We identified and replicated an association between ITGAM (CD11b) at 16p11.2 and risk of systemic lupus erythematosus (SLE) in 3,818 individuals of European descent. The strongest association was at a nonsynonymous SNP, rs1143679 (P = 1.7 x 10(-17), odds ratio = 1.78). We further replicated this association in two independent samples of individuals of African descent (P = 0.0002 and 0.003; overall meta-analysis P = 6.9 x 10(-22)). The genetic association between ITGAM and SLE implicates the alpha(M)beta2-integrin adhesion pathway in disease development.

We recently identified a novel non-synonymous variant, rs1143679, at exon 3 of the ITGAM gene associated with systemic lupus erythematosus (SLE) susceptibility in European-Americans (EAs) and African-Americans. Using genome-wide association approach, three other studies also independently reported an association between SLE susceptibility and ITGAM or ITGAM-ITGAX region. The primary objectives of this study are to assess whether single or multiple causal variants from the same gene or any nearby gene(s) are involved in SLE susceptibility and to confirm a robust ITGAM association across nine independent data sets (n = 8211). First, we confirmed our previously reported association of rs1143679 (risk allele 'A') with SLE in EAs (P = 1.0 x 10(-8)) and Hispanic-Americans (P = 2.9 x 10(-5)). Secondly, using a comprehensive imputation-based association test, we found that ITGAM is one of the major non-human leukocyte antigen susceptibility genes for SLE, and the strongest association for EA is the same coding variant rs1143679 (log(10)Bayes factor=20, P = 6.17 x 10(-24)). Thirdly, we determined the robustness of rs1143679 association with SLE across three additional case-control samples, including UK (P = 6.2 x 10(-8)), Colombian (P = 3.6 x 10(-7)), Mexican (P = 0.002), as well as two independent sets of trios from UK (P(TDT) = 1.4 x 10(-5)) and Mexico (P(TDT) = 0.015). A meta-analysis combing all independent data sets greatly reinforces the association (P(meta) = 7.1 x 10(-50), odds ratio = 1.83, 95% confidence interval = 1.69-1.98, n = 10 046). However, this ITGAM association was not observed in the Korean or Japanese samples, in which rs1143679 is monomorphic for the non-risk allele (G). Taken together along with our earlier findings, these results demonstrate that the coding variant, rs1143679, best explains the ITGAM-SLE association, especially in European- and African-derived populations, but not in Asian populations.

Objective. Autoimmune diseases often have susceptibility genes in common, indicating similar molecular mechanisms. Increasing evidence suggests that rs6822844 at the IL2-IL21 region is strongly associated with multiple autoimmune diseases in individuals of European descent. This study was undertaken to attempt to replicate the association between rs6822844 and 6 different immune-mediated diseases in nonEuropean populations, and to perform disease-specific and overall meta-analyses using data from previously published studies.Methods. We evaluated case-control associations between rs6822844 and celiac disease (CD) in subjects from Argentina; rheumatoid arthritis (RA), type 1 diabetes mellitus (DM), primary Sjögren's syndrome (SS), and systemic lupus erythematosus (SLE) in subjects from Colombia; and Behçet's disease (BD) in subjects from Turkey. Allele and gene distributions were compared between cases and controls. Meta-analyses were performed using data from the present study and previous studies.Results. We detected significant associations of rs6822844 with SLE (P ‫؍‬ 0.008), type 1 DM (P ‫؍‬ 0.014), RA (P ‫؍‬ 0.019), and primary SS (P ‫؍‬ 0.033) but not with BD (P ‫؍‬ 0.34) or CD (P ‫؍‬ 0.98). We identified little evidence of population differentiation (F ST ‫؍‬ 0.01) within cases and controls from Argentina and Colombia, suggesting that association was not influenced by population substructure. Disease-specific meta-analysis indicated significant association for RA (P meta ‫؍‬ 3.61 ؋ 10 ؊6 ), inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis) (P meta ‫؍‬ 3.48 ؋ 10 Conclusion. Our results indicate that there is an association between rs6822844 and multiple autoimmune diseases in non-European populations. Metaanalysis results strongly reinforce this robust association across multiple autoimmune diseases in both European-derived and non-European populations.Genetic susceptibility plays an important role in autoimmune diseases.

Our results demonstrate that the coding variant rs763361 in CD226 gene is associated with multiple ADs in non-European populations.