Fragile X, Follow-up Analysis
Use
The test is useful for confirming the methylation status of the repeat expansion allele in the FMR1 gene. This confirmation aids in diagnosing FMR1-related disorders such as Fragile X Syndrome, Fragile X Tremor/Ataxia Syndrome, and Primary Ovarian Insufficiency.
Special Instructions
This test is only orderable as a reflex test and does not require an additional specimen. The laboratory utilizes the specimen they already have for this test. For more information, refer to the main test for Fragile X Syndrome, Molecular Analysis.
Limitations
The test may not reliably predict disease severity for prenatal assessment due to variable expression and incomplete penetrance of the FMR1 expansion. Less than 1% of clinically diagnosed fragile X syndrome cases may have a different FMR1 gene alteration other than CGG expansion. Methylation status assessment is not performed on chorionic villus specimens or if the reported sex is female.
New York Approved
Methodology
PCR-based (Methylation Sensitive)
Biomarkers
LOINC Codes
- 48767-8
- 31208-2
- 18771-6
Result Turnaround Time
8-10 days
Related Documents
For more information, please review the documents below
Specimen
Other
Volume
Not provided
Minimum Volume
Not provided
Collection Instructions
Lab will utilize existing specimen in the lab.