The megalencephaly-polymicrogyria-polydactyly-hydrocephalus (MPPH) syndrome characterized by:
- Brain overgrowth or megalencephaly (MEG) – presents often at birth
- Abnormalities of the surface of the brain (cortical malformations, such as polymicrogyria)
- Hydrocephalus
- Extra fingers or digits (polydactyly)
Typically caused by mutations that are de novo (i.e. not inherited).
Focal brain malformations such as hemimegalencephaly (HMEG) and focal cortical dysplasia (FCD) characterized by early onset epilepsy.
Typically caused by mutations that are de novo (i.e. not inherited) and mosaic (i.e. present only in a subset of cells such as the brain).
Diffuse brain overgrowth with polymicrogyria (similar to MCAP syndrome) associated with:
- Epilepsy
- Oromotor issues (expressive speech delays, difficulties handling oral secretions, difficulties swallowing or dysphagia)
Typically caused by mutations that are de novo (i.e. not inherited).
Diffuse brain overgrowth without cortical dysplasia associated with:
- Intellectual disability
- Autism spectrum disorders
- Behavioural issues
Typically caused by mutations that are de novo (i.e. not inherited).