Dravet syndrome is a type of developmental epileptic encephalopathy (DEE), which typically begins in the first year of life with a febrile hemi-clonic seizure. This later progresses to more frequent, prolonged afebrile seizure types including focal and generalized clonic, myoclonic, and atypical absence seizures that are refractory to treatment. Within a year of seizure onset, developmental delay becomes evident and the child eventually shows profound cognitive and behavioral deficits. Because of frequent convulsive seizures, the patients with Dravet syndrome have a much higher risk of sudden unexpected death in epilepsy (SUDEP) at ~9.3 per 1000 patient-years, which is almost the same as adults with drug-resistant epilepsy. In fact, the most common cause of death in Dravet syndrome is SUDEP.