Myotonic Dystrophy 2 (ZNF9/CNBP) Genetic Testing (Repeat Expansion)
Use
Type 2 myotonic dystrophy results from a mutation in the CNBP gene known as a tetranucleotide repeat expansion. This mutation increases in size of the repeated CCTG segment in the CNBP gene. People with type 2 myotonic dystrophy have from 75 to more than 11,000 CCTG repeats.
Special Instructions
This genetic assay is currently unavailable for patients residing in New York state. Physicians need to be aware of this restriction when considering testing options for their patients.
Limitations
The test may yield false positive or false negative results due to factors such as insufficient information on rare genetic variants, potential allele dropout, history of blood transfusions or bone marrow transplantation, somatic or tissue-specific mosaicism, or errors like mislabeled samples. It is important to note the maximum reportable sizes for repeat expansion in various genes, which can impact the interpretation of results. Results are not cleared or approved by the FDA, indicating that it is developed and its performance characteristics determined by Labcorp.
Methodology
PCR-based
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 |