Resources
Testing & diagnosis for the Fragile X premutation
A plain-language overview of what testing can (and can’t) tell you, what results may look like, and questions to ask your health-care team.
Start here
When to consider testing
People seek Fragile X (FMR1) testing for different reasons. If any of these sound familiar, it may be worth discussing testing with a clinician or genetic counsellor.
Testing “on-demand” may not be readily available in many jurisdictions. Generally a requistion from a medical practitioner is required.
There are private clinics available who will provide testing at cost. Names of such companies will be provided in later updates to this website.
Family history
A relative has Fragile X syndrome, an FMR1 premutation, or an unexplained intellectual disability/autism where Fragile X is being considered.
Reproductive planning
You’re planning a pregnancy, are pregnant, or are using fertility care and want to understand the chance of passing on an FMR1 change.
Health questions in adulthood
You have symptoms that could be related to the premutation (for example, tremor/ataxia in later life or primary ovarian insufficiency) and want to explore possible causes.
Clarifying a previous result
You’ve had genetic testing before and want help interpreting terms like intermediate, premutation, full mutation, or mosaic.
How testing works
What the test measures (in simple terms)
Fragile X testing looks at the FMR1 gene and counts a repeated DNA pattern (often called CGG repeats). The repeat count helps classify results into ranges (for example: typical, intermediate/“gray zone”, premutation, or full mutation). Labs may also report other details that can affect interpretation.
Repeat size category (range)
Whether the gene is methylated
Mosaic or mixed results
AGG interruptions (when reported)