Familial aggregation and genome-wide association studies established that the genomic region located on chromosome 6p21 harboring the Human Leukocyte Antigen (HLA) class II genes, mainly DRB1, DQA1 and DQB1 accounts for about half of the T1D genetic risk (3, 4). Here, HLA-DRB1 is linked to type 1 diabetes mellitus.