Genome-wide association (GWA) studies in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) in Caucasian populations have independently identified risk variants in and near the tumor necrosis factor alpha (TNFalpha)-induced protein 3 gene (TNFAIP3), which is crucial for the regulation of TNF-mediated signaling and Toll-like receptor signaling. The aim of this study was to assess the role of TNFAIP3 in the development of SLE and RA in Japanese subjects.
We selected 2 single-nucleotide polymorphisms (SNPs) from previous GWA studies. Rs2230926 is a nonsynonymous SNP in TNFAIP3 and is associated with SLE, while rs10499194 is an intergenic SNP associated with RA. We then performed 2 independent sets of SLE case-control comparisons (717 patients and 1,362 control subjects) and 3 sets of RA case-control comparisons (3,446 patients and 2,344 control subjects) using Japanese subjects. We genotyped SNPs using TaqMan assays.
We observed a significant association between rs2230926 and an increased risk of SLE and RA in the Japanese population (for SLE, odds ratio [OR] 1.92, 95% confidence interval [95% CI] 1.53-2.41, P = 1.9 x 10(-8); for RA, OR 1.35, 95% CI 1.18-1.56, P = 2.6 x 10(-5)). The intergenic SNP rs10499194 was also associated with SLE and RA, while the risk allele for RA in Caucasians was protective against the diseases in our population.
We demonstrated a significant association between the nonsynonymous variant in TNFAIP3 and the risk for SLE and RA in the Japanese population. TNFAIP3, similar to STAT4 and IRF5, may be a common genetic risk factor for SLE and RA that is shared between the Caucasian and Japanese populations.