Pseudohypoparathyroidism

Genetic MONDO:0019992 Pathograph 19 Show in embeddings browser Endocrine Disorder Calcium-Phosphate Metabolism Disorder

Pseudohypoparathyroidism (PHP) is a group of disorders caused by impaired signaling at the GNAS locus, producing resistance to parathyroid hormone and, in many patients, additional endocrine and developmental abnormalities. The phenotype reflects both parent-of-origin effects (imprinting) and tissue-specific dependence on Gs alpha signaling.

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5
Pathophys.
14
Phenotypes
6
Hypotheses
19
Pathograph
1
Genes
2
Medical Actions
3
Subtypes
2
Datasets
1
References
5
Hyp. Reports
🏷

Classifications

ISDS Skeletal Nosology
acromelic dysplasias
◆

Subtypes

3
PHP1A
Usually caused by maternally inherited inactivating GNAS variants with parathyroid hormone resistance, additional hormone resistance, and Albright hereditary osteodystrophy features.
Show evidence (1 reference)
PMID:40972900 SUPPORT Human Clinical
"While maternal mutations result in PHP type 1A, which consists of PTH resistance and AHO, paternal mutations lead to pseudo-pseudohypoparathyroidism (PPHP), that is, AHO without hormone resistance."
Confirms maternal-allele mutations classically produce PHP1A with PTH resistance and AHO.
PHP1B
Usually caused by GNAS methylation defects (often including STX16-related imprinting abnormalities) with predominant renal PTH resistance and less pronounced Albright hereditary osteodystrophy.
Show evidence (1 reference)
PMID:40972900 SUPPORT Human Clinical
"Epigenetic alterations of GNAS cause PHP type 1B (PHP1B), defined by PTH resistance in the absence of AHO."
Supports the subtype definition of PHP1B as an epigenetic GNAS disorder with predominant PTH resistance.
Pseudopseudohypoparathyroidism
Usually caused by paternally inherited inactivating GNAS variants and characterized by Albright hereditary osteodystrophy features with limited or absent hormone resistance.
Show evidence (1 reference)
PMID:40972900 SUPPORT Human Clinical
"While maternal mutations result in PHP type 1A, which consists of PTH resistance and AHO, paternal mutations lead to pseudo-pseudohypoparathyroidism (PPHP), that is, AHO without hormone resistance."
Directly distinguishes paternal-allele PPHP from maternal-allele PHP1A.
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Mechanistic Hypotheses

6
Canonical GNAS Imprinting Model
canonical_imprinting_model CANONICAL PHP1A PHP1B Pseudopseudohypoparathyroidism
Evidence balance 1 support
Parent-of-origin-specific GNAS expression explains subtype stratification: maternal alterations more often produce hormone resistance, while paternal coding variants favor AHO-predominant phenotypes.
Retained as CANONICAL per the 2026 falcon hypothesis-search report (kb/hypotheses/Pseudohypoparathyroidism/canonical_imprinting_model; openscientist timed out on this hypothesis). The parent-of-origin framework is robustly supported by tissue-specific Gnas knockout mouse models and the molecular control region (1A DMR). Key refinements: (1) the STX16-ICR boundary establishes imprinting via OCT4-dependent chromatin conformation during embryogenesis; (2) the iPPSD nomenclature integrates GNAS-imprinting disorders with other cAMP-pathway disorders (acrodysostosis via PRKAR1A/PDE4D; PTHLH; TRPS1) sharing brachydactyly phenotypes; (3) tissue distribution of imprinting (renal proximal tubule, thyroid, pituitary, ovary, DMH hypothalamus) underlies the PHP1A-specific endocrine resistance and obesity pattern absent in PPHP.
Pathograph links
GNAS Imprinting-Dependent Signaling Defect -> Renal PTH Resistance DIRECT Defective Gs alpha signaling blunts cAMP response to PTH in proximal renal tubules.
GNAS Imprinting-Dependent Signaling Defect -> Multihormone Resistance INDIRECT KNOWN INTERMEDIATES Resistance may extend to other Gs alpha-coupled endocrine pathways including TSH and GHRH. Intermediates: TSH resistance; growth hormone deficiency
GNAS Imprinting-Dependent Signaling Defect -> AHO Developmental Tissue Effects INDIRECT KNOWN INTERMEDIATES Reduced GNAS signaling in bone and adipose lineages drives Albright hereditary osteodystrophy features. Intermediates: altered Gs alpha-cAMP signaling in mesenchymal lineages
Deep research
Falcon citations 20 citations 2026-05-23T06:23:57.643184
Show evidence (1 reference)
PMID:40972900 SUPPORT Human Clinical
"Thus, genomic imprinting plays a key role in the phenotypes associated with GNAS alterations."
Supports imprinting as the organizing principle for subtype-specific phenotype patterns.
Endocrine Resistance Model
endocrine_resistance_model CANONICAL PHP1A PHP1B
Evidence balance 1 support
Impaired Gs alpha signaling in hormone-responsive tissues causes PTH-centered mineral metabolism abnormalities and variable resistance to additional endocrine axes such as TSH and GH pathways.
Retained as CANONICAL per the 2026 falcon hypothesis-search report (kb/hypotheses/Pseudohypoparathyroidism/endocrine_resistance_model; openscientist timed out). Multi-axis resistance pattern (PTH, TSH, GHRH, gonadotropin) is supported by tissue-specific Gsα-mediated GPCR signaling failure in imprinted tissues. Key qualifications: (1) PHP1A and PHP1B differ in non-PTH endocrine resistance — PHP1A typically has TSH/gonadotropin resistance while PHP1B is predominantly PTH-resistant; (2) novel ACRDYS-like resistance syndromes (PRKAR1A, PDE4D mutations) reproduce the phenotype with different molecular lesions in the same cAMP signaling cascade.
Pathograph links
GNAS Imprinting-Dependent Signaling Defect -> Multihormone Resistance INDIRECT KNOWN INTERMEDIATES Resistance may extend to other Gs alpha-coupled endocrine pathways including TSH and GHRH. Intermediates: TSH resistance; growth hormone deficiency
Renal PTH Resistance -> Hyperphosphatemia DIRECT Reduced renal phosphate excretion causes chronic phosphate retention.
Renal PTH Resistance -> Hypocalcemia DIRECT Impaired renal response to PTH contributes to persistent low serum calcium.
Renal PTH Resistance -> Elevated Parathyroid Hormone DIRECT Secondary hyperparathyroidism develops as parathyroid output rises to compensate.
Multihormone Resistance -> Hypothyroidism DIRECT TSH resistance can lead to biochemical and clinical hypothyroidism.
Multihormone Resistance -> Short Stature INDIRECT KNOWN INTERMEDIATES Combined endocrine resistance and skeletal effects can limit linear growth. Intermediates: growth hormone deficiency
Deep research
Falcon citations 36 citations 2026-05-23T06:34:59.176852
Show evidence (1 reference)
PMID:29959430 SUPPORT Human Clinical
"specific features, such as PTH resistance, TSH resistance, growth hormone deficiency"
Consensus guidance supports a multiaxis endocrine resistance framework.
AHO Mesenchymal Differentiation Model
aho_mesenchymal_model CANONICAL PHP1A Pseudopseudohypoparathyroidism
Evidence balance 1 support
Altered GNAS-dependent signaling in bone and mesenchymal lineages drives brachydactyly, ectopic ossification, and related AHO structural phenotypes.
Retained as CANONICAL per the 2026 falcon hypothesis-search report (kb/hypotheses/Pseudohypoparathyroidism/aho_mesenchymal_model; openscientist timed out). The chondrocyte-specific (PMID:15765186) and osteoblast-specific (PMID:15797856) Gsα knockout mouse studies establish biallelic Gsα expression in bone/cartilage as the mechanistic basis for AHO features in both PHP1A and PPHP. α-SMA- expressing dermal sheath cells were recently identified as the cellular source of heterotopic subcutaneous ossifications (PMID:40256763). AHO-like brachydactyly also arises from mutations in other PTHrP→Gsα→cAMP→PKA pathway nodes (PRKAR1A, PDE4D, PTHLH, TRPS1), so the model is pathway-correct but not GNAS-exclusive.
Pathograph links
GNAS Imprinting-Dependent Signaling Defect -> AHO Developmental Tissue Effects INDIRECT KNOWN INTERMEDIATES Reduced GNAS signaling in bone and adipose lineages drives Albright hereditary osteodystrophy features. Intermediates: altered Gs alpha-cAMP signaling in mesenchymal lineages
Multihormone Resistance -> Short Stature INDIRECT KNOWN INTERMEDIATES Combined endocrine resistance and skeletal effects can limit linear growth. Intermediates: growth hormone deficiency
AHO Developmental Tissue Effects -> Brachydactyly DIRECT Disordered endochondral growth shortens metacarpals and other tubular bones.
AHO Developmental Tissue Effects -> Subcutaneous Ossifications DIRECT Ectopic dermal and subcutaneous ossification forms firm palpable nodules.
Deep research
Falcon citations 52 citations 2026-05-23T06:57:06.028899
Show evidence (1 reference)
PMID:29959430 SUPPORT Human Clinical
"resistance to PTH, ectopic ossifications, brachydactyly and early-onset obesity."
Supports the core AHO morphologic feature set grouped in this model.
Neurohypocalcemia Symptom Model
neurohypocalcemia_model CANONICAL PHP1A PHP1B
Evidence balance 1 support
Neurologic symptoms, including tetany and seizures, arise primarily from downstream hypocalcemia and associated mineral imbalance.
Retained as CANONICAL per the 2026 falcon hypothesis-search report (kb/hypotheses/Pseudohypoparathyroidism/neurohypocalcemia_model; openscientist timed out). Hypocalcemia from impaired renal-tubular PTH responsiveness is the proximal driver of tetany, seizures, and Trousseau/Chvostek signs in PHP1A and PHP1B. Key qualification: intracerebral calcifications (basal ganglia, dentate) develop independently of acute calcium status and may reflect chronic phosphate-calcium dysregulation. Cognitive impairment in PHP1A is partly dissociable from calcium status — linked to early-onset Gsα haploinsufficiency in CNS development rather than acute neurohypocalcemia alone.
Pathograph links
Renal PTH Resistance -> Mineral Ion Imbalance and Neuromuscular Excitability INDIRECT KNOWN INTERMEDIATES Severe calcium-phosphate imbalance destabilizes neuromuscular function. Intermediates: hypocalcemia; hyperphosphatemia
Mineral Ion Imbalance and Neuromuscular Excitability -> Tetany DIRECT Increased neuromuscular excitability causes cramps, spasms, and carpopedal signs.
Mineral Ion Imbalance and Neuromuscular Excitability -> Seizures DIRECT Marked hypocalcemia can precipitate focal or generalized seizures.
Deep research
Falcon citations 20 citations 2026-05-23T07:12:12.944148
Show evidence (1 reference)
PMID:38423572 SUPPORT Human Clinical
"This case demonstrates the importance of screening for hypocalcaemia in patients with de novo epileptic seizures."
Supports neurologic manifestations as a downstream consequence of hypocalcemia in PHP.
GNAS-Related Neuroendocrine Obesity Model
neuroendocrine_obesity_model EMERGING PHP1A PHP1B
Evidence balance 1 support
Early-onset obesity may reflect disrupted Gs alpha-dependent GPCR signaling in energy-homeostasis pathways, superimposed on classic PHP endocrine and skeletal mechanisms.
Retained as EMERGING per the 2026 falcon hypothesis-search report (kb/hypotheses/Pseudohypoparathyroidism/neuroendocrine_obesity_model; openscientist timed out). The most rigorous mechanistic finding (PMID:27991864) demonstrates that maternal Gsα loss in the dorsomedial nucleus of the hypothalamus (DMH) impairs MC4R/Gsα signaling, reducing energy expenditure and BAT activation without causing hyperphagia. This DMH-imprinting model explains why obesity is specific to PHP1A (maternal mutations) and absent in PPHP (paternal mutations). Additional candidate contributions: TSH/GH resistance contributing to metabolic-rate suppression, and melanocortin/PCSK1 pathway dysregulation.
Pathograph links
AHO Developmental Tissue Effects -> Obesity INDIRECT KNOWN INTERMEDIATES Altered GNAS-dependent metabolic regulation contributes to early-onset adiposity. Intermediates: MC4R-related appetite and energy homeostasis signaling
Deep research
Falcon citations 46 citations 2026-05-23T07:31:07.233571
Show evidence (1 reference)
PMID:38103632 SUPPORT Human Clinical
"Genetic or epigenetic alterations in GNAS are known to cause pseudohypoparathyroidism in its different subtypes and have been recently associated with isolated, early-onset, severe obesity."
Supports obesity-specific mechanistic superimposition on canonical PHP pathophysiology.
Cerebral Gsalpha Imprinting Model
cerebral_gsalpha_imprinting_model EMERGING PHP1A
Evidence balance 1 support
Tissue-specific paternal imprinting of GNAS is proposed to extend to the brain, so maternally inherited (PHP1A) but not paternally inherited (PPHP) Gsalpha-inactivating variants cause CNS Gsalpha haploinsufficiency and neurodevelopmental/cognitive impairment, distinct from the AHO mesenchymal and neurohypocalcemia mechanisms.
Added to close a gap flagged in issue #6980: the "Developmental Delay" causal edge previously carried no hypothesis_groups value because cognitive impairment in PHP1A is attributed to early-onset CNS Gsalpha haploinsufficiency, which fit neither aho_mesenchymal_model (bone/ mesenchymal differentiation) nor neurohypocalcemia_model (acute hypocalcemic symptoms). A single-family case series pooled with the published literature (PMID:17803690) found cognitive impairment in 79% of PHP1A subjects versus 10% of PPHP subjects sharing the same GNAS mutations within affected kindreds (P < 1e-6), and excluded concurrent (mild, promptly treated) hypothyroidism as the cause — consistent with the neurohypocalcemia_model note that cognitive impairment is "partly dissociable from calcium status." Marked EMERGING rather than CANONICAL: the source infers cerebral imprinting from the PHP1A/PPHP discordance pattern rather than from direct brain-tissue methylation or expression data.
Pathograph links
AHO Developmental Tissue Effects -> Developmental Delay INDIRECT UNKNOWN INTERMEDIATES Some patients show neurodevelopmental effects with learning or global delay, most prevalent in PHP1A. Attributed to early-onset Gs alpha haploinsufficiency in CNS development (proposed cerebral GNAS imprinting) rather than to bone/mesenchymal differentiation or to acute hypocalcemia-driven neurologic symptoms.
Show evidence (1 reference)
PMID:17803690 SUPPORT Human Clinical
"CI occurred only in the five PHP-Ia but not in the six PPHP subjects."
Reports the within-family PHP1A-versus-PPHP cognitive-impairment discordance underlying the cerebral Gsalpha imprinting hypothesis.
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Pathophysiology

