Nephropathic cystinosis: ineffectiveness of cysteamine therapy for ocular changes.

The biochemical hallmark of nephropathic cystinosis is the intralysosomal accumulation of free cystine in various organs, including the conjunctiva, cornea, bone marrow, leukocytes, lymph nodes, and internal organs. A patient with the infantile form of nephropathic cystinosis develops several renal tubular malfunctions during the first year of life; these eventually lead to end-stage renal failure and eventual death by the time the patient is 10 years of age. Ocular changes are prominent and may be so typical that an early diagnosis can be achieved by an ophthalmologic examination before the nephropathic signs become evident.