Among the 11 papers focusing on TNF –308G>A, 7 [27, 28, 31, 34, 36, 37, 44] reported genotype and allele frequencies for all participants and for overall migraine, as well as stratified by gender and aura; however, the remaining 4 papers did not [26, 30, 35, 45]. This evidence concerns the gene TNF and migraine disorder.