[Cutaneous osteoma and Albright's hereditary osteodystrophy].Ann Dermatol Venereol 1994; 121(5):408-13AD
Albright's hereditary osteodystrophy has been diagnosed in a 35-year-old woman who presented recurrent cutaneous ossifications of the auricular area. The patient exhibited other cutaneous ossifications, a short stature with obesity, round face, stocky hands and feet, radiological calcifications of the skull and of the hands, cataract, auditive impairment and dental abnormalities. Serum calcium, phosphorus and parathyroid hormone levels were normal. Urine excretion of phosphorus and cyclic adenosine monophosphate (cAMP) markedly increased after intravenous injection of parathyroid hormone, referring to pseudopseudohypoparathyroidism. Albright's hereditary osteodystrophy is associated either with pseudohypoparathyroidism type 1a characterized by parathyroid hormone and other hormones resistance or with pseudopseudohypoparathyroidism without hormone resistance. This two conditions are considered variants of the same defect of the stimulatory G protein of adenylate cyclase which is necessary for the action of parathyroid hormone, and other hormones to use cAMP as an intracellular second messenger. But Albright's hereditary osteodystrophy may be associated with other biochemical abnormalities, such as defect of catalytic activity of adenylate cyclase in pseudohypoparathyroidism type 1c. There is an important variability of the clinical, biochemical and genetical expression of pseudohypoparathyroidism and today classification is provisional.