[Familial idiopathic hypoparathyroidism associated with progressive sensorineural deafness(1)]

A 29-year-old man came to our hospital with tetany and sensorineural deafness. Routine laboratory testing revealed a serum calcium of 5.5 mg/dl and a serum phosphate of 6.1 mg/dl. The level of circulating immunoreactive parathyroid hormone was undetectable, and he showed hyperresponsiveness to the exogenous parathyroid hormone (synthetic hPTH (1-34), 100U). Thus, he was diagnosed as having idiopathic hypoparathyroidism. The other endocrine functions were normal. The parathyroid antibody was negative and no moniliasis was found. On the examination of his family, it was found that his male sibling and one of his female siblings also had hypocalcemia (6.4 mg/dl and 6.0 mg/dl) and undetectable levels of circulating immunoreactive parathyroid hormone, and all his siblings, his father and one of his nieces had sensorineural deafness, so he was diagnosed as as having familial idiopathic hypoparathyroidism and familial progressive sensorineural deafness. In addition to this case, we have experienced two siblings of another family having the same combination of these disorders (unpublished observation). Since familial idiopathic hypoparathyroidism is not common, it seems that the present combination of these disorders is not a chance association.