Rett Syndrome

Definition

Rett syndrome is a problem with the development of the nervous system. It is most common in girls. Rett syndrome occurs in one out of every 10,000-23,000 female births. Boys with Rett syndrome are usually stillborn or die shortly after birth.

Rett syndrome can be classified into classic and atypical based on the symptoms.

Many people with Rett syndrome live into adulthood. Most have severe disabilities including an inability to talk or walk. People with Rett syndrome usually have a full range of feelings and often communicate through their eyes. Daily care throughout their life is often needed.

Causes

Rett syndrome is most often caused by nonhereditary mutations on a specific gene on one X chromosome.

Females have two X chromosomes. Males have one X and one Y chromosome. Males usually die from Rett syndrome because they lack a second normal X chromosome. The second normal X chromosome in girls may provide some protection.

In Rett syndrome, the mutated gene affects methyl cytosine binding protein 2 (called MECP2). When it is mutated, there is a deficiency of this important protein. This is an area that is still being studied.

Ninety-five percent of girls with Rett Syndrome and 50% of those with the atypical form have the MECP2 mutation. But, not everyone with this mutation will have Rett syndrome. Some females may be normal or have only mild symptoms. But, these women can pass the gene to their daughters. The daughters may then be more severely affected.

It is not clear what causes the Rett gene to mutate. Rett syndrome is usually nonhereditary. This means it does not run in families.

Risk Factors

There are no known risk factors for Rett syndrome, except being female. The mutation that causes the syndrome appears to be sporadic.

Symptoms

A girl with Rett syndrome will start developing normally. She will smile, move, and pick items up with her fingers. But by 18 months of age, the developmental process seems to stop or reverse itself. The age of onset and the severity of symptoms is different from person to person. There are four stages. Symptoms for each stage include:

Stage IV: Late Motor Deterioration Stage

• Occurs at age when stage III ceases, can be anywhere from age 5 to 25
• Can last up to decades and include:
  • Decreased ability to walk
  • Muscle weakness or wasting
  • Stiffness of muscles
  • Spastic movements
  • Scoliosis (curvature of the spine)
  • Breathing trouble and seizures often decrease with age
  • Puberty usually begins at the expected age

Scoliosis

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Diagnosis

The doctor will ask about your child’s symptoms and medical history. A physical and neurological exam will be done. Genetic testing can often confirm the diagnosis. Your doctor may also do tests to rule out other conditions like autism.

Some symptoms of Rett syndrome are similar to those of autism. Children with autism, who are more often boys, do not maintain person-to-person contact. Most girls with Rett syndrome, though, prefer human contact to focusing on inanimate objects. These differences may give the first clue in diagnosing Rett syndrome.

Physical and developmental symptoms can often lead your doctor to a Rett syndrome diagnosis.

Tests that may be done include:

• Blood test—to check for genetic mutation (MECP2)
• Electroencephalogram (EEG)—a test that records the electrical activity of the brain
• Video-EEG—a test that combines EEG with a video to see if some of the child's movements are caused by seizures

Treatment

There is no cure for Rett syndrome. People with this condition need to be monitored for problems of the bones and heart.

Treatment aims to control symptoms and includes:

Prevention

There is no way to prevent Rett syndrome. If you have questions about the risk of Rett syndrome in your family, talk to a genetic counselor.