Familial Hypouricemia Due to Isolated Renal Tubular Defect

A 37-year-old female was found to have hypouricemia (1.1-1.9 mg%) with markedly increased uric acid clearance (24.7039.5 ml/min). Uric acid excretion was only slightly affected by pyrazinamide, a drug which suppresses renal tubular uric acid secretion, and by probenecid, a drug which inhibits tubular uric acid reabsorption. The attenuated response in this subject to both drugs suggest a renal tubular defect in the proximal high capacity-high affinity uric acid reabsorption mechanism. No other renal tubular or metabolic abnormalities were detected. A survey of the family-three sisters and two brothers, revealed two similarly affected sisters. The abnormality described in this family is defined as familial renal hypouricemia due to an isolated renal tubular defect with attenuated response of uric acid clearance to probenecid and pyrazinamide.