CTLA4 and Hashimoto thyroiditis: Furthermore logistic regression analysis showed that, when adjusted for age and gender, AG and GG genotype of Exon 1 +49A/G polymorphism of CTLA4 gene increase the risk of autoimmune hypothyroidism by 4.319 fold (95% CI: 1.408 to 13.249, p = 0.011) and 4.309 fold (95% CI: 1.102 to 16.855, p = 0.036) respectively (Table 2).