Renal Hypouricemia Associated with Hyperoxypurinemia due to Decreased Renal Excretion of Oxypurines: a New Defect in Renal Purine Transport

A decrease in uric acid level associated with an increase in oxypurine (xanthine and hypoxanthine) level in both plasma and urine is known as a principal feature of hereditary xanthinuria due to a defect of xanthine oxidase (EC. 1.2.3.2) (Holmes and Wyngaarden, 1989). In this paper, we report a case of renal hypouricemia associated with increased plasma levels of oxypurines caused by renal tubular dysfunction. We examined renal handling of urate and oxypurines by loading probenecid and pyrazinamide. The results suggest that the renal handling of oxypurines as well as urate is affected in this patient.