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Genetic and Rare Diseases Information Center (GARD)

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Other Names for this Disease
  • Familial schizencephaly
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What is schizencephaly?

What causes schizencephaly?

What is schizencephaly?

Schizencephaly is a developmental birth defect. It is characterized by abnormal slits or clefts in the cerebral hemispheres of the brain. People with clefts in both hemispheres commonly have developmental delays, delays in speech and language skills, seizures, and problems with brain-spinal cord communication. Individuals with clefts in only one hemisphere are often paralyzed on one side of the body, may have seizures, and may have average to near-average intelligence. Other signs and symptoms may include an abnormally small head (microcephaly), hydrocephalus, intellectual disability, partial or complete paralysis, or poor muscle tone (hypotonia). Treatment generally consists of physical therapy and drugs to prevent seizures. In cases that are complicated by hydrocephalus, a surgically implanted tube, called a shunt, is often used to divert fluid to another area of the body where it can be absorbed.[1]
Last updated: 9/29/2011

What causes schizencephaly?

The exact cause of schizencephaly is unknown.[2] Some individuals with schizencephaly have been found to have mutations in the EMX2 gene, but some investigators have concluded that EMX2 mutations are a very rare cause of schizencephaly.[3] Another study reported detecting mutations in the SIX3 and SHH genes in individuals with schizencephaly; mutations in these genes have also been found to cause holoprosencephaly.[4] There have been reports of familial schizencephaly (occurring in siblings), which supports a genetic cause in some cases.[2]

In a study published in 2005, the authors found that there was an association with young parental age in isolated schizencephaly (occurring alone without other abnormalities); this was also seen in mothers, but not fathers, of non-isolated cases. Monozygotic (identical) twins may also be at increased risk for schizencephaly. One third of cases they studied had a non-CNS (central nervous system) abnormality, over half of which could be classified as secondary to vascular disruption (disruption of blood flow or supply during development), including gastroschisis, bowel atresias (absence or closure of part of the intestines), and amniotic band disruption sequence. Other apparent rare causes included chromosomal aneuploidy (extra or missing chromosomes), non-random associations (occurring with something else more often than due to chance alone), and unusual syndromes.[5]
Last updated: 4/28/2011

  1. NINDS Schizencephaly Information Page. NINDS. May 6, 2010; Accessed 9/28/2011.
  2. Hilburger AC, Willis JK, Bouldin E, Henderson-Tilton A. Familial schizencephaly. Brain & Development. May-June 1993; 15(3):234-236. Accessed 4/28/2011.
  3. Cassandra L. Kniffin et al. SCHIZENCEPHALY. OMIM. August 20, 2008; Accessed 4/28/2011.
  4. Hehr U et al. Heterozygous mutations in SIX3 and SHH are associated with schizencephaly and further expand the clinical spectrum of holoprosencephaly. Human Genetics. March 2010; 127(5):555-561. Accessed 4/28/2011.
  5. Curry CJ, Lammer EJ, Nelson V, Shaw GM. Schizencephaly: heterogeneous etiologies in a population of 4 million California births. American Journal of Medical Genetics. Part A. August 30, 2005; 137(2):181-189. Accessed 4/28/2011.