[Vitamin D-dependent type-1 rickets: diagnosis and treatment of a further case].

We describe a child with vitamin D dependent rickets type 1, who developed clinical signs of the disease at three months of age. The principal manifestations were hypocalcemia and seizure with EEG abnormalities. The circulating level of 1 alpha, 25 (OH)2D3 was low despite a normal level of 25 (OH)D3 and an adequate vitamin D supplementation. The patient responded to calcium gluconate infusions and pharmacologic doses of 1 alpha, 25 (OH)2D3 and a normalization of calcemia was obtained. After six months the therapy was progressively reduced to physiological dosage with optimal metabolic control. The patient is now 2.5 years old and receive a maintenance dose of calcitriol of 0.125 mcg/day. His clinical, biochemical and radiologic features are normal.