Hereditary episodic ataxia (EA) represents a group of neurological disorders characterized by recurrent episodes of ataxia and vertigo which may be progressive. Weakness, dystonia and ataxia are sometimes present in the interictal period. Seven types of EA have been described to date (EA type 1 to EA type 7), but most of the reported cases belong to EA1 and EA2. The disease is Monarch Disease Ontology id MONDO_0016227 (hereditary episodic ataxia). Also known as: episodic ataxia.