TNF-alpha G/A308 polymorphism association with nasal polyposis in North part of Iran.

Nasal Polyposis (NP) is a complex multi-factorial disease; associated with several environmental, genetic and inflammatory factors. TNF-alpha is one of the major pro-inflammatory cytokines involved in NP pathogenesis. Some of the polymorphisms of this gene affect its expression. Therefore, the aim of this study was to evaluate the polymorphism of TNF-alpha G/A308 gene and its association with nasal polyposis in north part of Iran. In this case-control study, 60 patients with NP and 75 healthy individuals referred to Guilan University hospital were evaluated. After DNA extraction, RFLP-PCR was used to determine polymorphism. Chi-square test was used to compare the frequency distribution of genotype and alleles of TNF-alpha gene with NP. The frequency of genotype G/G, A/A and G/A in the NP group was 46.7, 10.0 and 43.3%, and in the control group was 65.3, 5.3 and 29.3%, respectively. There was a statistically significant difference between genotype G/G in two groups (P = 0.006, OR 2.58, CI 1.27-5.23). In addition, the frequency of allele A in patients and controls was 31.7 and 20%, respectively; and this difference was statistically significant (p = 0.02). The findings of this study demonstrated that polymorphism in TNF-alpha gene might be a risk factor for NP in north part of Iran and the minor frequency of G308A allele in the current study is slightly more than other major populations. However, more investigations with high number of population are necessary in future.