“…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 ]. After contacting the authors of these papers, we obtained complete data for one study [ 35 ]. Among the eight papers discussing NOS3 +894G>T, six reported genotype and allele frequencies for all participants and for overall migraine as well as those stratified by aura [ 33 , 38 , 49 – 51 , 53 ], while the remaining two did not [ 27 , 47 ].…”