What is Fragile X Syndrome?

Fragile X is a family of genetic conditions, which can impact individuals and families in various ways. These genetic conditions are related in that they are all caused by gene changes in the same gene, called the FMR1 gene.

Fragile X includes:

Fragile X syndrome (FXS), the most common cause of inherited mental impairment. This impairment can range from learning disabilities to more severe cognitive or intellectual disabilities. (Sometimes referred to as mental retardation.) FXS is the most common known cause of autism or “autistic-like” behaviors. Symptoms also can include characteristic physical and behavioral features and delays in speech and language development.

Fragile X-associated tremor/ataxia syndrome (FXTAS), a condition which affects balance, tremor and memory in some older male gene carriers.

Fragile X-associated primary ovarian insufficiency (FXPOI), a problem with ovarian function which can lead to infertility and early menopause in some female gene carriers.

Some gene carriers do not exhibit any of these features. To learn more about carriers click here.

Autism and Fragile X Syndrome

Fragile X can be passed on in a family by individuals who have no apparent signs of this genetic condition. In some families a number of family members appear to be affected, whereas in other families a newly diagnosed individual may be the first family member to exhibit symptoms.

Fragile X syndrome can cause a child to have Autism or an Autism Spectrum Disorder (ASD) though not all children with fragile X syndrome have Autism or an ASD.

  • FACT: For between 2% and 6% of all children diagnosed with Autism, the cause is the Fragile X gene mutation.
  • FACT: Approximately one-third of all children diagnosed with fragile X syndrome also have some degree of Autism.
  • FACT: Fragile X syndrome is the most common known single gene cause of Autism.

If your child is diagnosed with Autism, or an Autism spectrum disorder (ASD), please ask the doctor to rule out fragile X syndrome by ordering the DNA blood test for Fragile X. http://www.fragilex.org/html/testing.htm

If your child is diagnosed with fragile X syndrome, and you believe your child also has Autism or an Autism Spectrum Disorder, please consult with your child’s doctor and ask that he or she be evaluated for Autism or an ASD.

To learn more about the relationship between Fragile X and Autism please click here: http://www.fragilex.org/html/autism.htm or call the National Fragile X Foundation at 1-800-688-8765.