PTPN22 and systemic lupus erythematosus: Namjou et al. [29] reported findings from genotyping of ten SNPs in four large multi-ethnic populations and using their results in conjunction with data from the Hap-Map project, concluded that SLE association with PTPN22 was largely accounted for by the R620W variant (rs2476601) in individuals of European ancestry [21–26, 30, 31].