What Is Rett Syndrome?

Rett syndrome is a rare disorder that is:

Neurodevelopmental, meaning that it affects how the brain functions and develops

Not neurodegenerative, meaning brain cells will not become damaged or die

Complex and can have a variety of symptoms that may change over time

Rett typically affects girls (but boys can have Rett too).

Three children living with Rett syndrome smiling

~6,000-9,000 people

are living with Rett syndrome in the United States

Diagnosing Rett syndrome

The path to a Rett diagnosis isn’t always simple. It can be years of frustrating twists, turns, and tests for families before a confirmed diagnosis, as they fight to get proper care.

The diagnosis for Rett syndrome is based on your child’s symptoms and behaviors that your doctor has observed in their office and what you have observed in your child at home. A genetic test is not required for diagnosis.

While symptoms for Rett syndrome can start as early as 6 months, most children aren’t diagnosed until they’re about 3 years old.

A period of regression is often noticed as the first sign of Rett. During this regression, your child may lose skills or miss developmental milestones. This period is usually followed by a period of stabilization, which means some of the previous symptoms seem to be getting better.

Typical signs and symptoms for a Rett syndrome diagnosis

Partial or complete loss of acquired spoken communication

This could look like a loss of words they once said, or they may make sounds but not say any meaningful words

Difficulty walking (or crawling) or loss of ability

This could look like walking on toes or balls of feet, or walking with feet wide apart, or not being able to walk at all

Typical signs and symptoms of Rett syndrome highlighted on a human body.

Mechanical, repetitive hand movements

This could look like handwringing, squeezing, clapping/tapping, mouthing, washing and/or rubbing of their hands

Partial or complete loss of purposeful hand skills

This could look like the loss of ability to grasp and intentionally touch things

Not all children with Rett syndrome will show these signs and symptoms.

Other signs and symptoms of Rett your doctor may look for when making a diagnosis are:

Breathing disturbances when awake
Slowed growth and development
Teeth grinding when awake (bruxism)
Small cold hands and feet
Sleep disturbances
Inappropriate laughing/screaming spells
Abnormal muscle tone
Decreased response to pain
Poor blood circulation in hands and feet
Intense eye communication, “eye pointing”
Abnormal curvature of spine (scoliosis/kyphosis)

Since Rett syndrome is so rare, these symptoms may be mistaken for more commonly known disorders like autism, cerebral palsy, or nonspecific developmental delays.

Support and therapy options

Discover a range of therapies and supportive care options designed to address the unique signs and symptoms of Rett.

Explore care approaches

We want to live out loud with Rett syndrome. There’s no shame in this. It’s really quite the opposite.

Matthew, Lucy’s Dad

No two experiences with Rett are alike

Rett syndrome can be challenging to navigate since each child’s experience is unique. Two children could be the same age and have the same mutation but have different Rett symptoms.

Use this interactive timeline to learn what symptoms your child may experience at different phases of their life. Remember, not all children will have the same symptoms since Rett presents differently in every individual.

~6 to 18 months

Your child may appear to be hitting age-appropriate milestones for their first 6 months. Around the 6- to 18-month mark, there may be signs of regression that could be difficult to notice since changes may happen gradually.

You may see:

Rett syndrome symptom delays in crawling and vocalization

Delays in crawling and vocalizations

Rett syndrome regression symptom delays in sitting upright and standing

Delays in sitting upright, standing (postural delays)

Rett syndrome regression symptom low muscle tone

Low muscle tone (hypotonia)

Rett syndrome regression symptom smaller head size

Smaller head size (microcephaly)

These symptoms can last for months, sometimes even over a year.

Child living with Rett syndrome at 6-18 months wrapped in blankets

Lucy at 6-18 months

Child living with Rett syndrome at 6-18 months playing in toddler walker

Lucy at 6-18 months

~6 to 18
months

You may see:

months

Delays in crawling and vocalizations

Delays in sitting upright, standing (postural delays)

Low muscle tone (hypotonia)

Smaller head size (microcephaly)

These symptoms can last for months, sometimes even over a year.

Lucy at 6-18 months

~1 to 4
years old

During this time, your child may gradually or suddenly start to lose some of their verbal and motor skills that they’ve already developed.

