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Hereditary Hemorrhagic Telangiectasia
Clinical Genetic Test
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offered by
Genetic Diagnostic Laboratory
View lab's test page
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GTR Test Accession: Help GTR000227625.6
INHERITED DISEASECARDIOVASCULARDYSMORPHOLOGY ... View more
Last updated in GTR: 2017-05-08
View version history
Last annual review date for the lab: 2023-06-21 LinkOut
At a Glance
Test purpose: Help
Diagnosis; Mutation Confirmation
Conditions (2): Help
Telangiectasia, hereditary hemorrhagic, type 1; Telangiectasia, hereditary hemorrhagic, type 2
Genes (3): Help
ACVRL1 (12q13.13), ENG (9q34.11), SMAD4 (18q21.2)
Methods (3): Help
Molecular Genetics - Deletion/duplication analysis: High resolution aCGH; ...
Target population: Help
Individuals affected with clinical symptoms of HHT (nosebleeds, PAVM, CAVM, …
Clinical validity: Help
Not provided
Clinical utility: Help
Not provided
Ordering Information
Offered by: Help
Genetic Diagnostic Laboratory
View lab's website
View lab's test page
Test short name: Help
HHT
Specimen Source: Help
  • Amniocytes
  • Amniotic fluid
  • Chorionic villi
  • Cord blood
  • Fetal blood
  • Fibroblasts
  • Fresh tissue
  • Frozen tissue
  • Isolated DNA
  • Paraffin block
  • Peripheral (whole) blood
  • Product of conception (POC)
  • Saliva
  • View specimen requirements
Who can order: Help
  • Genetic Counselor
  • Health Care Provider
  • In-State Patients
  • Licensed Physician
  • Nurse Practitioner
  • Out-of-State Patients
  • Physician Assistant
  • Registered Nurse
Test Order Code: Help
HHT
View other test codes
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 refer to the "INSTRUCTIONS FOR SAMPLE SUBMISSION" page in our paperwork.
Order URL
Test service: Help
Clinical Testing/Confirmation of Mutations Identified Previously
Confirmation of research findings
    Comment: call lab
Test additional service: Help
Custom Prenatal Testing
    Comment: call lab
Test development: Help
Test developed by laboratory (no manufacturer test name)
Informed consent required: Help
Based on applicable state law
Test strategy: Help
Full sequencing of coding exons and intron-exon borders is performed first for ACVRL1 and ENG; if sequence is normal, automatic reflex to deletion/duplication analysis of coding exons. SMAD4 sequencing analysis is also available to order as a seperate test or in combination with ACRVL1/ENG.
Pre-test genetic counseling required: Help
No
Post-test genetic counseling required: Help
No
Recommended fields not provided:
Lab contact for this test
Conditions Help
Total conditions: 2
Condition/Phenotype Identifier
Test Targets
Genes Help
Total genes: 3
Gene Associated Condition Germline or Somatic Allele (Lab-provided) Variant in NCBI
Methodology
Total methods: 3
Method Category Help
Test method Help
Instrument
Deletion/duplication analysis
High resolution aCGH
Sequence analysis of the entire coding region
Bi-directional Sanger Sequence Analysis
Applied Biosystems 3500XL
Targeted variant analysis
Bi-directional Sanger Sequence Analysis
Applied Biosystems 3500XL
Clinical Information
Test purpose: Help
Diagnosis; Mutation Confirmation
Target population: Help
Individuals affected with clinical symptoms of HHT (nosebleeds, PAVM, CAVM, telangiectases) and at-risk family members with a known mutation identified in a proband.
View citations (1)
  • Richards-Yutz J, Grant K, Chao EC, Walther SE, Ganguly A. Update on molecular diagnosis of hereditary hemorrhagic telangiectasia. Hum Genet. 2010;128(1):61-77. doi:10.1007/s00439-010-0825-4. Epub 2010 Apr 23. PMID: 20414677.
Variant Interpretation:
What is the protocol for interpreting a variation as a VUS? Help
Our variant classification system is based on the American College of Medical Genetics and Genomics guidelines (Genet Med. 2015 May;17(5):405-24). This includes evaluating the variant using in gene-specific mutation databases, ExAC, dbSNP, and 1,000 genomes, and software (SIFT, PolyPhen).

Are family members with defined clinical status recruited to assess significance of VUS without charge? Help
Yes. Free testing for VUS in family members is offered on a case by case basis; information will be collected by the lab to see which family members are available and if their results will help assess for the significance of the variant.

Will the lab re-contact the ordering physician if variant interpretation changes? Help
Yes. A modified report is written and faxed to the ordering physician and genetic counselor.
Research:
Is research allowed on the sample after clinical testing is complete? Help
Specimens are retained by the lab for use in validation of future test development and for research studies. Samples are de-identified for research studies.
Recommended fields not provided:
Clinical validity, Clinical utility, Sample negative report, Sample positive report
Technical Information
Test Procedure: Help
Quality control for all samples includes identity testing against a second preparation of DNA from the original blood tube. Positive results are confirmed on a new DNA preparation using bidirectional Sanger sequencing or quantitative PCR.
Test Confirmation: Help
Quality control for all samples includes identity testing against a second preparation of DNA from the original blood tube. Positive results are confirmed on a new DNA preparation using bidirectional Sanger sequencing or quantitative PCR.
Test Comments: Help
For maximum benefit of testing, first family member to be tested should be affected.
Availability: Help
Tests performed
Entire test performed in-house
Analytical Validity: Help
Approximately 87% of individuals who meet the clinical criteria for HHT carry a detectable mutation in the coding sequence of either the endoglin gene (ENG) (called HHT type 1) or the activin receptor-like kinase 1 gene (ACVRL1) (called HHT type 2). Sensitivity decreases when the number of clinical symptoms decreases … View more
View citations (1)
  • Richards-Yutz J, Grant K, Chao EC, Walther SE, Ganguly A. Update on molecular diagnosis of hereditary hemorrhagic telangiectasia. Hum Genet. 2010;128(1):61-77. doi:10.1007/s00439-010-0825-4. Epub 2010 Apr 23. PMID: 20414677.
Proficiency testing (PT):
Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Intra-Laboratory

PT Provider: Help
Other
VUS:
Software used to interpret novel variations Help
SIFT, PolyPhen

Laboratory's policy on reporting novel variations Help
Novel variations will be reported with added interpretation based on variant type and in the context of known mutations for the specific gene.
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.