The common amino acid sequence at positions 70–74 in the DRβ chain showed an increased RA risk (QKRAA, QRRAA or RRRAA), while alleles that changed from Q/R => D at position 70 exerted a protective effect against RA, especially those alleles containing the 70DERAA74 sequence, such as DRB1*01:03, *13:01, *13:02 or *04:02. This evidence concerns the gene HLA-DRB1 and rheumatoid arthritis.