Our analyses, which included more SNPs and incorporated HapMap information for all SNPs highly correlated with SNPs genotyped in our study, permitted a comprehensive analysis of the genetic architecture of 9q33.2 region, allowing us to localize the RA-susceptibility effects to a 70 kb region (LD Block 1) that includes a portion of PHF19, all of TRAF1 and the majority of the TRAF1-C5 intergenic region, but excludes the C5 coding region, narrowing the true region of interest. This evidence concerns the gene TRAF1 and rheumatoid arthritis.