Nephropathic cystinosis: effect of long-term cysteamine therapy.

Three children with nephropathic cystinosis received cysteamine therapy, mostly in the form of phosphocysteamine, for more than six years. The patients were between two and three years of age at the start of the study. The daily dose of cysteamine was 60 mg/kg as cysteamine base. In all three, rapidly progressive renal failure occurred before their 10th birthday. When comparing their evolution with data on the natural history of childhood cystinosis, no improvement was observed in terms of growth and glomerular function. It is concluded that cysteamine therapy did not provide clear benefit to the three patients reported here.