CACNA1A and episodic ataxia type 2: Mutations in CACNA1A, which encodes Cav2.1, the α1A subunit of the P/Q-type voltage-gated Ca2+ channel, cause three neurological channelopathies: FHM type 1, EA type 2 (EA2), and spinocerebellar ataxia type 6 (30).