Fragile X syndrome (FXS) is the most common cause of inherited intellectual disabilities. About 1 in 7,000 males and 1 in 11,000 females have been diagnosed with FXS. 

This article will answer your biggest questions about FXS, including:

• What is Fragile X syndrome (FXS)?
• What are the symptoms and signs of Fragile X?
• What behavioral or psychological conditions co-occur with Fragile X syndrome?
• What causes Fragile X?
• How is Fragile X syndrome (FXS) connected with autism spectrum disorder (ASD)?
• What other conditions are associated with Fragile X syndrome?
• How is Fragile X diagnosed?
• If I am a Fragile X carrier but I don’t have any symptoms, am I at risk of any health problems?
• What treatment options are available for Fragile X syndrome? 
• Where can I find help for FXS?

What is Fragile X syndrome (FXS)?

Fragile X syndrome (FXS) is a genetic condition, genetic disorder, or genetic mutation associated with a specific gene in the body called FMR1. Mutated FMR1 genes lead to complications in cognitive function, behavior, mental health, and physical features, most of which are apparent by age 2.  

FXS is called “Fragile X” because part of the X chromosome looks broken or fragile when seen through a microscope.

While there is no cure for Fragile X, there are treatment options, and life expectancy is not affected by the condition.

Other names for Fragile X syndrome include:

• Fra(X) syndrome
• FRAXA syndrome
• FXS
• Marker X syndrome
• Martin-Bell syndrome
• X-linked mental retardation and macroorchidism

What are the symptoms and signs of Fragile X?

Fragile X symptoms include the following:

• Slow early childhood development in walking, talking, or toilet training
• Cognitive impairments
• Developmental delays
• Inherited intellectual disabilities
• Refusal to make eye contact
• Frequent ear infections
• Difficulty sleeping
• Seizures
• Sensory challenges
• Symptoms of autism spectrum disorders (ASD)

Physical features of Fragile X may be more prominent after puberty, particularly in males. These include:

• Large head
• Long face
• Prominent forehead and chin
• Protruding ears
• Loose joints
• Large testes, also called macroorchidism (in males)

What behavioral or psychological conditions co-occur with Fragile X syndrome?

Fragile X may coexist with other behavioral challenges and psychological conditions. These may include:

• Aggression, like impulsive hitting
• Anxiety, including generalized anxiety disorder, panic disorder, separation anxiety, selective mutism, and phobias
• Attention-deficit/hyperactivity disorder (ADHD)
• Compulsive behaviors or obsessive-compulsive disorder (OCD)
• Depression
• Learning disabilities (LDs) or specific learning disabilities (SLDs)
• Unpredictable mood swings

What causes Fragile X?

In the human body, there is a gene called the Fragile X Messenger Ribonucleoprotein 1 (FMR1) gene. The FMR1 gene makes a protein that helps create and maintain connections between cells in the brain and nervous system. Fragile X occurs when the FMR1 gene has a mutation that does not allow it to make enough of the protein.

The severity of the symptoms depends on how many of the genes are affected.

How is Fragile X syndrome (FXS) connected with autism spectrum disorder (ASD)?

FXS and autism often co-exist. The FMR1 gene is one of more than 800 genes considered to be linked to autism. People with Fragile X syndrome make up approximately 1% to 6% of autism cases around the world. According to the Cleveland Clinic, if a child has autism, they have a 2% to 6% chance of also having Fragile X syndrome. 

Clinicians rely heavily on research and surveys to better understand the genetic connection between Fragile X and autism.

One such study is called FORWARD-MARCH. This study is a collaborative effort between the CDC and the Fragile X Online Registry With Accessible Research Database (FORWARD), through a new program called Multiple Assessments for Research Characterization (MARCH). 

FORWARD-MARCH will help researchers learn more about the lives of people with Fragile X, giving us a clearer idea of how best to support children and families with FXS, especially as they age. 

To learn more about this study and how to get involved, see the article on the National Fragile X Foundation website.

How is Fragile X diagnosed?

