Definition:

The Dravet syndrome is a rare form of epileptic encephalopathy, and is accompanied by impaired psychomotor and neurologic development, occurring in the first year of life in apparently normal infants. Patients typically present with febrile hemiclonic or generalised tonic-clonic status epilepticus, followed by the development of other seizure types including myoclonic, focal, absence and atonic seizures between 1-4 years. All seizure types are pharmacoresistent, but a trend toward less severe epilepsy and cognitive impairment is usually observed after the age of 5 years. Development is normal in the first year of life with subsequent developmental slowing and sometimes regression. Approximately 80% of patients have point mutations or small insertions or deletions in the SCN1A gene.