Familial hemiplegic migraine (FHM) is a rare monogenic form of migraine with aura including motor weakness [1], and three FHM causative genes have been identified: CACNA1A (coding for the α1a subunit of the CaV2.1 calcium channel) for the FHM1 [8]; ATP1A2 (coding for the α2 subunit of Na,K‐ATPase) for the FHM2 [9]; and SCN1A (coding for the α subunit of the NaV1.1 sodium channel) for the FHM3 [10]. The gene discussed is CACNA1A; the disease is familial hemiplegic migraine.