Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 56 8 2018 11 26 508 515 EN Amir Hossein Faghfouri Department of Nutrition, Urmia University of Medical Sciences, Urmia, Iran. Morteza Bagheri Department of Genetics, Cellular and Molecular Research Center, Urmia University of Medical Sciences, Urmia, Iran. Alireza Mehdizadeh Department of Endocrinology, Urmia University of Medical Sciences, Urmia, Iran. Parvin Ayremlou Department of Epidemiology, Clinical Researches Development Unit, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, Iran. Rasoul Zarrin Department of Nutrition, Urmia University of Medical Sciences, Urmia, Iran. 2017 11 29 2018 03 13 The Autoimmune thyroid diseases (AITDs) are among the most common endocrine disorders. Vitamin D as an immunomodulator and Vitamin D receptor (VDR) gene polymorphisms may be effective in AITDs pathogenesis. The aim of this study was to evaluate the vitamin D level and VDR BsmI and TaqI polymorphisms in Iranian Azeri Turkish patients with AITDs. This case-control study included 121 adults with AITDs and 117 non-AITDs controls. Serum level of 25-hydroxyvitamin D was measured by electrochemiluminescence (ECL) immunoassay. BsmI and TaqI polymorphisms were assessed by polymerase chain reaction fragment length polymorphism technique. The serum level of 25-hydroxyvitamin D in AITDs patients were lower than controls (P=0.03). The frequencies of TT, TC, CC, T and C genotypes/alleles at TaqI (rs731236) marker were 52.1%, 34.7%, 13.2% , 69.4% and 30.6% in AITDs and 44.4%, 41.9%, 13.7%, 65.4% and 34.6% in controls, respectively. The frequencies of AA, AG, GG, A and G genotypes/alleles at BsmI (rs1544410) marker were 14%, 64.5%, 21.5% , 46.3% and 53.7% in AITDs and 26.5%, 58.1%, 15.4%, 55.6% and 44.4% in controls, respectively. BsmI (rs1544410) GG+AG genotypes and G allele were more frequent among patients with Hashimoto compared with control group (86.6% vs. 73.5% (OR: 2.34, 95% CI: 1.16-4.70, P = 0.014) and 54.29% vs. 44.44% (OR: 1.48, 95% CI: 1.02-2.15, P = 0.038), respectively). Vitamin D status can be related to AITDs pathogenesis. BsmI (rs1544410) GG+AG genotypes and G allele may play an important role in the predisposition to Hashimoto.  https://acta.tums.ac.ir/index.php/acta/article/view/6865 https://acta.tums.ac.ir/index.php/acta/article/download/6865/5137