Glutathione S-transferase M1 and T1 genetic polymorphism in Egyptian patients with nonsegmental vitiligo.

Oxidative stress and accumulation of free radicals might play a role in the pathogenesis of vitiligo. Glutathione S-transferase (GST) is a multigene family of enzymes that detoxify oxidative stress products. In this study, genotyping by multiplex PCR of GSTM1 and GSTT1 in 101 women with nonsegmental vitiligo vulgaris and 101 age-matched healthy female volunteers showed that only the GSTM1 null genotype (P=0.04) was significantly overexpressed in patients with vitiligo. Analysis of the combined effect of GSTM1 and GSTT1 genotyping identified a significant association of risk for vitiligo with the GSTT1/GSTM1 double-null type only (P=0.01; OR=2.69; 95% CI 1.12-6.46). Age of onset of vitiligo was significantly earlier in patients with the T1 null genotype (P<0.01) and those with the T1-/M1+ and T1-/M1- combined genotypes (P<0.01 and P=0.01, respectively). In conclusion, the GSTM1 gene and the GSTM1/GSTT1 double-null genotype may be a risk factor for vitiligo in Egyptian patients. Inability to cope with oxidative stresses because of GST deficiency may cause early disease onset.