In addition to mutations in the SCN8A gene, non-genetic modifications in Nav1.6 expression and function may also contribute to excitability disorders, such as neuropathic pain [31,118,119], autism-spectrum disorders [106,120], ischemia [121], and stress-induced disorders [122,123] in addition to epilepsy [12,27,124]. The gene discussed is SCN8A; the disease is epilepsy.