HLA DQA1* and HLA-DQB1* alleles and genetic susceptibility to autoimmune thyroiditis in Down syndrome children: An Indonesian study

<b>Objective.</b> The purpose of this study was to investigate the role of the HLA-DQA1 and HLADQB1 alleles in Indonesian children who had autoimmune thyroiditis (AITD) and Down syndrome (DS). <b>Methods.</b> At Dr. Soetomo Hospital, 49 DS-AITD patients and 42 controls participated in a cross-sectional study. Alleles of HLA-DQA1*0103 and HLA-DQB1*0401 were genotyped by PCRRFLP assays. Allelic relationships were assessed by statistical studies. <b>Results.</b> In the DS-AITD group, the HLA-DQA1*0103 and HLA-DQB1*0401 alleles were more frequently found. The HLA-DQB1*0303, *0402, and *0501/0604 alleles, on the other hand, were significantly more common in the control group. While the HLA-DQB1 *0303 (odds ratio [OR]=0.169, 95% confidence interval [CI]: 0.065-0.435, p=0.000) alleles significantly reduced AITD risk, the HLA-DQA1*0103 (OR=3.9, 95% CI: 1.552-9.797, p=0.003), and HLA-DQB1*0401 (OR=4.5, 95% CI: 1.326-15.277, p=0.010) alleles considerably increased AITD risk. <b>Conclusion.</b> HLA-DQA1*0103 and HLA-DQB1*0401 are risk alleles, while HLA-DQB1 *0303 are protective alleles for AITD in children with DS. Further studies are required to obtain more data on Indonesians with DS.