Mondo Description Type II xanthinuria, a type of classical xanthinuria, is a rare autosomal recessive disorder of purine metabolism characterized by the deficiency of both xanthine dehydrogenase and aldehyde oxidase, leading to the formation of urinary xanthine urolithiasis and leading, in some patients, to kidney failure. Other less common manifestations include arthropathy, myopathy and duodenal ulcer, while some patients remain asymptomatic.

Uniprot Description A disorder characterized by excretion of very large amounts of xanthine in the urine and a tendency to form xanthine stones. Uric acid is strikingly diminished in serum and urine. In addition, XAN2 patients cannot metabolize allopurinol into oxypurinol due to dual deficiency of xanthine dehydrogenase and aldehyde oxidase.