Before 1960, every person born with cystinosis died in infancy because of the renal Fanconi syndrome or in the first decade of life because of chronic glomerular failure. In the late 1960s, renal allograft procedures for children dramatically increased the longevity of these patients, but the effects of kidney losses remain unremitting: Seventeen of our 92 patients who had transplantation were uremic. Moreover, long-term cystine accumulation continued to damage nonrenal tissues. Organs previously thought to be spared by cystinosis, such as the brain, the liver, and muscle, became affected (2). Initial reports described only a few cases of each late complication. Now, as children with cystinosis survive into adulthood, the true burden of disease conferred by mutations in CTNS, especially homozygosity for the 57-kb deletion, has become clear. Specifically, the mortality rate of cystinosis in adulthood approximates one third, and death generally occurs before 30 years of age. The causes of death among patients with cystinosis are varied and somewhat expected, but a new finding is involvement of the gastrointestinal tract: Three bowel perforations and 3 fatal incidents of peritonitis implicate chronic intestinal damage as a cause of death.