The Role of Vitamin D Receptor Gene Polymorphisms in Thyroid-Associated Orbitopathy

Purpose: Thyroid-associated orbitopathy (TAO) is an autoimmune disease that typically occurs in the course of Graves' disease. VDR gene has been tested for its association with autoimmune thyroid diseases, with conflicting results. The study aimed to evaluate the association of selected VDR polymorphisms (rs2228570, rs1544410, rs7975232, rs731236, and rs11568820) with susceptibility to TAO. Methods: 108 TAO patients and 130 control subjects were enrolled. Polymorphisms were studied by PCR-RFLP or TaqMan real-time PCR. Results: Genotype distributions of rs2228570 differed significantly between TAO and controls under a dominant model (OR = 2.05; 95% CI: 1.03-4.08; p = .04). TAO patients also had slightly increased frequency of C allele of rs2228570 comparing to controls (p = .05). However, the study failed to find any associations between VDR polymorphisms and the analyzed clinical features of the disease. Conclusions: These preliminary results have shown that C allele of rs2228570 may contribute to the development of TAO in patients of Caucasian Polish origin.