Agenesis of the Corpus Callosum

Overview

Our brain has two main functional areas, the cerebrum, and cerebellum. The cerebrum is further divided into two cerebri – the right and left cerebral cortex. The two cerebri are connected to each other by a bundle of fibres known as the corpuscallosum. These fibres act as wires transferring signals from one lobe of the cerebrum to the other.  

Agenesis of the corpus callosum is a birth defect in which there is improper development of the corpus callosum. The term agenesis means when there is either an absence of an organ or the functional cells of the organ.  

As with other pathologies associated with the brain, this disease comes up with many different possible outcomes in babies. Agenesis of the corpus callosum can be asymptomatic i.e., without any symptoms, or can have serious developmental problems which can make hamper your daily life. In this article, we will go through some of the features associated with the agenesis of the corpus callosum. 

Signs and Symptoms

Symptoms associated with agenesis of corpus callosum vary depending on various factors such as the degree to which the other structures of the brain are involved. The babies may not show any signs of developmental problems when they are born while some babies can indicate the agenesis of corpus callosum right away. Some of the common symptoms of presenting with this condition:  

  • Seizures  
  • Poor feeding and difficulty swallowing  
  • Cognitive debilities (problems) 
  • Delayed development of motor and language systems, for example, difficulty speaking, walking, or sitting up 
  • Hearing problems  
  • Vision impairment  
  • Sleeping disturbances such as insomnia  
  • Constant crying is especially associated with sleep 
  • Psychosocial abnormalities such as ADD (attention deficit disorder), OCD (obsessive-compulsive disorder), and anti-social behaviour 
  • Learning or thinking problems 
Image by Benioff Children’s Hospital

Causes and Risk Factors

In most cases, the cause of abnormal development of the corpus callosum is not known.

Causes may include:

  • An inherited disorder. Babies can acquire this condition from their parents. It can be an autosomal recessive or an X-linked dominant condition. A dominant trait is more likely to pass on to a child than a recessive trait.  
  • Unborn baby being exposed to certain toxins or medication that interfere in the development of corpus callosum, e.g., frequent alcohol or tobacco use 
  • Mothers can pass on certain viral infections to the developing baby, such as rubella 
  • Presence of brain cysts (a fluid-filled cavity), which can impair the development of the corpus callosum 

Risk factors may include: 

  • Genetic or hereditary association. It can be passed on from a carrier mother or father, hence a family relative having this disease is a risk factor 
  • Certain other congenital (inborn) anomalies are often associated with ACC. These include: 

– Arnold-Chiari malformation  

– Hydrocephalus – a condition in which there is excessive fluid pressure in your brain 

– Dandy-Walker syndrome  

– Trisomy – in which your child has an extra copy of chromosome 8,13, or 18.  

– Andermann syndrome  

– Acrocallosal syndrome, etc.  

Diagnosis

Your routine prenatal (during pregnancy) ultrasound exams may indicate agenesis of the corpus callosum. Also, a Paediatrician may suspect this anomaly while examining your baby in the early years after they are born. The physician can ask you to get certain diagnostic procedures done which may include: 

  • High-resolution ultrasound for confirming the absence of corpus callosum (during pregnancy) 
  • Foetal MRI (magnetic resonance imaging) scan can be done to check for the presence of ACC and other associated congenital anomalies (during pregnancy) 
  • MRI or CT scan of your child’s brain can be performed to confirm the diagnosis  
  • Genetic testing is also recommended by some physicians due to the association of ACC with other genetic problems 
Frank Gaillard, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

Treatment

Currently, there is no absolute treatment for restoring the corpus callosum. Children affected by this condition are treated symptomatically, i.e., managing the complications with available treatments. The treatment options include: 

  • Medications. Medications can be used to control disorders like seizures and other personality disorder  
  • Speech, physical or occupational therapies may be prescribed to manage the respective disorders 
  • Special education can be used to enhance cognitive abilities and thinking skills 

Complications and Preventions

Agenesis of the corpus callosum can produce complications like seizures which can be very disturbing. As for preventive measures, there are no set guidelines for preventing this condition in your child, however, you can: 

  • Get vaccinated against pathogens like rubella 
  • Avoid the use of alcohol during your pregnancy  
References
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