Dravet Syndrome: Diagnosis and Long-Term Course.
Dravet syndrome is one of the most severe epilepsy syndromes of early childhood, and it comes with very high morbidity and mortality. The typical presentation is characterized by hemiclonic or generalized clonic seizures triggered by fever during the first year of life, followed by myoclonic, absence, focal and generalized tonic-clonic seizures. Non-convulsive status epilepticus and epileptic encephalopathy are common. Development is normal in the first year of life, but most individuals eventually suffer from intellectual impairment. Dravet syndrome is associated with mutations in the sodium channel alpha1 subunit gene (SCN1A) in 70-80% of individuals. SCN1A mutation results in inhibition of the GABAergic inhibitory interneurons, leading to excessive neuronal excitation. The "interneuron hypothesis" is the current most accepted pathophysiological mechanism of Dravet syndrome. The mortality rate is increased significantly in Dravet syndrome. Ataxia, a characteristic crouched gait and Parkinson's symptoms may develop in some individuals. It is likely that Dravet syndrome is underdiagnosed in adults with treatment-resistant epilepsy. Early diagnosis is important to avoid anti-seizure medications that exacerbate seizures.
Department of Paediatrics,British Columbia's Children's Hospital and University of British Columbia,Vancouver,British Columbia,Canada.
Mary B
MB
Connolly
D000818:Animals; D004831:Epilepsies, Myoclonic / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics / Q000628:therapy*; D006801:Humans; D009154:Mutation / Q000235:genetics; D062550:NAV1.1 Voltage-Gated Sodium Channel / Q000235:genetics
D062550:NAV1.1 Voltage-Gated Sodium Channel; C568242:SCN1A protein, human
Dravet syndrome; comorbidities; electroclinical features; prognosis