Structural brain abnormalities including hemimegalencephaly (HMEG) and focal cortical dysplasia (FCD) associated with early onset epilepsy.
Mutations are most often post-zygotic (mosaic; i.e. present in a fraction of cells).
Diffuse brain overgrowth with polymicrogyria with changes in the pigmentation of the skin associated with:
- Epilepsy
- Oromotor weakness (expressive speech delay, difficulties handling oral secretions, dysphagia and other feeding issues)
Mutations are usually post-zygotic (mosaic) or rarely germline (constitutional).
Diffuse brain overgrowth without cortical dysplasia associated with:
- Intellectual disability
- Autism spectrum disorders
- Behavioural issues
Mutations are most often heterozygous de novo or rarely post-zygotic (mosaic).