SCN1A and familial hemiplegic migraine: While this form of migraine is not a focus of this review, it is worth mentioning that mutations in the CACNA1A gene, ATP1A2 gene and SCN1A gene lead to the three forms of FHM, respectively, i.e., FHM1, FHM2 and FHM3 (Tottene et al., 2002; De Fusco et al., 2003; Carreño et al., 2013).