CACNA1A and migraine, familial hemiplegic, 1: Since the end of the 1990s, three autosomal dominant disorders are associated with mutations in CACNA1A, the gene that encodes the Cav2.1 subunit: Episodic Ataxia type 2 (EA2, OMIM #108500), Familial Hemiplegic Migraine type 1 (FHM1, OMIM #141500) and Spinocerebellar Ataxia type 6 (SCA6, OMIM #183086) [16].