Furthermore, it has been suggested that MMMP-2 plasma concentrations are higher in migraine with aura than in migraine without aura (Gonçalves et al., 2013) and increased MMP-9 activity has been reported in women with migraine without aura (Martins-Oliveira et al., 2012), suggesting that distinct mechanisms are involved in each form of migraine. This evidence concerns the gene MMP9 and migraine disorder.