Nephropathic cystinosis is a lysosomal storage disorder characterised by the build-up of cystine in cells, which leads to progressive organ failure. Clinically, nephropathic cystinosis presents with Fanconi syndrome between 6 and 12 months of age showing signs of fluid and electrolyte loss, aminoaciduria, glycosuria, phosphaturia, renal tubular acidosis, rickets and growth retardation. Untreated cases progress to end-stage renal failure in the first decade of life. A rare late-onset form of cystinosis occurs in older children, manifesting at age 10 to 12 years with proteinuria due to glomerular damage, as opposed to tubular damage that occurs in infantile cystinosis. Adults with 'benign' cystinosis have asymptotic corneal cystine deposition but do not have progressive renal damage.
Mutations in CTNS gene, which encodes cystinosin is associated with nephropathic cystinosis.