Cystinosis is an inherited disease characterized by abnormal accumulation of cystine in the
reticuloendothelial system, leukocytes, and fibroblasts. It is caused by mutations in the CTNS gene and is inherited autosomal recessively. As a result of cystine accumulation, disorders such as Fanconi syndrome, chronic renal failure, growth retardation, cystine crystal accumulation in the cornea and conjunctiva can be seen. There is no definitive guideline for the follow-up and treatment of the disease, and approaches may differ between centers. The life expectancy and quality of patients, who were frequently followed by pediatric nephrologists, have increased as a result of medical developments. For this reason, adult physicians should recognize this disease and play an active role in its management.