DRAVET SYNDROME (DS)

Overview
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Seizure Classification
Generalized onset seizure
- Motor Onset
- Non-Motor Onset
Focal Onset Seizure
- By Onset Feature
- Focal to Bilateral Tonic-Clonic
- Hemispheric lateralization
- Lobar localization
  - Frontal
  - Temporal
  - Parietal
  - Occipital
Unknown Onset Seizure
Neonatal Seizure
Epilepsy Classification
Generalized Epilepsy
Focal Epilepsy
Generalized and Focal Epilepsy
Unknown Epilepsy
Epilepsy Syndromes
Neonate/Infant
- Self-limited
- With developmental and epileptic encephalopathy
Childhood
- Self-limited focal epilepsy syndromes
  - Remission expected in all cases by adolescence
    - Self-limited epilepsy with centrotemporal spikes
    - Self-limited epilepsy with autonomic seizures
  - Remission expected in most cases by adolescence
    - Childhood occipital visual epilepsy
    - Photosensitive occipital lobe epilepsy
- Genetic generalised epilepsy syndromes
  - Epilepsy with eyelid myoclonia
  - Epilepsy with myoclonic absence
- Idiopathic generalised epilepsy syndrome
  - Childhood absence epilepsy
- With developmental and/or epileptic encephalopathy
Variable Age
- Idiopathic generalised epilepsy syndromes
- Focal epilepsy syndromes
- Combined generalised and focal epilepsy syndrome
  - Epilepsy with reading-induced seizures
- With developmental and/or epileptic encephalopathy or progressive neurological deterioration
  - Progressive myoclonus epilepsies
  - Rasmussen syndrome
Epilepsy Etiologies
Genetic Etiologies
- Chromosomal abnormalities
- Gene abnormalities
Structural Etiologies
- Malformations of cortical development
- Vascular malformations
- Hippocampal sclerosis
- Hypoxic-Ischemic
- Traumatic brain injury
- Tumors
- Porencephalic Cyst
Metabolic Etiologies
Immune Etiologies
Infectious Etiologies
Unknown Etiologies
Encephalopathy
Epilepsy imitators

DRAVET SYNDROME (DS)

GENETICS

PATTERN OF INHERITANCE

This syndrome is due to pathogenic SCN1A variants, which are identified in >80% cases, most are de novo variants, but 5-10% are inherited (autosomal dominant or from a mosaic parent). Carrier relatives can be unaffected or have a milder epilepsy syndrome e.g. genetic epilepsy with febrile seizures plus spectrum. Germline and somatic mosaicism have been reported.

KNOWN GENES

SCN1A is the main cause, other genes rarely associated with this syndrome include GABRG2, GABRA1, and STXBP1.

FAMILY HISTORY OF SEIZURES/EPILEPSY

A family history of epilepsy and/or febrile seizures is present in 30-50% of patients. In some children with Dravet syndrome, the family history is consistent with genetic epilepsy with febrile seizures plus spectrum.