FCGR2A and rheumatoid arthritis: We therefore undertook additional genotyping in our original RA cohorts and examined SNPs in FCGR2A, FCGR2B and FCGR3B; examined the extent of linkage disequilibrium at this locus; and analyzed FCGR haplotypes for association with disease in order to investigate the possibility that there are other RA susceptibility variants at this locus.