The causative gene for EA5 (OMIM: 613855, ORPHA:211067) is calcium voltage-gated channel auxiliary subunit beta 4 (CACNB4) gene located on chromosome 2q23.2 and encoding voltage-dependent L-type calcium channel subunit beta-4 (CACNA4β4) protein. This evidence concerns the gene CACNB4 and episodic ataxia type 5.