Renal impairment in urate excretion in patients with Down's syndrome.

Uric acid and creatinine clearance studies were performed in nine subjects with Down's syndrome and in eight mentally retarded controls. The urate clearance was significantly decreased in subjects with Down's syndrome compared with controls. Their mean creatinine clearances were also significantly lower than the controls. No significant differences were shown in erythrocyte lactate dehydrogenase activity, in blood lactate and in blood beta-hydroxybutyrate levels between 20 subjects with Down's syndrome and 16 controls. Glomerular dysfunction would seem to contribute to hyperuricemia in Down's syndrome.