The Wellcome Trust Case Control Consortium (WTCCC) identified nine single SNPs putatively associated with rheumatoid arthritis at P = 1 x 10(-5) - 5 x 10(-7) in a genome-wide association screen. One, rs6920220, was unequivocally replicated (trend P = 1.1 x 10(-8)) in a validation study, as described here. This SNP maps to 6q23, between the genes oligodendrocyte lineage transcription factor 3 (OLIG3) and tumor necrosis factor-alpha-induced protein 3 (TNFAIP3).