The diagnosis in a 1-year-old female with skeletal and chemical rickets, generalized hyperaminoaciduria, and metabolic acidosis was uncertain, and primary renal disease (i.e., Fanconi "syndrome") was considered. She had been on a diet which was deficient in calcium (approximately 21 to 36 mg calcium daily) but adequate for phosphorus and vitamin D. Her skeletal and renal lesions resolved within 3 months on a high calcium diet. Early in her hospital course, an intravenous calcium infusion provided 10 mg/kg calcium, as calcium gluconate over 3 hours; 8 to 10 hours later, a significant reduction in urinary amino acids and phosphorus was observed. The mechanism through which this response was mediated is postulated to be via reduction in circulating parathormone.