We previously performed a GWAS of RA using a Japanese case-control cohort (2,303 cases and 3,380 controls) and identified significant associations in major histocompatibility complex, class II, DR beta 1 (HLA-DRB1 [MIM 142857]), and chemokine (C-C motif) receptor 6 (CCR6 [MIM 601835]) loci (PGWAS<5×10−8) [6]. This evidence concerns the gene HLA-DRB1 and rheumatoid arthritis.