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Lissencephaly is a rare, gene-linked brain malformation characterized by the absence of convolutions (folds) in the cerebral cortex and an extremely small head (microcephaly). The word lissencephaly literally means "smooth brain." Children with lissencephaly usually have head sizes in the expected range at birth. Children with a smaller head size at birth are typically diagnosed with microlissencephaly.

Lissencephaly is caused by defective neuronal migration during embryonic development, the process through which nerve cells move from their place of origin to a permanent location within cerebral cortex gray matter. Symptoms of the disorder may include:

  • Facial differences
  • Difficulty swallowing
  • Failure to thrive (slow physical development)
  • Muscle spasms
  • Seizures
  • Severe psychomotor impairment
  • Congenital limb differences in the hands, fingers, or toes

Lissencephaly may be associated with other diseases including isolated lissencephaly sequence, Miller-Dieker syndrome, and Walker-Warburg syndrome. Sometimes it can be difficult to distinguish between these conditions clinically so consultation with national experts is recommended to help ensure correct diagnosis and possible molecular testing. The prognosis for children with lissencephaly depends on the degree of the disease.

How can I or my loved one help improve care for people with lissencephaly?

Lissencephaly is considered a rare disease, which often means there is not much information known about it. This is usually the case because doctors and researchers do not see many people with lissencephaly, which makes it hard to learn from them through observations or large studies.

Consider participating in a clinical trial so clinicians and scientists can learn more about lissencephaly and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with lissencephaly at

Where can I find more information about lissencephaly?

The following organizations and resources help individuals, families, friends, and caregivers of people living with lissencephaly:

Genetic and Rare Diseases (GARD) Information Center


March of Dimes
Phone: 888-663-4637

National Organization for Rare Disorders (NORD)
Phone: 203-744-0100 or 800-999-6673; 844-259-7178 Spanish


The Arc of the United States
Phone: 202-534-3700 or 800-433-5255

Content source: Accessed June 23, 2023.

The information in this document is for general educational purposes only. It is not intended to substitute for personalized professional advice. Although the information was obtained from sources believed to be reliable, MedLink, its representatives, and the providers of the information do not guarantee its accuracy and disclaim responsibility for adverse consequences resulting from its use. For further information, consult a physician and the organization referred to herein.

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