Online ISSN: 2515-8260

Vitamin-D Receptor (VDR) Gene Polymorphisms (FokI and TaqI) in Patients with Hashimoto's thyroiditis of Iraqi Population

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Wajdy Jabbar Majid1 , Abdul Hussein Alwan Algenabi2 , Alaa Abood Alwadees3


ABSTRACT Background: Hashimoto's thyroiditis is a multifactorial disease in which different environmental factors may trigger the already carried genetic susceptibility in affected individuals. One of the involved theories in the progression of autoimmune disorders is the impairment of immunomodulatory activities of vitamin D or its receptors. The gene polymorphism of vitamin D receptor was reported as an associate of numerous autoimmune diseases including Addison's disease or type I diabetes mellitus. The association between vitamin D receptor gene (VDR) polymorphisms and risk of Hashimoto's thyroiditis was not analyzed in our community yet. Methods: A case-control study was conducted on 182 Hashimoto's thyroiditis patients visiting the Al-Hussein teaching hospital in Al-Nasiriah city and Al-Sadder medical city in Al-Najaf in addition to 200 healthy individuals as a control group. Serum vitamin D3, FT3, FT4, TSH, anti-TG and anti TPO concentrations were determined by Electrochemiluminescence methods using Cobas e411 from Roche Company. The genotyping of VDR gene (TaqI and FokI) was achieved by PCR-RFLP method in all participants. Results: Dominant homozygous genotype (FF) were significantly higher in the Hashimoto's thyroiditis patients compared with those of the control group (OR= 2.22; P=0.0002), while the OR for the heterozygous Ff genotype (0.63; p=0.029) and recessive homozygous ff genotype were (0.40; p=0.017) suggesting that the individuals carrying homozygous dominant FF genotype were two times more susceptible for development of Hashimoto's thyroiditis than individuals carrying the ff or Ff genotypes which were more protective from disease. In addition, results regarding VDR-TaqI polymorphism showed that individuals carrying dominant homozygous TT genotype or T allele have higher risks to develop Hashimoto's thyroiditis (OR= 2.64 and OR=1.78 respectively). Conclusion: The current study data of VDR gene polymorphisms suggesting that Iraqi individuals carrying dominant homozygous FF of rs2228570 SNP and dominant homozygous TT of rs731236 SNP were more susceptible for development of Hashimoto's thyroiditis while individuals carrying the ff homozygous or Ff heterozygous of rs2228570 SNP and heterozygous Tt of rs731236 SNP were more protective from disease. However, such associations were not related to vitamin D status of the studied Hashimoto's thyroiditis population.

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