Agenesis of the Corpus Callosum

Description

There are a group of disorders of the corpus callosum. These are birth defects in which there are problems with the connection between the left and the right side of the brain (termed the corpus callosum).

• Agenesis: partial or complete absence of the corpus callosum
• Dysgenesis: malformation of the corpus callosum
• Hypogenesis: a partial formation of the corpus callosum
• Hypoplasia: underdevelopment of the corpus callosum

This can occur by itself or in combination with other brain formation problems or syndromes.

Causes

For many children, we cannot identify a single cause. In these cases, there are likely multiple. These factors may include genetics, metabolic disorders, and structural interruptions. 

Known causes of disorders of the corpus callosum include

• Chromosomal defects that affect fetal brain development
• Certain viral infections that a mother has while pregnant
• Exposure of the unborn baby to certain toxins (like alcohol) or medications
• Abnormal brain development caused by cysts

Diagnosis 

Diagnosis is made by viewing the brain. This is with MRI, CT scan, or prenatal or post-natal ultrasound. 

Associated Developmental and Learning Issues

Children with disorders of the corpus callosum have a range of learning abilities and disabilities. The level of difficulty depends on the number of brain structure problems and the presence of other syndromes. Some children have mild learning problems. Others have severe intellectual disabilities.

Other developmental skills and abilities often go along with cognitive abilities. The more brain structure problems a child has, the more likely they are to have slow development of speech, motor skills, and social skills. Some children who learn well may have more “hidden” disabilities related to how they learn. For these children, specialized evaluation of their learning strengths and weaknesses will be important to support their success. 

For children with primary disorders of the corpus callosum (without other syndromes or brain formation problems), it is common to experience the following:

• Cognitive disabilities including learning problems through intellectual disabilities
• Problems with abstract thinking and problem solving
• Low muscle tone and poor motor coordination
• Attention Deficit Disorder
• Social immaturity

Associated Medical Conditions

Many children with Disorders of the corpus callosum have other health complications. It is important that these are recognized and treated. A child with disorders of the corpus callosum who is physically healthy is more likely to do well in school and in other treatments. This contributes to more independence, better daily functioning, and better quality of life. The type and severity of health problems is often dependent upon whether the disorder of the corpus callosum is part of syndrome or something that occurred by itself. If the child has a syndrome, it is important to understand the health issues associated with that syndrome. 

• Acrocallosal syndrome
• Aicardi syndrome
• Arnold-Chiari malformation
• Andermann syndrome
• Dandy-Walker syndrome
• Differences in the appearance of the face, including wide space between the eyes, and hypertelorism (differences in appearance of the skin around the eyes)
• Fetal Alcohol syndrome
• Hearing problems
• Holoprosencephaly (failure of the forebrain to divide into lobe)
• Hydrocephalus
• Microcephaly (small head)
• Midline facial defects
• Poor muscle tone and coordination
• Schizencephaly (clefts or deep divisions in brain tissue)
• Seizures
• Shapiro syndrome
• Trisomy 13
• Trisomy 18
• Vision problems

Associated Behavioral Conditions

• ADHD
• Insomnia and other sleep problems