Many epilepsy patients with hemizygous NaV1.1 loss of function display ataxia and motor delays and deficiencies (Claes et al., 2001; Fujiwara et al., 2003), which has traditionally been attributed to loss of NaV1.1 function in the brain, namely, the cerebellum (Kalume et al., 2007). This evidence concerns the gene SCN1A and Ataxia.