[Case of pseudohypoparathyroidism type 1b diagnosed as having hypocalcemia]

The patient (age 46; female) had hypocalcemia without characteristic physical findings of Albright hereditary osteodystrophy in July, 1998. She had no evidence of tetany. Her blood test revealed elevated serum concentration of parathyroid hormone (PTH) in spite of hypocalcemia and hyperphosphatemia. Her Ellsworth-Howard test presented decreased excretion of both phosphate and cAMP in urine after PTH injection compared with normal range of response, indicating end-organ resistance to the actions of PTH. Finally, Ellsworth-Howard test, together with lack of clinical manifestations, resulted in diagnosis of pseudohypoparathyroidism type 1b.