TNF-α gene polymorphism in Iranian Azeri population

Abstract

BackgroundTumor necrosis factor (TNF-α) is one of the major cytokines in the immune system that plays a major role in the inflammation in the body. The single nucleotide polymorphism (SNP) in the gene of this cytokine at position −308A/G that occurs in the promoter affects its expression level and subsequently predisposes to some malignancies and diseases. This study was conducted to investigate the TNF-α gene polymorphism at position −308A/G in the Azeri population. Material and methodsBlood samples were collected from 240 healthy and non-relevant Azeri individuals. After DNA extraction, the frequency of TNF-α gene genotypes and alleles at -308A/G was determined by allele specific-PCR method. Then comparisons between allele frequencies and TNF-α genotypes with other populations were performed using chi-square test and P value of <0.05 was considered significant. ResultsThe frequency percentage of GG, AG and AA genotypes in TNF-α cytokines at -308A/G in Azeri population was 70.8%, 26.7% and 2.5%, respectively. The frequency percentage of G and A alleles were 84.2% and 15.8%, respectively. The occurrence of TNF-α allele A at -308A/G is associated with high expression of this cytokine. ConclusionThe frequency of AA genotype was much lower than the other two genotypes, with low prevalence observed in other populations, which had a significant association with many diseases and even cancer; therefore, there was no significant difference with most studies examining the polymorphism of this cytokine in the same position.