What is agenesis of the corpus callosum?
This term is sometimes referred to as "Agenesis of the Corpus Callosum (ACC)"
The corpus callosum is a structure that connects the two sides of the brain. Agenesis means it did not develop normally or is missing. This can happen on its own or with other conditions.
ACC is often found during pregnancy on a routine ultrasound scan. If the doctor thinks your baby might have ACC, you may be referred to a fetal medicine specialist for a detailed scan.
Sometimes, another test called a fetal MRI (a special type of scan) is done to get a clearer picture of the baby’s brain.
After birth, doctors may do more tests, such as a brain scan (MRI or ultrasound), to confirm the diagnosis and check how the baby’s brain is developing.
In many cases, the cause of agenesis of the corpus callosum (ACC) is not known. It can happen when the baby’s brain does not develop in the usual way during early pregnancy.
Sometimes, ACC can be linked to:
- Changes in chromosomes or genes (genetic conditions)
- Problems with brain development early in pregnancy
- Infections or other issues during pregnancy (though this is rare)
Often, ACC happens on its own, without other problems. Your fetal medicine or genetics team can offer tests and explain if there is a known reason in your baby’s case.
ACC can affect each baby differently. Some babies with ACC grow and develop normally, while others may have learning, movement, or communication difficulties as they get older.
It depends on whether ACC happens on its own or with other brain or genetic conditions.
After birth, your baby may have check-ups and developmental assessments to see how they are growing and learning. Support and early help can make a big difference for babies and children with ACC.
- You will be looked after by the specialist fetal medicine team and you may need more detailed scans.
- You may be offered a fetal MRI to get a clearer picture of your baby’s brain.
- Further tests, such as amniocentesis, may be offered to check for any chromosome or genetic conditions.
- You will have regular ultrasound scans to monitor your baby’s growth and development.
- The specialist team will discuss the findings with you, explain what they mean, and support you with your pregnancy options.
- After birth, your baby may have a brain scan (MRI or ultrasound) to confirm the diagnosis, and you may be referred to a paediatrician or neurologist for follow-up and support.
In most cases, ACC happens by chance and is unlikely to occur again in future pregnancies.
However, if ACC is linked to a genetic or chromosome condition, there may be a small chance it could happen again.
Your fetal medicine or genetics team can offer tests and advice to help understand the cause in your baby and the likelihood of it happening in another pregnancy.