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. The disease is MONDO_0011346 (xanthinuria type II). Also known as: XAN2, XDH and AOX dual deficiency, xanthine dehydrogenase and aldehyde oxidase, combined deficiency of, xanthine dehydrogenase and xanthine aldehyde oxidase dual deficiency.