CACNA1A and Familial paroxysmal ataxia: Mutations in the pore-forming unit of the P/Q-type VGCC (CACNA1A) in humans give rise to the channelopathies familial hemiplegic migraine type 1 (FHM1) and episodic ataxia type 2 (EA2) (Cain and Snutch, 2011).