From genes to goiters: Autoimmune thyroiditis and rs225014 in Bengal’s mountain belt

Background: Hypothyroidism is very common in the sub-Himalayan population of West Bengal, India. Although iodine deficiency is one of the major causes, the rate of autoimmune thyroiditis is also increasing. The different genetic polymorphisms of Deiodinase gene and its relation to autoimmune thyroiditis are not extensively studied. This study tries to fill the gap and find out whether there is any predisposition of De-iodinase gene polymorphism in hypothyroid patients of sub-Himalayan population of West Bengal. Aims and Objectives: The aim and objective of this study are to find out the possible relationship of anti-thyroid peroxidase (TPO) antibody (Ab) level, Deiodinase gene polymorphism, and thyroid hormones (freeT4, thyroid-stimulating hormone [TSH]) in hypothyroid patients of sub-Himalayan population. Materials and Methods: This institution-based observational cross-sectional study conducted in the Department of Biochemistry at North Bengal Medical College and Hospital included 55 hypothyroid patients and 53 age and sex matched healthy control subjects. The serum level of TSH and free T4 was determined by Chemiluminescent immunoassay method, and anti-TPO Ab estimation by the Sandwich enzyme-linked immunosorbent assay method. Deiodinase gene polymorphism (rs225014) has been studied by polymerase chain reaction-restriction fragment length polymorphism method. Results: Anti-TPO Ab levels in hypothyroid patients were found to be significantly higher (P<0.05) than in the control subjects. A significant positive correlation (P<0.05) was also found between the anti-TPO Ab and TSH levels among the hypothyroid patients. Relative prevalence of the three polymorphic forms of Deiodinase gene (rs225014) is being reported in this population for the 1st time, though no statistically significant relationship with Hypothyroidism was found. Conclusion: This study shows a high prevalence of autoimmune thyroiditis in hypothyroid patients in the studied population. Prevalence of the allelic forms of Deiodinase gene is studied in this population for the 1st time by the present study.