Page header image

Fragile X Syndrome



  • Fragile X syndrome is a genetic disorder that causes problems with the way the brain and body develop. It can cause severe behavior, health, and learning problems.
  • Speech, language, occupational, and physical therapy are very important to help your child. Medicine may be used to treat health or behavior problems. Treatment will also include doing activities at home.


What is fragile X syndrome?

Fragile X syndrome is a genetic disorder that causes problems with the way the brain and body develop. It can cause hyperactivity, emotional problems, and severe learning problems.

What is the cause?

Inside each cell of your body are genes. Genes contain the information that tells your body how to develop and work. Changes in the genes can be passed from parents to children.

Fragile X is caused by a problem in a gene that prevents the body from making normal amounts of a protein called FMRP. The less of this protein your child has, the more severe symptoms will be.

Fragile X affects both males and females. Usually boys are affected more severely than girls.

What are the symptoms?

There are many symptoms, but not all children with fragile X will have all of these symptoms. They may have some symptoms that are not on this list.

Physical signs

Most infants with fragile X syndrome look normal. As children get older, they often have:

  • Long face and large ears
  • Extra flexible joints, especially the fingers
  • Flat feet
  • Low muscle tone

During puberty, boys usually develop large testicles.

Health problems

Children with fragile X syndrome may have:

  • Frequent ear infections
  • Hernias
  • Joint problems
  • Strabismus, a condition in which the eyes point in different directions
  • A heart valve problem called mitral valve prolapse
  • Seizures

Learning problems

Children with mild learning problems may:

  • Be slower than most children in learning to walk, feed themselves, and talk
  • Learn to read, write, solve problems, and do math only up to the 3rd or 6th grade level. Girls are more likely to have problems with math.

Children with severe learning problems may:

  • Learn only basic skills such as bathing and feeding themselves by teen years
  • Have very limited ability to communicate with others. Most boys have speech delays

Behavior problems

The major problems with fragile X syndrome include:

  • Short attention span and high activity level
  • Being shy or anxious
  • Being moody and irritable
  • Being very sensitive to new sights, sounds, smells, touches, or changes in their routine
  • Being aggressive and having temper tantrums
  • Unusual behaviors such as hand flapping, hand biting, poor eye contact, chewing on clothes, and pulling away from touch
  • Asking questions over and over again even after hearing the answer

Most boys and some girls with fragile X have some symptoms of autistic spectrum disorder, and the child has problems with communicating and getting along with others.

How is it diagnosed?

Pregnant mothers can have tests to check for fragile X. The diagnosis before birth may be based on:

  • Blood tests from the umbilical cord
  • Chorionic villus sampling, or CVS, which tests a sample of cells from the placenta
  • Amniocentesis, which uses a needle to get samples of the fluid that surrounds the baby in the uterus

After your baby is born, a special type of blood test can be done to confirm that your child has fragile X syndrome. The test can also show how severe the disorder is.

How is it treated?

There is no one best treatment for all children with fragile X. Before you decide on your child's treatment, find out what your options are. Learn as much as you can and make your choice for your child's treatment based on your child's needs. There is no cure for fragile X syndrome.

Usually children attend public schools, and the school district provides needed services. Services will include working with a speech therapist, occupational therapist, school psychologist, social worker, school nurse, or aide. You may want to visit public schools in your area to see the type of programs they offer to special needs children.

A team of professionals will help evaluate your child and put a plan together. You may also ask your healthcare provider to review the plan. Ask and find out all the services that may be available for your child.

Speech, language, occupational, and physical therapy are very important to help your child. A cognitive behavioral therapist can help your child learn to manage stress. Other therapies may include art therapy, music therapy, or sensory integration, which may help reduce your child's sensitivity to touch or sound. Treatment will also include doing activities at home.

Your provider will treat ear infections, heart conditions, seizures, or other problems as needed. Medicine may be used to treat anxiety or behavioral problems. These medicines must be prescribed by a healthcare provider experienced with their use in children with this disorder.

Parents often learn of new or alternative treatments through friends or the media. No diet or dietary supplement has been proven to treat fragile X. Your provider can help you decide if alternative treatments could help or harm your child.

How can I help my child?

  • Look for your child’s strengths. No one knows what your child may be able to do in time, so don’t set your expectations too low. Encourage your child to try new things.
  • Work with your child’s treatment team to learn how best to help your child, including ways to respond to behavior problems.
  • Join a support group. Support groups can help by sharing common concerns and solutions to problems with other families in the same situation. You can find these services through your healthcare provider, schools, therapy programs, and local and national support organizations.
  • See a mental health professional to help you cope with your stress.
  • Learn as much as you can about fragile X. For more information, contact:
Developed by Change Healthcare.
Pediatric Advisor 2022.1 published by Change Healthcare.
Last modified: 2021-11-03
Last reviewed: 2018-10-19
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2022 Change Healthcare LLC and/or one of its subsidiaries
Page footer image