Concurrence of Features of Pseudohypoparathyroidism, Pseudopseudohypoparathyroidism and Basal-Cell Nevus Syndrome
A patient is reported with features of three uncommon clinical entities, i.e. pseudohypoparathyroidism, pseudopseudohypoparathyroidism and basal cell nevus syndrome. The patient's short metacarpals and metatarsals, tetany, intermittent hypocalcemia and relative end organ insensitivity to parathyroid extract suggested pseudohypoparathyroidism. However, the usually normal serum calcium and phosphorus concentrations, in association with the physical defects of pseudohypoparathyroidism, suggested pseudopseudohypoparathyroidism. The features of basal cell nevus syndrome in the patient were jaw cysts, multiple nevi, strabismus, calcification of the falx cerebri, and a calcified pelvie mass. These observations strengthen previous contentions that these syndromes are variants of the same genetic defect. Following infusion of calcium intravenously, the return of serum calcium to normal preinfusion level was markedly delayed in this patient. This response was completely different from that previously described for pseudohypoparathyroidism. No comparable reports of this test are available in pseudopseudohypoparatbyroidism or basal cell nevus syndrome.