Classic view of this page
Myotonic Dystrophy
Clinical Genetic Test
Help
offered by
Genetics Laboratory
GTR Test Accession: Help GTR000500416.2
CAP
INHERITED DISEASECARDIOVASCULARMUSCULOSKELETAL ... View more
Last updated in GTR: 2016-03-07
View version history
Last annual review date for the lab: 2023-02-08 Past due LinkOut
At a Glance
Test purpose: Help
Diagnosis
Conditions (1): Help
Steinert myotonic dystrophy syndrome
Genes (1): Help
DMPK (19q13.32)
Methods (1): Help
Molecular Genetics - Targeted variant analysis: Trinucleotide repeat by PCR or Southern Blot
Target population: Help
This test confirms a diagnosis of DM in patients with …
Clinical validity: Help
Factors such as age, family history, penetrance, and variable expressivity …
Clinical utility: Help
Establish or confirm diagnosis
Ordering Information
Offered by: Help
Genetics Laboratory
View lab's website
Test short name: Help
DM
Specimen Source: Help
  • Cord blood
  • Fetal blood
  • Isolated DNA
  • Peripheral (whole) blood
Who can order: Help
  • Genetic Counselor
  • Health Care Provider
  • Licensed Physician
  • Nurse Practitioner
  • Physician Assistant
CPT codes: Help
**AMA CPT codes notice

Copyright: 2023 American Medical Association. All rights reserved.

Contact Policy: Help
Laboratory can only accept contact from health care providers. Patients/families are encouraged to discuss genetic testing options with their health care provider.
How to Order: Help
Samples should be submitted with the appropriate requisition form (DNA test request form). Samples are received Monday through Saturday. Blood should be collected in EDTA or ACD tubes.
Test service: Help
Clinical Testing/Confirmation of Mutations Identified Previously
Genetic counseling
Prenatal tesing
FISH Analysis
Drug Metabolism testing
Cytogenetics Analysis
Maternal Serum Screening
Uniparental Disomy (UPD) Testing
X-Chromosome Inactivation Studies
Test development: Help
Test developed by laboratory but exempt from FDA oversight (eg. NYS CLEP approved, offered within a hospital or clinic)
Informed consent required: Help
Decline to answer
Pre-test genetic counseling required: Help
Decline to answer
Post-test genetic counseling required: Help
Decline to answer
Recommended fields not provided:
Test Order Code, Lab contact for this test, Test strategy
Conditions Help
Total conditions: 1
Condition/Phenotype Identifier
Test Targets
Genes Help
Total genes: 1
Gene Associated Condition Germline or Somatic Allele (Lab-provided) Variant in NCBI
Methodology
Total methods: 1
Method Category Help
Test method Help
Instrument *
Targeted variant analysis
Trinucleotide repeat by PCR or Southern Blot
* Instrument: Not provided
Clinical Information
Test purpose: Help
Diagnosis
Clinical validity: Help
Factors such as age, family history, penetrance, and variable expressivity preclude an accurate determination of clinical sensitivity and specificity with alleles between the range of 50 and 100 repeats. Repeat sizes greater than this are approximately 100%.
View citations (1)
  • Technical standards and guidelines for myotonic dystrophy type 1 testing. Prior TW, et al. Genet Med. 2009;11(7):552-5. doi:10.1097/GIM.0b013e3181abce0f. PMID: 19546810.
Clinical utility: Help
Establish or confirm diagnosis
View citations (1)
  • Technical standards and guidelines for myotonic dystrophy type 1 testing. Prior TW, et al. Genet Med. 2009;11(7):552-5. doi:10.1097/GIM.0b013e3181abce0f. PMID: 19546810.

Target population: Help
This test confirms a diagnosis of DM in patients with muscle wasting, myotonia, and very mild weakness to severe and potentially fatal congenital hypotonia. Testing of children with questionable symptoms and signs in an affected family and testing of newborns with severe hypotonia and/or facial diplegia are also available.
View citations (1)
  • An unstable triplet repeat in a gene related to myotonic muscular dystrophy. Fu YH, et al. Science. 1992;255(5049):1256-8. doi:10.1126/science.1546326. PMID: 1546326.
Recommended fields not provided:
What is the protocol for interpreting a variation as a VUS?, Are family members with defined clinical status recruited to assess significance of VUS without charge?, Will the lab re-contact the ordering physician if variant interpretation changes?, Is research allowed on the sample after clinical testing is complete?, Sample negative report, Sample positive report
Technical Information
Test Confirmation: Help
Positive results are compared to known positive controls
Availability: Help
Tests performed
Entire test performed in-house
Analytical Validity: Help
CTG-repeat expansion mutations account for >99% of cases of DM1. Therefore, the analytical sensitivity and specificity of tests that effectively detect and measure the CTG repeat in the 3′ UTR of the DMPK1 gene approaches 100%.
View citations (1)
  • Technical standards and guidelines for myotonic dystrophy type 1 testing. Prior TW, et al. Genet Med. 2009;11(7):552-5. doi:10.1097/GIM.0b013e3181abce0f. PMID: 19546810.
Proficiency testing (PT):
Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Formal PT program

PT Provider: Help
American College of Medical Genetics / College of American Pathologists, ACMG/CAP
Recommended fields not provided:
Assay limitations, Description of internal test validation method, Description of PT method, Major CAP category, CAP category, CAP test list
Regulatory Approval
FDA Review: Help
Category: FDA exercises enforcement discretion
Additional Information

IMPORTANT NOTE: NIH does not independently verify information submitted to GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.