Mutations in the voltage gated sodium channel subunit SCN1A are found in approximately 80% of patients with DS [50] and mice engineered to heterozygously express a clinically observed truncation mutation in Scn1a (R1407X, hereafter referred to as Scn1a+/-) display rare spontaneous seizures with a normal interictal electroencephalogram [30, 31, 51]. The gene discussed is SCN1A; the disease is Dravet syndrome.