Episodic ataxia type 5 (EA5) is an extremely rare form of Hereditary episodic ataxia characterized by recurrent episodes of vertigo and ataxia lasting several hours. The disease is Monarch Disease Ontology term MONDO_0013464 (episodic ataxia type 5). Also known as: CACNB4 hereditary episodic ataxia, hereditary episodic ataxia caused by mutation in CACNB4.