Abstract
Hashimoto's thyroiditis (HT) is a chronic inflammation of the thyroid gland and is known as the most common autoimmune disease. Development of autoimmune destruction of thyroid cells is a multi-step process involving convergence of genetic and environmental factors. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) has an important role in homeostasis and negative regulation of immune responses, and is therefore considered to be a key element in the development of autoimmune diseases. The present study evaluated the association of the CTLA-4 gene polymorphisms 318C/T (rs5742909) and +49A/G (rs231775) with HT in an Iranian population (including 82 patients with HT and 104 healthy controls who were referred for routine premarital blood screenings). Genotyping was performed using the tetra-primer amplification refractory mutation system polymerase chain reaction technique. No significant differences were observed in genotype and allele frequencies in the single nucleotide polymorphisms (SNPs) between cases and controls. In the cases as well as in the controls, the TT genotype in the -318C/T polymorphism was absent and the predominant genotype was CC, while the predominant genotype for the +49A/G SNP was AA. As only few studies in this field have assessed Iranian and even Middle Eastern populations, additional studies with a higher number of samples are recommended to further assess the impact of -318C/T (rs5742909) and +49A/G (rs231775) polymorphisms of CTLA-4 on HT.