Agenesis of the corpus callosum (ACC) is a birth defect in the brain. The corpus callosum, a bundle of nerves connecting the left and right sides of the brain, is either missing or partially missing. Symptoms range from minor intelligence issues to developmental delays and seizures. ACC is usually diagnosed in the first two years of life.
Agenesis of the corpus callosum (ACC) is a birth defect that affects the brain. A person with ACC has a missing or partially missing corpus callosum. The corpus callosum is a thick bundle of nerve fibers that connects the right and left hemispheres (halves) of the brain. It allows both sides of the brain to communicate with each other.
The effects of ACC can be subtle or severe. It depends on how much of the corpus callosum is missing and whether there are any other problems with the brain. Some experience mild social, emotional or mental effects. Others may have severe impairments or seizures.
An absent corpus callosum can occur by itself but is sometimes associated with other congenital disorders (defects present at birth), such as:
ACC is the most common congenital defect of the brain. But it is still rare, affecting only 0.05 to 0.07% of the population.
Scientists don’t fully understand the causes of ACC, but it has been associated with:
The signs and symptoms of ACC vary. It depends on how much of the corpus callosum is missing and the presence of any other associated disorders.
The signs often show up during the first two years of life, but mild cases are sometimes not noticed for many years.
Symptoms might include:
Some people with ACC can also have physical signs of the disorder:
If a healthcare provider suspects that you or your child have ACC, you will need a physical examination. The healthcare provider will talk to you about any symptoms and developmental delays, then examine the body.
Your provider will order imaging tests to take pictures inside the head. Computed tomography (CT) or magnetic resonance imaging (MRI) will show whether the corpus callosum is missing or partially developed.
Treatment for an absent corpus callosum depends on how the disorder affects an individual. It often includes:
It’s not entirely possible to prevent ACC. Pregnant women can reduce the risk of congenital defects by avoiding alcohol, infection or injury.
The outlook for a person with ACC depends on how severe the condition is. Many children with ACC lead normal lives with only minor effects. Others need medications to prevent seizures and therapy to improve function. For those who have an intellectual disability, it does not get worse over time.
ACC doesn’t usually cause death.
Because ACC affects people in different ways, consider asking your healthcare provider:
A note from Cleveland Clinic
Agenesis of the corpus callosum, a brain defect present at birth, can be mild or severe. It’s usually not fatal, and specific therapies can help. Although the disorder is generally diagnosed in the first two years of life, some cases are diagnosed later. Talk to your healthcare provider if you or your child are experiencing any troubling symptoms.
Last reviewed by a Cleveland Clinic medical professional on 11/01/2021.
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