Normocalcaemic pseudohypoparathyroidism with unusual phenotype.

Abstract

A boy is described who presented at 4 yr of age radiological hyperparathyroidism, osteosclerosis and necrosis of the femoral heads. Plasma biochemistry was normal but the parathyroid hormone (PTH) level was very high. He was deaf and had an unusual facies but did not have the phenotype of Albright''s hereditary osteodystrophy. Plasma and urine cyclic AMP responses to bovine PTH were markedly subnormal. Vitamin D produced sustained hypercalcemia and a fall in plasma P. After 4 hyperplastic parathyroid glands were removed he became hypocalcemic and plasma P rose. After operation he remained unresponsive to exogenous PTH. He evidently had a form of pseudohypoparathyroidism without the phenotype of Albright''s hereditary osteodystrophy and with some residual skeletal and renal responsiveness to PTH.