Association analysis of HLA haplotypes in a large case–control cohort of the same population (n = 1191 RA patients and 1558 healthy controls), corroborated that HLA-DRB1*15 is also the HLA variant that is most strongly associated with RA risk in Spain (P = 8.86e − 11, Additional file 31: Table S25). The gene discussed is HLA-DRB1; the disease is rheumatoid arthritis.