HLA-DRB1 and type 1 diabetes mellitus: Patient populations with a family history of autoimmune disease, genetic loci associated with susceptibility to T1D (e.g. specific combinations of HLA-DRB1, -DQA1, and -DQB1 alleles), or environmental triggers such as heavy metal exposure or certain viral infections are at higher risk for development of disease-associated auto-antibodies.