The most significant difference in association of ACPA-positive RA between Asian and European populations is in the type of amino acid at position 11 of HLA-DRB1 which generates the highest risk: in the Asian population, it is Asp, instead of Val, and this corresponds to the HLA-DRB1*09 group haplotype [30]. Here, PRTN3 is linked to rheumatoid arthritis.