Fragile X Syndrome
Educational information. Individual clinical review of this presentation by Dr. Ehsan is not yet documented. It does not replace personal medical evaluation.
Source: MedlinePlus, National Library of Medicine. Read the original source
MedlinePlus data edition September 26, 2026. Imported September 27, 2026. These dates do not indicate a new clinical review of the article.
Fragile X syndrome is the most common form of inherited developmental disability. A problem with a specific gene causes the disease. Normally, the gene makes a protein you need for brain development. But the problem causes a person to make little or none of the protein. This causes the symptoms of Fragile X.
People with only a small change in the gene might not show any signs of Fragile X. People with bigger changes can have severe symptoms. These might include:
- Intelligence problems, ranging from learning disabilities to severe intellectual disabilities
- Social and emotional problems, such as aggression in boys or shyness in girls
- Speech and language problems, especially in boys
A genetic blood test can diagnose Fragile X. There is no cure. You can treat some symptoms with educational, behavioral, or physical therapy, and with medicines. Getting treatment early can help.
NIH: National Institute of Child Health and Human Development
Symptoms, tests and care options
Further reading selected by MedlinePlus. Links open the original organizations’ websites.
- Fragile X 101 · National Fragile X Foundation
- How Do Health Care Providers Diagnose Fragile X Syndrome? · Eunice Kennedy Shriver National Institute of Child Health and Human Development
- What Are the Symptoms of Fragile X Syndrome? · Eunice Kennedy Shriver National Institute of Child Health and Human Development
- What Are the Treatments for Fragile X Syndrome? · Eunice Kennedy Shriver National Institute of Child Health and Human Development
Questions for your care team
General prompts to help prepare for your appointment.
- How does this information apply to my situation?
- Which symptoms or results need evaluation?
- Which tests are useful, and what can they tell us?
- What care options, benefits, and risks should we discuss?
- When should I seek urgent help, and whom should I call?
- When is follow-up, and how will we know whether the plan is working?
For a life-threatening emergency, call 911 in the U.S. or your local emergency number.
Browse all patient guides