Vitamin D receptor polymorphisms and Parkinson's disease in a Korean population: Revisited

Recently, the effect of genetic variants in the Vitamin D receptor (VDR) gene on Parkinson's disease (PD) has gained interest. However, the precise relationship between VDR polymorphisms and PD remains unclear. In Korea, one study reported an association between VDR gene polymorphisms and PD. However, this study was conducted with a small sample size, and only the Bsml locus was evaluated. Therefore, further investigations about the relationship between VDR polymorphisms and PD are necessary in a Korean population. A total of 300 subjects were included in this study. One hundred and forty-six PD patients were diagnosed according to the United Kingdom Parkinson's Disease Society Brain Bank (UKPDBB) criteria with abnormal dopamine transporter imaging, and 154 healthy control subjects were also enrolled. We used a TaqMan genotyping assay to identify four SNPs of the VDR gene, including BsmI, FokI, ApaI, and TaqI (rs731236, rs2228570, rs7976091, and rs731236). A significant association was not noted between the risk of PD and genetic polymorphisms in the four loci in a Korean population. However, when the genetic variants of the VDR gene were analyzed after adjusting for the serum 25-OH vitamin D3 level, the TaqI and BsmI minor allele increased the risk of PD. Our data suggest no correlation between PD and the VDR polymorphisms, including BsmI, FokI, ApaI, and TaqI, in a Korean population; however, the results should be interpreted carefully because gene-environment interactions may exist. Further investigations of the VDR and its relationship with PD are required to identify the role of vitamin D in the pathogenesis of PD.