CACNA1A and Familial paroxysmal ataxia: Episodic ataxia type 2 (EA2) is an autosomal dominant disorder caused by mutations in theCACNA1A gene, which encodes the α1A subunit of the presynaptic P/Q-typecalcium channel Cav2.1 (Gancher and Nutt,1986; Ophoff et al.,1996).