5
GNAS Imprinting-Dependent Signaling Defect
Pathogenic variants or epigenetic abnormalities at the GNAS locus reduce functional Gs alpha signaling. Because GNAS expression is parent-of-origin dependent in selected tissues, maternal defects disproportionately impair receptor signaling in renal proximal tubules and endocrine targets.
AHO Mesenchymal Differentiation Model Canonical GNAS Imprinting Model Endocrine Resistance Model
GNAS hgnc:4392 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves GNAS (hgnc:4392). hgnc:4392 is a gene from the HUGO Gene Nomenclature Committee.
genomic imprinting GO:0071514 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves genomic imprinting (GO:0071514). GO:0071514 is a biological process from the Gene Ontology. adenylate cyclase-modulating G protein-coupled receptor signaling pathway GO:0007188 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves adenylate cyclase-modulating G protein-coupled receptor signaling pathway (GO:0007188). GO:0007188 is a biological process from the Gene Ontology.
Downstream
Renal PTH Resistance Defective Gs alpha signaling blunts cAMP response to PTH in proximal renal tubules. Canonical GNAS Imprinting Model
Multihormone Resistance Resistance may extend to other Gs alpha-coupled endocrine pathways including TSH and GHRH. Canonical GNAS Imprinting Model Endocrine Resistance Model
AHO Developmental Tissue Effects Reduced GNAS signaling in bone and adipose lineages drives Albright hereditary osteodystrophy features. Canonical GNAS Imprinting Model AHO Mesenchymal Differentiation Model
Show evidence (2 references)
PMID:40972900 SUPPORT Human Clinical
"Thus, genomic imprinting plays a key role in the phenotypes associated with GNAS alterations."
Establishes imprinting as the upstream mechanism determining subtype-specific manifestations.
PMID:25905388 SUPPORT Human Clinical
"PHP1A and PHP1B are caused by maternally-inherited changes at the imprinted GNAS complex gene"
Supports maternal-allele GNAS alterations as a core etiologic mechanism.
Renal PTH Resistance
Kidney target tissues fail to mount a normal phosphaturic and calcium-preserving response to PTH. This produces biochemical findings of hypocalcemia and hyperphosphatemia despite elevated circulating PTH.
Endocrine Resistance Model Neurohypocalcemia Symptom Model
epithelial cell of proximal tubule CL:0002306 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves epithelial cell of proximal tubule (CL:0002306). CL:0002306 is a cell type from the Cell Ontology.
response to parathyroid hormone GO:0071107 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves response to parathyroid hormone (GO:0071107). GO:0071107 is a biological process from the Gene Ontology. phosphate ion homeostasis GO:0055062 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves phosphate ion homeostasis (GO:0055062). GO:0055062 is a biological process from the Gene Ontology. calcium ion homeostasis GO:0055074 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves calcium ion homeostasis (GO:0055074). GO:0055074 is a biological process from the Gene Ontology.
kidney UBERON:0002113 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in kidney (UBERON:0002113). UBERON:0002113 is an anatomical location from the Uberon multi-species anatomy ontology. proximal tubule UBERON:0004134 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in proximal tubule (UBERON:0004134). UBERON:0004134 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Hyperphosphatemia Reduced renal phosphate excretion causes chronic phosphate retention. Endocrine Resistance Model
Hypocalcemia Impaired renal response to PTH contributes to persistent low serum calcium. Endocrine Resistance Model
Elevated Parathyroid Hormone Secondary hyperparathyroidism develops as parathyroid output rises to compensate. Endocrine Resistance Model
Mineral Ion Imbalance and Neuromuscular Excitability Severe calcium-phosphate imbalance destabilizes neuromuscular function. Neurohypocalcemia Symptom Model
Show evidence (2 references)
PMID:40972900 SUPPORT Human Clinical
"including the proximal renal tubule, where PTH exerts critical actions."
Identifies proximal renal tubule as the key imprinting-sensitive site for PTH resistance.
PMID:37014531 SUPPORT Human Clinical
"It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone."
Confirms the biochemical triad resulting from end-organ PTH resistance.
Mineral Ion Imbalance and Neuromuscular Excitability
Hypocalcemia increases neuronal and neuromuscular excitability, lowering seizure threshold and producing intermittent acute neurologic symptoms.
Neurohypocalcemia Symptom Model
calcium ion homeostasis GO:0055074 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves calcium ion homeostasis (GO:0055074). GO:0055074 is a biological process from the Gene Ontology.
Downstream
Tetany Increased neuromuscular excitability causes cramps, spasms, and carpopedal signs. Neurohypocalcemia Symptom Model
Seizures Marked hypocalcemia can precipitate focal or generalized seizures. Neurohypocalcemia Symptom Model
Show evidence (1 reference)
PMID:35410271 SUPPORT Human Clinical
"Laboratory assessments of the patient revealed hypokalemia, hypocalcemia and hyperphosphatemia despite elevated PTH levels."
Demonstrates clinically relevant mineral imbalance expected from PTH resistance.
Multihormone Resistance
In affected subtypes, resistance extends beyond PTH to additional Gs alpha-coupled hormonal pathways, especially thyroid and growth axes.
AHO Mesenchymal Differentiation Model Endocrine Resistance Model
hormone-mediated signaling pathway GO:0009755 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves hormone-mediated signaling pathway (GO:0009755). GO:0009755 is a biological process from the Gene Ontology.
Downstream
Hypothyroidism TSH resistance can lead to biochemical and clinical hypothyroidism. Endocrine Resistance Model
Short Stature Combined endocrine resistance and skeletal effects can limit linear growth. Endocrine Resistance Model AHO Mesenchymal Differentiation Model
Show evidence (1 reference)
PMID:29959430 SUPPORT Human Clinical
"specific features, such as PTH resistance, TSH resistance, growth hormone deficiency"
Supports that endocrine resistance in PHP commonly extends beyond PTH signaling.
AHO Developmental Tissue Effects
Albright hereditary osteodystrophy reflects altered developmental signaling in bone, adipose tissue, and other mesenchymal lineages, partially independent of biochemical severity.
AHO Mesenchymal Differentiation Model Cerebral Gsalpha Imprinting Model GNAS-Related Neuroendocrine Obesity Model
osteoblast CL:0000062 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves osteoblast (CL:0000062). CL:0000062 is a cell type from the Cell Ontology. adipocyte CL:0000136 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves adipocyte (CL:0000136). CL:0000136 is a cell type from the Cell Ontology.
endochondral ossification GO:0001958 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves endochondral ossification (GO:0001958). GO:0001958 is a biological process from the Gene Ontology. ossification GO:0001503 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves ossification (GO:0001503). GO:0001503 is a biological process from the Gene Ontology.
bone element UBERON:0001474 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in bone element (UBERON:0001474). UBERON:0001474 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Brachydactyly Disordered endochondral growth shortens metacarpals and other tubular bones. AHO Mesenchymal Differentiation Model
Subcutaneous Ossifications Ectopic dermal and subcutaneous ossification forms firm palpable nodules. AHO Mesenchymal Differentiation Model
Obesity Altered GNAS-dependent metabolic regulation contributes to early-onset adiposity. GNAS-Related Neuroendocrine Obesity Model
Developmental Delay Some patients show neurodevelopmental effects with learning or global delay, most prevalent in PHP1A. Attributed to early-onset Gs alpha haploinsufficiency in CNS development (proposed cerebral GNAS imprinting) rather than to bone/mesenchymal differentiation or to acute hypocalcemia-driven neurologic symptoms. Cerebral Gsalpha Imprinting Model
Show evidence (2 references)
PMID:29959430 SUPPORT Human Clinical
"resistance to PTH, ectopic ossifications, brachydactyly and early-onset obesity."
Defines the core AHO-associated developmental phenotype cluster.
PMID:40972900 SUPPORT Human Clinical
"While maternal mutations result in PHP type 1A, which consists of PTH resistance and AHO, paternal mutations lead to pseudo-pseudohypoparathyroidism (PPHP), that is, AHO without hormone resistance."
Supports parent-of-origin partitioning of AHO features versus hormone resistance.
⬡

