Genetic susceptibility factors may influence RA's age of onset with HLA-DRB1*04 alleles [18]–[21] and multiple single nucleotide polymorphisms (SNPs) such as those tagging VEGFA[22], RANKL[19], [23], MMP1-3[22] and PTPN22[24], [25] loci associating with YORA. Here, HLA-DRB1 is linked to rheumatoid arthritis.