- Fragile X
- Treatment & Intervention
- Support the NFXF
Fragile X syndrome (FXS) and fragile X-associated tremor ataxia syndrome (FXTAS) are not the same condition. Both FXS and FXTAS are caused by mutations of the same gene, the FMR1 gene. But they are caused by different changes in this gene. FXS is caused by a full mutation of the FMR1 gene, FXTAS by a premutation of the FMR1 gene.
Even more important in distinguishing between FXS and FXTAS are the different features, age of onset, and diagnostic criteria of the two conditions.
FXS is present (though often not diagnosed) at birth. Children display features of the condition early in life, usually noticed by family members in infancy, toddlerhood or early childhood. These features include:
FXTAS develops in adulthood—usually after age 50. The symptoms may appear slowly and develop over years or decades. Individuals with FXTAS usually are healthy, usually with normal cognitive skills prior to the onset of the condition. They have no unique physical characteristics and did not experience the developmental delays in childhood that are seen in FXS.