Rett syndrome is a neurological disorder that mostly affects females and is associated with problems in cognitive, sensory, emotional, and motor skills. It also has an impact across the nervous system that controls involuntary (or autonomic) functions such as breathing and digestion.

These problems often lead to severe difficulties in learning, speech, mood, movement, and breathing, as well as in the cardiac and gastrointestinal systems.

Symptoms associated with Rett, which is mainly caused by mutations in the MECP2 gene, which encodes a protein of the same name, generally begin to become evident early in life. Usually, normal development in infants or toddlers with Rett starts to slow, stagnate or regress, often between ages 6 and 18 months.

Common symptoms, which can vary greatly among individuals with Rett, are summarized below.

Growth defects

As early as age 3 months, an infant may begin to show slowing head growth that can result in microcephaly, a condition characterized by a smaller head circumference than would be expected for the child’s age and sex.

However, children with the Zapella variant — known as the preserved speech form of Rett syndrome – and those with late childhood regression form often have a normal head size.

Slowed development across the body may appear between 6 and 18 months of age, and usually is more evident in children with the congenital variant of Rett syndrome, also known as the Rolando variant.

The hands and feet may be less developed among some Rett patients and, for some, frequently cold.

Motor problems

Between ages 1 and 4, children with Rett show poorer hand control with characteristic hand movements — usually hand wringing or squeezing, clapping, rubbing, or repetitive movement of the hand to the mouth. Early in life, children also show a decreasing ability to crawl or walk as would be expected for their age. Loss of these abilities may be rapid at first but, over time, continue more gradually. As patients age, their muscles become weak, rigid, or spastic (muscle stiffness or spasms), causing abnormal movement and positioning.

Difficulties with chewing and swallowing also may be observed, which leads to a decrease in food intake.

Loss of muscle tone, a condition known as hypotonia, is particularly evident during the first months of life in children with classic Rett.

In general, later problems with motor skills can become evident after age 10. Some children with classic Rett may never be able to walk, whereas others may gradually lose this ability.

Most affected individuals develop dystonia, a condition characterized by abnormal, uncontrolled movements and postures — like repetitive or twisting movements — due to continuous muscle contractions.

Some individuals with Rett syndrome may have difficulties with balance, due to problems in coordinating the voluntary muscles of the legs. This condition is called gait ataxia.

Symptoms similar to those seen in Parkinson’s disease, such as poorer facial expression, rigidity, and tremor, also may occur.

Children with the late childhood regression form of Rett have a more gradual decrease of motor skills when compared with children with the classic form of the disease. Those with the Zapella variant can regain motor skills.

Communication issues

Children with Rett typically begin to lose the ability to speak and show autism-like symptoms such as social withdrawal and reduced eye contact. They may become disinterested in other people, toys, and their surroundings.

Some children manifest a sudden loss of speech, which can be accompanied by a decline in intellectual function. This worsening can be rapid or gradual.

Over time, however, these children can gradually re-establish eye contact, and develop nonverbal communication skills. Better person-to-person interaction also is possible.

Children with the Zapella variant recover language skills, but show more autism-like symptoms. Regression on language skills also is more gradual in patients with the disease’s late childhood regression form.


Apraxia is characterized by an inability to perform familiar movements on command, even though the person understands what is being requested and would like to comply or respond. It can affect communication and movement. This neurological disorder can occur in children with Rett.

Eye movements

Children with Rett syndrome tend to have unusual eye movements, which include making intense eye contact, blinking, crossed eyes, or keeping one eye closed at a time.

Breathing problems

Problems with breathing can be common in children with Rett and include breath-holding, hyperventilation or rapid breathing, forceful exhalation of air or saliva, and air swallowing, known as aerophagia. Shallow breathing or temporary cessation of breathing (apnea) can occur during sleep. Breathing disturbances tend to aggravate with stress.

Irritability and crying

A state of irritability and excitement also may be seen in children with Rett. This symptom is likely to get worse as the child grows older. Sudden and unreasonable cries and screams may occur and last for long periods. Some children may experience fears and anxiety, with manifestations such as panic attacks and teeth grinding.

Children with the Zapella variant usually have more aggressive behaviors.


Seizures may occur at some point during a patient’s life and are common in children ages 1 to 4.

Children with the Hanefeld variant — also called the early onset seizure type – usually have seizures before 6 months of age.


Scoliosis, which refers to a sideways curvature of the spine, is common in individuals with Rett syndrome. It typically starts between ages 8 and 11, and may require surgery in severe cases.

Irregular heartbeat

Although most people with Rett live to adulthood with proper care, patients are at risk of sudden and unexpected death. Such deaths occur in nearly 25% of patients, and are thought to be partly related to problems with the electrical nerve impulses that regulate the heartbeat, or the rhythmic pumping of the heart muscle.

Sleep issues

Sleep problems in Rett include excessive daytime sleepiness, difficulty in falling asleep at night, and waking during the night. Breathing disturbances during sleep, in the form of sleep apnea, are frequent symptoms.

Abnormal behaviors

Children may show strange facial expressions, episodes of laughter for no reason, and may lick their hands and grab their hair or clothes. Behavioral issues may ease as patients get older.

Bone problems

Some people with Rett develop osteopenia, a condition characterized by low bone mass, which may result in weak and fragile bones that are more likely to break.

Gastrointestinal issues

Gastrointestinal problems are caused by abnormal muscle contractions or problems with the nerves that control the bowel. These problems can include constipation, gastroesophageal reflux, and abnormal dilation of the colon. People with Rett also may be prone to gallbladder disorders and may develop gallstones that may require medical treatment.


Last updated: April 28, 2021


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