What Is Lissencephaly?

Medically Reviewed by Christopher Melinosky, MD on May 04, 2023
3 min read

Lissencephaly is a rare condition that causes a child’s brain to develop the wrong way during pregnancy.

A child with the disorder may have an unusual-looking face or a hard time swallowing, among the many health issues it can cause.

How a child will get along with the condition varies. Some have near-normal development while others never go beyond a 5-month-old level. There’s no cure, but supportive care helps in some cases. It can be life-threatening for some kids, but other children grow into adulthood.

Because there is such a wide range of complications, you should seek out a specialist in this condition.

During pregnancy, a baby’s brain should develop many folds and wrinkles as it grows. These folds allow the brain to function normally. In rare cases during the 9th and 12th weeks, this does not happen. The brain is mostly smooth and forms few wrinkles.

Infants can have this condition by itself. You may hear a doctor call it “isolated lissencephaly sequence.”

Other children can have it as a result of another condition. Some that might go along with it are:

  • Miller-Dieker syndrome. Kids with this tend to have large foreheads, small jaws and other facial issues. They may grow more slowly and have breathing problems.
  • Norman-Roberts syndrome. Complications can include wide-set eyes, seizures, and reduced mental abilities.
  • Walker-Warburg syndrome. This causes severe muscle weakness and wasting.

About 1 in every 100,000 babies is born with lissencephaly.

Researchers have found that a problem in any one of several different genes can cause it. Most of these gene changes aren’t necessarily passed down from a parent. Instead, they can appear at random in a person’s genetic makeup when there is no family history of the condition.

Some people with the condition don’t have changes in any of the genes that are known to be connected with it. They may have irregularities in genes that researchers have not yet identified, or their condition could have other unknown causes.

Some research shows uterine infections during pregnancy could cause the condition. It may also be possible for a baby in the womb to have a stroke that leads to it.

Lissencephaly has varying levels of severity and symptoms.

The condition can stunt the growth of the brain. Infants may have an unusually small head at birth or sometime thereafter. Other possible signs and symptoms may include:

  • Difficulty swallowing
  • Muscle spasms
  • Severe mental and physical challenges

Some kids may never be able to sit, stand, walk or roll over. They might have poor muscle tone. Their hands, fingers, or toes may be deformed.

Other people, however, may develop normally and show few signs of a learning disability.

Infantile spasms, a type of seizure, are common in babies with lissencephaly. About 8 of 10 babies will have them.

These seizures may be undetectable or not appear serious. They don’t cause the type of convulsions that people may imagine a seizure to be. If your baby has infantile spasms, it might look like they are startled or having colic or reflux. But they can be more serious than typical seizures. They can cause brain damage and further hinder your child’s growth. It’s important to seek medical attention right away.

Some 9 out of 10 babies with lissencephaly will develop epilepsy, a type of brain disorder that also causes seizures, within the first year of life.

Doctors use brain scans to diagnose it. These may include a CT scan or MRI.

After a doctor confirms a diagnosis, genetic testing might find a mutation that caused the condition.

There is no cure for lissencephaly, but some people can improve over time. Doctors and parents focus on controlling and addressing the symptoms.

Physical, occupational, and speech therapy could help in some cases. People living with the condition might need medications to control seizures.

Children can sit in wheelchairs or chairs that keep them upright. Some might need a feeding tube if they have trouble swallowing.

Trouble with breathing and swallowing -- and seizures -- are common causes of death among people who have lissencephaly.

Parents should remember every case is different. Although some children with the condition don’t live past age 10, others go on to become adults. You should seek out a specialist to give you more information about your child’s condition and support services.