Agenesis of the Corpus Callosum

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What is agenesis of the corpus callosum? 

Agenesis of the corpus callosum (ACC) is a brain disorder in which the tissue that connects the left and right sides of the brain (its hemispheres) is partially or completely missing. It is caused by a disruption of brain cell migration during fetal development.

ACC can occur as an isolated condition or in combination with other cerebral abnormalities, including Chiari malformations, Dandy-Walker syndrome, schizencephaly, and holoprosencephaly. ACC can also be associated with malformations in other parts of the body, such as midline facial defects. The effects of the disorder range from subtle or mild to severe, depending on associated brain abnormalities. Children with the most severe brain malformations may have: 

  • Intellectual impairment 
  • Seizures  
  • Hydrocephalus  
  • Spasticity 

People who have a disorder of the corpus callosum typically have: 

  • Delays in attaining developmental milestones such as walking, talking, or reading 
  • Clumsiness and poor motor coordination particularly with skills that require coordination of left and right hands and feet, such as swimming, bicycle riding, and driving
  • Problems with mental and social processing 
  • Impairment in social interaction and communication that may overlap with autism spectrum disorder behaviors and typically become apparent between adolescence and adulthood 

Females may have a gender-specific condition called Aicardi syndrome, which causes severe cognitive impairment and developmental delays, seizures, abnormalities in the vertebra of the spine, and lesions on the retina of the eye.  

Other disorders of the corpus callosum include dysgenesis, in which the corpus callosum is developed in a malformed or incomplete way, and hypoplasia, in which the corpus callosum is thinner than usual. Individuals with these disorders have a higher risk of hearing problems and cardiac abnormalities.

Treatment for ACC usually involves management of symptoms and seizures. It is estimated that at least one in 4,000 individuals has a disorder of the corpus callosum. 

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 agenesis of the corpus callosum? 

Unfortunately, agenesis of the corpus callosum is a rare disorder. This means there is often not much information known about the disorder and doctors and researchers do not see enough patients with it. This 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 agenesis of the corpus callosum 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 ACC at

Where can I find more information about agenesis of the corpus callosum? 

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

Genetic and Rare Diseases (GARD) Information Center

National Organization for Disorders of the Corpus Callosum
Phone: 714-747-0063 


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.