Analysis of Vitamin D Receptor Gene Polymorphisms in Vitiligo

Abstract

<b><i>Background:</i></b> Vitiligo is a progressive depigmenting disorder characterized by the loss of functional melanocytes from the epidermis. The etiopathogenesis of vitiligo is still unclear. Vitamin D has both stimulatory and protective effects on melanocytes and acts through its nuclear vitamin D receptor (VDR) on target cells. <b><i>Aim:</i></b> The aim of this study was to investigate the association between VDR gene polymorphisms and susceptibility to vitiligo. <b><i>Methods:</i></b> 98 patients with vitiligo and 216 age- and sex-matched controls recruited from dermatology outpatients attending the same department were included in the study. Genomic DNA was extracted from peripheral blood leukocytes using a DNA isolation kit. The VDR polymorphisms of <i>Bsm</i>I, <i>Apa</i>I, <i>Taq</i>I, <i>Fok</i>I and Cdx2 were investigated by rapid capillary PCR with melting curve analysis. Differences in genotype distributions and allele frequencies in vitiligo cases versus controls were compared for statistical significance using χ<sup>2</sup> test. <b><i>Results:</i></b> Subjects with <i>Taq</i>I polymorphism had a 2.23-fold increased risk of developing vitiligo. Furthermore, a haplotype analysis showed that <i>Bsm</i>I/<i>Apa</i>I/<i>Taq</i>I/<i>Fok</i>I/Cdx2 GCCCG was<b> </b>significantly overrepresented in the vitiligo patients in comparison with controls (p = 0.031). <b><i>Conclusion:</i></b> This study showed that VDR <i>Taq</i>I gene polymorphism and the haplotype <i>Bsm</i>I/<i>Apa</i>I/ <i>Taq</i>I/<i>Fok</i>I/Cdx2 GCCCG may be considered as novel risk factors in vitiligo.