This is most clearly demonstrated by the fact that clinical approved sodium channel blockers are contraindicated in treatment of seizures associated with Dravet syndrome (Horn et al., 1986; Guerrini et al., 1998; Brunklaus et al., 2012), a condition believed to be due to a reduction in Nav1.1 current. The gene discussed is SCN1A; the disease is encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.