Replication Of Gwas-Identified Systemic Lupus Erythematosus Susceptibility Genes Affirms B-Cell Receptor Pathway Signalling And Strengthens The Role Of Irf5 In Disease Susceptibility In A Northern European Population

Objective. A large number of genes, including several not previously implicated in SLE susceptibility, have recently been identified or confirmed by genome-wide association studies (GWAS). In this study, we sought to replicate some of these results in Finnish SLE patients (n = 275) and control individuals (n = 356).Methods. We genotyped 32 single nucleotide polymorphisms (SNPs) in 12 of the best-supported GWAS-identified SLE genes and loci. We further investigated gene-gene interactions between the loci included in the study.Results. The strongest evidence of association was found at the IRF5-TNPO3 locus, with the most significant P-value being 2.0 x 10(-7) and an odds ratio of 1.95 (95% CI 1.51, 2.50). Association between SLE and TNFAIP3, FAM167A-BLK, BANK1 and KIAA1542 was also confirmed, although at a lower significance level and contribution to individual risk. No significant association was found with 1q25.1, PXK, ATG5, ICA1, XKR6, LYN and SCUBE1. Furthermore, no significant gene-gene interactions were detected.Conclusion. Replication of previous GWAS findings across diverse populations is of importance to validate these associations and to get a better understanding of potential genetic heterogeneity between populations in SLE susceptibility. Our results attest the importance of B-cell receptor pathway and IFN signalling in SLE pathogenesis.