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What is Rett syndrome?

Rett syndrome is a genetic disorder that causes a loss of spoken language and motor skills, as well as behavioral and neurological problems. Children with Rett syndrome may also have a variety of other medical problems, including intestinal, breathing, orthopedic, and heart complications.

Children with Rett syndrome often have normal development during the first six to 18 months of life. After this time, they have a period of regression (loss of skills) and they may lose speech and other developmental milestones. The symptoms can range from mild to severe. Almost all children with Rett syndrome are female.

Symptoms & Causes

What are the symptoms of Rett syndrome?

Children with Rett syndrome have a wide variety of symptoms and a range of physical and mental impairments. Symptoms can include:

  • Significantly impaired communication and cognitive (thinking) abilities
  • Loss of the ability to speak
  • Autistic-like symptoms, such as social isolation or withdrawal and reduced eye contact
  • Compulsive hand movements, such as hand wringing, hand clasping, hand clapping, or repeatedly moving the hands toward the mouth
  • Loss of motor skills, such as walking or crawling
  • Breathing problems, including breath holding and hyperventilation
  • Seizures
  • Sleep problems
  • Gastrointestinal problems, such as reflux and constipation
  • Heart rhythm abnormalities, such as QT syndrome
  • Scoliosis
  • Kyphosis
  • Microcephaly (small head size)
  • Low muscle tone
  • Irritability or agitation
  • Teeth grinding (bruxism)
  • Difficulty chewing and swallowing (dysphagia)
  • Drooling

What are the causes of Rett syndrome?

Rett syndrome results from disease-causing changes in the MECP2 gene located on the long arm of the X chromosome. This gene produces a protein called methyl-CpG binding protein 2, which is important for brain development and is believed to be involved in controlling the function of other genes. This protein is essential for the proper function of nerve cells and communication between neurons (brain cells). The specific job of the protein is not yet well understood. However, harmful changes in the gene lead to the symptoms of Rett syndrome.

Rett syndrome most often occurs as a result of a sporadic, or newly occurring, change in the MECP2 gene that was not inherited from the child’s parents.

Diagnosis & Treatments

How is Rett syndrome diagnosed?

Rett syndrome is diagnosed by a physical exam and detailed information about the child’s development and medical history. Key features of a Rett syndrome diagnosis include:

  • Loss of normal hand use
  • Loss of spoken language
  • Trouble walking
  • Abnormal hand movements such as hand wringing or clapping

Your child’s doctor may also order a genetic DNA blood test to support the diagnosis of Rett syndrome. This genetic test may detect a disease-causing change within the MECP2 gene. Most people with a clinical diagnosis of Rett syndrome (80 to 97 percent) have a change in this gene.

However, even if a MECP2 variation is found, the child may not be diagnosed with Rett syndrome if he or she doesn’t fit the clinical diagnostic criteria. For this reason, Rett syndrome is diagnosed by observing signs and symptoms during early development.

Criteria for diagnosing Rett syndrome

The guidelines for diagnosing Rett syndrome are divided into three types: essential, supportive, and exclusion.

Essential criteria

Essential criteria include symptoms that must be present for a child to be diagnosed with Rett syndrome. The essential criteria include:

  • A period of normal development until between 6 to 18 months followed by a loss of skills, then recovery or stabilization of skills
  • Partial or complete loss of purposeful hand skills
  • Partial or complete loss of spoken language
  • Dyspraxic gait (often an unsteady, wide-based, and stiff-legged gait)
  • Repetitive hand movements (such as hand wringing or squeezing, clapping or tapping, or hand mouthing movements)

Supportive criteria

These include symptoms that are not necessary for a diagnosis of classic Rett syndrome but are often present in people with the disorder. A child who has supportive criteria, but no essential criteria does not have Rett syndrome. Supportive criteria include the following:

