On the other hand, in animal models, Gorman J.A. et al. showed that mice with the two human autoimmune risk variants, IFIH1 (rs1990760) and PTPN22 (rs2476601), increased the incidence of autoimmune diabetes by low-dose STZ challenge more than those with non-risk allele or those with one risk allele, demonstrating that an additive effect of risk alleles could promote the development of T1D [51]. This evidence concerns the gene PTPN22 and type 1 diabetes mellitus.