Brachydactyly in 14 genetically characterized pseudohypoparathyroidism type Ia patients.

Brachydactyly, classically described as shortening of III, IV, and V metacarpals and I distal phalanx, is the typical and most specific sign of Albright's hereditary osteodystrophy, a peculiar phenotype reported in subjects with pseudohypoparathyroidism type Ia (PHP-Ia) caused by mutations in the GNAS gene, which encodes for the alpha-subunit of the stimulatory G protein (Gsalpha). It has been reported in 70% of PHP subjects from routine radiological examinations, but there are no specific data for hand alterations in genetically characterized PHP-Ia subjects. We evaluated the metacarpophalangeal pattern profile in 14 GNAS-mutated PHP-Ia subjects and determined the prevalence and patterns of left hand bone shortening.