Fragile X (FMR1) with Reflex to Methylation Analysis
Also known as: FRAG X PCR
Use
The test is primarily used for diagnosing fragile X syndrome and identifying carriers of the disorder. Fragile X syndrome is a genetic condition that causes a range of developmental problems including intellectual disabilities and cognitive impairment. This test is appropriate for patients with a family history of fragile X or those exhibiting clinical symptoms associated with fragile X syndrome. It analyzes the FMR1 gene to detect CGG repeat expansions and abnormal methylation patterns that are indicative of the disorder.
Special Instructions
Genetic counseling and informed consent are recommended due to the nature of the test. New York clients are required to provide informed consent with the submission. The test uses whole blood specimens and has specific conditions for stability and rejection. Additional charges apply for methylation analysis if specific CGG repeat patterns are detected.
Limitations
Diagnostic errors may occur due to rare sequence variations. This test will not detect rare FMR1 variants unrelated to trinucleotide expansion. A specific CGG repeat size estimate is not provided for full mutation alleles. It does not assess AGG trinucleotide interruptions within the FMR1 CGG repeat tract. It is not cleared or approved by the FDA, though it is performed in a CLIA-certified laboratory and intended for clinical purposes.
New York Approved
Methodology
PCR-based (Capillary Electrophoresis)
Biomarkers
LOINC Codes
- 45321-7
- 45322-5
- 41107-4
- 36913-2
- 66746-9
Result Turnaround Time
4-14 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
2 mL
Minimum Volume
1 mL
Container
Lavender (K2EDTA), pink (K2EDTA), or yellow (ACD solution A or B)
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 1 week |
| Refrigerated | 1 month |
| Frozen | Unacceptable |