Agenesis of corpus callosum is a rare type of congenital brain defect in which the corpus callosum fails to develop properly or form at all. The corpus callosum is a large bundle of nerve fibers that serves as the primary pathway for electrical communication between the left and right hemispheres of the brain. When the structure is not fully intact, a person may have difficulties with reasoning, problem solving, interacting with others, and coordinating body movements. There is no cure for agenesis of corpus callosum, and treatment measures are supportive in nature. With support from family, doctors, and special education programs, many patients with the disorder are able to eventually lead somewhat independent lives.
The causes of agenesis of corpus callosum are not well understood, but many different factors can be involved. Some evidence suggests that an inherited or spontaneous genetic mutation may predispose infants to the disorder. Injuries to the fetus during early development, such as physical trauma, infection, or maternal drug or alcohol abuse, may also lead to poor nerve growth in a new brain. The corpus callosum may only be partially developed or completely absent at the time of birth.
The severity of symptoms can vary greatly with agenesis of corpus callosum. Some infants do not show unusual characteristics for two years or longer after birth. Many young children with the condition are able to keep up with their peers on such tasks as reading, speaking, walking, and elementary schoolwork. In serious cases, however, infants quite obviously suffer from mental retardation, difficulties moving and feeding, and seizure disorders. They may have additional physical defects and life-threatening heart or lung conditions.
Most milder cases of agenesis of corpus callosum become problematic by that time children reach the age of about 10 or 11. The corpus callosum is nearly fully functional and developed in healthy children of that age, allowing them to begin building skills in abstract thinking, problem solving, and social interactions. Children and adolescents with agenesis of corpus callosum may not be able to develop such skills even if they are of average intelligence. They may have trouble on math and critical thinking problems, empathizing with others, and picking up on body language and spoken cues during conversation.
There are no specific treatments for patients who are diagnosed with agenesis of corpus callosum. Doctors and therapists try to educate family members on the disorder and explain what they can do to make their loved one's home life easier. Some patients require around-the-clock care and monitoring, while others can lead relatively normal childhoods despite their conditions. Occupational therapy and counseling programs are available to help adults with the disorder become productive members of their communities.