SCHIZENCEPHALY

OVERVIEW

Schizencephaly is an uncommon malformation of cortical development that results in a cleft, lined by polymicrogyria, that extends from the ependyma of the ventricles to the pia mater. The majority of clefts are posterior frontal or parietal, but temporal or occipital location can occur. Hypoplasia of the optic nerves and midline brain abnormality (agenesis of the septum pellucidum) may also be present ('septo-optic dysplasia plus').

Causes

• Gene abnormalities e.g. COL4A1
• Intrauterine cerebral injury, after approximately 20 weeks gestation, e.g. infection such as CMV, or hypoxia-ischemia

Clinical Context

The clinical presentation of schizencephaly depends on whether the malformation is unilateral or bilateral, and open- or closed-lipped. Developmental, cognitive and motor impairments are common, and more significant in those with bilateral schizencephaly. In unilateral schizencephaly, the impairment may be limited to a hemiparesis or the individual may only have epilepsy. Seizure onset is usually in the first two years of life, with earlier age of seizure onset seen in those with bilateral/open-lipped clefts. Hydrocephalus can occur, and is more frequently seen in open-lipped clefts.

CAUTION developmental and cognitive outcome may be worse in children with uncontrolled seizures in early life, especially if epileptic spasms or generalized seizure types appear, therefore proactive seizure control is important, this may include epilepsy surgery, if seizures are not controlled with medication.