episodic ataxia type 2 true true 2015-10-06T16:26:26Z OMIM:108500 lschriml EA2 is characterised by periods of cerebellar ataxia lasting minutes to hours, which are triggered by physical and emotional stress. Gait and upper limb ataxia may be accompanied by dysarthria, nystagmus, vertigo, nausea and headache. EA2 can be distinguished from seizures by recognition of triggers, family history and retention of awareness during events. EA2 is associated with mutations in the calcium ion channel gene CACNA1A. Variants in this gene are associated with familial hemiplegic migraine and spinocerebellar ataxia type 6 and some phenotypic overlap with these disorders may occur. There may be gaze-evoked nystagmus in between episodes and over time vertical nystagmus may develop. https://www.ncbi.nlm.nih.gov/pubmed/27025991 disease_ontology DOID:0050990 An episodic ataxia that is characterized by periodic ataxia and nystagmus, and has_material_basis_in autosomal dominant inheritance of mutation in the calcium channel gene CACNA1A. episodic ataxia