Mutations such as truncations or missense mutations in the SCN1A gene, which encodes the αsubunit of the Nav1.1 channel, can lead to Dravet syndrome (25), SCN1A mutations are frequently associated with a spectrum of clinical manifestations, including epilepsy, autism, and intellectual disability. The gene discussed is SCN1A; the disease is encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.