Pathograph

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

14
Endocrine 2
Elevated Parathyroid Hormone VERY_FREQUENT Elevated circulating parathyroid hormone level HP:0003165 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Elevated circulating parathyroid hormone level (HP:0003165). HP:0003165 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:35410271 SUPPORT Human Clinical
"Laboratory assessments of the patient revealed hypokalemia, hypocalcemia and hyperphosphatemia despite elevated PTH levels."
Supports elevation of PTH despite biochemical hypocalcemia-hyperphosphatemia.
Hypothyroidism OCCASIONAL HP:0000821 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Hypothyroidism (HP:0000821). HP:0000821 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29959430 SUPPORT Human Clinical
"specific features, such as PTH resistance, TSH resistance, growth hormone deficiency"
TSH resistance provides mechanistic support for hypothyroid manifestations in PHP.
Limbs 1
Brachydactyly FREQUENT HP:0001156 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Brachydactyly (HP:0001156). HP:0001156 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29959430 SUPPORT Human Clinical
"resistance to PTH, ectopic ossifications, brachydactyly and early-onset obesity."
Consensus statement lists brachydactyly among major diagnostic criteria.
Metabolism 2
Hypocalcemia VERY_FREQUENT HP:0002901 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Hypocalcemia (HP:0002901). HP:0002901 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:37014531 SUPPORT Human Clinical
"It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone."
Confirms hypocalcemia as a defining biochemical consequence of PHP.
Hyperphosphatemia VERY_FREQUENT HP:0002905 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Hyperphosphatemia (HP:0002905). HP:0002905 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:37014531 SUPPORT Human Clinical
"It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone."
Confirms hyperphosphatemia as part of the hallmark PHP biochemical triad.
Musculoskeletal 2
Tetany OCCASIONAL HP:0001281 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Tetany (HP:0001281). HP:0001281 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:35410271 SUPPORT Human Clinical
"Seven months after delivery, she experienced tetany and dysphonia with diarrhea."
Documents tetany as an acute symptomatic manifestation in PHP.
Subcutaneous Ossifications FREQUENT HP:0034282 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Subcutaneous ossification (HP:0034282). HP:0034282 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29959430 SUPPORT Human Clinical
"subcutaneous and/or deeper ectopic ossifications and neurocognitive impairment."
Consensus guidance highlights subcutaneous ectopic ossifications as a monitored feature.
Nervous System 2
Seizures OCCASIONAL HP:0001250 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Seizure (HP:0001250). HP:0001250 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:38423572 SUPPORT Human Clinical
"We describe a case in which epileptic seizures and abnormalities in dental development were the main clinical manifestation of PHP type 1B."
Supports seizures as a clinically important presentation in PHP1B.
Developmental Delay OCCASIONAL Global developmental delay HP:0001263 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Global developmental delay (HP:0001263). HP:0001263 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29959430 SUPPORT Human Clinical
"subcutaneous and/or deeper ectopic ossifications and neurocognitive impairment."
Neurocognitive impairment in consensus guidance supports developmental and cognitive phenotype burden.
Growth 2
Short Stature FREQUENT HP:0004322 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Short stature (HP:0004322). HP:0004322 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29959430 SUPPORT Human Clinical
"include short bones, short stature, a stocky build, early-onset obesity and ectopic ossifications"
Identifies short stature as part of the core physical phenotype in PHP-related disorders.
Obesity FREQUENT HP:0001513 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Obesity (HP:0001513). HP:0001513 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:38103632 SUPPORT Human Clinical
"Genetic or epigenetic alterations in GNAS are known to cause pseudohypoparathyroidism in its different subtypes and have been recently associated with isolated, early-onset, severe obesity."
Supports mechanistic and clinical linkage between GNAS defects and early-onset obesity.
Other 3
Chiari Malformation Type 1 OCCASIONAL Chiari type I malformation HP:0007099 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Chiari type I malformation (HP:0007099). HP:0007099 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:36662765 SUPPORT Human Clinical
"prevalence of CM1 is at least 10-fold higher"
Krishnan et al. (2023) demonstrate that PHP1A patients have at least 10-fold higher CM1 prevalence than the general population (10.8% by imaging; 21.7% with LLCT), correlating with mouse-model evidence of aberrant cranial base development.
Basal Ganglia Calcification OCCASIONAL HP:0002135 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Basal ganglia calcification (HP:0002135). HP:0002135 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:35410271 SUPPORT Human Clinical
"CT scanning of the brain revealed globus pallidus calcification"
CT-confirmed globus pallidus calcification documented in a PHP1B patient, supporting basal ganglia calcification as a phenotype that develops in the setting of chronic mineral dysregulation.
Round Face FREQUENT HP:0000311 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Round face (HP:0000311). HP:0000311 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:29072892 SUPPORT Human Clinical
"The Albright hereditary osteodystrophy (AHO) phenotype (short stature, round facies, and subcutaneous ossifications) and brachydactyly type E"
GeneReviews names round facies as a component of the AHO triad, alongside short stature and subcutaneous ossifications, supporting this phenotype directly rather than through a truncated fragment.
PMID:29072892 SUPPORT Human Clinical
"Although PHP-Ib is characterized principally by PTH resistance, some individuals also have partial TSH resistance and mild features of AHO (e.g., brachydactyly)."
This supports the description's claim that AHO features are not uniformly absent in PHP1B - mild features, notably brachydactyly, are reported - which is why this phenotype is scoped to PHP1A rather than asserted to exclude PHP1B.
🧬

