For example, two well-studied channelopathies—episodic ataxia type 2 (EA2) and familial hemiplegic migraine type 1 (FHM1)—arise from point mutations in the CACNA1A gene that encodes the α1A subunit (Jen et al., 2007; Pietrobon, 2007, 2010). Here, CACNA1A is linked to familial or sporadic hemiplegic migraine.