HAS3 and rheumatoid arthritis: Furthermore, six candidate genes were identified on ECA3; WWP2, PSMD7, NQO1, NOB1, NFAT5 and HAS3. Additionally, we identified several genes (SEMA7A [10], CSK [11], GUCY1A2 [12], EMCN [13], OPRM1 [14]) that are associated with rheumatoid arthritis (RA).