crsheader Index Fragile X Syndrome

What is fragile X syndrome?

Fragile X syndrome is an inherited disorder. It can cause hyperactivity, learning problems, and emotional problems. It can also cause mental retardation and is the most common known cause of autism. Some children with fragile X have normal IQs. Fragile X affects both males and females.

What is the cause?

More than 100 trillion cells make up the human body. Inside each cell are genes. Genes contain the information used by other parts of the cell to make proteins, the body’s building blocks. Each protein does a specific job.

If the information in a gene is changed, the cell may not be able to make that protein. Or it may not be able to make a form of the protein that the body can use. Fragile X occurs because a gene called FMR1 cannot make normal amounts of a protein called FMRP.

A person with nearly normal levels of FMRP usually has mild or no symptoms, while a person with very little or no normal FMRP has more severe symptoms. Usually boys are affected more severely than girls.

A special type of blood text can be done to confirm whether your child has fragile X syndrome. The test can also show how severe the disorder is.

Pregnant mothers can have tests to check for fragile X. This can be done with chorionic villus sampling, or CVS, in which a small sample of the placenta is drawn into a needle or a small tube for analysis. A pregnant woman can also have amniocentesis, in which a needle is inserted into the mother’s belly to draw a sample of amniotic fluid. Another test that can be done is umbilical blood sampling.

What are the symptoms?

  1. Physical appearance

    Boys affected by fragile X syndrome often have large ears, a large head, a broad forehead, extra flexible finger joints, a high palate, soft skin, and flat feet. During puberty, boys usually develop large testicles and a longer face than most people. Most children with fragile X syndrome look normal.

    Girls may also have large ears, flexible finger joints, and flat feet.

  2. Health concerns

    In general, children with fragile X syndrome do not have a lot of medical problems. The health problems they may have include:

    • frequent ear infections
    • a hernia
    • joint problems
    • strabismus, a weak eye muscle, occurs in some children with fragile X
    • mitral valve prolapse, a heart valve problem, which occurs in about 50% of adults with fragile X
    • seizures (in about 20% of children and adults with fragile X)
  3. Behavioral problems

    The major problems with fragile X syndrome include:

    • learning problems
    • short attention span
    • shyness
    • being moody and irritable
    • mentally retarded, meaning that their IQs are below 70.
    • being very sensitive to new sights, sounds, smells, touches, or changes in their routine
    • anxious
    • temper tantrums and aggressive behavior
    • high activity level
    • slow language development. Most boys do not talk much by age 3.
    • unusual behaviors such as hand flapping, hand biting, poor eye contact, excessive chewing on clothes, and pulling away from touch
    • asking questions over and over again even after hearing the answer

    About 20% to 35% of children with fragile X have autism.

Children with fragile X syndrome also have many strengths, such as:

  • social abilities (although shyness is common)
  • a wonderful sense of humor
  • an excellent memory for people, events, and directions
  • intense interests
  • outstanding imitation skills

What is the treatment?

There is no cure for fragile X syndrome, but new medicines are being tested. There are several other medicines and therapies that may help.

  1. Therapy

    If your child is diagnosed in infancy, your provider will discuss infant stimulation programs. Special preschool programs are helpful for children under 5 years of age.

    Speech, language, occupational, and physical therapy are very important to help your child develop motor skills and language. Sensory integration therapy can be helpful for behavioral problems. The therapist will teach techniques such as deep pressure back rubs and joint compression. These techniques may help to calm behavior outbursts or tantrums at home.

    Your provider or psychologist can help you set up a behavior program at home.

  2. Education

    Your child should have an Individualized Educational Plan (IEP) developed by his teachers, therapists and you. His school program should include both time in the regular classroom and individual help from a special education teacher. Getting a tutor can also help. Speech and language therapy, occupational therapy, and computer use may also help your child learn. Your school and healthcare provider can help you arrange these services and the proper kinds of therapy when needed.

  3. Medical care and medicines

    Most children with Fragile X do not have serious medical problems. Your provider will treat ear infections, heart conditions, seizures, or other problems as needed.

    Your provider may prescribe medicines that can improve behavioral or emotional symptoms. Medicine may be used with other kinds of treatment. Such medicines are used for a trial period and are continued only if they help. If your child has a side effect from the medicine, call your provider.

Where can my family get help and support?

When parents hear for the first time that their child has fragile X, they can feel grief, anger, guilt, and many other emotions. Children with fragile X syndrome are not easy to raise, and parents need to have personal time and recovery time. Talk with your provider. He or she can help you. You can learn what help is available from:

The National Fragile X Foundation
Phone: 1-800-688-8765
Web site:

Written by Randi Hagerman, MD, Fragile X Research Chair in Pediatrics and Medical Director of the MIND Institute, UC Davis Medical Center. Published by RelayHealth.
Last modified: 2011-06-09
Last reviewed: 2011-06-01 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. References
Pediatric Advisor 2011.4 Index
© 2011 RelayHealth and/or its affiliates. All rights reserved.