Cystinosis is a genetic disease which characterized by the renal tubular Fanconi syndrome in infancy, followed by progressive glomerular damage requiring dialysis and transplantation by 10 years of age. Among several other clinical manifestations is severe growth retardation. Cystinosis is treated with a cystine depleting thiol, cysteamine, which in addition to aiding other organs, also increases growth. However, most children with cystinosis still remain well below the 3rd percentile for height. Children with cystinosis are not growth hormone deficient, however, preliminary data in older children show that daily injections of growth hormone does stimulate growth. Though growth improves, there is also evidence that glomerular function may decrease in these older children as they experience increased growth. The design of this clinical trial is to determine if growth hormone will significantly increase growth velocity without having an adverse effect on glomerular function in cystinosis patients. Approximately 30 patients will receive growth hormone and 15 patients will serve as non-placebo controls for 24 months.
