The C55A Single Nucleotide Polymorphism in CTLA-4 Gene, a New Possible Biomarker in Thyroid Autoimmune Pathology Such as Hashimoto's Thyroiditis.

Hashimoto's thyroiditis (HT) is a chronic autoimmune disorder characterized by the production of autoantibodies against the thyroid gland. Different studies have shown that several genes may be associated with HT, which explains why patients often have family members with thyroiditis or other autoimmune diseases. The aim of this case-control study was to evaluate the correlation between polymorphisms at the level of exon 1 from the CTLA-4 gene and the susceptibility to developing HT. In this study, we found that there is no statistically significant association between the polymorphism rs231775 (A22G in exon 1) of the CTLA-4 gene and a genetic predisposition to HT. In contrast, a strong association was discovered for the first time between C55A in exon 1 of the CTLA-4 gene and HT. Our findings suggest that there is a genetic relationship between the CTLA-4 (+55A/C) genotype and the seropositivity against thyroid autoantigens, such as anti-thyroid peroxidase (ATPO) and anti-thyroglobulin antibodies (ATG).