Prevalence:

• 1 in 100,000 births.

Ultrasound diagnosis:

• 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.

Associated abnormalities:

• The incidence of chromosomal abnormalities and genetic syndromes is not increased.

Investigations:

• 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:

• Follow-up should be standard.

Delivery:

• Standard obstetric care and delivery.

Prognosis:

• Very poor: severe developmental delay and intractable epilepsy. Additionally, there is blindness if the condition is associated with septo-optic dysplasia.

Recurrence:

• No increased risk of recurrence.