Neuronal Migration Disorders

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What are neuronal migration disorders?

Neuronal migration disorders (NMDs) are a group of birth defects caused by the abnormal migration of neurons (nerve cells) in the developing brain and nervous system. In the developing brain, nerve cells migrate or move from their place of origin to the place where they will remain for life. When this process goes wrong, neurons do not end up where they belong. This can result in structurally abnormal or missing areas of the brain in the cerebral hemispheres, cerebellum, brainstem, or hippocampus. Types of NMDs include:

  • Agenesis of the corpus callosum
  • Agenesis of the cranial nerves
  • Agyria
  • Lissencephaly
  • Microgyria
  • Micropolygyria
  • Neuronal heterotopias (including band heterotopia)
  • Pachygyria
  • Polymicrogyria
  • Porencephaly
  • Schizencephaly

Symptoms vary but often feature:

  • Poor muscle tone and motor function
  • Seizures
  • Developmental delays
  • Impaired cognitive development
  • Failure to grow and thrive
  • Difficulties with feeding
  • Swelling in the extremities
  • A small head

    Some disorders have characteristic facial or skull features that can be recognized by a neurologist. Several genetic abnormalities in children with NMDs have been identified, but the role they play in the development of these disorders is not yet well-understood.

    Treatment is symptomatic and may include anti-seizure medication and special or supplemental education consisting of physical, occupational, and speech therapies.

    The outlook for children with NMDs varies depending on the specific disorder and the degree of brain abnormality and the resulting neurological signs and symptoms.

    Learn About Clinical Trials
    Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

    How can I or my loved one help improve care for people with neuronal migration disorders?

    Consider participating in a clinical trial so clinicians and scientists can learn more about NMDs. 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 NMDs at

    Where can I find more information about neuronal migration disorders?

    Information may be available from the following resources:

    March of Dimes

    National Organization for Rare Disorders (NORD)

    PMG Awareness Organization

    Learn about related topics

    Order publications from the NINDS Catalog
    The NINDS Publication Catalog offers printed materials on neurological disorders for patients, health professionals, and the general public. All materials are free of charge, and a downloadable PDF version is also available for most publications.