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Frataxin (FXN) gene GAA triplet repeat test
Clinical Genetic Test
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offered by
Neurogenetics Department
View lab's test page
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GTR Test Accession: Help GTR000137034.4
INHERITED DISEASENERVOUS SYSTEM
Last updated in GTR: 2015-11-26
View version history
Last annual review date for the lab: 2021-01-29 Past due 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: Trinucleotide repeat by PCR or Southern Blot
Target population: Help
Ataxia patients
Clinical validity: Help
Not provided
Clinical utility: Help
Establish or confirm diagnosis
Ordering Information
Offered by: Help
Neurogenetics Department
View lab's website
View lab's test page
Test short name: Help
FRDA, Friedreich ataxia
Specimen Source: Help
Who can order: Help
  • Genetic Counselor
  • Health Care Provider
  • Licensed Physician
Test Order Code: Help
28-3
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
Completion of the laboratory referral letter by the referring physician/scientist. Provision of a signed informed consent form. Both forms are available on the laboratory website.
Order URL
Test service: Help
Clinical Testing/Confirmation of Mutations Identified Previously
Test additional service: Help
Custom Prenatal Testing
Custom mutation-specific/Carrier testing
Test development: Help
Test developed by laboratory (no manufacturer test name)
Informed consent required: Help
Yes
Pre-test genetic counseling required: Help
Yes
Post-test genetic counseling required: Help
Yes
Recommended fields not provided:
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; Mutation Confirmation; Pre-symptomatic; Risk Assessment
Clinical utility: Help
Establish or confirm diagnosis
View citations (2)

Target population: Help
Ataxia patients
View citations (2)
  • Recent advances in the molecular pathogenesis of Friedreich ataxia. Puccio H, et al. Hum Mol Genet. 2000;9(6):887-92. doi:10.1093/hmg/9.6.887. PMID: 10767311.
  • The relationship between trinucleotide (GAA) repeat length and clinical features in Friedreich ataxia. Filla A, et al. Am J Hum Genet. 1996;59(3):554-60. PMID: 8751856.
Recommended fields not provided:
Clinical validity, 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 Procedure: Help
[1] PCR based detection of the GAA trinucleotide repeat size in the first intron of the frataxin (FXN) gene on chromosome 9q13. A long PCR protocol as described by Filla et al (1996) is followed. [2] PCR amplification and automated sequence analysis of the above trinucleotide repeat. The primer sequences … View more
View citations (2)
  • Recent advances in the molecular pathogenesis of Friedreich ataxia. Puccio H, et al. Hum Mol Genet. 2000;9(6):887-92. doi:10.1093/hmg/9.6.887. PMID: 10767311.
  • The relationship between trinucleotide (GAA) repeat length and clinical features in Friedreich ataxia. Filla A, et al. Am J Hum Genet. 1996;59(3):554-60. PMID: 8751856.
Test Confirmation: Help
different method or new sample
Availability: Help
Tests performed
Entire test performed in-house
Analytical Validity: Help
99% precise
Proficiency testing (PT):
Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Formal PT program

PT Provider: Help
European Molecular Genetics Quality Network, EMQN
Recommended fields not provided:
Assay limitations, Description of internal test validation method, Citations for Analytical validity, Description of PT method, Major CAP category, CAP category, CAP test list
Regulatory Approval
FDA Review: Help
Category: Not Applicable
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.