Embryology

• Incomplete forebrain (prosencephalon) division into 2 hemispheres Etiologies
• Genetic: Trisomy 13, sonic hedgehog gene mutations
• Environmental: maternal alcohol use, retinoic acid Clinical features
• CNS abnormalities
  • Range from asymptomatic to seizures, severe intellectual disability, death
• Midface abnormalities
  • Range from mild hypotelorism and cleft lip/palate to cyclopia, primitive nose, facial cleft