An in-depth analysis identifies two new independent signals in 11q23.3 associated with vitiligo in the Chinese Han population.

Background: Vitiligo is an autoimmune disease, characterized by progressive loss of skin pigmentation, which is caused by the interactions of multiple factors, such as heredity, immunity and environment. Recently, a single nucleotide polymorphism (SNP) rs638893 at 11q23.3 region was identified as a risk factor for vitiligo in genome-wide association studies and multiple SNPs in this region have been associated with other autoimmune diseases.

Objective: This study aims to identify additional susceptibility variants associated with vitiligo at 11q23.3 in the Chinese Han population.

Methods: We selected and genotyped 26 SNPs at 11q23.3 in an independent cohort including 2924 cases and 4048 controls using the Sequenom MassArray iPLEX system. Bonferroni adjustment was used for multiple comparisons and P value <1.92×10 (0.05/26) was considered statistically significant.

Results: The A allele of rs613791 and G allele of rs523604 located in CXCR5 were observed to be significantly associated with vitiligo (OR=1.21, 95% CI: 1.11-1.31, P=1.20×10; OR=1.14, 95% CI: 1.07-1.23, P=1.90×10, respectively). The C allele of rs638893 (a previously reported one) located upstream of DDX6 was also significantly associated with vitiligo (OR=1.25, 95% CI: 1.12-1.38, P=3.04×10). The genotypes distribution of 3 SNPs also showed significant differences between case and control (rs613791: P=7.00×10, rs523604: P=4.00×10, rs638893: P=1.20×10, respectively). The two newly identified SNPs (rs613791 and rs523604) showed independent associations with vitiligo by linkage disequilibrium analysis and conditional logistic regression.

Conclusions: The study identified two new independent signals in the associated locus 11q23.3 for vitiligo. The presence of multiple independent variants emphasizes an important role of this region in disease susceptibility.