Episodic Ataxia 1 (EA1) is an autosomal dominant inherited form of ataxia caused by genetic variation in the human KCNA1 gene, which encodes the KCNA1 (Kv1.1) voltage-gated potassium (Kv) channel (1). The gene discussed is KCNA1; the disease is episodic ataxia type 1.