- 1 in 100,000 births.
- Unilateral or bilateral cleft between the ventricular system and the subarachnoid space.
- In about 70% of cases the lesion is in the parietal lobe.
- In 50-90% of cases there are other associated brain abnormalities, including agenesis of the cavum septum pellucidum, septo-optic dysplasia and severe ventriculomegaly.
- The incidence of chromosomal abnormalities and genetic syndromes is not increased.
- Detailed ultrasound examination, including neurosonography.
- Fetal brain MRI is necessary to distinguish schizencephaly, which is a migration disorder, from porencephaly which is a vascular insult. MRI is also important for detection of polymicrogyria (excessive folding of the brain) which is an invariable finding in schizencephaly.
- Follow-up should be standard.
- Standard obstetric care and delivery.
- Very poor: severe developmental delay and intractable epilepsy. Additionally, there is blindness if the condition is associated with septo-optic dysplasia.
- No increased risk of recurrence.