CACNA1A and familial hemiplegic migraine: Different mutations in three genes have been linked to a rare form of migraine called familial hemiplegic migraine (FHM): (a) CACNA1A, provoking a gain of function in a L-type Ca++ channel, (b) ATP1A2, leading to a loss of function of the Na+, K+, -ATPase transporter and (c) SCN1A causing a gain of function of a voltage-gated Na+ channel [11–13].