Clinical Characteristics

The megalencephaly-polymicrogyria-polydactyly-hydrocephalus (MPPH) syndrome characterized by:

  • Brain overgrowth or megalencephaly (MEG) – often congenital
  • Cortical brain malformations, specifically polymicrogyria
  • Hydrocephalus – may require neurosurgical intervention
  • Extra fingers or digits (polydactyly)

Focal brain malformations including hemimegalencephaly (HMEG) and focal cortical dysplasia (FCD) characterized by early onset, often intractable, epilepsy.

Diffuse megalencephaly (MEG) with polymicrogyria (similar to MCAP syndrome) associated with:

  • Epilepsy
  • Oromotor dysfunction (expressive speech delays, difficulties handling oral secretions, dysphagia)

Diffuse megalencephaly without cortical dysplasia associated with:

  • Intellectual disability
  • Autism spectrum disorders
  • Behavioural issues