DNA purification, genotyping, and quality-control procedures are described in the Supplementary Appendix. In the genomewide association study, we determined the genotypes of patients with vitiligo for approximately 610,000 markers by using the Illumina 610-Quad BeadChip. All mitochondrial markers and Y-chromosome markers were excluded, leaving 579,146 SNPs that were present in both patients and controls in the genomewide association data set. Genotype data were then subjected to extensive quality-control filtering. In the two replication studies, genotyping of the SNPs that showed genomewide significance (P<5×10−8) or near significance in the genomewide association study was performed with the use of the Sequenom MassArray iPLEX genotyping system. We also imputed genotypes for rs12206499, which is related to major-histocompatibility-complex (MHC) class I molecules and for technical reasons could not be genotyped, and genotyped several SNPs in the NLRP1 (NLR family, pyrin domain–containing 1 gene) region, which was previously shown to be associated with vitiligo (see the Supplementary Appendix).