Recently, a comprehensive meta-analysis (93) showed that PTPN22 C1858T SNP is strongly associated with nine autoimmune diseases: T1D, RA, SLE, Graves’ disease, Addison’s disease, AAV, juvenile idiopathic arthritis, myasthenia gravis and Graves’ disease with other concomitant autoimmune diseases, with the T allele increasing the risk of disease. This evidence concerns the gene PTPN22 and type 1 diabetes mellitus.