ATP1A2 and familial hemiplegic migraine: In brief, genes in familial hemiplegic migraine (FHM) (CACNA1A, ATP1A2 and SCN1A) encode subunits of ion transporters (neuronal voltage-gated CaV2.1 Ca2+, NaV1.1 Na+ channels, and glial Na+K+ ATPases, respectively) and functional studies in cellular and animal models suggest neuronal hyperexcitability as a common theme.