Contributor: Gordon K. Klintworth
Cystinuria is an autosomal recessive inherited disease in which high quantities of cystine is excreted in the urine. Different types of cystinuria are recognized (cystinuria type I, cystinuria type II,  cystinuria type III). Mutations in the SLC3A1 gene cause cystinuria type I and type II. Cystinuria type III is caused by a mutation at a different locus. A complication of cystinuria is the development of yellow calculi composed of cystine in the kidney and bladder. Cystinuria should not be confused with cystinosis.