Inactivating mutations in the Gsα encoding exons of GNAS result in Albright hereditary osteodystrophy (AHO) characterized by a variably expressed array of clinical features such as short stature, brachymetacarpia, subcutaneous ossifications, and mental retardation due to haploinsufficiency of Gsα. The gene discussed is GNAS; the disease is pseudohypoparathyroidism type 1A.