PHP Type 1A general features include:

PHP Type 1A general features include:

• A. Autosomal dominant
• B. Autosomal recessive
• C. X-linked
• D. Mitochondrial inheritance

Answer: (A)

Pseudohypoparathyroidism type 1A is caused by mutations in the GNAS gene, which encodes the Gs alpha subunit. Its inheritance is autosomal dominant, but with a parent-of-origin effect due to genomic imprinting. If the mutant allele is inherited from the mother, there is resistance to parathyroid hormone (and often resistance to other hormones) along with Albright hereditary osteodystrophy features. If the mutant allele comes from the father, hormone resistance is usually not present (though skeletal changes can occur). This maternal imprinting pattern explains why a single mutated allele can cause disease and why the inheritance is not purely autosomal recessive, X-linked, or mitochondrial.

Pseudohypoparathyroidism type 1A is caused by mutations in the GNAS gene, which encodes the Gs alpha subunit. Its inheritance is autosomal dominant, but with a parent-of-origin effect due to genomic imprinting. If the mutant allele is inherited from the mother, there is resistance to parathyroid hormone (and often resistance to other hormones) along with Albright hereditary osteodystrophy features. If the mutant allele comes from the father, hormone resistance is usually not present (though skeletal changes can occur). This maternal imprinting pattern explains why a single mutated allele can cause disease and why the inheritance is not purely autosomal recessive, X-linked, or mitochondrial.