MAPK13 and rheumatoid arthritis: Most of the ‘highly verified’ RA-associated genes such as TUBB, HSP90AB1, RPS18, BRD2, PHTF1, MAPK13, BAK1, HLA-F, IER3, RNASET2, HLA-G, ZKSCAN4 and HFE were showed in the STRING Network Visualization.