Agenesis of the corpus callosum

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at September 24, 2016
StartDiseasesAgenesis of the corpus callosum

Agenesis of the corpus callosum, also known as agenesis of the corpus callosum, is a condition where the two sides of the brain are either partially connected or not connected at all. There is an entire spectrum of possible symptoms that range from mild to severe. Mild cases involve slight issues with motor skills, while more severe cases will involve a low IQ, blindness, seizures, spastic movements, and more.


Definition & Facts

Originally, agenesis of the corpus callosum was thought to be a rare condition. With the development of magnetic resonance imaging (MRI)s and other diagnostic procedures, it has been discovered that agenesis of the corpus callosum is more common than originally thought. Up until recent times, many people were living completely unaware of the nature of their condition.

Agenesis of the corpus callosum can sometimes be detected during a medical ultrasound, but often it isn't diagnosed for a decade or more due to the relative rarity of the condition. There are a number of different ideas of just how rare agenesis of the corpus callosum is.

Some researchers say that as many as seven people out of 1,000 have agenesis of the corpus callosum. Other sources estimate that it occurs in one out of every 4,000 people. Sometimes, agenesis of corpus callosum occurs in those who have spina bifida, which is a condition that involves a birth defect affecting the spine. Those with spina bifida are usually confined to a wheelchair.

Agenesis of corpus callosum is a permanent condition. It does not get better or worse. Some people with agenesis of the corpus callosum have an average intelligence and can function in society. Some with agenesis of the corpus callosum never learn to speak and cannot control their bladder. In severe cases like that, they will always need supervision or a guardian.

Symptoms & Complaints

Agenesis of corpus callosum often manifests in the form of seizures. It can happen in a baby just a few weeks after birth or it might begin at the age of 1 or 2 years old. 90% of those with agenesis of the corpus callosum show symptoms by the age of 2. Not all patients with this condition have seizures.

Other warning signs in children include those who have difficulty eating and cannot keep their heads erect. Often, it will take these children longer to learn how to walk, stand up or sit down. Mental and physical development is delayed and slowed and is often agenesis of the corpus callosumompanied by fluid in the skull, a condition known as hydrocephalus.

Some cases are so mild that there might not be any symptoms for a number of years. Symptoms in mild cases include speaking in a monotone voice and frequent headaches. Those with mild cases of agenesis of the corpus callosum read at a low level and often have difficulty focusing in an area with repetitive noises like a fan or the ticking of a clock. Other symptoms include:

Mental retardation may occur as well as various mental disorders and behavioral problems.


Researchers have yet to determine a cause for agenesis of the corpus callosum. It may be a type of genetic disorder. Chromosome abnormalities may play a role. Agenesis of the corpus callosum may also be caused by infections in pregnant women which causes the brain of the fetus to develop abnormally.

In general, males develop more severe cases of agenesis of the corpus callosum than females. Males have a greater risk of dying before they are born, particularly when they have a subform of agenesis of the corpus callosum known as Aicardi syndrome. Almost everyone living with Aicardi syndrome is female. It is also believed that fetal alcohol syndrome and other forms of prenatal exposure to toxic substances can lead to agenesis of the corpus callosum.

Diagnosis & Tests

Diagnosing agenesis of corpus callosum often starts with a complete review of the medical history and a comprehensive physical examination of the patient. Agenesis of the corpus callosum can be detected while the baby is still in the womb. Sometimes the condition is noticed in an ultrasound. Other times, agenesis of the corpus callosum is detected through a computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan of the patient.

Doctors are often unfamiliar with this condition which can lead to it being misdiagnosed as a form of Asperger syndrome, due to the similarity of some of the symptoms. Agenesis of the corpus callosum is entirely different, as it involves problems in the connection between the two hemispheres in the brain. In some cases, patients have a condition known as holoprosencephaly, in which the forebrain never splits into two hemispheres.

Treatment & Therapy

Those with agenesis of the corpus callosum often are put through a number of treatment plans and programs including special education programs. Physical therapy is often undertaken to help the patient develop their motor skills. Those who have seizures are kept on a strict regimen of anticonvulsants to protect them.

If the patient has hydrocephalus they may need surgery to drain fluid from their cranium to reduce pressure on the brain. This may take the form of a cerebral shunt.

Physicians agree that those with agenesis of the corpus callosum should see a behavioral psychologist, a speech-language pathologist, a neurologist and an ophthalmologist as soon as they are diagnosed so that they can promptly address any developmental problems.

Prevention & Prophylaxis

Sometimes agenesis of the corpus callosum cannot be prevented as they are suspected to be inherited through genetic mutations. People who are pregnant should be absolutely certain not to drink alcohol and to take care of any kind of illness or infection. Quitting smoking and avoiding secondhand smoke as well as exposure to environmental toxicants are crucial as well for pregnant women.