You may see:

years old

Rett syndrome regression symptom loss of mobility and coordination

Loss of mobility and coordination

Rett syndrome regression symptom problems with communication, language, and memory

Problems with communication, language, and memory

Rett syndrome regression symptom repeated hand movements

Repeated hand movements: handwringing, clapping, washing, rubbing of hands

Rett syndrome symptom regression hyperventilation

Abnormally fast or deep breathing (hyperventilation), breath-holding, swallowing air

Child living with Rett syndrome 1-4 years old lying with hands crossed behind her head

Lucy at 1-4 years old

Child living with Rett syndrome 1-4 years old and brother sitting on stairs

Lucy at 1-4 years old

Child living with Rett syndrome 1-4 years old riding a horse with assistance

Lucy at 1-4 years old

Child living with Rett syndrome 1-4 years old sitting and smiling

Lucy at 1-4 years old

~2 to 10+
years old

At this time of your child’s life, some of the previous symptoms may seem to be stabilizing or getting better. You may even see improvements in perception, memory, and understanding.

Your child may show more interest in their surroundings, may be more alert, and even engage in eye-pointing to communicate. However, their ability to have coordinated and purposeful hand and body movement may be severely reduced.

Some children living with Rett may also experience seizures, which often begin within this age range.

years old

Lucy at 2-10 years old

Child living with Rett syndrome 2-10 years old bouncing on trampoline with caregiver

Lucy at 2-10 years old

Child living with Rett syndrome 2-10 years old in adaptive stroller on snowy slopes with family

Lucy at 2-10 years old

Child living with Rett syndrome 2-10 years old and her dad in front of a blue sky

Lucy at 2-10 years old

~10+
years old

From around age 10 onward, some children living with Rett may experience a decline in movement. Many transition to wheelchairs and/or have a gastrostomy tube (G-tube or feeding tube).

They may develop:

years old

Rett syndrome symptom regression physical disability

Physical disability

Rett syndrome symptom regression reduced muscle mass

Reduced muscle mass

Rett syndrome symptom regression dystonia

Abnormal muscle tone and involuntary muscular spasms that cause repetitive or twisting movements (dystonia)

Rett syndrome symptom regression bradykinesia

Loss of deliberate actions and extreme slowness of movements and/or freezing (bradykinesia)

Sideways curvature of the spine (scoliosis)

Sideways curvature of the spine (scoliosis)

Some children may also experience additional difficulties with movement and motor control. Since symptoms and severity of Rett syndrome can vary, not every child will experience these symptoms, nor will the stages happen at the same age in a child’s life.

Child living with Rett syndrome at 10+ years old holding her hands and smiling

Lucy at 10+ years old

Child living with Rett syndrome at 10+ years old feeding a horse with some assistance

Lucy at 10+ years old

Child living with Rett syndrome at 10+ years old at physical therapy

Lucy at 10+ years old

Child living with Rett syndrome at 10+ years old in a gym playing adaptive games

Lucy at 10+ years old

Child living with Rett syndrome at 10+ years old swims in the pool with her mom

Lucy at 10+ years old

Lucy Revealed: Getting a Diagnosis

When Lucy missed her milestones, her parents sensed something was off. Find out how they persisted and ultimately found clarity in a Rett syndrome diagnosis.

Watch now

I’ve learned that if we’re willing to find a way, she’s always willing to go. These experiences have brought our family closer and given my sons a deeper connection with their sister.

Matthew, Lucy’s Dad

Genetic testing

Following a clinical diagnosis, your doctor may recommend a genetic test for confirmation. A genetic test could help you and your doctor gain a better understanding of your child’s specific MECP2 gene mutation and it may make it possible to participate in future clinical trials.

Talk to your doctor about genetic testing for the MECP2 gene.

Child living with Rett syndrome and Rett syndrome caregiver talking to doctor

Learn how to navigate a Rett diagnosis

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Diagnosing Rett syndrome

The path to a Rett diagnosis isn’t always simple. It can be years of frustrating twists, turns, and tests for families before a confirmed diagnosis, as they fight to get proper care.

While symptoms for Rett syndrome can start as early as 6 months, most children aren’t diagnosed until they’re about 3 years old.

Typical signs and symptoms for a Rett syndrome diagnosis

Partial or complete loss of acquired spoken communication

This could look like a loss of words they once said, or they may make sounds but not say any meaningful words