CACNA1A and Ataxia: Two knockin mouse models carry mutations (S218L in the CaV2.1 channel [56] and G301R in the α2 Na/K ATPase [58]) which cause more severe FHM attacks that may include, in addition to hemiplegic migraine, prolonged coma/torpor or confusional state, epileptic seizures, elevated temperature, cerebral edema, and may also cause transient or permanent cerebellar signs such as ataxia, nystagmus and cerebellar atrophy [63, 64].