Symptoms of Rett syndrome

Last updated Sept. 11, 2025, by Marisa Wexler, MS
Fact-checked by Jose Lopes, PhD

Rett syndrome is a genetic disorder that primarily affects girls. It is marked by symptoms that include abnormalities in development, issues with motor function, and communication problems.

There is no cure for Rett syndrome; treatment for this progressive condition focuses on supportive care to manage symptoms and help patients and their families maximize life quality. Recognizing the early signs and symptoms of Rett syndrome can help ensure that families are quickly connected to support that can help them.

Understanding how Rett syndrome symptoms progress

Babies with Rett syndrome will develop normally for the first few months of life, reaching early milestones such as making eye contact and rolling over. Then, at about 6 to 18 months of age, normal development will stop, marking the first signs of Rett. Children will go through a period of rapid regression, where they lose skills that they had previously acquired.

The regression in Rett syndrome is followed by a period of stabilization in which patients will generally retain their skills and may even pick up new ones. Later, patients will usually start to experience increasing motor dysfunction. The characteristic pattern of normal development followed by regression and then stabilization or recovery is a defining feature used to establish a Rett syndrome diagnosis.

Rett syndrome can cause a wide array of different symptoms, and specific manifestations may vary from person to person. Common manifestations of the disease include:

slowed head growth
difficulty communicating
loss of hand skills
uncontrolled, repetitive hand movements
seizures
abnormal spine curvature, or scoliosis
sleep problems
behavioral issues, ranging from unexplained crying or laughing to profound anxiety
abnormal cognitive development
digestive issues, such as constipation or difficulty swallowing
breathing problems

Other common Rett syndrome symptoms include:

unusual eye movements
difficulty feeding
abnormal heart rhythm

Rett syndrome symptoms by stage

There are four Rett syndrome stages:

stage I, where symptoms first appear
stage II, marked by rapid regression
stage III, characterized by stabilization or easing of symptoms
stage IV, marked by the onset and progression of more substantial motor dysfunction

It is important to highlight that these different stages are just general descriptors for how Rett syndrome tends to manifest and progress. Rett affects everyone differently, and not everyone with condition will necessarily go through every stage.

Stage I

The first stage of Rett syndrome, sometimes called the early onset phase, is when symptoms first appear. This typically occurs between 6 to 18 months of age, and may last a few months to a year.

Prior to this stage, babies with Rett develop normally or have abnormalities that are so subtle that they are only noticeable in retrospect. Then, as the first stage begins, normal development will stop or stall, resulting in early symptoms of Rett, such as:

slowed growth of the head
limited eye contact
loss of interest in toys
low muscle tone
difficulty feeding
hand-wringing movements
gross motor delays

For most children with Rett, gross motor delays manifest as not being able to sit up or crawl within developmentally typical timeframes.

Stage II

The second stage of Rett syndrome, sometimes referred to as the rapid destructive phase, usually starts between the ages of 1 and 4. This stage is marked by rapid regression, in which children will lose skills that they had previously acquired. This typically occurs over the course of weeks or months.

Common Rett symptoms seen at this stage of the disease include:

frequent repetitive hand movements, such as clasping or squeezing
loss of speaking ability and reductions in social interaction
loss of motor skills and purposeful hand movements
irritability and screaming or crying for no clear reason
problems sleeping

Stage III

The third stage of Rett syndrome is sometimes called the plateau phase. During this phase, development will stabilize and some skills may improve — for example, patients may have a better ability to communicate, fewer behavioral issues, and improved coordination when moving their hands.

This phase usually begins between the ages of 2 and 10 and commonly lasts many years. Many people with Rett syndrome spend the majority of their lives in this stage.

Seizures, which rarely occur earlier than age 2, typically begin in this stage.

Stage IV

The fourth stage of Rett syndrome is known as the late motor deterioration phase. This phase begins after the age of 10, and it is marked by movement abnormalities, including:

involuntary muscle movements, known as dystonia
abnormally slowed movement, known as bradykinesia
scoliosis
muscle weakness
contractures, where joints become fixed in place

Although new motor challenges typically become apparent at this stage, communication abilities will usually be maintained. Abnormal hand movements and breathing problems are generally less common in this stage than in earlier stages, and seizures may be less frequent.

Rett syndrome in girls is often accompanied by an earlier than normal onset of puberty, though a later than normal onset of menstruation.

How symptoms can differ

Most people with Rett syndrome have what’s called the classic or typical form of the disease. Typical Rett syndrome is marked by symptom progression as outlined: the first stage starts between 6 to 18 months of age, followed by rapid regression, plateauing, and motor dysfunction later on. Although people with typical Rett will usually follow this general pattern of disease progression, there can be substantial variability from person to person in exactly how the disease manifests.

Atypical Rett syndrome, which is defined by markedly different patterns of symptom manifestation, has been estimated to occur in nearly a third of Rett patients. People with atypical Rett do not meet all the diagnostic criteria for typical Rett syndrome, though they still have several of the main and supportive criteria to diagnose Rett. Individuals with atypical Rett syndrome less commonly carry a MECP2 mutation, which is the cause of most Rett cases.

As of now, there are five defined forms of atypical Rett syndrome:

The early-onset seizure type, also called the Hanefeld variant, is marked by seizures that start in infancy instead of later in childhood.
The congenital or Rolando variant is characterized by loss of muscle tone and developmental delay in the first months of life.
The forme fruste variant is marked by milder purposeless hand movements and better hand coordination than is seen in typical Rett syndrome.
The late childhood regression form is characterized by a later and more gradual loss of communication and motor skills than in typical Rett syndrome.
The preserved speech variant, also called the Zappella variant, is characterized by symptoms that start similarly to classic Rett syndrome, but with a more pronounced recovery, such that patients regain some language and motor skills.

Rett Syndrome News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.