[Pseudohypoparathyroidism, calcifying arteriopathy and ischemic skin necrosis]

A patient with longstanding pseudohypoparathyroidism undergoing substitution with dihydrotachysterin, with normal to low serum calcium and phosphorus levels, developed extensive calcification of the subcutaneous tissue and an obliterative and calcified arteriopathy of the small subcutaneous arteries with ischemic skin signs (livedo reticularis, skin infarction and ulcerative necrosis). After stimulation with exogenous parathyroid hormone there was no increase in urinary cyclic AMP and the G-unit was significantly decreased. It was concluded that the patient is suffering from pseudohypoparathyroidism type 1a. The likely pathophysiological mechanisms and the therapeutic implications are discussed.