Diagnosing Fragile X involves a DNA test. The test goes by two names: FMR1 DNA Test and Fragile X DNA Test. This DNA testing detects more than 99% of people who have or carry FXS.

The following people should consider DNA testing:

• People with inherited intellectual disabilities, developmental delay, or autism.
• Women with elevated follicle-stimulating hormone (FSH) levels associated with reproductive or fertility problems.
• Anyone who experiences late-onset intention tremor and cerebellar ataxia.
• Women who are pregnant or trying to get pregnant. If a pregnant woman is a carrier, her doctor will likely encourage her to get the fetus tested as well via amniocentesis (sampling from amniotic fluid) or chorionic villus sampling (cell sample from the placenta).

What conditions are associated with Fragile X syndrome?

People who have other Fragile X-associated disorders have changes in their FMR1 gene, but their body still produces the FMRP protein. This premutation may cause the following Fragile X-associated conditions:

• Fragile X-Associated Primary Ovarian Insufficiency (FXPOI) may cause infertility and early menopause. 
• Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) is a nervous system disorder. FXTAS may cause problems with walking, balance, memory, mood disorders, and tremors.

If I am a Fragile X carrier but I don’t have any symptoms, am I at risk of any health problems? 

Yes. People who carry the FMR1 mutation but do not have symptoms of Fragile X syndrome are at a higher risk of developing certain health conditions. These include:

• Early menopause (in women)
• Dementia
• High blood pressure
• Depression
• Anxiety
• Migraines
• Hypothyroidism
• Chronic pain
• Sleep apnea

If you take care of a child diagnosed with Fragile X syndrome, don’t forget to take care of yourself along the way. Regular checkups with your primary care provider can help you discover and treat potential health concerns for Fragile X carriers.

What treatment options are available for Fragile X syndrome?

There is no cure for FXS, but Fragile X treatments are being studied in clinical trials. Current  Fragile X treatment is primarily done through medications to treat individual symptoms and therapies to teach social and coping skills. Therapies may include:

• Cognitive behavioral therapy (CBT)
• Occupational therapy (OT)
• Physical therapy (PT)
• Speech language therapy (SLP) 

Some children with Fragile X syndrome may also need accommodations or curriculum modifications to succeed at school. Special education considerations like individualized education plans (IEPs) and 504 plans can help parents and educators work together to create the best learning environment for children with FXS. 

Is Fragile X syndrome a lifelong condition?

Yes. Children diagnosed with FXS will carry the condition for the rest of their lives. 

Because symptoms are generally milder in women than in men, women with Fragile X syndrome tend to be more independent than men with the condition, although anyone diagnosed with FXS can go on to live a full, independent, and authentic life. 

A national family survey of adults with FXS showed:

• 4 in 10 women achieved a high or very high level of independence in adult life compared to 1 in 10 men.
• 4 in 10 women lived independently, often with a spouse or romantic partner, compared to 1 in 10 men who lived independently, often without a spouse or romantic partner. 
• 8 in 20 women with FXS required no assistance with daily life compared to 1 in 20 men. 
• The majority of women with FXS graduated at least from high school, while the majority of men did not. 
• Almost 50% of women with FXS had full-time jobs, compared to 2 in 10 men. 

Where can I find help for Fragile X syndrome?

When looking for doctors who can diagnose Fragile X syndrome, your family doctor, primary care physician, or pediatrician is a good place to start. If you have private medical insurance through a family member, job, or marketplace, an insurance representative may be able to help you find in-network primary care providers and specialists. 

In addition, Ability Central offers a searchable database of nonprofits that can help with everything from diagnosis to treatment. Use our Service Locator tool to find an organization near you that serves people and families with Fragile X syndrome. 

In addition, The National Fragile X Foundation can connect you with the latest research and information.

To learn more about co-existing conditions, see:

• Autism spectrum disorder (ASD)
• Specific learning disabilities (LDs and SLDs)
• Attention-deficit/hyperactivity disorder (ADHD)