Genetic Associations

1
GNAS (Loss-of-Function Variant or Imprinting Defect)
Gene: GNAS hgnc:4392 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is GNAS (hgnc:4392). hgnc:4392 is a gene from the HUGO Gene Nomenclature Committee.
Autosomal dominant
Show evidence (1 reference)
PMID:37014531 SUPPORT Human Clinical
"Pseudohypoparathyroidism (PHP) is a disorder caused by mutations and/or epigenetic changes at the complex GNAS locus."
Supports both genetic and epigenetic GNAS mechanisms in disease causation.
💊

Medical Actions

2
Calcium and Active Vitamin D Replacement
Action: PharmacotherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. NCIT:C15986
Agent: calcium CHEBI:29108 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses calcium, annotated with calcium(2+) (CHEBI:29108). CHEBI:29108 is a therapeutic agent from Chemical Entities of Biological Interest. calcitriol CHEBI:17823 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses calcitriol (CHEBI:17823). CHEBI:17823 is a therapeutic agent from Chemical Entities of Biological Interest.
Calcium supplementation combined with active vitamin D (calcitriol or alfacalcidol) to correct hypocalcemia and hyperphosphatemia. Standard of care for PHP1A and PHP1B; correction of hypocalcemia resolves tetany, seizures, and dyskinesias.
Target Phenotypes: Hypocalcemia HP:0002901 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Hypocalcemia (HP:0002901). HP:0002901 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25905388 SUPPORT Human Clinical
"Calcium and vitamin D are the standard therapy"
Endocrinology textbook reference frames calcium and active vitamin D supplementation as the cornerstone of hypoparathyroidism / PHP treatment for correcting hypocalcemia-driven neuromuscular symptoms.
Intravenous Calcium Gluconate (Acute Tetany)
Action: PharmacotherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. NCIT:C15986
Agent: calcium gluconate CHEBI:3309 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses calcium gluconate (CHEBI:3309). CHEBI:3309 is a therapeutic agent from Chemical Entities of Biological Interest.
Intravenous calcium gluconate is the acute treatment for symptomatic hypocalcemic tetany, seizures, and laryngospasm in PHP. Used emergently before transition to oral calcium + active vitamin D maintenance therapy.
Target Phenotypes: Hypocalcemia HP:0002901 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Hypocalcemia (HP:0002901). HP:0002901 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:35410271 SUPPORT Human Clinical
"Tetany symptoms were relieved after intravenous calcium gluconate"
Case report of PHP1B with tetany symptoms documents resolution after intravenous calcium gluconate supplementation, illustrating the acute emergency use of IV calcium for symptomatic hypocalcemia.
🔬

Biochemical Markers

3
Parathyroid Hormone (Elevated)
Context: Elevated PTH with hypocalcemia and hyperphosphatemia supports hormone resistance.
Show evidence (1 reference)
PMID:37014531 SUPPORT Human Clinical
"It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone."
Directly supports elevated PTH in the context of end-organ resistance.
Serum Calcium (Decreased)
Context: Persistent or recurrent hypocalcemia is common at presentation.
Show evidence (1 reference)
PMID:37014531 SUPPORT Human Clinical
"It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone."
Supports hypocalcemia as a central biochemical finding.
Serum Phosphate (Elevated)
Context: Renal phosphate retention leads to chronic hyperphosphatemia.
Show evidence (1 reference)
PMID:37014531 SUPPORT Human Clinical
"It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone."
Supports persistent hyperphosphatemia in PHP.
📊

Prevalence

1
Japan period prevalence
Period Prevalence 0.34 per 100,000 1–9 per 1,000,000
A nationwide Japanese survey provides one of the few population-based prevalence estimates for pseudohypoparathyroidism.
Show evidence (2 references)
PMID:10695258 SUPPORT Human Clinical
"Using these data, the period prevalence of the diseases were 7.2 (5.5-8.8) per million population in idiopathic hypoparathyroidism, and 3.4 (2.6-4.2) in pseudohypoparathyroidism (95% confidence intervals in parentheses)."
This nationwide epidemiologic survey directly estimates pseudohypoparathyroidism prevalence in Japan.
PMID:32481259 SUPPORT Human Clinical
"Pseudohypoparathyroidism (PHP) indicates a group of rare disorders characterized by end-organ resistance to various hormones, primarily parathyroid hormone (PTH)."
This modern case report reinforces that PHP remains a rare disorder in current clinical practice.
📊

Related Datasets

2
Novel genetic variants of KHDC3L and other members of the subcortical maternal complex associated with Beckwith-Wiedemann syndrome or Pseudohypoparathyroidism 1B and multi-locus imprinting disturbances geo:GSE195873
Beckwith–Wiedemann syndrome (BWS) and Pseudohypoparathyroidism type 1B (PHP1B) are imprinting disorders (ID) caused by deregulation of the imprinted gene clusters located at 11p15.5 and 20q13.32, respectively. In both of these diseases a subset of the patients is affected by multi-locus imprinting disturbances (MLID). In several families, MLID is associated with damaging variants of maternal-effect genes encoding protein components of the subcortical maternal complex (SCMC). However, frequency, penetrance and recurrence risks of these variants are still undefined.
human METHYLATION n=18
PMID:35643636
Identified by GEO DataSets index search for Pseudohypoparathyroidism (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-01. Title, sample count, and organism are GEO's own values.
Molecular Defects in Pseudohypoparathyroidism or Related Disorders dbgap:phs000476
Maintaining calcium levels within a narrow normal range is of critical importance for numerous different cellular functions. One of the most important regulators of blood calcium levels is parathyroid hormone (PTH), which mediates its actions through the PTH/PTHrP receptor, a Gαs-coupled receptor.
Located via OmicsDI, which aggregates across omics repositories; this record comes from dbgap. Only repositories with no other discovery route in this project and with a working accession resolver are curated from OmicsDI -- GEO, ArrayExpress, PRIDE, MetaboLights and EGA hits are excluded as duplicates of dedicated passes. Matched because the disease is named in the dataset's own title ("Pseudohypoparathyroidism"). Retrieved 2026-08-02.
{ }

