Familial hypouricaemia due to an isolated tubular defect of urate reabsorption

Hypouricaemia due to an isolated renal tubular defect is a rare condition. Several members from an affected family are described. The propositus is a 12-year-old girl with hypouricaemia (0.7-1.1 mg/dl) and increased fractional excretion of uric acid (50%). Pyrazinamide and sulphinpyrazone tests revealed an attenuated response in this subject to both drugs. The mother and one of the propositus' two brothers have the same defect. The other brother has uric acid levels at the lower limit of normal and increased fractional excretion of uric acid. These results suggest familial hypouricaemia due to a pre-secretory reabsorptive tubular defect, transmitted by autosomal dominant inheritance.