Rett syndrome is a rare genetic neurological and developmental disorder that affects the way the brain develops, causing a progressive inability to use muscles for eye and body movements and speech. It occurs almost exclusively in girls.
Most babies with Rett syndrome seem to develop normally at first, but after about 6 months of age, they lose skills they previously had — such as the ability to crawl, walk, communicate or use their hands.
Over time, children with Rett syndrome have increasing problems with the use of muscles that control movement, coordination and communication. Rett syndrome can also cause seizures and intellectual disability.
Although there's no cure for Rett syndrome, potential treatments are being studied. Current treatment focuses on improving movement and communication and providing care and support for children and adults with Rett syndrome and their families.
Babies with Rett syndrome are generally born after a normal pregnancy and delivery. The age at which symptoms begin and their severity and associated disability varies widely among individuals. However, most babies with Rett syndrome seem to grow and behave normally for the first six months. After that, signs and symptoms start to appear.
The most pronounced changes generally occur at 12 to 18 months of age, suddenly, or over a period of weeks or months.
Rett syndrome signs and symptoms include:
- Slowed growth. Brain growth slows after birth. Smaller than normal head size (microcephaly) is usually the first sign that a child has Rett syndrome. As children get older, delayed growth in other parts of the body becomes evident.
- Loss of normal movement and coordination. The first signs often include reduced hand control and a decreasing ability to crawl or walk normally. At first, this loss of abilities occurs rapidly and then it continues more gradually. Eventually muscles become weak or may become rigid or spastic with abnormal movement and positioning.
- Loss of communication abilities. Children with Rett syndrome typically begin to lose the ability to speak, to make eye contact and to communicate in other ways. They may become disinterested in other people, toys and their surroundings. Some children have rapid changes, such as a sudden loss of speech. Over time, most children gradually regain eye contact and develop nonverbal communication skills.
- Abnormal hand movements. Children with Rett syndrome typically develop repetitive, purposeless hand movements that may differ for each person. Hand movements may include hand wringing, squeezing, clapping, tapping or rubbing.
- Unusual eye movements. Children with Rett syndrome tend to have unusual eye movements, such as intense staring, blinking, crossed eyes or closing one eye at a time.
- Breathing problems. These include breath-holding, abnormally rapid breathing (hyperventilation), forceful exhalation of air or saliva, and swallowing air. These problems tend to occur during waking hours, but not during sleep.
- Agitation and irritability. Children with Rett syndrome become increasingly agitated and irritable as they get older. Periods of crying or screaming may begin suddenly, for no apparent reason, and last for hours.
- Other abnormal behaviors. These may include, for example, sudden, odd facial expressions and long bouts of laughter, hand licking, and grasping of hair or clothing.
- Cognitive disabilities. Loss of skills can be accompanied by a loss of intellectual functioning.
- Seizures. Most people who have Rett syndrome experience seizures at some time during their lives.
- Abnormal curvature of the spine (scoliosis). Scoliosis is common with Rett syndrome. It typically begins between 8 and 11 years of age and increases with age. Surgery may be required if the curvature is severe.
- Irregular heartbeat. This is a life-threatening problem for many children and adults with Rett syndrome and can result in sudden death.
- Pain. Because of health problems, people with Rett syndrome may have an increased risk of pain. But communication problems may prevent others from recognizing these pain issues. In one small study, one-fourth of the parents estimated that their daughters have more than a week of pain each month.
- Other symptoms. A variety of other symptoms can occur, such as thin, fragile bones prone to factures; small hands and feet that are usually cold; problems with chewing and swallowing; and teeth grinding. Symptoms can vary greatly from child to child.
Stages of Rett syndrome
Rett syndrome is commonly divided into four stages:
- Stage I: early onset. Signs and symptoms are subtle and easily overlooked during the first stage, which starts between 6 and 18 months of age and can last for a few months or a year. Babies in this stage may show less eye contact and start to lose interest in toys. They may also have delays in sitting or crawling.
- Stage II: rapid destruction. Starting between 1 and 4 years of age, children lose the ability to perform skills they previously had. This loss can be rapid or more gradual, occurring over weeks or months. Symptoms of Rett syndrome occur, such as slowed head growth, abnormal hand movements, hyperventilating, screaming or crying for no apparent reason, problems with movement and coordination, and a loss of social interaction and communication.
- Stage III: plateau. The third stage usually begins between the ages of 2 and 10 years and can last for many years. Although problems with movement continue, behavior may have limited improvement, with less crying and irritability, and some improvement in hand use and communication. Seizures may begin in this stage and generally don't occur before the age of 2.
- Stage IV: late motor deterioration. This stage usually begins after the age of 10 and can last for years or decades. It's marked by reduced mobility, muscle weakness, joint contractures and scoliosis. Understanding, communication and hand skills generally remain stable or improve slightly, and seizures may occur less often.
When to see a doctor
Signs and symptoms of Rett syndrome can be subtle in the early stages. See your child's doctor right away if you begin to notice physical problems or changes in behavior after apparently normal development, such as:
- Slowed growth of your child's head or other parts of the body
- Decreased coordination or mobility
- Repetitive hand movements
- Decreasing eye contact or loss of interest in normal play
- Delayed speech development or loss of previously acquired speech abilities
- Problem behavior or marked mood swings
- Any clear loss of previously gained milestones in gross motor or fine motor skills
Rett syndrome is a rare genetic disorder. Classic Rett syndrome, as well as five known variations (atypical or variant) with milder or more severe symptoms, can occur based on the specific genetic mutation.
The genetic mutation that causes the disease occurs randomly, usually on the MECP2 gene. Only in a few cases is this genetic disorder inherited. The mutation appears to result in problems with the protein production critical for brain development. However, the exact cause is not fully understood and is still being studied.
Rett syndrome in boys
Because males have a different chromosome combination from females, boys who have the genetic mutation that causes Rett syndrome are affected in devastating ways. Most of them die before birth or in early infancy.
A very small number of boys have a different mutation that results in a less destructive form of Rett syndrome. Similar to girls with Rett syndrome, these boys will likely live to adulthood, but they're still at risk of a number of intellectual and developmental problems.
Rett syndrome is rare. The genetic mutations known to cause the disease are random, and no risk factors have been identified. In a few cases, inherited factors — for instance, having close family members with Rett syndrome — may play a role.
Complications of Rett syndrome include:
- Needing lifelong care and assistance with activities of daily living
- Sleep problems, including unusual sleep patterns such as falling asleep during the day or waking up at night
- Difficulty eating, leading to poor nutrition and delayed growth
- Constipation, which can be a severe, ongoing problem, as well as other gastrointestinal (GI) problems, such as gastroesophageal reflux disease (GERD)
- Muscle and joint problems
- Anxiety and problem behavior that may compromise social functioning
- Shortened life span — people with Rett syndrome don't live as long as most people because of heart problems and other health complications
There's no known way to prevent Rett syndrome. In most cases, the genetic mutation that causes the disorder occurs spontaneously. Even so, if you have a child or other family member with Rett syndrome, you may want to ask the doctor about genetic testing.