TGFB1 and rheumatoid arthritis: Interestingly, two novel risk variant loci were identified associated with TGFβ1 (transforming growth factor β1) and FOXP3 (forkhead box P3) genes (group 4 and group 6 in Figure 1; Supplementary Table 3) whereas other known variations of these two genes were previously found to be involved in the risk to RA [12-14].