Pseudopseudohypoparathyroidism

Pseudopseudohypoparathyroidism is a rare genetic condition that affects the body's skeletal system and physical development. It causes features similar to another disorder called pseudohypoparathyroidism but without the hormone resistance that affects calcium levels. People with this condition often have short stature, round face, and shortened fingers and toes. Despite these physical changes, their blood calcium and phosphate levels remain normal. The condition mainly impacts the bones and physical appearance but does not cause the metabolic problems seen in related disorders.

Pseudopseudohypoparathyroidism is a genetic disorder characterized by the presence of Albright hereditary osteodystrophy (AHO) phenotype without the biochemical abnormalities of parathyroid hormone (PTH) resistance. It results from mutations in the GNAS gene, which encodes the alpha subunit of the stimulatory G protein (Gsα), leading to imprinting defects that affect hormone signaling. Unlike pseudohypoparathyroidism type 1a, patients with pseudopseudohypoparathyroidism have normal serum calcium, phosphate, and PTH levels. The condition is clinically significant due to its distinctive skeletal abnormalities such as brachydactyly, short stature, and subcutaneous ossifications, but without the endocrine dysfunction seen in related disorders. It is inherited in an autosomal dominant pattern with parental imprinting influencing the phenotype.