Myotonic Dystrophy Type 1 (DMPK) CTG Expansion
Also known as: DM1 PCR
Use
Use to diagnose myotonic dystrophy type 1 (DM1) in symptomatic individuals. May be used for screening in adults with a family history. Myotonic dystrophy type 1 is a multisystem disorder characterized by myotonic myopathy affecting the eye, heart, endocrine system, and central nervous system. The clinical presentation varies from mild to severe, with subtypes such as mild, classic, and congenital DM1, each associated with different manifestations and age of onset. Full-penetrance disease alleles, which contain 50 or more CTG repeats, are associated with DM1 manifestations. Offspring of affected individuals may inherit expanded alleles with potential for transmission expansion.
Special Instructions
Specific allele sizing estimates cannot be determined for expanded alleles with greater than 150 CTG repeats. Informed consent for genetic testing is required for New York patients. Specimens from New York clients will be sent out to a New York state-approved laboratory.
Limitations
The assay will not detect myotonic dystrophy type 2. Specific allele sizing estimates cannot be determined for CTG repeats greater than 150. Diagnostic errors can occur due to rare sequence variations. This test was developed and its performance characteristics determined by ARUP Laboratories and is intended for clinical purposes. It is not FDA cleared or approved.
Methodology
PCR-based (PCR)
Biomarkers
LOINC Codes
- 31208-2
- 35751-7
- 35750-9
- 50398-7
Result Turnaround Time
7-10 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
1 mL
Container
Lavender (K2EDTA), pink (K2EDTA), or yellow (ACD solution A or B)
Storage Instructions
Refrigerated. Also acceptable: Ambient.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 1 week |
| Refrigerated | 1 month |
| Frozen | Unacceptable |
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