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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).

Lucy, Minna, and Magnolia 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

Speech bubble.

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

Person walking.

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


Mechanical, repetitive hand movements

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

Hand touching something.

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.

Lucy Revealed: Life With Lucy

Learn more about Lucy, a 14-year-old living with Rett syndrome.

Lucy’s Rett diagnosis wasn’t obvious at first. Watch as Anna and Matthew, Lucy’s parents, describe Lucy’s journey to her diagnosis, and the impact it had on their family of five.

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.

Hand touching something.

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.

Lucy Revealed: Diagnosis

Find out what led Matthew and Anna to Lucy’s diagnosis of Rett syndrome.

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.

Two chat bubbles.

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

Minna and her mom talking to their doctor.

Learn how to navigate a Rett diagnosis