[Treatment of rickets caused by infantile cystinosis using 1 alpha-hydroxyvitamin D]

Two unrelated girls presented with cystinotic rickets: bone lesions were severe in the first case despite high vitamin D intake, and moderate but significant in the second patient who received physiologic vitamin D prophylaxis since early life. At 56 and 13 months respectively, both patients were given 1 alpha hydroxyvitamin D, 0.5 to 1 microgram/d, with good to excellent results. These data suggest that: 1. Cystinotic bone lesions are to some extent dependent on renal 1 alpha hydroxylase deficiency; 2. 1 alpha OHD thus appears as an effective and appropriate therapy.