The Association between Human Leukocyte Antigen Class II DR3–DQ2 Haplotype and Type 1 Diabetes in Children of the East Azerbaijan State of Iran

BACKGROUND Type 1 diabetes mellitus (T1D) is an autoimmune disease. Several associations between human leukocyte antigen (HLA) complex and T1D were found in various populations. Associations with various HLA types depend on the investigated populations. However, such associations have not yet been investigated in the East Azerbaijan state of Iran with Turkish ethnicity. OBJECTIVES The aims of the current study was to describe T1D genetic susceptibility conferred by HLA class II alleles (DRB1*0301, DQA1*0501 and DQB1*0201) and to determine haplotype frequencies among T1D patients. PATIENTS AND METHODS This study was a case-control study. The number of samples was determined using the Cochran formula. Eighty unrelated T1D patients, including 42 (52.5%) females and 38 (47.5%) males, were randomly recruited from the East Azerbaijan state of Iran. Typing of HLA was performed by polymerase chain reaction-sequence-specific priming (PCR-SSP) on DNA extracted from peripheral blood mononuclear cells of 80 unrelated patients and 80 unrelated healthy control donors, who were selected randomly. For haplotype analysis, the logistic regression model was performed that allows joint estimation of Single-nucleotide polymorphisms (SNPs) via haplotypes. RESULTS The frequency of drb1*0301 (82.5% vs. 11.3%), dqa1*0501 (82.5% vs. 36.3%) and dqb1*0201 (81.3% vs. 35%) were significantly higher among patients compared with that of healthy subjects. CONCLUSIONS Our investigation demonstrated that there is a highly significant association between the studied alleles and T1D. It can be construed that haplotype HLA-DR3-DQ2 has a very modest effect with respect to the risk of T1D.