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Friedreich Ataxia (FRDA) via the FXN GAA Repeat Expansion
Clinical Genetic Test
Help
offered by
PreventionGenetics, part of Exact Sciences
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GTR Test Accession: Help GTR000613202.1
INHERITED DISEASENERVOUS SYSTEM
Registered in GTR: 2024-04-03
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Last annual review date for the lab: 2024-05-20 LinkOut
At a Glance
Test purpose: Help
Diagnosis; Mutation Confirmation; Pre-symptomatic; ...
Conditions (1): Help
Friedreich ataxia 1
Genes (1): Help
FXN (9q21.11)
Methods (1): Help
Molecular Genetics - Targeted variant analysis: PCR with allele specific hybridization
Target population: Help
We recommend FXN repeat expansion testing for individuals (both symptomatic …
Clinical validity: Help
Not provided
Clinical utility: Help
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
20060
View other test codes
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: 20060
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:
Lab contact for this test, Contact policy, 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
PCR with allele specific hybridization
Other
Clinical Information
Test purpose: Help
Diagnosis; Mutation Confirmation; Pre-symptomatic; Risk Assessment; Screening
Target population: Help
We recommend FXN repeat expansion testing for individuals (both symptomatic and asymptomatic) with a family history of FRDA or early-onset progressive ataxia and individuals with clinical features consistent with FRDA.
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:
Clinical validity, Clinical utility, Is research allowed on the sample after clinical testing is complete?, Sample negative report, Sample positive report
Technical Information
Test Procedure: Help
This test is designed to only detect pathogenic expansions of a GAA trinucleotide repeat in intron 1 of the FXN gene and does not assess for repeat interruptions or other potentially pathogenic variants within FXN. Our assay involves two amplicon-length assays from both the 3’ and 5’ ends of the … View more
Availability: Help
Tests performed
Entire test performed in-house
Analytical Validity: Help
This test for GAA repeat expansions in intron 1 of FXN has approximately 96% clinical sensitivity for molecular confirmation of FRDA. The remaining 4% of FRDA cases require NGS of FXN to identify sequence and copy number variants in addition to repeat expansion testing (Bidichandani et al. 1998. PubMed ID: … 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:
Test Confirmation, 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: 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.