Polymorphisms in the melanocortin-1 receptor (MC1R) and agouti signaling protein (ASIP) genes in Korean vitiligo patients

We have examined the frequency of SNP polymorphisms within the melanocortin-1 receptor (MC1R) and agouti signaling protein (ASIP) genes in 114 Korean vitiligo patients and 111 normal controls to assess the association of these loci with vitiligo risk. Using direct sequencing techniques, we found the following five MC1R coding region SNPs: Arg67Gln (G200A), Val92Met (G274A), Ile120Thr (T359C), Arg160Arg (C478A), and Gln163Arg (A488G). Of these, the most common were Val92Met at 14% in patients vs. 9% in controls (P = 0.17) and Gln163Arg at 17% in patients vs. 17% in controls (P = 0.84). Presence of the A allele of Val92Met (G274A) was higher in vitiligo patients {P = 0.12, odds ratio (OR) [95% confidence interval (CI)] = 1.68 (0.86-3.25)}. The other three variants showed a frequency <5% of both patients and controls. The ASIP 3'UTR genotype (g.8818A-G) was also assessed in the same subjects. The frequency of the G allele of 3'UTR in ASIP was 17% in vitiligo and 12% in controls [P = 0.14, OR (95% CI) = 1.49 (0.87-2.54)]. Carriage of the G allele was higher in vitiligo patients [P = 0.17, OR (95% CI) = 1.50 (0.83-2.72)], and those who also carried MC1R Val92Met were more prone to vitiligo [eight of 111 patients vs. four of 111 in controls, P = 0.14, OR (95% CI) = 2.75 (0.71-8.69)]. None of these associations, however, reached statistical significance.