Health Information For Parents

A to Z: Fragile X Syndrome


May also be called: FXS, Martin-Bell Syndrome, Escalante’s Syndrome, Marker X Syndrome, FRAXA Syndrome

Fragile X syndrome is a genetic birth defect that causes mental impairment, ranging from learning disabilities to mental retardation, autistic behaviors, and problems with attention and hyperactivity.

More to Know

The genes that you inherit from your parents are like chemical blueprints affecting the way your body looks and functions. Fragile X syndrome happens when someone is born with a defect in a gene called Fragile X mental retardation 1 (FMR1). The FMR1 gene makes a protein that is important for normal brain development. When kids are born with Fragile X syndrome, the defect in the FMR1 gene means that their bodies don’t produce this protein. As a result, they have some degree of mental impairment, which can range from mild to severe.

Children with Fragile X have different features that include a long face, large ears, flat feet, and extremely flexible joints, especially fingers. Boys have the syndrome more often than girls and are more likely to have substantial intellectual disability rather than milder learning problems. Both boys and girls are likely to have emotional and behavioral problems.

Some states screen newborns for Fragile X syndrome, but many children with the condition are not identified until they are toddlers. Children with developmental delays may be referred for genetic testing that can identify Fragile X. Treatment for Fragile X syndrome depends on the severity of the mental impairment and the symptoms it causes. Kids with Fragile X syndrome often get therapy to learn important skills and medicine to help with some behavioral issues.

Keep in Mind

Early diagnosis and a treatment plan that includes parents, caregivers, teachers, and others close to them can help kids with Fragile X reach their full potential. There is no cure for Fragile X, although researchers are exploring ways to prevent it and deal with the complications.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.

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