Lissencephaly Overview

A Type of Brain Malformation

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Drawing of a brain
Brain, Drawing. BSIP / Contributor / Getty Images


The word lissencephaly comes from two Greek words: lissos, meaning "smooth," and enkaphalos, meaning "brain." If you look at a normal brain, the gray matter (cerebrum) has ridges and valleys in its surface. In lissencephaly, the brain surface is almost completely smooth. The physical structure of the brain did not develop correctly during pregnancy.


Researchers believe that there are several possible causes of lissencephaly.

It may be caused by injury to the fetus during its development, such as from a viral infection or insufficient blood flow to the brain. Another cause may be a genetic mutation. Researchers have identified two genes associated with lissencephaly. One is on chromosome 17, named LIS1. The other is on the X chromosome, named XLIS or Doublecortin. Whether lissencephaly can be inherited is not yet clear.


Like other disorders, lissencephaly can occur in varying degrees. Generally, though, the child will have:


It may not be apparent at birth that a child has lissencephaly because outwardly the child may appear healthy and normal. Around ages 2 to 6 months, though, the parents will notice that the child is not developing normally.

Seizures may start to occur, including a severe type called "infantile spasms." It may be difficult to get the seizures under control.

If lissencephaly is suspected based on the child's symptoms, magnetic resonance imaging (MRI) or computed tomography (CT scan) can look at the brain and confirm the diagnosis.


There is no way to reverse the effects of lissencephaly; however, some of the problems children with lissencephaly can develop, such as muscle contractures or pneumonia, may be prevented through good medical care and physical and occupational therapy. Each child can be assisted to reach his/her potential level of development.


The prognosis for children with lissencephaly depends on the degree of brain malformation. Many will die before the age of 10 years. The cause of death is usually aspiration of food or fluids, respiratory disease, or severe seizures. Some will survive but show no significant development -- usually not beyond a 3- to 5-month-old level. Others may have near-normal development and intelligence. Because of this range, it is important to seek the opinion of specialists in lissencephaly and support from family groups with connection to these specialists.


The National Institute of Neurological Disorders and Stroke conducts and supports a wide range of studies that explore the complex systems of normal brain development, including neuronal migration. Recent studies have identified genes that are responsible for lissencephaly. The knowledge gained from these studies provides the foundation for developing treatments and preventive measures for neuronal migration disorders.


Cleveland Clinic. Lissencephaly.

"Lissencephaly." Index of Rare Diseases. 2002. National Organization for Rare Disorders.

"NINDS Lissencephaly Information Page." Disorders A-Z. 29 Oct 2008. National Institute of Neurological Disorders and Stroke.

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