Analysis of vitamin D receptor gene (VDR) polymorphisms in Turner syndrome patients

Abstract

Individuals with Turner syndrome (TS) have increased risk for autoimmune diseases, especially thyroid abnormalities. The function of the vitamin D receptor (VDR) gene is influenced by several genetic polymorphisms which are associated with a susceptibility to a range of autoimmune diseases. Thus, we have hypothesized a possible relationship between thyroid abnormalities and VDR polymorphisms (ApaI/G1025-49T, TaqI/T1056C, FokI/T2C and BsmI G1024 + 283A) in TS patients. A case-control study was performed comprising 101 Brazilian women with TS and a control group consisting of 133 healthy fertile women without a history of autoimmune diseases. In TS group, 21.8% had Hashimoto’s thyroiditis. Detection of VDR polymorphisms was performed using TaqMan system by real-time PCR. The χ² was used to compare allele and genotype frequencies between groups. Combined genotypes of VDR gene polymorphisms were assessed by the haplotype analysis. A p value <0.05 was considered statistically significant. Relatively similar VDR polymorphisms genotype and allelic frequencies in cases and controls were found, even when only considering the patients with thyroid abnormalities. Haplotype analysis showed that none of the VDR haplotypes were associated to thyroid diseases in TS patients. In conclusion, the results showed no association between VDR gene polymorphisms and thyroid abnormalities in Brazilian TS patients tested.

Keywords::

• Autoimmune disease
• gene VDR
• polymorphism
• thyroid
• Turner syndrome

Acknowledgements

The authors wish to thank FAPESP (Fundação de Amparo a Pesquisa do Estado de São Paulo) for grants No. 2009/05250-0 and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for granting student Bianca Bianco a post-doctoral scholarship.

Declaration of interest: The authors declare no conflicts of interest.