Definition

Rett syndrome is a developmental nervous system disorder. It primarily affects girls. It is uncommon, but not rare. It occurs in one out of every 10,000-23,000 female births. Boys with the gene defect that causes this disorder are usually stillborn or die shortly after birth.

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

Many people with Rett syndrome live into adulthood. Most have severe disabilities. While many cannot talk or walk, they usually have a full range of feelings and often communicate through their eyes. People with Rett syndrome usually need daily care throughout their life.

Causes

The majority of cases are caused by nonhereditary mutations in the Rett syndrome gene on one X chromosome. Females have two X chromosomes. Males have one X and one Y chromosome. Males usually die from mutations in the Rett syndrome gene. This is because they lack the second normal X chromosome, which partially protects females.

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.

Scientists have not discovered why the Rett syndrome gene is susceptible to mutation. They also have not found what factors lead to this genetic damage. There do appear to be some “hot spots” on the gene. These hot spots are more likely to develop mutations. Because Rett syndrome is usually nonhereditary, it does not commonly occur in multiple children within a family.

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 can vary. There are four stages. Symptoms include:

Stage I: Early Onset Stage

  • Age: 6 to 18 months
  • Duration: months

Symptoms may include:

  • Less eye contact with parents
  • Less interest in toys and play
  • Handwringing
  • Slow head growth
  • Calm, quiet baby

Stage II: Rapid Destructive Stage

  • Age: 1 to 4 years
  • Duration: weeks to months

Symptoms may include:

  • Small head
  • Mental retardation
  • Loss of muscle tone
  • Inability to purposely use hands
  • Loss of (previous) ability to talk
  • Repeatedly moving hands to mouth
  • Other hand movements, such as clapping, tapping, or random touching
  • Hand movements stop during sleep
  • Holding breath, gaps in breathing, taking rapid breaths
  • Irregular breathing stops during sleep
  • Teeth grinding
  • Laughing or screaming spells
  • Decreased social interactions
  • Irritability
  • Trouble sleeping
  • Tremors
  • Cold feet
  • Trouble crawling or walking

Stage III: Plateau Stage

  • Age: preschool through school years
  • Duration: years

Symptoms may include:

  • Difficulty controlling movement
  • Seizures
  • Less irritability and crying
  • Communication may improve

Stage IV: Late Motor Deterioration Stage

  • Age: when stage III ceases, can be anywhere from age 5 to 25
  • Duration: up to decades

Symptoms may 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

A Woman with Scoliosis
© 2009 Nucleus Medical Art, Inc.

Diagnosis

The doctor will:

  • Ask about your child’s symptoms and medical history
  • Do a physical and neurological exam
  • Exclude other disorders, such as autism
  • Do genetic testing can often confirm the diagnosis

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.

Some of the motor functions 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.

Aside from genetic testing, the diagnosis is confirmed by comparing the physical and developmental findings with those typically found in Rett syndrome.

Tests may 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:

  • Skeletal problems
  • Heart problems

Treatment aims to control symptoms and includes:

Medication

  • Anticonvulsants to control seizure activity
  • Stool softeners or laxatives if constipated
  • Drugs to help with breathing
  • Drugs to ease agitation
  • Histone deacetylase inhibitors—Scientists are investigating this group of medications to treat Rett syndrome.

Nutrition Support

  • Small, frequent meals
  • Supplements
  • Tube feeding , if the patient is unable to consume enough food
  • Fluids and high- fiber foods to help control constipation

Rehabilitation Therapies

  • Occupational therapy—to help patients learn to perform daily activities, such as dressing and eating
  • Physical therapy—to help patients improve coordination and movement (can sometimes prolong the ability to walk), braces and splints may be recommended
  • Speech therapy aids—to build communication skills
  • Social workers—to help a family cope with caring for a child with Rett syndrome

Techniques for Limiting Problem Behaviors

Keeping a diary of your child's behaviors and activities helps determine the cause of agitation. The following may help to prevent or control behavior problems:

  • Warm baths
  • Massage
  • Soothing music
  • Quiet environment

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.