SCN1A and migraine disorder: Familial hemiplegic migraine (FHM) is a rare autosomal dominant subtype of migraine associated with genetic lesions in three genes, FHM1 encoding the α1 subunit of the voltage-gated Ca2+ channel CACNA1A, FHM2 encoding the α2 subunit of the Na+,K+-ATPase ATP1A2, and FHM3 encoding the α1 subunit of the voltage-gated Na+ channel SCN1A [2].