Dravet Syndrome is an epileptic encephalopathy with onset usually during infancy.
Criteria for clinical Dravet syndrome:
(1) normal development before seizure onset
(2) >= 2 seizures before age 12 months
(3) myoclonic, hemiclonic or generalized tonic-clonic seizures
(4) >= 2 seizures lasting > 10 minutes
(5) refractory seizures after the age of 2 years
Additional findings:
(1) seizures may be triggered by a febrile episode, often starting during infancy
(2) seizures may be triggered by a hot water bath
(3) seizures may be triggered by vaccination
(3) sleep problems are common
(4) developmental delays, behavioral problems, ataxia and spasticity may develop
(5) seizures may be exacerbated by some antiepileptic drugs (carbamazepine, lamotrigine)
(6) may show a good response to a ketogenic diet
Most but not all patients will have a mutation in the SCN1A gene (sodium voltage-gated channel alpha subunit 1) at 2q24.3. Some mutations are inherited (autosomal dominant) and some are de novo.
