Agenesis of the Corpus Callosum

What is Agenesis of the Corpus Callosum?

It is a rare, congenital birth defect that is characterized by a partial or total absence of the corpus callosum, a broad transversal nerve tract joining the two cerebral hemispheres. It is actually a condition marked by the failure a failure in the development of the Corpus Callosum.

Agenesis of the Corpus Callosum ICD 9 Code

The ICD 9 code for Agenesis of the Corpus Callosum (ACC) is 742.2.

Agenesis of the Corpus Callosum Incidence

ACC is the most common type of brain malformation. It has an incidence of 0.05-0.07% in the American population. This is a rare disorder. The condition was earlier said to occur in approximately 5 out of every 1000 newborns. It now occurs in 1 out of approximately 4,000 infants.

Agenesis of the Corpus Callosum Causes

Medical researchers have not yet been able to have a clear understanding of the causes of Agenesis of Corpus Callosum. A number of factors have, however, been suspected as the possible causes of this disorder. A disruption to the fetal brain development between 3 – 12 weeks of pregnancy is believed to be the most possible cause of the condition.

During early development, injuries to the fetus in the form of physical trauma, maternal alcohol or drug abuse or prenatal infection may also result in poor growth of nerves in the fetal brain. This can lead to partial or non-development of the Corpus Callosum during birth.

According to some medical evidence, a spontaneous or inherited genetic mutation may make infants susceptible to the disorder even before they have been born.

Some other factors that are held responsible for this condition include

  • Chromosomal errors
  • Prenatal toxic exposures
  • Structural blockage by cysts
  • Brain abnormalities
  • Metabolic disorders

In most cases, it is impossible to know the cause of ACC or any other callosal disease in an individual.

Agenesis of the Corpus Callosum Symptoms

An underdeveloped or undeveloped Callosum structure typically makes sufferers experience difficulties in areas like:

  • Problem solving
  • Coordinating body movements
  • Reasoning
  • Interacting with others

The signs and symptoms of this condition as well as other callosal disorders differ greatly among sufferers. However, certain common symptoms experienced by patients of callosal conditions include problems like,

  • Vision impairment
  • Low muscle tone (hypotonia)
  • Poor motor coordination
  • Delays in motor milestones such as walking and sitting
  • Reduced sensation of pain
  • Delayed toilet training
  • Difficulties in chewing
  • Swallowing difficulties

In some cases, symptoms also include difficulties like

  • Seizures
  • Spasticity
  • Early feeding difficulties
  • Gastric reflux
  • Mental retardation
  • Hearing impairments
  • Abnormal head features
  • Unusual facial features

Laboratory research has proved that AAC-affected have difficulties in passing on more complicated information from one hemisphere of their brain to the other. They have also been found to have difficulties in cognition and social interaction even when they have a normal IQ (Intelligence Quotient). These abnormal social behaviors during childhood are often confused with signs of Asperger syndrome or autistic disorders.

Agenesis of the Corpus Callosum Differential Diagnosis

The Differential Diagnosis for ACC involves differentiating the condition from moderate Hydrocephaly. Isolated cases of ACC are often misdiagnosed for this condition. Unlike ACC, however, Hydrocephaly involves the presence of the cavum septum pellucidum. This serves as a clue for differential diagnosis.

Agenesis of the Corpus Callosum Diagnosis

A brain scan is the only way of diagnosing Callosal disorders. This may be facilitated by imaging studies like

  • MRI scan
  • CT scan
  • Prenatal ultrasound scan
  • Prenatal MRI scan

Standard transverse views of the brain fail to detect corpus callosum abnormalities. However, the enlargement of the posterior horns and the absence of the cavum septum pellucidum make it easier to suspect a case of ACC. Midsagittal and Midcoronal views demonstrate ACC and may require Vaginal Sonography.

Agenesis of the Corpus Callosum Treatment

As of now, no specific treatment is available for ACC sufferers. Cure mainly aims at managing the symptoms of the condition, such as seizures, if and when they appear. Therapists and doctors try to educate family members of ACC sufferers about the disorder and explain them the ways of managing the condition. Some sufferers require round-the-clock observance and care while others can have a relatively normal childhood in spite of the disorder. Counseling programs and Occupational therapy can help ACC sufferers as well as those around them lead their lives in a more normal way.

Friends and family members of ACC-affected patients can consult healthcare providers like neuropsychologists, neurologists, physical therapists, occupational therapists, geneticists and early childhood intervention specialists. They can provide the necessary education and guidance for handling this disorder.

Agenesis of the Corpus Callosum Prognosis

The prognosis or outcome of ACC varies depending on the type of callosal abnormality, extent of malformation as well as any associated syndromes or conditions. There is no scope for increase in mental retardation or regeneration of the Corpus Callosum.

Kim Peek, an American savant, was born with ACC and suffered from damage to the cerebellum along with Macrocephaly. He was the inspiration behind the multiple-Oscar winning 1988 Hollywood drama “Rain Man”.

Agenesis of the Corpus Callosum Life Expectancy

Fortunately, the condition does not usually lead to the death of suffering children. Certain individuals with callosal disorders are found to lead normal lives with average intelligence. In around 90% cases of isolated ACC, development is found to be normal.

Agenesis of the Corpus Callosum Support

Parents of a child affected with AAC should begin cognitive and behavioral training as early as possible. This will help maximize the abilities of the child. Neuropsychological testing is necessary to evaluate the cognitive skills of a patient. As every patient has unique needs, it is important for parents to work with teachers, learning disability specialists and other professionals to formulate an Individualized Education Program (IEP). Sufferers must be educated about their disability and provided with direct, consistent feedback due to their reduced cognitive and social skills.


  1. carrie mereen April 4, 2013
  2. Selena April 16, 2018

Leave a Reply