CTLA4 and type 1 diabetes mellitus: For example, the association between various SNPs in PTPN22, PTPN2, IL10, IL2, IFIH1, INS, HLA-DRA, and CTLA4 genes and their impact on the gut microbiota composition has recently been revealed in individuals with autoimmunity and T1D [12,17,18,42,191].