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Facts about Fragile X Syndrome

Facts

Fragile X syndrome (FXS) is a genetic disorder. A genetic disorder means that there are changes to the person’s genes. FXS is caused by changes in the fragile X mental retardation 1 (FMR1) gene. The FMR1 gene usually makes a protein called fragile X mental retardation protein (FMRP). FMRP is needed for normal brain development. People who have FXS do not make this protein. People who have other fragile X-associated disorders have changes in their FMR1 gene but usually make some of the protein.

FXS affects both males and females. However, females often have milder symptoms than males. The exact number of people who have FXS is unknown, but it has been estimated that about 1 in 5,000 males are born with the disorder. (1)

Learn how FXS is inherited »

Laptop ComputerWatch a video about what causes fragile X syndrome [VIDEO - 3.20 MB] (Note: If you have difficulty viewing the clip, please send us an email.) or download a transcript.

Signs and Symptoms

Signs that a child might have FXS include:

  • Developmental delays (not sitting, walking, or talking at the same time as other children the same age);
  • Learning disabilities (trouble learning new skills); and
  • Social and behavior problems (such as not making eye contact, anxiety, trouble paying attention, hand flapping, acting and speaking without thinking, and being very active).

Males who have FXS usually have some degree of intellectual disability that can range from mild to severe. Females with FXS can have normal intelligence or some degree of intellectual disability. Autism spectrum disorders (ASDs) also occur more frequently in people with FXS.

Woman doctor in scrubsDiagnosis

FXS can be diagnosed by testing a person's DNA from a blood test. A doctor or genetic counselor can order the test. Testing also can be done to find changes in the FMR1 gene that can lead to fragile X-associated disorders.

A diagnosis of FXS can be helpful to the family because it can provide a reason for a child’s intellectual disabilities and behavior problems. This allows the family and other caregivers to learn more about the disorder and manage care so that the child can reach his or her full potential. However, the results of DNA tests can affect other family members and raise many issues. So, anyone who is thinking about FXS testing should consider having genetic counseling prior to getting tested.

Learn more about diagnosing FXS at the following websites:

Treatments

There is no cure for FXS. However, treatment services can help people learn important skills. Services can include therapy to learn to talk, walk, and interact with others. In addition, medicine can be used to help control some issues, such as behavior problems. To develop the best treatment plan, people with FXS, parents, and health care providers should work closely with one another, and with everyone involved in treatment and support—which may include teachers, childcare providers, coaches, therapists, and other family members. Taking advantage of all the resources available will help guide success.


Early Intervention Services

Early intervention services help children from birth to 3 years old (36 months) learn important skills. These services may improve a child’s development. Even if the child has not been diagnosed with FXS, he or she may be eligible for services. These services are provided through an early intervention system in each state. Through this system, you can ask for an evaluation. In addition, treatment for particular symptoms, such as speech therapy for language delays, often does not need to wait for a formal diagnosis. While early intervention is extremely important, treatment services at any age can be helpful.

Learn more about early intervention »

Photo: Mother and father holding babyFinding Support

Having support and community resources can help increase confidence in managing FXS, enhance quality of life, and assist in meeting the needs of all family members. It might be helpful for parents of children with FXS to talk with one another. One parent might have learned how to address some of the same concerns another parent has. Often, parents of children with special needs can give advice about good resources for these children.

Remember that the choices of one family might not be best for another family, so it’s important that parents understand all options and discuss them with their child’s health care providers.

  • Contact the National Fragile X Foundation at 1-800-688-8765 or Treatment@FragileX.org to get information about treatments, educational strategies, therapies and intervention.

  • Connect with a LINKS group at the National Fragile X Foundation. LINKS groups are organized and run by parent volunteers and provide support to families.

References

  1. Am J Hum Genet. 2009 Oct;85(4):503-14. Incidence of fragile X syndrome by newborn screening for methylated FMR1 DNA. Coffee B, Keith K, Albizua I, Malone T, Mowrey J, Sherman SL, Warren ST.

Genes

Each cell in the human body contains thousands of genes. Genes have a special code called DNA that determines many things about the person. For example, what people look like and whether they are likely to have certain illnesses.

 

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  • Page last reviewed: April 15, 2013
  • Page last updated: August 27, 2013
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