Familial juvenile gout; Hereditary nephropathy with hyperuricemia and gout; FJHN
Definition and Characteristics
Autosomal dominant renal transport defect leading to hyperuricemia associated with a grossly reduced fractional uric acid clearance (FEur = uric acid clearance factored by creatinine clearance ×100) of 5.1 ± 1.6% irrespective of age or sex, which precedes deterioration in renal function (Fig. 1).
Nephropathy, Familial Juvenile Hyperuricemic. Figure 1
Reduced fractional excretion of uric acid is the biochemical hallmark of FJHN. In the normal kidney, approximately 90% of uric acid is reabsorbed leaving a fraction of 10% excreted. In FJHN, the fraction of uric acid excreted is reduced to 5%, setting plasma uric acid levels abnormally high.
Rare, but an EU database records 113 patients found mainly in two countries (GB 90, CZ 19), indicating poor clinical awareness. Reported in Japanese and Polynesians as well as in Ca...