Hereditary xanthinuria is a purine metabolism disorder due to inherited deficiency of the xanthine dehydrogenase/oxidase enzyme and is characterized by very low (or undetectable) concentrations of uric acid in blood and urine and very high concentration of xanthine in urine, leading to urolithiasis. The disease is hereditary xanthinuria (MONDO_0018106). Also known as: classic xanthinuria, xanthic urolithiasis, xanthine dehydrogenase deficiency, xanthine stone disease.