DESCRIPTION
ACC is a rare birth defect. In ACC, the structure connecting the two halves of the brain has not formed properly. The outlook for children with ACC depends on:
- Severity of the condition
- The presence of other brain abnormalities
Children who have ACC but no other brain abnormalities may have no symptoms. However, more severely affected children can suffer from seizures, learning difficulties, vision problems, and other issues.
Definitions
- Corpus callosum (CC). The structure connecting the brain’s two hemispheres, or sides.
- Hypoplasia. An abnormally thin formation of the CC.
- Dysgenesis. A malformation of the CC.
- Agenesis of the Corpus callosum (ACC). A complete absence of the CC.
- Isolated ACC. Problems with the CC when the rest of the brain is normal.
Note: For simplicity, this page refers to all disorders of corpus callosum formation as ACC.
SIGNS AND SYMPTOMS
Diagnosis
Prior to Birth
ACC can sometimes be diagnosed on an ultrasound of a fetus before birth. MRI (magnetic resonance image) of the fetus can confirm these findings. A prenatal MRI can also provide more details on:
- Whether or not there are other brain abnormalities
- The severity of ACC or other abnormalities
After Birth
Often, however, ACC is not seen on a prenatal ultrasound. In these cases, ACC may be detected after birth using imaging. Imaging that can find ACC after birth include:
- Ultrasound
- CT (computed tomography) scan
- MRI
MRI may also be used in infants for other reasons. It can help doctors to better understand symptoms. It can also look for other causes of symptoms.
Symptoms
Some cases of ACC are mild. These cases do not cause any symptoms. Other cases cause symptoms, but not right away. When the symptoms are delayed, there can be a delay in diagnosis, too.
Symptoms of ACC can include:
- Microcephaly. This is when the head is abnormally small.
- Macrocephaly. This is when the head is abnormally large.
- Developmental delays. There may be delays in reaching milestones such as:
- Rolling over
- Sitting
- Standing
- Walking
- Talking
- Learning
- Using hands
- Problems with motor control and movement. This can include:
- Muscles that are too tight or too floppy
- Problems with balance and eye-hand coordination
- Unpredictable movements
- Problems with speech. This can include:
- Problems forming words
- Problems understanding language
- Learning disabilities. Some children will need extra help at school or to be enrolled in special education.
- Issues with vision and hearing. Some children will require vision or hearing therapy, hearing aids, or special accommodations at school.
- Epilepsy. Children may develop seizures requiring medication, procedures and/or a specialized medical diet.
- Facial differences. Some children may not look like their parents due to abnormal face development. Some may have features common to certain genetic syndromes.
OUTLOOK
There is no cure for ACC. The severity of ACC can differ a lot from case to case. It depends on the amount of the brain involved. Some children with partial ACC never develop symptoms. Other children with ACC have difficulty:
- Meeting developmental milestones
- Participating in regular classrooms
- Having a job
- Living independently
Early and consistent therapy may be helpful for some children. Important therapies include physical, occupational, speech, and vision therapies. Many will need daily medication to prevent seizures or treat other complications. Some will benefit from a feeding tube for extra nutrition.
ACC is often found alongside hydrocephalus. This is a buildup of fluid around the brain. A shunt may be needed to relieve pressure in the head for children with hydrocephalus.