Association of Dopamine D2 Receptor (DRD2) C939T and a Lack of Association of Tumor Necrosis Factor-β (TNF-β) +A252G Polymorphisms with Susceptibility to Migraine in A Northern Iranian Population

Genetic factors including TNF-β and DRD2 have been considered as essential components in the etiology of migraine. Several studies have investigated the association between TNF-β +A252G or DRD2 C939T polymorphisms and migraine risk, with debatable results. We aimed to examine whether TNF-β +A252G and DRD2 C939T polymorphisms confer genetic susceptibility to migraine in a Northern Iranian case-control sample. In total, 151 migraineurs (105 with MO 46 with MA) and 144 healthy control subjects were included in this study. Genotyping of the two SNPs, rs6275 DRD2 and rs909253 TNF-β, was determined by PCR-RFLP. The RNA secondary structure was predicted using the RNAfold web server online software. Considering the distribution of genotypes and allelic frequencies between the patient and control groups, no significant difference was detected in genotype and allele frequencies for the rs909253 nucleotide polymorphism. In contrast, the DRD2 C939T polymorphism in an over dominant model significantly (P = 0.002) contributed to increased risk of migraine susceptibility, with its dominant model (P = 0.005) decreasing the risk of migraine. Our case-control study supports a protective effect of the variant genotype CC and allele C of rs6275 DRD2 SNP against migraine, while demonstrating a lack of involvement of TNF-β +A252G in susceptibility to migraine.