Hereditary renal hypouricemia. Isolated tubular defect of urate reabsorption.

A consanguineous Iraqi Jewish kindred is presented in which asymptomatic and apparently benign hypouricemia, secondary to an isolated renal defect, segregates as an autosomal recessive trait affecting four of eight siblings. The 8-year-old proband was ascertained during an evaluation for an apparently unrelated inherited neurologic disorder with which an older normouricemic sibling was also affected. Urate clearance in three affected siblings was 22.6, 35.2, and 60.8 ml/minute, while that in normouricemic siblings was 8.6 to 10.6 ml/minute. Pyrazinamide administration to one affected sibling reduced the urate clearance from 61 to 14.7 ml/minute. A recessively inherited single gene lesion producing a tubular defect is postulated; the exact site(s) is uncertain.