الفهرس 
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Abstract
Vitiligo is a progressive depigmenting disorder characterized by the loss of functional melanocytes from the epidermis, affecting 1–2% of the population worldwide. One of the major hypotheses in the pathogenesis of vitiligo is the oxidative stress hypothesis, which is based on the reality of the formation of some toxic metabolites during melanin biosynthesis. Hydrogen peroxide formed at the end of all these alterations gives rise to the destruction of melanocytes.The genes coding for paraoxonase enzymes are located adjacent to each other on the long arm of chromosome 7. The polymorphisms found in the PON1 gene and the interaction of the PON1 gene with other factors, may contribute to differences in activity levels and individual’s risk for disease development.The purpose of that work was to investigate the association between the genetic polymorphism at L55M (Rs 854560) and vitiligo in Egyptian patients.This study included two groups; patients group included 100 patients with vitiligo and control group included 50 healthy age and sex matched individuals. All patients were subjected to history taking and clinical examination to assess the site and extent of vitiligo.Results of the present study showed that AA and AT genotypes and A allele increase the risk of vitiligo development. There was significant higher incidence of stress as a provocative factor in patients with AA and AT genotypes and in A allele.