Role of FOXP3 (rs3761548) Polymorphism in Modulating FOXP3 Protein Level in Iraqi Patients with Thyroid Disorder

Background: Thyroid disorders are a major clinical concern that negatively impacts the thyroid gland. Thyroid issues have been connected to the FOXP3 gene, which is an important immune system regulator. FOXP3 protein levels can be affected by genetic differences, which may impair regulatory T-cell activity and exacerbate immunological abnormalities. Objectives: To investigate the influence of FOXP3 gene polymorphisms on circulating FOXP3 protein levels and their association with thyroid dysfunction. Methods: This study included 100 patients with thyroid disorders and 50 healthy controls. Thyroid function was assessed by measuring serum T3, T4, and TSH levels using a Cobas analyzer. Serum FOXP3 protein levels were quantified by ELISA. Genomic DNA was extracted and analyzed for FOXP3 gene variations using PCR and sequencing. Results: No significant differences were observed in serum T3 and T4 levels between patients and controls. However, TSH levels were significantly elevated in the patient group. Serum FOXP3 levels were significantly lower in patients compared to controls. The distribution of the three FOXP3 gene genotypes (AA, AC, and CC) did not differ significantly between patients and controls. Individuals with the heterozygous (AC) genotype exhibited significantly higher serum FOXP3 levels compared to the other two genotypes. Conclusions: Individuals with thyroid disorders had reduced levels of FOXP3, which may indicate an association between thyroid disease and impaired immunity. The study emphasizes the complicated interaction of genetic and environmental factors, even if it could not identify an obvious connection with the rs3761548 gene variation.