Tumor necrosis factor-α -308G/A polymorphism is associated with active vitiligo vulgaris in a northeastern Mexican population

Abstract

Vitiligo is a skin disease characterized by depigmentation. Its etiopathogenesis is unclear, but it has been associated with autoimmune processes. Gene polymorphisms in the tumor necrosis factor-α (TNF-α) have been associated with several imflammatory diseases. In particular, the -308G/A polymorphism in the gene promoter region has been reported to be associated with increased plasma levels of TNF-α and with an increased risk to develop autoimmune diseases. To date, this polymorphism has not been associated with vitiligo. To assess a possible association between the TNF-α -308G/A and vitiligo vulgaris (VV), 198 vitiligo patients and 395 control subjects were recruited for the study. A complete demographic and clinical profile of each case was registered to analyze the possible risk factors of vitiligo. Genomic DNA isolated from peripheral blood was subjected to PCR-RFLP for genotyping of the TNF-α -308G/A polymorphism. Causal associations were determined by χ 2 test and their respective OR was assessed in a 2x2 contingency table. When population variables of type of vitiligo, gender, age of disease onset, and active disease status were considered, an association between active VV and the TNF-α GA genotype was found (P=0.0295, OR=2.0; 95% CI 1.01-3.93). All other variables were irrelevant to vitiligo. Our data suggest a possible association between the TNF-α -308 GA genotype and the active form of VV in a Mexican population.