Association of Proinflammatory 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 proinflammatory cytokines like tumor necrosis factor (TNF)α, Interleukin (IL)1, and IL6. This study aims to evaluate genes polymorphism in some proinflammatory cytokines in a group of Iranian MD patients compared to the healthy controls. In this casecontrol 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 sequencespecific primers assay. MD patients and controls were examined in terms of allele, genotype, and haplotype frequency of proinflammatory cytokine genes. Only the frequencies of alleles A/G at position 238 in the promoter of the TNFα 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 TNFα gene promoter sequence. In addition, the heterozygote AG variant of 238 A/G TNFα 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 proinflammatory cytokine genes in an Iranian MD sample. This study shows the association between TNFα and susceptibility to MD.