Association study of ACE and eNOS single nucleotide polymorphisms with Henoch-Schönlein purpura nephritis

Inducible nitric oxide synthase gene polymorphisms are associated with a risk of nephritis in Henoch-Schönlein purpura children

Henoch-Schönlein purpura (HSP) is the most common form of systemic small-vessel vasculitis in children, and HSP nephritis (HSPN) is a major complication of HSP and is the primary cause of morbidity and mortality. Previous studies have suggested that inducible nitric oxide synthase (iNOS) may play an important role in the pathogenesis of HSP. In this study, we performed a detailed analysis to investigate the potential association between iNOS polymorphisms and the risk of HSP and the tendency for children with HSP to develop HSPN in a Chinese Han population. A promoter pentanucleotide repeat (CCTTT)n and 10 functional single-nucleotide polymorphisms (SNPs) from 532 healthy controls and 513 children with HSP were genotyped using the MassARRAY system and GeneScan. The results suggested that the allelic and genotypic frequencies of the rs3729508 polymorphism were nominally associated with susceptibility to HSP. In addition, there was a significant difference in the allelic distribution of the (CCTTT)12 repeats and rs2297518 between the HSP children with and without nephritis; the HSP children with nephritis exhibited a significantly higher frequency of the (CCTTT)12 repeats and A allele of rs2297518 than the HSP children without nephritis (P _FDR = 0.033, OR = 1.624, 95% CI = 1.177-2.241 and P _FDR = 0.030, OR = 1.660, 95% CI = 1.187-2.321, respectively).

CONCLUSION

Our results support that iNOS polymorphisms are associated with the risk of HSP and may strongly contribute to the genetic basis of individual differences in the progression to nephritis among children with HSP in the Chinese Han population. What is Known: • The etiology of HSP is unknown, but the genetic factors may play an important role in the pathogenesis of HSP. • iNOS could contribute to the development and clinical manifestations of HSP, and this has not been studied extensively so far. What is New: • Our results support that iNOS polymorphisms not only are associated with HSP risk but also strongly contribute to the genetic basis of individual differences in the progression of HSP to nephritis among Chinese Han children.

Association of Endothelial Nitric Oxide Synthase Gene Polymorphism with Susceptibility and Nephritis Development of Henoch-Schönlein Purpura in Chinese Han Children

OBJECTIVE

Henoch-Schönlein purpura (HSP) is the most common form of systemic small-vessel vasculitis in children. Previous studies suggested endothelial nitric oxide synthase (eNOS) plays an important role in the pathogenesis and clinical manifestations of HSP. This study aimed to investigate the potential association between 10 single-nucleotide polymorphisms (SNPs) within the eNOS gene and HSP risk and nephritis development in a Chinese Han population.

MATERIALS AND METHODS

A case-control study was conducted including 459 healthy children and 423 children with HSP. SNPs were genotyped by using the MassARRAY system.

RESULTS

The genotypic frequency of rs11771443 was nominally associated with the risk of HSP (p = 0.010), and the C allele significantly increased the risk of HSP (p = 0.003, odds ratio [OR] = 1.331, confidence interval [95% CI] = 1.104-1.605). There was a significant difference in allelic and genotypic distribution of rs1799983 between children with HSP and healthy controls (p = 0.002 and 0.0001, respectively). Strong linkage disequilibrium was observed in two blocks. Significantly fewer T-A-G haplotypes (p = 0.0001, OR = 0.593, 95% CI = 0.448-0.786) were found in children with HSP. No significant association was identified between the 10 SNPs and the pathogenesis of HSP progression to HSP nephritis (HSPN).

CONCLUSIONS

The polymorphisms of eNOS contribute to genetic susceptibility to HSP, but may have no effect on children with HSP progressing to HSPN.