In cystinosis, cystine accumulates in the reticuloendothelial cells. It is inherited in an autosomal recessive manner. The exact mechanism is unknown but it is thought to be a defect of cystine transport across the lysosomal membrane. Three forms are recognized: the infantile form is usually fatal in the first year owing to renal failure; the intermediate form presents in early/young adult life with fever and renal problems; and the adult form is benign. The generalized aminoaciduria seen in these patients often causes confusion with the Fanconi syndrome. Corneal deposits of cystine are seen.