Schizencephaly is a rare malformation of cortical development characterised by a cleft extending from the brain surface to the lateral ventricle and lined by abnormal grey matter. Epilepsy is common but not universal.
Open-lip and closed-lip clefts
Schizencephalic clefts are traditionally described as open-lip when the cleft walls are separated by cerebrospinal fluid and closed-lip when the walls are in apposition. This anatomical description does not by itself determine seizure severity.
Neurological features
The clinical spectrum is broad. Motor impairment, developmental delay, learning disability and epilepsy can occur, but severity depends on cleft size, location, whether one or both hemispheres are affected and associated malformations.
Epilepsy
Seizures are often focal and may become drug-resistant. The epileptogenic network may involve cortex around the cleft or other associated dysplastic regions.
MRI
MRI is the key diagnostic test because it demonstrates the full-thickness grey-matter-lined cleft and associated abnormalities such as polymicrogyria or absent septum pellucidum.
Treatment
Management may include antiseizure medicine, physiotherapy, occupational therapy, speech and language support, spasticity treatment and other rehabilitation. Drug-resistant focal epilepsy can lead to specialist surgical evaluation in selected cases.
Do not confuse schizencephaly with porencephaly
Porencephalic cavities usually reflect destructive brain injury and are not lined by dysplastic grey matter in the same way. MRI helps distinguish the two.
Related reading
What schizencephaly is
Schizencephaly is a congenital cortical malformation defined by a cleft extending from the ventricular surface to the pia and lined by abnormal grey matter. The cleft may be open-lip or closed-lip and may be unilateral or bilateral.
Epilepsy is variable
Some people never develop epilepsy, while others have focal seizures beginning in childhood or later. Seizure severity does not depend only on whether the cleft is open or closed; associated cortical malformations and the extent of abnormal cortex also matter.
Associated findings
Polymicrogyria commonly lines the cleft. Septo-optic abnormalities, absent septum pellucidum, motor impairment, developmental disability and visual problems can coexist.
Causes are heterogeneous
Schizencephaly is not explained by one single gene or one single prenatal insult. Genetic, vascular and developmental mechanisms have all been reported, and causal interpretation should be cautious.
Drug-resistant epilepsy
When seizures remain drug resistant, presurgical evaluation can still be appropriate. The visible cleft does not necessarily define the entire epileptogenic network, so video-EEG, MRI review and sometimes invasive monitoring may be required.
Sources and further reading
- Schizencephaly: clinical spectrum, epilepsy, and pathogenesis. J Child Neurol. 2005. PMID: 15921232.
Evidence checked: September 2026.