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GTR Home > Conditions/Phenotypes > Pseudohypoparathyroidism type I A

Pseudohypoparathyroidism type I A

Synonyms
Albright hereditary osteodystrophy with multiple hormone resistance; PHP IA; Pseudohypoparathyroidism Ia (PHP-Ia); Pseudohypoparathyroidism Type IA; Pseudohypoparathyroidism type 1A
Modes of inheritance
Autosomal dominant inheritance (Orphanet)

Summary

Excerpted from the GeneReview: Disorders of GNAS Inactivation
Disorders of GNAS inactivation include the phenotypes pseudohypoparathyroidism Ia, Ib, and Ic (PHP-Ia, -Ib, -Ic), pseudopseudohypoparathyroidism (PPHP), progressive osseous heteroplasia (POH), and osteoma cutis (OC). PHP-Ia and PHP-Ic are characterized by: End-organ resistance to endocrine hormones including parathyroid hormone (PTH), thyroid-stimulating hormone (TSH), gonadotropins (LH and FSH), growth hormone-releasing hormone (GHRH), and CNS neurotransmitters (leading to obesity and variable degrees of intellectual disability and developmental delay); and The Albright hereditary osteodystrophy (AHO) phenotype (short stature, round facies, and subcutaneous ossifications) and brachydactyly type E (shortening mainly of the 4th and/or 5th metacarpals and metatarsals and distal phalanx of the thumb). Although PHP-Ib is characterized principally by PTH resistance, some individuals also have partial TSH resistance and mild features of AHO (e.g., brachydactyly). PPHP, a more limited form of PHP-Ia, is characterized by various manifestations of the AHO phenotype without the hormone resistance or obesity. POH and OC are even more restricted variants of PPHP: POH consists of dermal ossification beginning in infancy, followed by increasing and extensive bone formation in deep muscle and fascia. OC consists of extra-skeletal ossification that is limited to the dermis and subcutaneous tissues.
Full text of GeneReview (by section):
Summary
GeneReview Scope
Diagnosis
Clinical Characteristics
Genetically Related (Allelic) Disorders
Differential Diagnosis
Management
Genetic Counseling
Resources
Molecular Genetics
Chapter Notes
References
Authors:
Chad R Haldeman-Englert
Anna CE Hurst
Michael A Levine
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Available tests

24 tests are in the database for this condition.

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Clinical tests (24 available)

Molecular Genetics Tests

Genes See tests for all associated and related genes

  • Also known as: AHO, AIMAH1, C20orf45, GNAS1, GPSA, GSA, GSP, NESP, PITA3, POH, SCG6, SgVI, GNAS
    Summary: GNAS complex locus

Clinical features

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Imported from Human Phenotype Ontology (HPO)

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