association of pro-inflammatory cytokine gene polymorphism with meniere’s disease in an iranian sample

Meniere’s disease (md) is known as a rare chronic disorder of the inner ear with elevated serum levels of pro-inflammatory cytokines like tumor necrosis factor (tnf)-α, interleukin (il)- 1, and il-6. this study aims to evaluate genes polymorphism in some pro-inflammatory cytokines in a group of iranian md patients compared to the healthy controls. in this case-control study, 25 md patients and 139 healthy controls were enrolled. dna was extracted from blood samples, and single nucleotide polymorphisms were detected using polymerase chain reaction with sequence-specific primers assay. md patients and controls were examined in terms of allele, genotype, and haplotype frequency of pro-inflammatory cytokine genes. only the frequencies of alleles a/g at position -238 in the promoter of the tnf-α gene differed significantly between md patients and healthy controls. g to a allele ratio was 23 and 3.6 in md and controls, respectively. in individuals with md, genotype gg was found to be significantly more prevalent at position -238 of the tnf-α gene promoter sequence. in addition, the heterozygote ag variant of -238 a/g tnf-α gene polymorphism was lower in md patients than controls. compared to the control group, the haplotype tnf- (-308, -238) ag was higher in md patients, although not statistically significant. this is the first study that we know of that evaluates the frequencies of pro-inflammatory cytokine genes in an iranian md sample. this study shows the association between tnf-α and susceptibility to md.