Huntington Disease via the HTT CAG Repeat Expansion
GTR Test Accession: Help GTR000528355.12
NERVOUS SYSTEMINHERITED DISEASE
Last updated in GTR: 2019-06-28
Last annual review date for the lab: 2024-05-20 LinkOut
At a Glance
Diagnosis; Mutation Confirmation; Pre-symptomatic; ...
Huntington disease
Genes (1): Help
HTT (4p16.3)
Molecular Genetics - Targeted variant analysis: PCR with allele specific hybridization
Testing should follow the guidelines as proposed by the ACMG. …
Not provided
Not provided
Ordering Information
Offered by: Help
PreventionGenetics, part of Exact Sciences
View lab's website
View lab's test page
Specimen Source: Help
Who can order: Help
  • Genetic Counselor
  • Health Care Provider
  • Licensed Physician
Test Order Code: Help
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
Please visit Lab website for details. Additional specimen types may be acceptable based on method. Please contact us about prenatal cases.
Order URL
Test service: Help
Clinical Testing/Confirmation of Mutations Identified Previously
    OrderCode: 2299
Maternal cell contamination study (MCC)
    OrderCode: 800
Test additional service: Help
Custom Prenatal Testing
    OrderCode: 990
Test development: Help
Test developed by laboratory (no manufacturer test name)
Informed consent required: Help
No
Pre-test genetic counseling required: Help
No
Post-test genetic counseling required: Help
No
Recommended fields not provided:
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
PCR with allele specific hybridization
Applied Biosystems 3730 capillary sequencing instrument
Clinical Information
Test purpose: Help
Diagnosis; Mutation Confirmation; Pre-symptomatic; Risk Assessment; Screening
Target population: Help
Testing should follow the guidelines as proposed by the ACMG. All patients with symptoms suggestive of Huntington disease are candidates for this test. This test is also recommended for patients with a familial history of Huntington disease. Predictive testing is not recommended for patients under the age of 18 (to … View more
View citations (2)
  • Predictive testing for Huntington disease: interpretation and significance of intermediate alleles. Semaka A, et al. Clin Genet. 2006;70(4):283-94. doi:10.1111/j.1399-0004.2006.00668.x. PMID: 16965319.
  • Bean L, Bayrak-Toydemir P. American College of Medical Genetics and Genomics Standards and Guidelines for Clinical Genetics Laboratories, 2014 edition: technical standards and guidelines for Huntington disease. Genet Med. 2014;16(12):e2. doi:10.1038/gim.2014.146. Epub 2014 Oct 30. PMID: 25356969.
Variant Interpretation:
What is the protocol for interpreting a variation as a VUS? Help
The PreventionGenetics protocol for interpreting sequence variants has been carefully developed over a period of 10 years. We are conservative in our interpretations. We do not label a variant as pathogenic or benign without conclusive evidence. Although we use a variety of software to assist us in interpretation, we rely … View more

Are family members with defined clinical status recruited to assess significance of VUS without charge? Help
Yes. Please visit our website for details at https://www.preventiongenetics.com/forms.php for Targeted variant tests.

Will the lab re-contact the ordering physician if variant interpretation changes? Help
Yes. Please visit our website for details http://preventiongenetics.com/
Recommended fields not provided:
Technical Information
Availability: Help
Tests performed
Entire test performed in-house
Analytical Validity: Help
A minimum of twenty-two (22) samples were used for the test validation. A variety of positive and negative control DNA samples from affected and unaffected individuals were used to validate this test. Controls spanned the full range from the smallest normal alleles to near the largest expansion that has been … View more
Proficiency testing (PT):
Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Intra-Laboratory
VUS:
Software used to interpret novel variations Help
GeneSplicer, Human Splicing Finder, MaxEntScan, Mutation Taster, NNSPLICE, PolyPhen 2, SIFT and Splice Site Finder.

Laboratory's policy on reporting novel variations Help
Sequence variants found in our patients are contributed to ClinVar. Anonymous patient sequence data will also be shared with researchers for preparation of peer-reviewed publications.
Recommended fields not provided:
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.