HLA-DQA1 and type 1 diabetes mellitus: Integrating susceptible and resistant DQ residues, the current investigation was to explore their genotypic associations with T1D, especially, assessing heterodimeric associations with DQA1 and DQB1 alleles on the same chromosome (cis) and between homologous chromosomes (trans), with specific focus on the DQ2.5 and DQ8.1 haplotypes.