Clinical Genetic Test
offered by
GTR Test Accession:
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GTR000500907.6
Last updated in GTR:
2024-08-30
View version history
GTR000500907.6,
last updated:
2024-08-30
GTR000500907.5,
last updated:
2023-08-11
GTR000500907.4,
last updated:
2022-08-30
GTR000500907.3,
last updated:
2016-08-14
GTR000500907.2,
last updated:
2015-09-11
GTR000500907.1,
registered in GTR:
2014-10-06
Last annual review date for the lab: 2024-08-30
LinkOut
At a Glance
Test purpose:
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Diagnosis;
Mutation Confirmation;
Pre-symptomatic
Conditions (1):
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Huntington disease-like 2
Genes (1):
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JPH3 (16q24.2)
Methods (1):
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Molecular Genetics - Targeted variant analysis: Trinucleotide repeat by PCR or Southern Blot
Target population: Help
Patients with a clinical diagnosis who have tested negative for …
Clinical validity:
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HDL2 is a rare disorder and the clinical significance of …
Clinical utility:
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Not provided
Ordering Information
Offered by:
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Test short name:
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HDL2
Specimen Source:
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- Fibroblasts
- Isolated DNA
- Peripheral (whole) blood
- Saliva
- View specimen requirements
Who can order: Help
- Genetic Counselor
- Health Care Provider
Test Order Code:
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Huntington Disease-Like 2
View other test codes
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CPT codes:
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Lab contact:
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Contact Policy:
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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:
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Submit sample with completed requisition form
Order URL
Order URL
Test development:
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Test developed by laboratory (no manufacturer test name)
Informed consent required:
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Yes
Pre-test genetic counseling required:
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Decline to answer
Post-test genetic counseling required:
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Decline to answer
Recommended fields not provided:
Test strategy
Conditions
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Total conditions: 1
| Condition/Phenotype | Identifier |
|---|
Test Targets
Genes
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Total genes: 1
| Gene | Associated Condition | Germline or Somatic | Allele (Lab-provided) | Variant in NCBI |
|---|
Methodology
Total methods: 1
Method Category
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Test method
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Instrument *
Targeted variant analysis
Trinucleotide repeat by PCR or Southern Blot
* Instrument: Not provided
Clinical Information
Test purpose:
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Diagnosis;
Mutation Confirmation;
Pre-symptomatic
Clinical validity:
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HDL2 is a rare disorder and the clinical significance of some repeat lengths is still being characterized. Of patients of African ancestry with symptoms of Huntington disease who tested negative for HTT expansions, 7 of 20 (35%) had expansions of the JPH3 gene consistent with HDL2. In North Americans, 3/374 …
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View citations (5)
- Stevanin G, Fujigasaki H, Lebre AS, Camuzat A, Jeannequin C, Dode C, Takahashi J, San C, Bellance R, Brice A, Durr A. Huntington's disease-like phenotype due to trinucleotide repeat expansions in the TBP and JPH3 genes. Brain. 2003;126(Pt 7):1599-603. doi:10.1093/brain/awg155. Epub 2003 May 06. PMID: 12805114.
- Huntington's Disease-like 2 (HDL2) in North America and Japan. Margolis RL, et al. Ann Neurol. 2004;56(5):670-4. doi:10.1002/ana.20248. PMID: 15468075.
- Patients with features similar to Huntington's disease, without CAG expansion in huntingtin. Rosenblatt A, et al. Neurology. 1998;51(1):215-20. doi:10.1212/wnl.51.1.215. PMID: 9674805.
- Krause et al. (2002). Am J Hum Genet. Abstract 2098
- Margolis et al. (2003). Clin Neurosci Res 3:187-196
Target population:
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Patients with a clinical diagnosis who have tested negative for mutations in HTT
Variant Interpretation:
Are family members with defined clinical status recruited to assess significance of VUS without charge?
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Decline to answer.
Decline to answer.
Will the lab re-contact the ordering physician if variant interpretation changes?
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Decline to answer.
Decline to answer.
Recommended fields not provided:
Clinical utility,
What is the protocol for interpreting a variation as a VUS?,
Is research allowed on the sample after clinical testing is complete?,
Sample negative report,
Sample positive report
Technical Information
Availability:
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Tests performed
Entire test performed in-house
Entire test performed in-house
Analytical Validity:
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+/- 1 CTG repeat up to 40; +/- 2 CTG repeats 41-60; and, +/- 3 CTG repeats when >60 repeats.
Assay limitations:
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This assay may not detect expansions larger than 60 repeats. Analysis parameters are not designed to detect mosaicism.
Proficiency testing (PT):
Is proficiency testing performed for this test?
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Yes
Method used for proficiency testing: Help
Intra-Laboratory
Yes
Method used for proficiency testing: Help
Intra-Laboratory
Recommended fields not provided:
Test Confirmation,
Citations to support assay limitations,
Description of internal test validation method,
Citations for Analytical validity,
PT Provider,
Description of PT method,
Major CAP category, CAP category, CAP test list
Regulatory Approval
FDA Review:
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Category:
FDA exercises enforcement discretion
Additional Information
Clinical resources:
Molecular resources:
IMPORTANT NOTE:
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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.