Primary hyperparathyroidism in infancy associated with familial hypocalciuric hypercalcemia.

Clinical and biochemical evidence of primary hyperparathyroidism (prim. HPT) is reported in an infant with hypotonia, feeding problems and constipation from birth. Following a partial parathyroidectomy at the age of 12 months, the clinical condition improved. In her sister, mother and three other maternal relatives a familial hypocalciuric hypercalcemia (FHH) was subsequently demonstrated. All were clinically healthy in spite of increased total and ionized serum calcium, normal serum parathyroid hormone concentration, low urinary calcium excretion and normal renal excretion of cyclic AMP. Similar findings appeared in our patient after parathyroidectomy. An autosomal dominant inheritance of FHH is suggested. It is thus demonstrated, that a mother with FHH may give birth to healthy children with FHH as well as to infants with prim. HPT associated with FHH.