DESCRIPTION
Lissencephaly means “smooth brain.” In lissencephaly there are few or no folds in the brain.
During normal brain development in pregnancy, the brain starts as a smooth surface. Over time, it develops folds known as gyri. Normally, brain cells (neurons) first form deep in the brain. Then they move outward, as layers and folds of brain develop. This takes place prior to birth. The peak time for this to happen is during second trimester, or 3 to 5 months into pregnancy.
In lissencephaly, the neurons do not reach their final destination. They do not form normal bumps and grooves in the brain. There are two major types of lissencephaly
- Type I. Also known as “classic lissencephaly.” This results in a brain that is smooth. Type I can be further divided:
- Isolated lissencephaly. When only the brain is affected.
- Associated with another syndrome. When lissencephaly is one of the many other symptoms and is associated with another syndrome, other organs may also be affected.
- Type II. Also known as “cobblestone lissencephaly.” This results in a brain that forms bumps. The bumps look like cobblestones. Children with type II also develop muscle and eye disease. Like type I, there are many potential causes of type II.
Pachygyria is the name for a mild form of the condition.
SIGNS AND SYMPTOMS
Lissencephaly can be diagnosed on prenatal ultrasound. Another important tool for early detection is fetal MRI (magnetic resonance imaging). Fetal MRI can confirm findings and provide more detail even prior to birth. It can check the severity of the condition and look for any other brain malformations.
The condition can be diagnosed in infancy and childhood using:
- A head ultrasound (in infants only)
- A head CT (computed tomography) scan
- A brain MRI
Symptoms of lissencephaly are usually seen in infancy. Common symptoms include:
- Microcephaly. This is when the head is abnormally small.
- Macrocephaly. This is when the head is abnormally large.
- Epilepsy. Children may develop seizures. The seizures may require medications, procedures, or a specialized medical diet.
- Developmental delays. There may be delays in reaching milestones such as:
- Rolling over
- Sitting
- Standing
- Walking
- Talking
- Learning
- Using hands
- Learning disabilities. Children will need extra help at school. They may need to be enrolled in special education.
- Problems with motor control and movement. This can include:
- Difficulty controlling muscles
- Lack of movement
- Muscles that are too tight or too floppy
- Unpredictable movements
- Problems with communication. This can include trouble:
- Learning or saying words
- Understanding language
- Communicating with words, sign language, or pointing
- Problems with swallowing. Some children may not be able to swallow safely. Many children benefit from a feeding tube. The feeding tube can help them safely get nutrition and medications.
- Problems with vision and hearing. Some children may be blind and/or deaf. They may benefit from:
- Vision or hearing therapy
- Hearing aids
- Special accommodations at school
- Facial differences. Some children may not look like their parents due to abnormal face development.
Lissencephaly typically results in moderate or severe symptoms. The symptoms can put babies at risk for potentially life-threatening complications. These complications can include:
- Lung infections
- Difficulty breathing
- Seizures that are difficult to treat
OUTLOOK
There is no cure for lissencephaly. Symptoms are typically moderate or severe. However, severity differs depending upon the amount of the brain involved.
Early and consistent therapy can be very helpful for some children. Therapies may include physical, occupational, speech, or vision therapy. Most children with lissencephaly need daily medications to:
- Prevent seizures
- Treat other complications
Some children benefit from a feeding tube for extra nutrition.
This disorder is often found alongside hydrocephalus, a buildup of fluid around the brain. In these cases, shunt may be needed to relieve pressure in the head.
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