What Are Corpus Callosum Abnormalities?

Corpus callosum abnormalities are conditions that affect the corpus callosum, which is a bundle of fibers that connects the left and right sides of the brain. They are conditions that are present in a baby before birth.

Corpus callosum abnormalities can be isolated (no other problems with the brain or organs) or not isolated (when there are other problems with the brain or organs).

Are Corpus Callosum Abnormalities Common?

Corpus callosum abnormalities are one of the most common congenital conditions that doctors can diagnose in a fetus during pregnancy.

What Causes Corpus Callosum Abnormalities?

In most cases the reason for corpus callosum abnormalities are unknown. Some causes include:

  • Genetic conditions passed on from parents
  • Genetic conditions that occur at random
  • Alcohol or cocaine use during pregnancy
  • Certain infections during pregnancy

What Are the Different Corpus Callosum Abnormalities?

There are 4 types of corpus callosum abnormalities:

  • Complete agenesis of the corpus callosum. This is when the corpus callosum does not form at all. The front, middle, and back parts are all missing.
  • Partial agenesis of the corpus callosum. This is when part of the corpus callosum is missing, usually just the back part. Sometimes it is the middle or front part that is missing instead.
  • Hypoplasia of the corpus callosum. This is when all parts of the corpus callosum form, but the entire structure is very thin or very small.
  • Corpus callosum abnormality due to hydrocephalus. This is when too much fluid in the brain causes the corpus callosum to not form properly.

Rev. 7/2019. Mass General for Children and Massachusetts General Hospital do not endorse any of the brands listed on this handout. This handout is intended to provide health information so that you can be better informed. It is not a substitute for medical advice and should not be used to treatment of any medical conditions.