Only a few alleles in the DRB1 molecule, which are coding for QKRAA [Q (glutamine) K (lysine) R (arginine) and AA (alanine-alanine], QRRAA, or RRRAA amino acid sequences in the positions 70–74 of the third hypervariable region, have a strong association with RA. The gene discussed is HLA-DRB1; the disease is rheumatoid arthritis.