HLA-DRB1 and rheumatoid arthritis: It has beendemonstrated that the point mutations within the degenerate epitope change thecharge, affect the association with RA, and are often the only differencesbetween the risk and protective alleles DRB1*0103,DRB1*0402, DRB1*0701,DRB1*1102, and DRB1*1301 [6, 7,49, 52].