HEMIMEGALENCEPHALY

Overview
Log In For Videos
Give Feedback
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
Epilepsy Classification
Generalized Epilepsy
Focal Epilepsy
Generalized and Focal Epilepsy
Unknown Epilepsy
Epilepsy Syndromes
Neonatal/Infantile
- Self-limited neonatal seizures and Self-limited familial neonatal epilepsy
- Self limited familial and non-familial infantile epilepsy
- Early myoclonic encephalopathy
- Ohtahara syndrome
- West syndrome
- Dravet syndrome
- Myoclonic epilepsy in infancy
- Epilepsy of infancy with migrating focal seizures
- Myoclonic encephalopathy in non-progressive disorders
- Febrile seizures plus, genetic epilepsy with febrile seizures plus
Childhood
- Epilepsy with myoclonic-atonic seizures
- Epilepsy with eyelid myoclonias
- Lennox-Gastaut syndrome
- Childhood absence epilepsy
- Epilepsy with myoclonic absences
- Panayiotopoulos syndrome
- Childhood occipital epilepsy (Gastaut type)
- Photosensitive occipital lobe epilepsy
- Childhood epilepsy with centrotemporal spikes
- Atypical childhood epilepsy with centrotemporal spikes
- Epileptic encephalopathy with continuous spike-and-wave during sleep
- Landau-Kleffner syndrome
- Autosomal dominant nocturnal frontal lobe epilepsy
Adolescent/Adult
- Juvenile absence epilepsy
- Juvenile myoclonic epilepsy
- Epilepsy with generalized tonic-clonic seizures alone
- Autosomal dominant epilepsy with auditory features
- Other familial temporal lobe epilepsies
Any Age
- Familial focal epilepsy with variable foci
- Reflex epilepsies
- Progressive myoclonus epilepsies
Epilepsy Etiologies
Genetic Etiology
- Chromosomal abnormalities
- Gene abnormalities
Structural Etiology
- Malformations of cortical development
- Vascular malformations
- Hippocampal sclerosis
- Hypoxic-Ischemic
- Traumatic brain injury
- Tumors
- Porencephalic Cyst
Metabolic Etiology
Immune Etiology
- Rasmussen syndrome
- Antibody mediated
Infectious Etiology
Unknown Etiology
- Febrile infection related epilepsy syndrome
Epilepsy imitators

HEMIMEGALENCEPHALY

GENETICS

PATTERN OF INHERITANCE

De novo acquired somatic gene abnormality.

KNOWN GENES

Hemimegalencephaly has been linked with acquired somatic gene abnormalities in genes involved in the PI3K/AKT/mTOR pathway, including PIK3CA, AKT3, TSC1, TSC2. These gene abnormalities have been found directly in a small percentage of brain cells from the abnormal hemisphere.

FAMILY HISTORY

May be present (see above).

This website is owned by the International League Against Epilepsy. Text on this website, last updated July 15, 2022,
is available under a Creative Commons Attribution-ShareAlike 4.0 International License,
EXCEPTING all videos and images, which remain copyrighted by the International League Against Epilepsy.