The familial form, familial hemiplegic migraine (FHM), is usually inherited in an autosomal dominant manner, with pathogenic mutations in three main genes encoding cation transport proteins considered causal: CACNA1A, which encodes the pore-forming subunit of the Cav channel Cav2.1 (Ophoff et al., 1997); SCN1A, which encodes the pore-forming voltage-gated sodium channel Nav1.1; and ATP1A2, encoding the alpha-2 isoform of the Na+/K+-ATPase pump (Russell and Ducros, 2011). This evidence concerns the gene PSMA2 and familial hemiplegic migraine.