In our previous studies, we demonstrated that some polymorphisms of the genes for IL2RA, FAIM2, IFIH1, PADI4, or CTLA-4 appeared more frequently in children and adolescents with autoimmune diseases such as type 1 diabetes (T1D) and AITDs, which may be related to the occurrence and course of the disease [8,9]. This evidence concerns the gene CTLA4 and type 1 diabetes mellitus.