DELETION POLYMORPHISM OF THE ANGIOTENSIN-CONVERTING ENZYME GENE PREDICTS PERSISTENT PROTEINURIA IN HENOCH-SCHONLEIN PURPURA NEPHRITIS

Objective-To study the influence of deletion/insertion polymorphism in the 16th intron of the angiotensin converting enzyme (ACE) gene on cl inical manifestations of Henoch-Schonlein purpura nephritis. Study des ign-Cross sectional study. ACE gene polymorphism was determined in pat ients (4-15 years old at onset) with Henoch-Schonlein purpura nephriti s (n = 40) and compared with that in patients with IgA nephropathy (n = 79). Main outcome measures-ACE genotypes, systemic blood pressures, urine protein excretion rate, haematuria, creatinine clearance, serum ACE activities. Results-The initial clinical manifestations of both He noch-Schonlein purpura nephritis and IgA nephropathy were no different among homozygotes for insertion (II) and deletion (DD), and heterozyg otes (ID) for the ACE gene, In patients with Henoch-Schonlein purpura nephritis, the incidence of moderate to heavy proteinuria at four and eight years after onset was more than five times higher in the DD geno type than in the II or ID genotypes. No such trend was seen in patient s with IgA nephropathy. The number of patients with Henoch-Schonlein p urpura nephritis in whom proteinuria resolved at four and eight years after onset was significantly lower in the DD genotype compared with t he II genotype, whereas no differences were detected among the three d ifferent genotypes in patients with IgA nephropathy. Plasma ACE activi ties in patients with the DD genotype were significantly higher than i n those with non-DD genotypes. Conclusions-The ACE DD genotype predict s persistent proteinuria in Henoch-Schonlein purpura nephritis. The pr oteinuria might be related to a defective angiotensin system which is genetically determined by the D/I polymorphism.