The +1858C/T PTPN22 gene polymorphism confers genetic susceptibility to rheumatoid arthritis in Mexican population from the Western Mexico

► The +1858C/T polymorphism in PTPN22 gene is associated with susceptibility to RA in Mexican population. ► We demonstrated that the +1858T allele in the PTPN22 gene is a genetic risk factor for susceptibility to RA. ► The +1858T allele increase the risk for RA in positive patients for anti-CCP antibodies.