PRESYMPTOMATIC DETECTION OF FAMILIAL JUVENILE HYPERURICAEMIC NEPHROPATHY IN CHILDREN

We studied 34 apparently healthy children and 2 propositi from kindred s with familial juvenile hyperuricaemic nephropathy (FJHN) - a disorde r characterised by early onset, hyperuricaemia, gout, familial renal d isease and a similarly low urate clearance relative to glomerular filt ration rate (GFR) [fractional excretion of uric acid (FEur) 5.1 +/- 1. 6%] in young men and women. In addition to the propositi, 17 asymptoma tic children were hyperuricaemic mean plasma urate (368 +/- 30 mu mol/ l), twice that of controls (154 +/- 41 mu mol/l). Eight of them had a normal GFR (> 80 ml/min per 1.73 m(2)), and 11 renal dysfunction, whic h was severe in 5. The FEur in the 14 hyperuricaemic children with a G FR > 50 ml/min was 5.0 +/- 0.5% and in the 5 with a GFR less than or e qual to 50 ml/min was still low (11.5 +/- 0.2%) compared with controls (18.4 +/- 5.1%). The 17 normouricaemic children (185 +/- 37 mu mol/l) had a normal GFR (> 80 ml/min) and FEur (14.0 +/- 5.3%). The results highlight the dominant inheritance, absence of the usual child/adult d ifference in FEur in FJHN and presence of hyperuricaemia without renal disease in 42% of affected children, but not vice versa. Since early allopurinol treatment may retard progression to end-stage renal failur e, screening of all relatives in FJHN kindreds is essential.