Autosomal dominant hypoparathyroidism with variable, age-dependent severity.

Hypoparathyroidism (hypocalcemia, hyperphosphatemia, mild hypomagnesemia, and inappropriately low serum C-terminal parathyroid hormone concentration) was found in six members of a family representing three successive generations. No patient had aortic arch or conotruncal malformations, lymphopenia, or features of type I or type II autoimmune polyglandular syndromes. Two individuals had transient neonatal seizures without further difficulties despite persistent hypocalcemia. None of the four affected adults has had major complications of hypoparathyroidism (mental retardation, cataracts, or seizures). We believe that persistence of hypoparathyroidism after resolution of neonatal hypocalcemic seizures should prompt a survey of the family for hypoparathyroidism.