HLA-DRB1 and type 1 diabetes mellitus: The present study showed that the most frequently observed alleles in patients with T1D were from locus HLA-DRB1, DRB1*01, DRB1*03, DRB1*04, DRB1* 09, and for the locus HLA-DQB1, -DQB1*02 and -DQB1*03.