Since Kv1.1 channels are widely expressed in the nervous system, particularly in the cerebellum, hippocampus and hypothalamus (Albrecht et al., 1995; Geiger and Jonas, 2000; Herson et al., 2003), it is therefore perhaps not so surprising that EA1 patients exhibit such a variable clinical phenotype (Graves et al., 2010). This evidence concerns the gene KCNA1 and episodic ataxia type 1.