FXN (frataxin) (eg, Friedreich ataxia) gene analysis; evaluation to detect abnormal (expanded) alleles
CPT4 code
Name of the Procedure:
FXN (frataxin) Gene Analysis; Evaluation to Detect Abnormal (Expanded) Alleles
Common name: Frataxin Gene Test
Summary
The frataxin gene test is a genetic analysis used to detect abnormalities in the FXN gene, which are linked to Friedreich ataxia, a hereditary neurodegenerative disorder. This test checks for expanded alleles, which are indicative of the condition.
Purpose
The frataxin gene test aims to diagnose Friedreich ataxia, helping to confirm a suspected diagnosis based on clinical symptoms. Detecting abnormal (expanded) alleles helps in understanding the genetic cause of the disorder, which aids in management and family planning.
Indications
- Symptoms of Friedreich ataxia: progressive ataxia, muscle weakness, scoliosis, and heart disease.
- Family history of Friedreich ataxia.
- Unexplained neurological symptoms that suggest a hereditary cause.
Preparation
- No special preparation is typically required.
- Patients might be advised to provide a detailed medical and family history.
- Genetic counseling might be recommended before and after the test to discuss implications.
Procedure Description
- Sample Collection: A blood sample is typically collected from the patient.
- DNA Extraction: DNA is extracted from the blood sample in a laboratory.
- Gene Analysis: The FXN gene is analyzed using techniques such as PCR (polymerase chain reaction) to detect expanded alleles.
- Interpretation: Results are interpreted by a geneticist to determine the presence of abnormal expansions in the FXN gene.
Tools and equipment used include sterile syringes for blood draw, standard laboratory equipment for DNA extraction and analysis, and specific reagents for PCR.
Duration
The blood draw takes a few minutes. Laboratory analysis may take several days to a few weeks, depending on the laboratory's processing times.
Setting
- Blood sample collection: Outpatient clinic or doctor's office.
- Gene analysis: Diagnostic laboratory equipped for genetic testing.
Personnel
- Phlebotomists or nurses (for blood sample collection)
- Laboratory technicians or technologists (for DNA extraction and analysis)
- Geneticists (for interpreting results)
Risks and Complications
- Blood draw risks: mild discomfort, bruising, or infection at the puncture site.
- Misinterpretation of results: false positives/negatives, though rare, can occur.
Benefits
- Accurate diagnosis of Friedreich ataxia.
- Informs appropriate medical management and interventions.
- Provides valuable information for family planning.
Recovery
- No recovery time needed from the blood draw.
- Patients can resume normal activities immediately.
- Follow-up genetic counseling is recommended to discuss results.
Alternatives
- Clinical diagnosis based on symptoms and neurological examinations.
- Other types of genetic tests if FXN gene analysis is inconclusive.
- MRI or other neuroimaging techniques to assess neurological damage.
Pros and Cons:
- Genetic testing provides a definitive diagnosis but requires access to specialized laboratories.
- Clinical diagnosis can be quicker but may be less precise without genetic confirmation.
Patient Experience
During the blood draw, patients may feel a slight pinch and some discomfort. Slight bruising or tenderness at the puncture site may occur. Post-procedure, patients typically feel normal and can continue daily activities. Genetic counseling will address any concerns and provide support.