Xanthinuria increased urine xanthine level 2023-07-06T09:32:24Z hyperxanthinuria MPheno.ontology MP:0031479 excretion of excessive amounts of xanthine in the urine; xanthine (2,6-dihydroxypurine) is a purine formed in the metabolic breakdown of guanine, but is not present in nucleic acids xanthinuria increased urinary xanthine level abnormal urine xanthine level increased level of xanthine in urine