508 chunk 2): Pasireotide in Patients With Acromegaly Inadequately Controlled With First Generation Somatostatin Analogues. Novartis Pharmaceuticals. 2015. ClinicalTrials.gov Identifier: NCT02354508

  23. (daly2024thegeneticpathophysiology pages 5-6): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  24. (abboud2020gpr101drivesgrowth pages 8-8): Dayana Abboud, Adrian F. Daly, Nadine Dupuis, Mohamed Ali Bahri, Asuka Inoue, Andy Chevigné, Fabien Ectors, Alain Plenevaux, Bernard Pirotte, Albert Beckers, and Julien Hanson. Gpr101 drives growth hormone hypersecretion and gigantism in mice via constitutive activation of gs and gq/11. Nature Communications, Sep 2020. URL: https://doi.org/10.1038/s41467-020-18500-x, doi:10.1038/s41467-020-18500-x. This article has 71 citations and is from a highest quality peer-reviewed journal.

  25. (abboud2020gpr101drivesgrowth pages 2-3): Dayana Abboud, Adrian F. Daly, Nadine Dupuis, Mohamed Ali Bahri, Asuka Inoue, Andy Chevigné, Fabien Ectors, Alain Plenevaux, Bernard Pirotte, Albert Beckers, and Julien Hanson. Gpr101 drives growth hormone hypersecretion and gigantism in mice via constitutive activation of gs and gq/11. Nature Communications, Sep 2020. URL: https://doi.org/10.1038/s41467-020-18500-x, doi:10.1038/s41467-020-18500-x. This article has 71 citations and is from a highest quality peer-reviewed journal.

  26. (abboud2020gpr101drivesgrowth pages 10-11): Dayana Abboud, Adrian F. Daly, Nadine Dupuis, Mohamed Ali Bahri, Asuka Inoue, Andy Chevigné, Fabien Ectors, Alain Plenevaux, Bernard Pirotte, Albert Beckers, and Julien Hanson. Gpr101 drives growth hormone hypersecretion and gigantism in mice via constitutive activation of gs and gq/11. Nature Communications, Sep 2020. URL: https://doi.org/10.1038/s41467-020-18500-x, doi:10.1038/s41467-020-18500-x. This article has 71 citations and is from a highest quality peer-reviewed journal.

  27. (nadhamuni2020novelinsightsinto pages 10-11): Vinaya Srirangam Nadhamuni and Márta Korbonits. Novel insights into pituitary tumorigenesis: genetic and epigenetic mechanisms. Endocrine Reviews, 41:821-846, Mar 2020. URL: https://doi.org/10.1210/endrev/bnaa006, doi:10.1210/endrev/bnaa006. This article has 127 citations and is from a domain leading peer-reviewed journal.

  28. (daly2024thegeneticpathophysiology pages 13-13): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  29. (daly2024thegeneticpathophysiology pages 12-13): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  30. (NCT03882034 chunk 2): Safety and Efficacy of Pegvisomant in Children With Growth Hormone Excess. Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). 2019. ClinicalTrials.gov Identifier: NCT03882034

  31. (daly2024thegeneticpathophysiology media 4af4c0f4): Adrian F. Daly and Albert Beckers. The genetic pathophysiology and clinical management of the tadopathy, x-linked acrogigantism. Endocrine reviews, 45:737-754, May 2024. URL: https://doi.org/10.1210/endrev/bnae014, doi:10.1210/endrev/bnae014. This article has 16 citations and is from a domain leading peer-reviewed journal.

  32. (daly2024chromatinconformationcapture pages 9-10): Adrian F. Daly, Leslie A. Dunnington, David F. Rodriguez-Buritica, Erica Spiegel, Francesco Brancati, Giovanna Mantovani, Vandana M. Rawal, Fabio Rueda Faucz, Hadia Hijazi, Jean-Hubert Caberg, Anna Maria Nardone, Mario Bengala, Paola Fortugno, Giulia Del Sindaco, Marta Ragonese, Helen Gould, Salvatore Cannavò, Patrick Pétrossians, Andrea Lania, James R. Lupski, Albert Beckers, Constantine A. Stratakis, Brynn Levy, Giampaolo Trivellin, and Martin Franke. Chromatin conformation capture in the clinic: 4c-seq/hic distinguishes pathogenic from neutral duplications at the gpr101 locus. Genome Medicine, Sep 2024. URL: https://doi.org/10.1186/s13073-024-01378-5, doi:10.1186/s13073-024-01378-5. This article has 12 citations and is from a highest quality peer-reviewed journal.

  33. (daly2024chromatinconformationcapture pages 4-6): Adrian F. Daly, Leslie A. Dunnington, David F. Rodriguez-Buritica, Erica Spiegel, Francesco Brancati, Giovanna Mantovani, Vandana M. Rawal, Fabio Rueda Faucz, Hadia Hijazi, Jean-Hubert Caberg, Anna Maria Nardone, Mario Bengala, Paola Fortugno, Giulia Del Sindaco, Marta Ragonese, Helen Gould, Salvatore Cannavò, Patrick Pétrossians, Andrea Lania, James R. Lupski, Albert Beckers, Constantine A. Stratakis, Brynn Levy, Giampaolo Trivellin, and Martin Franke. Chromatin conformation capture in the clinic: 4c-seq/hic distinguishes pathogenic from neutral duplications at the gpr101 locus. Genome Medicine, Sep 2024. URL: https://doi.org/10.1186/s13073-024-01378-5, doi:10.1186/s13073-024-01378-5. This article has 12 citations and is from a highest quality peer-reviewed journal.

  34. (abboud2020gpr101drivesgrowth pages 1-2): Dayana Abboud, Adrian F. Daly, Nadine Dupuis, Mohamed Ali Bahri, Asuka Inoue, Andy Chevigné, Fabien Ectors, Alain Plenevaux, Bernard Pirotte, Albert Beckers, and Julien Hanson. Gpr101 drives growth hormone hypersecretion and gigantism in mice via constitutive activation of gs and gq/11. Nature Communications, Sep 2020. URL: https://doi.org/10.1038/s41467-020-18500-x, doi:10.1038/s41467-020-18500-x. This article has 71 citations and is from a highest quality peer-reviewed journal.

  35. (abboud2020gpr101drivesgrowth pages 8-9): Dayana Abboud, Adrian F. Daly, Nadine Dupuis, Mohamed Ali Bahri, Asuka Inoue, Andy Chevigné, Fabien Ectors, Alain Plenevaux, Bernard Pirotte, Albert Beckers, and Julien Hanson. Gpr101 drives growth hormone hypersecretion and gigantism in mice via constitutive activation of gs and gq/11. Nature Communications, Sep 2020. URL: https://doi.org/10.1038/s41467-020-18500-x, doi:10.1038/s41467-020-18500-x. This article has 71 citations and is from a highest quality peer-reviewed journal.

Artifacts