Source YAML

click to show 
name: Pseudohypoparathyroidism
creation_date: '2026-02-10T22:32:16Z'
description: >-
  Pseudohypoparathyroidism (PHP) is a group of disorders caused by impaired
  signaling at the GNAS locus, producing resistance to parathyroid hormone and,
  in many patients, additional endocrine and developmental abnormalities. The
  phenotype reflects both parent-of-origin effects (imprinting) and tissue-specific
  dependence on Gs alpha signaling.
category: Genetic
parents:
- Endocrine Disorder
- Calcium-Phosphate Metabolism Disorder
disease_term:
  preferred_term: pseudohypoparathyroidism
  term:
    id: MONDO:0019992
    label: pseudohypoparathyroidism
has_subtypes:
- name: PHP1A
  description: >-
    Usually caused by maternally inherited inactivating GNAS variants with
    parathyroid hormone resistance, additional hormone resistance, and Albright
    hereditary osteodystrophy features.
  evidence:
  - reference: PMID:40972900
    reference_title: "Imprinting and skeletal disorders: lessons from pseudohypoparathyroidism and related disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: While maternal mutations result in PHP type 1A, which consists of PTH resistance and AHO, paternal mutations lead to pseudo-pseudohypoparathyroidism (PPHP), that is, AHO without hormone resistance.
    explanation: Confirms maternal-allele mutations classically produce PHP1A with PTH resistance and AHO.
- name: PHP1B
  description: >-
    Usually caused by GNAS methylation defects (often including STX16-related
    imprinting abnormalities) with predominant renal PTH resistance and less
    pronounced Albright hereditary osteodystrophy.
  evidence:
  - reference: PMID:40972900
    reference_title: "Imprinting and skeletal disorders: lessons from pseudohypoparathyroidism and related disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Epigenetic alterations of GNAS cause PHP type 1B (PHP1B), defined by PTH resistance in the absence of AHO.
    explanation: Supports the subtype definition of PHP1B as an epigenetic GNAS disorder with predominant PTH resistance.
- name: Pseudopseudohypoparathyroidism
  description: >-
    Usually caused by paternally inherited inactivating GNAS variants and
    characterized by Albright hereditary osteodystrophy features with limited or
    absent hormone resistance.
  evidence:
  - reference: PMID:40972900
    reference_title: "Imprinting and skeletal disorders: lessons from pseudohypoparathyroidism and related disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: While maternal mutations result in PHP type 1A, which consists of PTH resistance and AHO, paternal mutations lead to pseudo-pseudohypoparathyroidism (PPHP), that is, AHO without hormone resistance.
    explanation: Directly distinguishes paternal-allele PPHP from maternal-allele PHP1A.
classifications:
  isds_skeletal_category:
  - classification_value: acromelic_dysplasias
    notes: >-
      ISDS Nosology of Genetic Skeletal Disorders, 2023 revision (Unger et al.,
      PMID:36779427), group 17 "Acromelic dysplasias", listed as "Albright
      hereditary osteodystrophy, GNAS-related" (NOS 17-0150, OMIM 103580). The
      2019 revision (Mortier et al., PMID:31633310) carried the same OMIM under
      the name "Pseudohypoparathyroidism type IA" in group 38, Brachydactylies
      with extraskeletal manifestations - so this is a rename plus a move, and
      searching the 2023 table for "pseudohypoparathyroidism" finds nothing.
      Scope: the assignment covers the PHP1A subtype only, which is the entity
      the committee lists. PHP1B and PHP2 are not listed in the nosology at all,
      so this entry is broader than its nosology counterpart. Despite being an
      inactivating PTH/PTHrP-signalling disorder, it does NOT belong to group 28
      (parathyroid hormone signaling cascade), which holds only the
      PTH1R/PTHLH/SIK3 set; placement follows the committee's listing, not the
      mechanism.
prevalence:
- population: Japan period prevalence
  measure_type: PERIOD_PREVALENCE
  prevalence_class: BAND_1_9_PER_1000000
  rate_per_100000: 0.34
  notes: >-
    A nationwide Japanese survey provides one of the few population-based
    prevalence estimates for pseudohypoparathyroidism.
  evidence:
  - reference: PMID:10695258
    reference_title: "Prevalence of idiopathic hypoparathyroidism and pseudohypoparathyroidism in Japan"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Using these data, the period prevalence of the diseases were 7.2 (5.5-8.8) per million population in idiopathic hypoparathyroidism, and 3.4 (2.6-4.2) in pseudohypoparathyroidism (95% confidence intervals in parentheses)."
    explanation: This nationwide epidemiologic survey directly estimates pseudohypoparathyroidism prevalence in Japan.
  - reference: PMID:32481259
    reference_title: "Identification of a novel mutation in pseudohypoparathyroidism type Ia in a Chinese family: A case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Pseudohypoparathyroidism (PHP) indicates a group of rare disorders characterized by end-organ resistance to various hormones, primarily parathyroid hormone (PTH)."
    explanation: This modern case report reinforces that PHP remains a rare disorder in current clinical practice.
mechanistic_hypotheses:
- hypothesis_group_id: canonical_imprinting_model
  hypothesis_label: Canonical GNAS Imprinting Model
  status: CANONICAL
  description: >-
    Parent-of-origin-specific GNAS expression explains subtype stratification:
    maternal alterations more often produce hormone resistance, while paternal
    coding variants favor AHO-predominant phenotypes.
  notes: >-
    Retained as CANONICAL per the 2026 falcon hypothesis-search report
    (kb/hypotheses/Pseudohypoparathyroidism/canonical_imprinting_model;
    openscientist timed out on this hypothesis). The parent-of-origin
    framework is robustly supported by tissue-specific Gnas knockout
    mouse models and the molecular control region (1A DMR). Key
    refinements: (1) the STX16-ICR boundary establishes imprinting via
    OCT4-dependent chromatin conformation during embryogenesis; (2) the
    iPPSD nomenclature integrates GNAS-imprinting disorders with other
    cAMP-pathway disorders (acrodysostosis via PRKAR1A/PDE4D; PTHLH;
    TRPS1) sharing brachydactyly phenotypes; (3) tissue distribution of
    imprinting (renal proximal tubule, thyroid, pituitary, ovary, DMH
    hypothalamus) underlies the PHP1A-specific endocrine resistance and
    obesity pattern absent in PPHP.
  applies_to_subtypes:
  - PHP1A
  - PHP1B
  - Pseudopseudohypoparathyroidism
  evidence:
  - reference: PMID:40972900
    reference_title: "Imprinting and skeletal disorders: lessons from pseudohypoparathyroidism and related disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Thus, genomic imprinting plays a key role in the phenotypes associated with GNAS alterations.
    explanation: Supports imprinting as the organizing principle for subtype-specific phenotype patterns.
- hypothesis_group_id: endocrine_resistance_model
  hypothesis_label: Endocrine Resistance Model
  status: CANONICAL
  description: >-
    Impaired Gs alpha signaling in hormone-responsive tissues causes PTH-centered
    mineral metabolism abnormalities and variable resistance to additional
    endocrine axes such as TSH and GH pathways.
  notes: >-
    Retained as CANONICAL per the 2026 falcon hypothesis-search report
    (kb/hypotheses/Pseudohypoparathyroidism/endocrine_resistance_model;
    openscientist timed out). Multi-axis resistance pattern (PTH, TSH,
    GHRH, gonadotropin) is supported by tissue-specific Gsα-mediated
    GPCR signaling failure in imprinted tissues. Key qualifications:
    (1) PHP1A and PHP1B differ in non-PTH endocrine resistance — PHP1A
    typically has TSH/gonadotropin resistance while PHP1B is
    predominantly PTH-resistant; (2) novel ACRDYS-like resistance
    syndromes (PRKAR1A, PDE4D mutations) reproduce the phenotype with
    different molecular lesions in the same cAMP signaling cascade.
  applies_to_subtypes:
  - PHP1A
  - PHP1B
  evidence:
  - reference: PMID:29959430
    reference_title: "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: specific features, such as PTH resistance, TSH resistance, growth hormone deficiency
    explanation: Consensus guidance supports a multiaxis endocrine resistance framework.
- hypothesis_group_id: aho_mesenchymal_model
  hypothesis_label: AHO Mesenchymal Differentiation Model
  status: CANONICAL
  description: >-
    Altered GNAS-dependent signaling in bone and mesenchymal lineages drives
    brachydactyly, ectopic ossification, and related AHO structural phenotypes.
  notes: >-
    Retained as CANONICAL per the 2026 falcon hypothesis-search report
    (kb/hypotheses/Pseudohypoparathyroidism/aho_mesenchymal_model;
    openscientist timed out). The chondrocyte-specific (PMID:15765186)
    and osteoblast-specific (PMID:15797856) Gsα knockout mouse studies
    establish biallelic Gsα expression in bone/cartilage as the
    mechanistic basis for AHO features in both PHP1A and PPHP. α-SMA-
    expressing dermal sheath cells were recently identified as the
    cellular source of heterotopic subcutaneous ossifications
    (PMID:40256763). AHO-like brachydactyly also arises from mutations
    in other PTHrP→Gsα→cAMP→PKA pathway nodes (PRKAR1A, PDE4D, PTHLH,
    TRPS1), so the model is pathway-correct but not GNAS-exclusive.
  applies_to_subtypes:
  - PHP1A
  - Pseudopseudohypoparathyroidism
  evidence:
  - reference: PMID:29959430
    reference_title: "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: resistance to PTH, ectopic ossifications, brachydactyly and early-onset obesity.
    explanation: Supports the core AHO morphologic feature set grouped in this model.
- hypothesis_group_id: neurohypocalcemia_model
  hypothesis_label: Neurohypocalcemia Symptom Model
  status: CANONICAL
  description: >-
    Neurologic symptoms, including tetany and seizures, arise primarily from
    downstream hypocalcemia and associated mineral imbalance.
  notes: >-
    Retained as CANONICAL per the 2026 falcon hypothesis-search report
    (kb/hypotheses/Pseudohypoparathyroidism/neurohypocalcemia_model;
    openscientist timed out). Hypocalcemia from impaired renal-tubular
    PTH responsiveness is the proximal driver of tetany, seizures, and
    Trousseau/Chvostek signs in PHP1A and PHP1B. Key qualification:
    intracerebral calcifications (basal ganglia, dentate) develop
    independently of acute calcium status and may reflect chronic
    phosphate-calcium dysregulation. Cognitive impairment in PHP1A is
    partly dissociable from calcium status — linked to early-onset Gsα
    haploinsufficiency in CNS development rather than acute
    neurohypocalcemia alone.
  applies_to_subtypes:
  - PHP1A
  - PHP1B
  evidence:
  - reference: PMID:38423572
    reference_title: "Epileptic seizures and abnormal tooth development as primary presentation of pseudohypoparathyroidism type 1B."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: This case demonstrates the importance of screening for hypocalcaemia in patients with de novo epileptic seizures.
    explanation: Supports neurologic manifestations as a downstream consequence of hypocalcemia in PHP.
