TNF and migraine disorder: In a similar study from Iran, Mazaheri et al. [157] found that MO patients had a higher frequency of the −308 A allele than the control subjects (40.6% versus 22.3%, OR: 3.73, confidence interval: [95% CI 2.4–5.82], p < 0.0001), and thus suggest that TNF or a locus in linkage disequilibrium (LD) with TNF could be involved in the risk of migraine.