Duchenne/Becker Muscular Dystrophy (DMD) Deletion/Duplication
Also known as: DMD DD
Use
This test is an appropriate first-tier genetic test for diagnostic testing or carrier screening for Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD). It helps identify large exon deletions or duplications in the DMD gene, which are a common cause of these conditions. The test is particularly recommended when a familial deletion or duplication has already been identified. For such cases, this analysis aids in confirming diagnosis or carrier status. Although this test does not detect small sequence variants, it remains a critical tool in the initial assessment of DMD/BMD genetic testing.
Special Instructions
Counseling and informed consent are recommended for individuals undergoing genetic testing. Special consent forms are required for patients from New York, and these must accompany the test order. Specimen requirements differ slightly for New York state clients, who must provide a minimum of 5 mL whole blood and adhere to refrigerated transport conditions.
Limitations
This test does not detect base pair substitutions, small deletions/duplications, deep intronic mutations, or mutations in regulatory regions. Additionally, single exon deletions/duplications may go undetected depending on breakpoint positions. Breakpoints for large deletions/duplications will not be precisely determined. As with all genetic tests, diagnostic errors can occur due to rare sequence variations. It is crucial to complement results with thorough clinical evaluations and family history assessments. Consideration of sequence-based testing is advised for cases where symptoms persist but no deletions/duplications are detected.
Methodology
Other
Biomarkers
LOINC Codes
- 66746-9
- 21247-2
Result Turnaround Time
7-14 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
1 mL
Container
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B)
Collection Instructions
New York State Clients: Collect 5 mL in a Lavender (EDTA) tube.
Storage Instructions
Preferred transport temp: Refrigerated. Also acceptable: Room temperature.
Causes for Rejection
Frozen specimens are unacceptable.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 1 week |
| Refrigerated | 1 month |
| Frozen | Unacceptable |
