Migraine clusters in families and is considered to be a strongly heritable disorder. Hemiplegic migraine is a rare subtype of migraine with aura that may occur as a familial or a sporadic condition. Three genes have been identified studying families with familial hemiplegic migraine (FHM). The first FHM gene that was identified is CACNA1A. A second gene, FHM2, has been mapped to chromosome 1 q 21-23. The defect is a new mutation in the α2 subunit of the Na/K pump (ATP1A2). A third gene (FHM3) has been linked to chromosome 2q24. It is due to a missense mutation in gene SCN1A (Gln1489Lys), which encodes an α1 subunit of a neuronal voltage-gated Na+ channel. Genome-wide association studies have identified many non-coding variants associated with common diseases and traits, like migraine. These variants are concentrated in regulatory DNA marked by deoxyribonuclease I hypersensitive sites. A role has been suggested for the two-pore domain potassium channel, TWIK-related spinal cord potassium channel. TWIK-related spinal cord potassium channel is involved in migraine by screening the KCNK18 gene in subjects diagnosed with migraine.