Familial renal hypouricemia with intact reabsorption of uric acid.

Three patients with renal hypouricemia in the same family are described. Serum urate levels in the mother were in the low normal range and were below normal in her 2 sons. In all 3 patients, the ratios of renal urate clearance to creatinine clearance were abnormally elevated. Clear responses to either pyrazinamide or probenecid administration were observed in these ratios. These results suggest that these 3 patients had renal hypouricemia with normal reabsorption of urate as judged by the criteria for differentiating abnormalities in renal urate handling. This corresponds to the previously postulated mechanism as renal urate hypersecretion. Possible limitations to the diagnostic use of probenecid and pyrazinamide are also discussed.