CTLA4 and type 1 diabetes mellitus: The human leukocyte antigen (HLA) area on chromosome 6p21, protein tyrosine phosphatase non-receptor type 22 (PTPN22) on 1p13, interleukin 2 receptor subunit alpha (IL2RA) on 10p15, the insulin gene (INS-VNTR) locus on 11p15, as well as the cytotoxic T-lymphocyte associated protein 4 (CTLA4) locus on 2q33 are all among the different genetic loci associated with T1D (8).