Prevalence of Bsml polymorphism (rs1544410) of the VDR gene’s genotypic and allelic variants in patients with autoimmune thyroiditis

Abstract

BACKGROUND: The most common among AITD is autoimmune thyroiditis (AIT), also known as Hashimoto's thyroiditis. This disease arises from a complex interaction of genetic predisposition and environmental factors.
OBJECTIVE: To assess the impact of allelic and genotypic variants of the VDR gene polymorphism BsmI (rs1544410) on thyroid function in patients with autoimmune thyroiditis.
MATERIALS AND METHODS: The study included 139 patients diagnosed with autoimmune thyroiditis, aged 20 to 44 years, who sought consultative care at the outpatient clinic of the 3rd clinic of Tashkent Medical Academy. Among them, 109 (78.4%) were women with an average age of 34.3±6.4 years, and 30 (21.6%) were men with an average age of 36.8±5.6 years. The control group consisted of 47 individuals with a mean age of 35.6±4.4 years. Serum concentrations of vitamin D – 25(OH)D, anti-thyroglobulin antibodies, anti-thyroid peroxidase antibodies, free thyroxine, free triiodothyronine, and thyroid-stimulating hormone were assessed.
RESULTS: In our study, a trend can be observed that the A allele has a predisposing effect on the development of autoimmune thyroiditis, reaching statistical significance (χ2=19.8; p=0.01), particularly in the development of euthyroidism, subclinical, and manifest hypothyroidism. As for the G allele, statistical data (χ2=19.8; p=0.01) indicate a protective effect, meaning that the G allele has a protective role against autoimmune thyroiditis, particularly in the development of euthyroidism, subclinical, and manifest hypothyroidism.
CONCLUSION: The study results indicated a potential role of the heterozygous A/G genotype in the development of autoimmune thyroiditis. The presence of this genotype significantly increased the risk of the disease by 6.6 times (χ2=11.5; p=0.01; RR=4.9; 95% CI: 3.76-6.28; OR=6.6; 95% CI: 2.22-19.64). Additionally, the presence of the heterozygous A/G genotype increased the risk of autoimmune thyroiditis with euthyroidism more than sixfold and the risk of developing subclinical hypothyroidism more than eightfold. Moreover, the most functionally favorable G/G genotype was more common in the control group, indicating a low probability of its association with the studied disease (χ2=17.9; p=0.01).

KEYWORDS

Manifest hypothyroidism, subclinical hypothyroidism, autoimmune thyroiditis, genotypic and allelic variants, polymorphism of BsmI (rs1544410) VDR gene.