Friedreich Ataxia Genetic Testing (Trinucleotide Repeat Expansion)
Use
Friedreich ataxia is a genetic condition that affects the nervous system and causes movement problems.
Special Instructions
This test is not available for patients in New York state. Testing procedures involve repeat-primed PCR and fragment length analysis to accurately determine the number of nucleotide repeats present in the specimen. Healthcare providers are advised to contact MNG Genetic Services for special instructions if extracted DNA needs to be submitted. Standard phlebotomy is required for blood samples, while specific kit instructions must be followed for oral swabs.
Limitations
The test may produce false positive or false negative results due to various unforeseen factors including but not limited to rare genetic variants, allele dropout, recent blood transfusions, bone marrow transplantation influencing results, somatic or tissue-specific mosaicism, or mislabeling of samples. The test's ability to measure repeat expansion length is limited by the maximum reportable size, such as up to 1300 repeats for the FXN gene. Results exceeding the maximum detectable range are reported as greater than the largest assessable repeat range.
Methodology
PCR-based (PCR)
Biomarkers
Result Turnaround Time
14-28 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
4 mL
Minimum Volume
2 mL
Container
lavender-top (EDTA) tube
Collection Instructions
Standard phlebotomy
Storage Instructions
Maintain specimen at room temperature or refrigerate at 4°C. Do not freeze.
Causes for Rejection
Frozen or hemolyzed specimen; quantity not sufficient for analysis; improper container
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 30 days |
| Frozen | do not freeze |