- hypothesis_group_id: neuroendocrine_obesity_model
  hypothesis_label: GNAS-Related Neuroendocrine Obesity Model
  status: EMERGING
  description: >-
    Early-onset obesity may reflect disrupted Gs alpha-dependent GPCR signaling
    in energy-homeostasis pathways, superimposed on classic PHP endocrine and
    skeletal mechanisms.
  notes: >-
    Retained as EMERGING per the 2026 falcon hypothesis-search report
    (kb/hypotheses/Pseudohypoparathyroidism/neuroendocrine_obesity_model;
    openscientist timed out). The most rigorous mechanistic finding
    (PMID:27991864) demonstrates that maternal Gsα loss in the
    dorsomedial nucleus of the hypothalamus (DMH) impairs MC4R/Gsα
    signaling, reducing energy expenditure and BAT activation without
    causing hyperphagia. This DMH-imprinting model explains why obesity
    is specific to PHP1A (maternal mutations) and absent in PPHP
    (paternal mutations). Additional candidate contributions: TSH/GH
    resistance contributing to metabolic-rate suppression, and
    melanocortin/PCSK1 pathway dysregulation.
  applies_to_subtypes:
  - PHP1A
  - PHP1B
  evidence:
  - reference: PMID:38103632
    reference_title: "The role of genetic and epigenetic GNAS alterations in the development of early-onset obesity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Genetic or epigenetic alterations in GNAS are known to cause pseudohypoparathyroidism in its different subtypes and have been recently associated with isolated, early-onset, severe obesity.
    explanation: Supports obesity-specific mechanistic superimposition on canonical PHP pathophysiology.
- hypothesis_group_id: cerebral_gsalpha_imprinting_model
  hypothesis_label: Cerebral Gsalpha Imprinting Model
  status: EMERGING
  description: >-
    Tissue-specific paternal imprinting of GNAS is proposed to extend to the
    brain, so maternally inherited (PHP1A) but not paternally inherited
    (PPHP) Gsalpha-inactivating variants cause CNS Gsalpha haploinsufficiency
    and neurodevelopmental/cognitive impairment, distinct from the AHO
    mesenchymal and neurohypocalcemia mechanisms.
  notes: >-
    Added to close a gap flagged in issue #6980: the "Developmental Delay"
    causal edge previously carried no hypothesis_groups value because
    cognitive impairment in PHP1A is attributed to early-onset CNS Gsalpha
    haploinsufficiency, which fit neither aho_mesenchymal_model (bone/
    mesenchymal differentiation) nor neurohypocalcemia_model (acute
    hypocalcemic symptoms). A single-family case series pooled with the
    published literature (PMID:17803690) found cognitive impairment in 79%
    of PHP1A subjects versus 10% of PPHP subjects sharing the same GNAS
    mutations within affected kindreds (P < 1e-6), and excluded concurrent
    (mild, promptly treated) hypothyroidism as the cause — consistent with
    the neurohypocalcemia_model note that cognitive impairment is "partly
    dissociable from calcium status." Marked EMERGING rather than CANONICAL:
    the source infers cerebral imprinting from the PHP1A/PPHP discordance
    pattern rather than from direct brain-tissue methylation or expression
    data.
  applies_to_subtypes:
  - PHP1A
  evidence:
  - reference: PMID:17803690
    reference_title: "Cognitive impairment is prevalent in pseudohypoparathyroidism type Ia, but not in pseudopseudohypoparathyroidism: possible cerebral imprinting of Gsalpha."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "CI occurred only in the five PHP-Ia but not in the six PPHP subjects."
    explanation: Reports the within-family PHP1A-versus-PPHP cognitive-impairment discordance underlying the cerebral Gsalpha imprinting hypothesis.
pathophysiology:
- name: GNAS Imprinting-Dependent Signaling Defect
  description: >-
    Pathogenic variants or epigenetic abnormalities at the GNAS locus reduce
    functional Gs alpha signaling. Because GNAS expression is parent-of-origin
    dependent in selected tissues, maternal defects disproportionately impair
    receptor signaling in renal proximal tubules and endocrine targets.
  genes:
  - preferred_term: GNAS
    term:
      id: hgnc:4392
      label: GNAS
  biological_processes:
  - preferred_term: genomic imprinting
    term:
      id: GO:0071514
      label: genomic imprinting
  - preferred_term: adenylate cyclase-modulating G protein-coupled receptor signaling pathway
    term:
      id: GO:0007188
      label: adenylate cyclase-modulating G protein-coupled receptor signaling pathway
  evidence:
  - reference: PMID:40972900
    reference_title: "Imprinting and skeletal disorders: lessons from pseudohypoparathyroidism and related disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Thus, genomic imprinting plays a key role in the phenotypes associated with GNAS alterations.
    explanation: Establishes imprinting as the upstream mechanism determining subtype-specific manifestations.
  - reference: PMID:25905388
    reference_title: "Hypoparathyroidism and Pseudohypoparathyroidism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: PHP1A and PHP1B are caused by maternally-inherited changes at the imprinted GNAS complex gene
    explanation: Supports maternal-allele GNAS alterations as a core etiologic mechanism.
  downstream:
  - target: Renal PTH Resistance
    description: Defective Gs alpha signaling blunts cAMP response to PTH in proximal renal tubules.
    hypothesis_groups:
    - canonical_imprinting_model
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:40972900
      reference_title: "Imprinting and skeletal disorders: lessons from pseudohypoparathyroidism and related disorders."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: including the proximal renal tubule, where PTH exerts critical actions.
      explanation: Supports direct imprinting-sensitive disruption of renal PTH signaling.
  - target: Multihormone Resistance
    description: Resistance may extend to other Gs alpha-coupled endocrine pathways including TSH and GHRH.
    hypothesis_groups:
    - canonical_imprinting_model
    - endocrine_resistance_model
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - TSH resistance
    - growth hormone deficiency
  - target: AHO Developmental Tissue Effects
    description: Reduced GNAS signaling in bone and adipose lineages drives Albright hereditary osteodystrophy features.
    hypothesis_groups:
    - canonical_imprinting_model
    - aho_mesenchymal_model
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - altered Gs alpha-cAMP signaling in mesenchymal lineages
- name: Renal PTH Resistance
  description: >-
    Kidney target tissues fail to mount a normal phosphaturic and calcium-preserving
    response to PTH. This produces biochemical findings of hypocalcemia and
    hyperphosphatemia despite elevated circulating PTH.
  cell_types:
  - preferred_term: epithelial cell of proximal tubule
    term:
      id: CL:0002306
      label: epithelial cell of proximal tubule
  locations:
  - preferred_term: kidney
    term:
      id: UBERON:0002113
      label: kidney
  - preferred_term: proximal tubule
    term:
      id: UBERON:0004134
      label: proximal tubule
  biological_processes:
  - preferred_term: response to parathyroid hormone
    term:
      id: GO:0071107
      label: response to parathyroid hormone
  - preferred_term: phosphate ion homeostasis
    term:
      id: GO:0055062
      label: phosphate ion homeostasis
  - preferred_term: calcium ion homeostasis
    term:
      id: GO:0055074
      label: calcium ion homeostasis
  evidence:
  - reference: PMID:40972900
    reference_title: "Imprinting and skeletal disorders: lessons from pseudohypoparathyroidism and related disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: including the proximal renal tubule, where PTH exerts critical actions.
    explanation: Identifies proximal renal tubule as the key imprinting-sensitive site for PTH resistance.
  - reference: PMID:37014531
    reference_title: "Variable Bone Phenotypes in Patients with Pseudohypoparathyroidism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone.
    explanation: Confirms the biochemical triad resulting from end-organ PTH resistance.
  downstream:
  - target: Hyperphosphatemia
    description: Reduced renal phosphate excretion causes chronic phosphate retention.
    hypothesis_groups:
    - endocrine_resistance_model
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:37014531
      reference_title: "Variable Bone Phenotypes in Patients with Pseudohypoparathyroidism."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone.
      explanation: Directly supports hyperphosphatemia as a primary biochemical output of PTH resistance.
  - target: Hypocalcemia
    description: Impaired renal response to PTH contributes to persistent low serum calcium.
    hypothesis_groups:
    - endocrine_resistance_model
    causal_link_type: DIRECT
  - target: Elevated Parathyroid Hormone
    description: Secondary hyperparathyroidism develops as parathyroid output rises to compensate.
    hypothesis_groups:
    - endocrine_resistance_model
    causal_link_type: DIRECT
  - target: Mineral Ion Imbalance and Neuromuscular Excitability
    description: Severe calcium-phosphate imbalance destabilizes neuromuscular function.
    hypothesis_groups:
    - neurohypocalcemia_model
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - hypocalcemia
    - hyperphosphatemia
- name: Mineral Ion Imbalance and Neuromuscular Excitability
  description: >-
    Hypocalcemia increases neuronal and neuromuscular excitability, lowering seizure
    threshold and producing intermittent acute neurologic symptoms.
  biological_processes:
  - preferred_term: calcium ion homeostasis
    term:
      id: GO:0055074
      label: calcium ion homeostasis
  evidence:
  - reference: PMID:35410271
    reference_title: "Clinical and genetic analysis of pseudohypoparathyroidism complicated by hypokalemia: a case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Laboratory assessments of the patient revealed hypokalemia, hypocalcemia and hyperphosphatemia despite elevated PTH levels.
    explanation: Demonstrates clinically relevant mineral imbalance expected from PTH resistance.
  downstream:
  - target: Tetany
    description: Increased neuromuscular excitability causes cramps, spasms, and carpopedal signs.
    hypothesis_groups:
    - neurohypocalcemia_model
    causal_link_type: DIRECT
  - target: Seizures
    description: Marked hypocalcemia can precipitate focal or generalized seizures.
    hypothesis_groups:
    - neurohypocalcemia_model
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:38423572
      reference_title: "Epileptic seizures and abnormal tooth development as primary presentation of pseudohypoparathyroidism type 1B."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: We describe a case in which epileptic seizures and abnormalities in dental development were the main clinical manifestation of PHP type 1B.
      explanation: Demonstrates seizure phenotype as a neurologic downstream consequence in PHP.
- name: Multihormone Resistance
  description: >-
    In affected subtypes, resistance extends beyond PTH to additional Gs alpha-coupled
