What to know
Fragile X syndrome (FXS) is an identifiable genetic disorder that is one of the more common heritable forms of intellectual disability. FXS and other fragile X-associated disorders are caused by mutations in a gene called the fragile X messenger ribonucleoprotein 1 (FMR1) gene. Any child with unexplained developmental delay, intellectual disability, and/or autism spectrum disorder should receive genetic testing for FXS. Healthcare professionals can support early identification and evaluation, which empowers families to make informed decisions about FXS-specific services for their child, as well as family planning. A diagnosis also helps healthcare providers assess comorbidities and associated conditions.
Top 5 things to know about FXS
Fact #1: There does not have to be a family history of FXS for a child to have the condition.
Fact #2: FXS cannot be diagnosed using a chromosome test or microarray.
Fact #3: Girls can have FXS, and boys with FXS are usually more severely affected.
Fact #4: Not all FXS patients can be recognized by unusual physical characteristics.
Fact #5: There is value in making a diagnosis of FXS even if there is no cure.
The material in this PDF was adopted from AAP News © July 2016 American Academy of Pediatrics. FXS Myth Busters was created under Cooperative Agreement Number U38OT000167, funded by the Centers for Disease Control and Prevention. Its contents are solely the responsibility of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention or the Department of Health and Human Services.
What you can do as a healthcare provider
Ensure that all children with developmental delay, intellectual disability and/or autism spectrum disorder are considered for a genetic evaluation.123
Use a family history tool to evaluate for a family history of related problems that can be seen in fragile X-associated disorders:
- A history of ataxia or "Parkinson-like" tremors in older males and some females on the maternal side.
- A history of early menopause or fertility problems on the maternal side.
Resources for healthcare professionals
CDC works with partners to provide resources for healthcare professionals to support the diagnosis and evaluation of patients who have or may have fragile X syndrome:
- Hersh JH, Saul RA; Committee on Genetics. Health supervision for children with fragile X syndrome. Pediatrics. 2011 May;127(5):994-1006.
- Moeschler JB, Shevell M; Committee on Genetics. Comprehensive evaluation of the child with intellectual disability or global developmental delays. Pediatrics. 2014 Sep;134(3):e903-18.
- Saul RA. Genetic and genomic literacy in pediatric primary care. Pediatrics. 2013 Dec;132(Suppl 3):S198-202.