Episodic ataxia (EA) is associated with SCA, and mutations in calcium channel genes may lead to EA; for example, mutations in CACNA1A and CACNB4 lead to EA2 (MIM: 108500) and EA5 (MIM: 613855), respectively [13, 14]. The gene discussed is CACNB4; the disease is autosomal dominant cerebellar ataxia.