    hormonal pathways, especially thyroid and growth axes.
  biological_processes:
  - preferred_term: hormone-mediated signaling pathway
    term:
      id: GO:0009755
      label: hormone-mediated signaling pathway
  evidence:
  - reference: PMID:29959430
    reference_title: "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: specific features, such as PTH resistance, TSH resistance, growth hormone deficiency
    explanation: Supports that endocrine resistance in PHP commonly extends beyond PTH signaling.
  downstream:
  - target: Hypothyroidism
    description: TSH resistance can lead to biochemical and clinical hypothyroidism.
    hypothesis_groups:
    - endocrine_resistance_model
    causal_link_type: DIRECT
  - target: Short Stature
    description: Combined endocrine resistance and skeletal effects can limit linear growth.
    hypothesis_groups:
    - endocrine_resistance_model
    - aho_mesenchymal_model
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - growth hormone deficiency
- name: AHO Developmental Tissue Effects
  description: >-
    Albright hereditary osteodystrophy reflects altered developmental signaling in
    bone, adipose tissue, and other mesenchymal lineages, partially independent
    of biochemical severity.
  cell_types:
  - preferred_term: osteoblast
    term:
      id: CL:0000062
      label: osteoblast
  - preferred_term: adipocyte
    term:
      id: CL:0000136
      label: adipocyte
  locations:
  - preferred_term: bone element
    term:
      id: UBERON:0001474
      label: bone element
  biological_processes:
  - preferred_term: endochondral ossification
    term:
      id: GO:0001958
      label: endochondral ossification
  - preferred_term: ossification
    term:
      id: GO:0001503
      label: ossification
  evidence:
  - reference: PMID:29959430
    reference_title: "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: resistance to PTH, ectopic ossifications, brachydactyly and early-onset obesity.
    explanation: Defines the core AHO-associated developmental phenotype cluster.
  - reference: PMID:40972900
    reference_title: "Imprinting and skeletal disorders: lessons from pseudohypoparathyroidism and related disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: While maternal mutations result in PHP type 1A, which consists of PTH resistance and AHO, paternal mutations lead to pseudo-pseudohypoparathyroidism (PPHP), that is, AHO without hormone resistance.
    explanation: Supports parent-of-origin partitioning of AHO features versus hormone resistance.
  downstream:
  - target: Brachydactyly
    description: Disordered endochondral growth shortens metacarpals and other tubular bones.
    hypothesis_groups:
    - aho_mesenchymal_model
    causal_link_type: DIRECT
  - target: Subcutaneous Ossifications
    description: Ectopic dermal and subcutaneous ossification forms firm palpable nodules.
    hypothesis_groups:
    - aho_mesenchymal_model
    causal_link_type: DIRECT
  - target: Obesity
    description: Altered GNAS-dependent metabolic regulation contributes to early-onset adiposity.
    hypothesis_groups:
    - neuroendocrine_obesity_model
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - MC4R-related appetite and energy homeostasis signaling
  - target: Developmental Delay
    description: >-
      Some patients show neurodevelopmental effects with learning or global delay,
      most prevalent in PHP1A. Attributed to early-onset Gs alpha
      haploinsufficiency in CNS development (proposed cerebral GNAS imprinting)
      rather than to bone/mesenchymal differentiation or to acute
      hypocalcemia-driven neurologic symptoms.
    hypothesis_groups:
    - cerebral_gsalpha_imprinting_model
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
phenotypes:
- name: Chiari Malformation Type 1
  category: Neurological
  subtype: PHP1A
  frequency: OCCASIONAL
  description: >-
    Chiari malformation type 1 (CM1) occurs at approximately 10-fold the
    general population prevalence in PHP1A, with 10.8% prevalence in
    imaging-confirmed cohorts (21.7% when including low-lying cerebellar
    tonsils). Mouse Gnas E1+/-m models show smaller cranial vault,
    increased cranial dome angle, hyperostosis, and premature spheno-
    occipital synchondrosis closure, providing a developmental etiology.
    CM1 prevalence is independent of GH deficiency status, and clinical
    threshold for brain imaging should be low. Surfaced by the 2026
    falcon deep-research review of the AHO mesenchymal differentiation
    model.
  phenotype_term:
    preferred_term: Chiari type I malformation
    term:
      id: HP:0007099
      label: Chiari type I malformation
  evidence:
  - reference: PMID:36662765
    reference_title: "Prevalence of Chiari malformation type 1 is increased in pseudohypoparathyroidism type 1A and associated with aberrant bone development."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "prevalence of CM1 is at least 10-fold higher"
    explanation: >
      Krishnan et al. (2023) demonstrate that PHP1A patients have at
      least 10-fold higher CM1 prevalence than the general population
      (10.8% by imaging; 21.7% with LLCT), correlating with mouse-model
      evidence of aberrant cranial base development.
- name: Basal Ganglia Calcification
  category: Neurological
  frequency: OCCASIONAL
  description: >-
    Intracranial calcifications (basal ganglia, globus pallidus, frontal
    cortex) develop in PHP patients and are frequent in PHP1B cohorts.
    Calcifications can develop independently of acute calcium status and
    may persist even after calcium normalization, reflecting chronic
    calcium-phosphate dysregulation. Surfaced by the 2026 falcon deep-
    research review of the neurohypocalcemia model
    (kb/hypotheses/Pseudohypoparathyroidism/neurohypocalcemia_model).
  phenotype_term:
    preferred_term: Basal ganglia calcification
    term:
      id: HP:0002135
      label: Basal ganglia calcification
  evidence:
  - reference: PMID:35410271
    reference_title: "Clinical and genetic analysis of pseudohypoparathyroidism complicated by hypokalemia: a case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "CT scanning of the brain revealed globus pallidus calcification"
    explanation: >
      CT-confirmed globus pallidus calcification documented in a PHP1B
      patient, supporting basal ganglia calcification as a phenotype
      that develops in the setting of chronic mineral dysregulation.
- name: Hypocalcemia
  category: Biochemical
  frequency: VERY_FREQUENT
  diagnostic: true
  description: Low serum calcium with elevated PTH due to end-organ resistance.
  phenotype_term:
    preferred_term: Hypocalcemia
    term:
      id: HP:0002901
      label: Hypocalcemia
  evidence:
  - reference: PMID:37014531
    reference_title: "Variable Bone Phenotypes in Patients with Pseudohypoparathyroidism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone.
    explanation: Confirms hypocalcemia as a defining biochemical consequence of PHP.
- name: Hyperphosphatemia
  category: Biochemical
  frequency: VERY_FREQUENT
  diagnostic: true
  description: Elevated serum phosphate from impaired renal phosphate excretion.
  phenotype_term:
    preferred_term: Hyperphosphatemia
    term:
      id: HP:0002905
      label: Hyperphosphatemia
  evidence:
  - reference: PMID:37014531
    reference_title: "Variable Bone Phenotypes in Patients with Pseudohypoparathyroidism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone.
    explanation: Confirms hyperphosphatemia as part of the hallmark PHP biochemical triad.
- name: Elevated Parathyroid Hormone
  category: Biochemical
  frequency: VERY_FREQUENT
  diagnostic: true
  description: Compensatory PTH elevation despite hypocalcemia.
  phenotype_term:
    preferred_term: Elevated circulating parathyroid hormone level
    term:
      id: HP:0003165
      label: Elevated circulating parathyroid hormone level
  evidence:
  - reference: PMID:35410271
    reference_title: "Clinical and genetic analysis of pseudohypoparathyroidism complicated by hypokalemia: a case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Laboratory assessments of the patient revealed hypokalemia, hypocalcemia and hyperphosphatemia despite elevated PTH levels.
    explanation: Supports elevation of PTH despite biochemical hypocalcemia-hyperphosphatemia.
- name: Tetany
  category: Neurological
  frequency: OCCASIONAL
  description: Neuromuscular irritability with spasm during hypocalcemic episodes.
  phenotype_term:
    preferred_term: Tetany
    term:
      id: HP:0001281
      label: Tetany
  evidence:
  - reference: PMID:35410271
    reference_title: "Clinical and genetic analysis of pseudohypoparathyroidism complicated by hypokalemia: a case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Seven months after delivery, she experienced tetany and dysphonia with diarrhea.
    explanation: Documents tetany as an acute symptomatic manifestation in PHP.
- name: Seizures
  category: Neurological
  frequency: OCCASIONAL
  description: Hypocalcemia-associated seizure episodes, often in childhood.
  phenotype_term:
    preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
  evidence:
  - reference: PMID:38423572
    reference_title: "Epileptic seizures and abnormal tooth development as primary presentation of pseudohypoparathyroidism type 1B."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: We describe a case in which epileptic seizures and abnormalities in dental development were the main clinical manifestation of PHP type 1B.
    explanation: Supports seizures as a clinically important presentation in PHP1B.
- name: Brachydactyly
  category: Skeletal
  frequency: FREQUENT
  diagnostic: true
  description: Shortened metacarpals and digits, especially in the fourth and fifth rays.
  phenotype_term:
    preferred_term: Brachydactyly
    term:
      id: HP:0001156
      label: Brachydactyly
  evidence:
  - reference: PMID:29959430
    reference_title: "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: resistance to PTH, ectopic ossifications, brachydactyly and early-onset obesity.
    explanation: Consensus statement lists brachydactyly among major diagnostic criteria.
- name: Short Stature
  category: Growth
  frequency: FREQUENT
  description: Reduced linear growth from endocrine and skeletal mechanisms.
  phenotype_term:
    preferred_term: Short stature
    term:
      id: HP:0004322
      label: Short stature
  evidence:
  - reference: PMID:29959430
    reference_title: "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: include short bones, short stature, a stocky build, early-onset obesity and ectopic ossifications
    explanation: Identifies short stature as part of the core physical phenotype in PHP-related disorders.
- name: Obesity
  category: Metabolic
  frequency: FREQUENT
  description: Early-onset weight gain and increased adiposity.
  phenotype_term:
    preferred_term: Obesity
    term:
      id: HP:0001513
      label: Obesity
  evidence:
  - reference: PMID:38103632
