Thus, the objective of this study wasto construct a GRS containing SNPs in five candidate genes for T1DM(INS, PTPN22, CTLA4,TYK2, and ERBB3), along with SNPs in theHLA DR/DQ loci, in order to discriminate patients with T1DMfrom a Southern Brazilian population. The gene discussed is PTPN22; the disease is type 1 diabetes mellitus.