Polymorphisms in angiotensin-converting enzyme gene and severity of renal disease in Henoch-Schoenlein patients

Background. The influence of angiotensin converting enzyme (ACE) gene polymorphism on the progression of primary IEA nephropathy (pIgAN) is still debated. Even though the allele frequency was reported to be similar to controls, in some studies D/D patients had a faster decline of renal function and need of dialysis. Since Henoch-Schoenlein purpura (HSP) nephritis is considered a systemic vasculitis with renal lesions indistinguishable from pIgAN, we investigated the effect of the ACE polymorphism on presentation and progression of HSP IgAN. Methods. We examined the insertion (I) and deletion (D) polymorphism in intron 16 of ACE gene by PCR amplification of genomic DNA of 82 patients (37 children), with biopsy-proven IgAN associated with HSP enrolled in a collaborative study. Results. No significant association with clinical presentation at onset or with final outcome was found (functional impairment at outcome in 31.8% D/D, 27.4% I/D and 44% I/I, heavy proteinuria in 36.3% D/D, 21.6% I/D, and 11.1% I/I). Patients homozygous for the D allele had a greater number of extrarenal relapses (P = 0.0028). No association was found between the ACE genotype and the presence of hypertension at onset and at the end of the follow-up. No difference was found between adults and children. Conclusions. In this cohort of HSP IgAN, no ACE I/D polymorphisms were found to be associated with progressive deterioration of renal function. Different genes possibly involved in vasculitis might more strictly modulate expression and evolution of HSP IgAN.