Rett syndrome

DEFINITION

Rett syndrome is a rare genetic disorder that affects the way the brain develops. It occurs almost exclusively in girls.

Most babies with Rett syndrome seem to develop normally at first, but symptoms surface after 6 months of age. Over time, children with Rett syndrome have increasing problems with movement, coordination and communication that may affect their ability to use their hands, communicate and walk.

Although there’s no cure for Rett syndrome, potential treatments are being studied. Current Rett syndrome treatment focuses on improving movement and communication and providing care and support for affected children and their families.

CAUSES

Rett syndrome is a genetic disorder, but in only a few cases is it inherited. Instead, the genetic mutation that causes the disease occurs randomly and spontaneously.

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 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 health and behavior problems.

SYMPTOMS

Babies with Rett syndrome are generally born after a normal pregnancy and delivery. Most 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, 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 is usually the first sign that a child has Rett syndrome. It generally starts to become apparent after 6 months of age. As children get older, delayed growth in other parts of the body becomes evident.
• Loss of normal movement and coordination. The most significant loss of movement skills (motor skills) usually starts between 12 and 18 months of age. The first signs often include a decrease of hand control and a decreasing ability to crawl or walk normally. At first, this loss of abilities occurs rapidly and then continues more gradually.
• Loss of communication and thinking abilities. Children with Rett syndrome typically begin to lose the ability to speak and to communicate in other ways. They may become uninterested 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. As the disease progresses, children with Rett syndrome typically develop their own particular hand patterns, which 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 or closing one eye at a time.
• Breathing problems. These include breath-holding (apnea), abnormally rapid breathing (hyperventilation), and forceful exhalation of air or saliva. These problems tend to occur during waking hours, but not during sleep.
• Irritability. Children with Rett syndrome become increasingly agitated and irritable as they get older. Periods of crying or screaming may begin suddenly and last for hours.
• Abnormal behaviors. These may include sudden, odd facial expressions and long bouts of laughter, screaming that occurs for no apparent reason, hand licking, and grasping of hair or clothing.
• Seizures. Most people who have Rett syndrome experience seizures at some time during their lives. Symptoms vary from person to person, and they can range from periodic muscle spasms to full-blown epilepsy.
• Abnormal curvature of the spine (scoliosis). Scoliosis is common with Rett syndrome. It typically begins between 8 and 11 years of age.
• Irregular heartbeat (dysrhythmia). This is a life-threatening problem for many children and adults with Rett syndrome.
• Constipation. This is a common problem in people with Rett syndrome.

Stages of Rett syndrome

Rett syndrome is commonly divided into four stages:

• Stage I. Signs and symptoms are subtle and easily overlooked during the first stage, which starts between 6 and 18 months of age. 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. Starting between 1 and 4 years of age, children with Rett syndrome gradually lose the ability to speak and to use their hands purposefully. Repetitive, purposeless hand movements begin during this stage. Some children with Rett syndrome hold their breath or hyperventilate and may scream or cry for no apparent reason. It’s often difficult for them to move on their own.
• Stage III. The third stage is a plateau that usually begins between the ages of 2 and 10 years and can last for years. Although problems with movement continue, behavior may improve. Children in this stage often cry less and become less irritable. Increased eye contact and using the eyes and hands to communicate generally improve during this stage.
• Stage IV. The last stage is marked by reduced mobility, muscle weakness and scoliosis. Understanding, communication and hand skills generally don’t decline further during this stage. In fact, repetitive hand movements may decrease. Although sudden death can occur, the average life span of people with Rett syndrome is more than 50 years. They usually need care and assistance throughout their lives.

When to see a doctor

Signs 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 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 (emotional dysregulation)
• Any clear loss of previously gained milestones in gross motor or fine motor skills