part_of part of phenotype affects entity xanthine Xanthinuria SNOMEDCT_US:190919008 HP:0010934 SNOMEDCT_US:54627004 2011-01-10T07:55:12Z Xanthinuria is generally caused by a defect in the xanthine oxidase, an enzyme that catalyzes the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid. The formation of xanthine stones in the urinary tract is the main evidence of this abnormality. An increased concentration of xanthine in the urine. Increased urinary xanthine UMLS:C0220988 Abnormal urine metabolite level increased urine xanthine level urine increased level of xanthine in urine