• Survival [ Time Frame: Lifetime ] [ Designated as safety issue: Yes ]
  

• Renal function, secondary complications of disease [ Time Frame: Decades ] [ Designated as safety issue: Yes ]
  

Drug: Cysteamine
Cystine-depleting agent

Patients with nephropathic cystinosis have been treated with the cystine-depleting agent cysteamine since 1978. This therapy prevents or delays renal deterioration, improves growth, and depletes parenchymal tissues of cystine. Based largely upon data produced through this protocol, the Food and Drug Administration approved cysteamine bitartrate for use in pre-transplant cystinosis patients on August 15, 1994, although it is also taken off-label by post-transplant patients to prevent non-renal complications of cystinosis. Cysteamine is available as Cystagon through Mylan Pharmaceuticals in 50 mg and 150 mg capsules. By virtue of the current protocol, patients are admitted to the NIH Clinical Center for investigations every two years, except for cases of great interest or urgency. On each 3-4 day admission, a battery of tests is performed and the adequacy of cystine depletion by cysteamine is monitored. This protocol will demonstrate the course of cystinosis patients treated with cysteamine, describe new complications of the disorder in poorly treated adults, and will maintain NHGRI expertise in the field. Its monitoring and follow-up of patients over the course of 3 decades represents an invaluable contribution to our understanding of the natural history of this rare disease.