The megalencephaly-polymicrogyria-polydactyly-hydrocephalus (MPPH) syndrome is characterized by:
- Brain overgrowth o megalencephaly – often congenital
- Structural brain abnormalities such as polymicrogyria
- Hydrocephalus – may require neurosurgical intervention
- Extra digits (either fingers or toes)
Mutations are most often de novo(i.e. not inherited).Mosaic mutations and autosomal dominant mutations are rarely seen as well.
Bilateral perisylvian polymicrogyria is characterized by:
- Epilepsy
- Oromotor weakness including dysphagia, difficulties handling oral secretions and expressive speech delay
Mutations are most often de novoor mosaic mutations.