Association of inducible nitric oxide synthase (iNOS) gene promoter polymorphism with vitiligo susceptibility in Saudis
Vitiligo is an acquired, immune system skin issue described by melanocyte misfortune coming about into dynamic depigmentation of skin and hair. Vitiligo commonly shows familial aggregation and multifactorial mode of inheritance. It is a polygenic disease and several genes related to oxidative stress have been associated with the pathogenesis of vitiligo. The present study was aimed to investigate any possible association of inducible nitric oxide synthase (iNOS) gene polymorphisms (iNOS 954 G/C and iNOS Ex16+14 C/T) with vitiligo in Saudis. This study includes 120 vitiligo cases and 120 healthy matched controls. Polymerase chain reaction with restriction fragment length polymorphism method was used for the analysis of genetic polymorphisms. The heterozygous genotype GC and variant allele-C of iNOS-954 G/C was significantly increased in vitiligo patients (p = 0.001), while the frequency of genotype GG was higher in controls. The frequencies of alleles and genotypes of iNOS-Ex16+14 polymorphism did not differ significantly in patient and control groups. However, when genotype GC of iNOS-954 was co-inherited with genotype CT of iNOS-Ex16+14 C/T, the significant association was observed with vitiligo (p = 0.001). Stratification of genotype and allele frequencies of iNOS-954 G/C and iNOS-EX16+14 C/T between males and females yielded no significant differences. These results indicated that iNOS-954-G/C polymorphism is significantly associated with vitiligo and could be considered as a genetic risk factor for vitiligo susceptibility in Saudis. However, additional studies are warranted using a large number of samples from different ethnicity and geographical areas to strengthen this.