  • Breathing irregularities while awake, such as apnea, hyperventilation, and air swallowing
  • Teeth-grinding
  • Abnormal sleep patterns
  • Abnormal muscle tone (hypotonia, rigidity, or spasticity)
  • Poor circulation in the hands and feet, with cold and bluish to red hands and feet
  • Scoliosis or kyphosis (curvature of the spine)
  • Delayed growth
  • Small hands and feet
  • Inappropriate laughing or screaming spells
  • Reduced response to pain
  • Intense eye communication or “eye pointing”

Exclusion criteria

Exclusion criteria allow doctors to rule out a diagnosis of Rett syndrome. A child with any of the following criteria does not have classic Rett syndrome:

  • A neurometabolic disease or other inherited degenerative disorder
  • A neurological disorder resulting from severe infection or head trauma
  • Evidence of brain damage acquired after birth
  • Grossly abnormal development in the first 6 months of life

How is Rett syndrome treated?

While there is no currently targeted treatment or gene therapy for Rett syndrome, a care plan can be adapted to the needs of each child. With appropriate interventions, people with Rett syndrome can live well into middle age and beyond and can take part in social, educational, and recreational activities at home and in the community.

In many cases, the physical symptoms of Rett syndrome can be eased and managed with a robust regimen of therapies:

Some children may also benefit from medications for seizures, muscle stiffness, anxiety, or sleep difficulties.

How we care for Rett syndrome at Boston Children’s Hospital

The Boston Children’s Hospital Rett Syndrome Program is dedicated to helping children and adults who have Rett syndrome. We bring together a team of physicians and therapists from various fields who have expertise in Rett syndrome. Our team will work with your child and family to choose the best combination of therapies and medication to manage your child’s symptoms. We can also help your family access resources to help your child learn and thrive.

Frequently Asked Questions

Females have two copies of the X chromosome and males have one X and one Y chromosome. The MECP2 gene is found on the X chromosome, so females born with one normal and one changed copy of the MECP2 gene usually develop the symptoms of Rett syndrome. Since males only have one copy of the X chromosome, they don’t have a normal backup copy of the MECP2 gene. Therefore, males with a MECP2 gene change may have an earlier onset of more severe symptoms (congenital encephalopathy). In rare cases, males do have classic Rett syndrome.

The progression of Rett syndrome starts with the disease-causing change in the MECP2 gene. The MECP2 gene makes the MECP2 protein that is essential for brain development and the normal functioning of nerve cells. The problems associated with Rett syndrome begin when the MECP2 protein fails to carry out its duties — just around the time your baby should be reaching important milestones.

No risk factors for Rett syndrome have been identified, other than being female. The disease-causing gene variation involved in Rett syndrome occurs at random in a child’s DNA.

The condition affects about one out of 10,000 live female births. Rett syndrome in boys is extremely rare.

Your chances of having another child with Rett syndrome are very small — less than 1 percent. Although Rett syndrome is a genetic disorder, the disease-causing gene change is rarely inherited from parents. It’s a common misconception that “genetic” always means “inherited.” In fact, “genetic” only means “caused by a gene.” Prenatal testing is available for families with a daughter who has an identified MECP2 mutation.

There is no known way to prevent Rett syndrome.

There’s no cure for Rett syndrome. However, research is underway on new drugs that may improve management of symptoms.

Your child should be able to attend school, but may need special accommodations. Getting early treatment, including physical therapy, speech therapy, and occupational therapy, can help your child learn and communicate.

Rett syndrome is a disease that progresses slowly throughout life. However, the speed at which it progresses varies greatly from child to child. Some children with Rett syndrome may have improvement in their symptoms between ages 2 and 10. During this time, your child may have an increased interest in surroundings, and improved alertness, attention span, and communication skills. Many children with Rett syndrome will remain in this stage for the rest of their lives and have no further decline in communication or motor skills.

While it is known that Rett syndrome shortens lifespan, not much is known about specific life expectancy rates for people with Rett syndrome. It generally depends on the age when symptoms first begin and their severity. On average, most individuals with the condition survive into their 40s or 50s.