Familial hypocalciuric hypercalcemia involving four members of a kindred including a girl with severe neonatal primary hyperparathyroidism.

A family with hypercalcemia in four members is reported. The proband, a newborn girl presenting with inadequate sucking due to muscle hypotonia, marked thoracic deformity due to decalcification, hypercalcemia, and hypophosphatemia, suffers from cerebral damage due to hypoxia despite successful total parathyroidectomy of four hyperplastic glands and replacement therapy. Her 31-year-old father showed CCa/Ccr of 0.0094, normal serum Mg, hypercalcemia, hypophosphatemia and normal renal concentrating ability without kidney stone and bone abnormality. Subtotal parathyroidectomy caused only a transient fall of serum Ca. His half sister and her daughter also had symptomless hypercalcemia. Recognition of familial hypocalciuric hypercalcemia is important to avoid unnecessary parathyroid surgery and to respond effectively to severe neonatal primary hyperparathyroidism occasionally seen in such kindred.