What is Lissencephaly?

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Lissencephaly, which literally means "smooth brain," is a rare, gene-linked brain malformation characterized by the absence of normal convolutions (folds) in the cerebral cortex and an abnormally small head (microcephaly). It is caused during embryonic development by defective neuronal migration, the process in which nerve cells move from their place of origin to their permanent location. Symptoms of the disorder may include unusual facial appearance, difficulty swallowing, failure to thrive, muscle spasms, seizures, and severe psychomotor retardation. Hands, fingers, or toes may be deformed. Lissencephaly may be associated with other diseases including isolated lissencephaly sequence, Miller-Dieker syndrome, and Walker-Warburg syndrome.

Is there any treatment?
The severe malformations of the brain in lissencephaly most likely will not respond to treatment. Normal supportive care may be needed to help with comfort and nursing needs. Seizures may be controlled with medication. Progressive hydrocephalus (an excessive accumulation of cerebrospinal fluid in the brain) may require shunting. If feeding becomes difficult, a gastrostomy tube may be considered.

What is the prognosis?
The prognosis for children with lissencephaly depends on the degree of brain malformation. Many will die before the age of 2. Some will survive, but show no significant development beyond a 3- to 5-month-old level. Others may have near-normal development and intelligence. Children with lissencephaly often die from aspiration of food or fluids, or from respiratory disease.

What research is being done?
The NINDS 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.