    reference_title: "The role of genetic and epigenetic GNAS alterations in the development of early-onset obesity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Genetic or epigenetic alterations in GNAS are known to cause pseudohypoparathyroidism in its different subtypes and have been recently associated with isolated, early-onset, severe obesity.
    explanation: Supports mechanistic and clinical linkage between GNAS defects and early-onset obesity.
- name: Subcutaneous Ossifications
  category: Skeletal
  frequency: FREQUENT
  description: Ectopic ossification in skin and soft tissues.
  phenotype_term:
    preferred_term: Subcutaneous ossification
    term:
      id: HP:0034282
      label: Subcutaneous ossification
  evidence:
  - reference: PMID:29959430
    reference_title: "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: subcutaneous and/or deeper ectopic ossifications and neurocognitive impairment.
    explanation: Consensus guidance highlights subcutaneous ectopic ossifications as a monitored feature.
- name: Round Face
  category: Craniofacial
  subtype: PHP1A
  frequency: FREQUENT
  description: >-
    Rounded facial appearance is a classic feature of Albright hereditary
    osteodystrophy, part of the AHO triad alongside short stature and
    subcutaneous ossifications. Characteristic of PHP1A. AHO features are
    much less prominent in PHP1B, consistent with this entry's PHP1B subtype
    description, but are not uniformly absent — mild AHO findings, notably
    brachydactyly, are reported in PHP1B — so this phenotype is scoped to
    PHP1A rather than asserted to exclude PHP1B. Surfaced by the GeneReviews
    baseline check requested during ai4c-agent review of the 2026
    deep-research PR.
  phenotype_term:
    preferred_term: Round face
    term:
      id: HP:0000311
      label: Round face
  evidence:
  - reference: PMID:29072892
    reference_title: "Disorders of GNAS Inactivation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The Albright hereditary osteodystrophy (AHO) phenotype (short stature,
      round facies, and subcutaneous ossifications) and brachydactyly type E
    explanation: >-
      GeneReviews names round facies as a component of the AHO triad, alongside
      short stature and subcutaneous ossifications, supporting this phenotype
      directly rather than through a truncated fragment.
  - reference: PMID:29072892
    reference_title: "Disorders of GNAS Inactivation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Although PHP-Ib is characterized principally by PTH resistance, some
      individuals also have partial TSH resistance and mild features of AHO
      (e.g., brachydactyly).
    explanation: >-
      This supports the description's claim that AHO features are not uniformly
      absent in PHP1B - mild features, notably brachydactyly, are reported -
      which is why this phenotype is scoped to PHP1A rather than asserted to
      exclude PHP1B.
- name: Hypothyroidism
  category: Endocrine
  frequency: OCCASIONAL
  description: TSH resistance causing low thyroid hormone effect.
  phenotype_term:
    preferred_term: Hypothyroidism
    term:
      id: HP:0000821
      label: Hypothyroidism
  evidence:
  - reference: PMID:29959430
    reference_title: "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: specific features, such as PTH resistance, TSH resistance, growth hormone deficiency
    explanation: TSH resistance provides mechanistic support for hypothyroid manifestations in PHP.
- name: Developmental Delay
  category: Neurological
  frequency: OCCASIONAL
  description: Variable neurodevelopmental impairment across disease subtypes.
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:29959430
    reference_title: "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: subcutaneous and/or deeper ectopic ossifications and neurocognitive impairment.
    explanation: Neurocognitive impairment in consensus guidance supports developmental and cognitive phenotype burden.
biochemical:
- name: Parathyroid Hormone
  presence: Elevated
  context: Elevated PTH with hypocalcemia and hyperphosphatemia supports hormone resistance.
  evidence:
  - reference: PMID:37014531
    reference_title: "Variable Bone Phenotypes in Patients with Pseudohypoparathyroidism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone.
    explanation: Directly supports elevated PTH in the context of end-organ resistance.
- name: Serum Calcium
  presence: Decreased
  context: Persistent or recurrent hypocalcemia is common at presentation.
  evidence:
  - reference: PMID:37014531
    reference_title: "Variable Bone Phenotypes in Patients with Pseudohypoparathyroidism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone.
    explanation: Supports hypocalcemia as a central biochemical finding.
- name: Serum Phosphate
  presence: Elevated
  context: Renal phosphate retention leads to chronic hyperphosphatemia.
  evidence:
  - reference: PMID:37014531
    reference_title: "Variable Bone Phenotypes in Patients with Pseudohypoparathyroidism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: It is characterized by hypocalcemia, hyperphosphatemia, and an elevated parathyroid hormone concentration secondary to the resistance of target tissues to the biological actions of parathyroid hormone.
    explanation: Supports persistent hyperphosphatemia in PHP.
genetic:
- name: GNAS
  gene_term:
    preferred_term: GNAS
    term:
      id: hgnc:4392
      label: GNAS
  association: Loss-of-Function Variant or Imprinting Defect
  evidence:
  - reference: PMID:37014531
    reference_title: "Variable Bone Phenotypes in Patients with Pseudohypoparathyroidism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Pseudohypoparathyroidism (PHP) is a disorder caused by mutations and/or epigenetic changes at the complex GNAS locus.
    explanation: Supports both genetic and epigenetic GNAS mechanisms in disease causation.
  inheritance:
  - name: Autosomal dominant
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
    expressivity: VARIABLE
    parent_of_origin_effect: Maternal inheritance typically causes hormone resistance; paternal inheritance more often causes AHO without marked PTH resistance.
    evidence:
    - reference: PMID:40972900
      reference_title: "Imprinting and skeletal disorders: lessons from pseudohypoparathyroidism and related disorders."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: While maternal mutations result in PHP type 1A, which consists of PTH resistance and AHO, paternal mutations lead to pseudo-pseudohypoparathyroidism (PPHP), that is, AHO without hormone resistance.
      explanation: Documents the parent-of-origin effect that modifies expression of dominantly inherited GNAS defects.
  notes: >-
    Parent-of-origin and epigenetic context at the GNAS locus strongly determine
    clinical subtype and severity.
treatments:
- name: Calcium and Active Vitamin D Replacement
  description: >-
    Calcium supplementation combined with active vitamin D (calcitriol or
    alfacalcidol) to correct hypocalcemia and hyperphosphatemia. Standard
    of care for PHP1A and PHP1B; correction of hypocalcemia resolves
    tetany, seizures, and dyskinesias.
  target_phenotypes:
  - preferred_term: Hypocalcemia
    term:
      id: HP:0002901
      label: Hypocalcemia
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: calcium
      term:
        id: CHEBI:29108
        label: calcium(2+)
    - preferred_term: calcitriol
      term:
        id: CHEBI:17823
        label: calcitriol
  evidence:
  - reference: PMID:25905388
    reference_title: "Hypoparathyroidism and Pseudohypoparathyroidism."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Calcium and vitamin D are the standard therapy"
    explanation: >
      Endocrinology textbook reference frames calcium and active vitamin
      D supplementation as the cornerstone of hypoparathyroidism / PHP
      treatment for correcting hypocalcemia-driven neuromuscular
      symptoms.
- name: Intravenous Calcium Gluconate (Acute Tetany)
  description: >-
    Intravenous calcium gluconate is the acute treatment for symptomatic
    hypocalcemic tetany, seizures, and laryngospasm in PHP. Used
    emergently before transition to oral calcium + active vitamin D
    maintenance therapy.
  target_phenotypes:
  - preferred_term: Hypocalcemia
    term:
      id: HP:0002901
      label: Hypocalcemia
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: calcium gluconate
      term:
        id: CHEBI:3309
        label: calcium gluconate
  evidence:
  - reference: PMID:35410271
    reference_title: "Clinical and genetic analysis of pseudohypoparathyroidism complicated by hypokalemia: a case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Tetany symptoms were relieved after intravenous calcium gluconate"
    explanation: >
      Case report of PHP1B with tetany symptoms documents resolution
      after intravenous calcium gluconate supplementation, illustrating
      the acute emergency use of IV calcium for symptomatic hypocalcemia.
references:
- reference: PMID:29072892
  title: "Disorders of GNAS Inactivation."
  tags:
  - GeneReviews
datasets:
- accession: geo:GSE195873
  title: Novel genetic variants of KHDC3L and other members of the subcortical maternal complex associated with Beckwith-Wiedemann syndrome or Pseudohypoparathyroidism 1B and multi-locus imprinting disturbances
  description: Beckwith–Wiedemann syndrome (BWS) and Pseudohypoparathyroidism type 1B (PHP1B) are imprinting disorders (ID) caused by deregulation of the imprinted gene clusters located at 11p15.5 and 20q13.32, respectively. In both of these diseases a subset of the patients is affected by multi-locus imprinting disturbances (MLID). In several families, MLID is associated with damaging variants of maternal-effect genes encoding protein components of the subcortical maternal complex (SCMC). However, frequency, penetrance and recurrence risks of these variants are still undefined.
  organism:
    preferred_term: human
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  data_type: METHYLATION
  sample_count: 18
  publication: PMID:35643636
  notes: Identified by GEO DataSets index search for Pseudohypoparathyroidism (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-01. Title, sample count, and organism are GEO's own values.
- accession: dbgap:phs000476
  title: Molecular Defects in Pseudohypoparathyroidism or Related Disorders
  description:  Maintaining calcium levels within a narrow normal range is of critical importance for numerous different cellular functions. One of the most important regulators of blood calcium levels is parathyroid hormone (PTH), which mediates its actions through the PTH/PTHrP receptor, a Gαs-coupled receptor.
  notes: Located via OmicsDI, which aggregates across omics repositories; this record comes from dbgap. Only repositories with no other discovery route in this project and with a working accession resolver are curated from OmicsDI -- GEO, ArrayExpress, PRIDE, MetaboLights and EGA hits are excluded as duplicates of dedicated passes. Matched because the disease is named in the dataset's own title ("Pseudohypoparathyroidism"). Retrieved 2026-08-02.
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References & Deep Research

References

1
PMID:29072892
Disorders of GNAS Inactivation.
No top-level findings curated for this source.