Cystinuria is an inherited autosomal recessive disorder. The kidneys do not adequately resorb certain amino acids during the filtering process, resulting in excess excretion of these amino acids. The amino acids may precipitate (solids separate from liquids) and form crystals or stones in the kidneys, ureters, or bladder. The disorder is usually diagnosed after an episode of stones, where analysis of the composition of the stones indicates cystine. Less than 3% of known urinary tract stones are cystine stones. Cystinuria affects approximately 1 out of 10,000 people. Cystine stones are most common in young adults under age 40.
| 
