PADI2 and rheumatoid arthritis: Six RNAm-SNPs inside known RA susceptibility genes were associated with circulating protein levels, including the m6A-SNPs rs1057151, rs28367598 and rs3177747 in HLA-B and rs2076595 in PADI2, m1A-SNP rs41541519 in HLA-B and the A-to-I-SNP rs72850280 in HLA-DRB1.