The Impact of Five VDR Polymorphisms on Multiple Sclerosis Risk and Progression: a Case-Control and Genotype-Phenotype Study

Vitamin D receptor polymorphisms have been the target of many studies focusing on multiple sclerosis. However, previously reported results have been inconclusive. The objective of this study was to investigate the association between five vitamin D receptor polymorphisms (EcoRV, FokI, ApaI, TaqI, and BsmI) and multiple sclerosis susceptibility and its course. The study was carried out as a case-control and genotype-phenotype study, consisted of 296 Czech multiple sclerosis patients and 135 healthy controls. Genotyping was carried out using polymerase chain reaction and restriction analysis. In multiple sclerosis men, allele and/or genotype distributions differed in EcoRV, TaqI, BsmI, and ApaI polymorphisms as compared to controls (EcoRV, p_a = 0.02; Taq, p_g = 0.02, p_a = 0.02; BsmI, p_g = 0.02, p_a = 0.04; ApaI, p_g = 0.008, p_a = 0.005). In multiple sclerosis women, differences in the frequency of alleles and genotypes were found to be significant in ApaI (controls vs multiple sclerosis women: p_g = 0.01, p_a = 0.05). Conclusive results were observed between multiple sclerosis women in the case of EcoRV differences in Expanded Disability Status Scale (p = 0.05); CT genotype was found to increase the risk of primary progressive multiple sclerosis 5.5 times (CT vs CC+TT p_corr = 0.01, sensitivity 0.833, specificity 0.525, power test 0.823)] and FokI borderline difference in Multiple Sclerosis Severity Score (p = 0.05)]. Our results indicate that the distribution of investigated vitamin D receptor polymorphisms is a risk factor for multiple sclerosis susceptibility and progression in the Czech population. The association between disease risk and polymorphisms was found to be stronger in men. The association of disease progression with polymorphisms was observed only in women.