ATXN3 (ataxin 3) (eg, spinocerebellar ataxia, Machado-Joseph disease) gene analysis, evaluation to detect abnormal (eg, expanded) alleles
CPT4 code
Name of the Procedure:
ATXN3 Gene Analysis (Spinocerebellar Ataxia, Machado-Joseph Disease)
Summary
ATXN3 gene analysis is a genetic test used to detect abnormal alleles in the ATXN3 gene, which are linked to spinocerebellar ataxia and Machado-Joseph disease. This non-invasive test analyzes a blood sample or cheek swab for specific genetic mutations.
Purpose
The test is designed to diagnose or confirm a diagnosis of spinocerebellar ataxia type 3 (SCA3) or Machado-Joseph disease. The primary goal is to detect expanded alleles in the ATXN3 gene, which cause these neurodegenerative disorders, thereby aiding in patient management and family planning.
Indications
- Onset of symptoms such as uncoordinated movements, difficulty walking, and speech abnormalities.
- A family history of spinocerebellar ataxia or Machado-Joseph disease.
- Unexplained neurological symptoms suggestive of ataxia.
Preparation
- No special preparation or fasting is required.
- Patients may need to provide a detailed family medical history.
- Informed consent must be obtained, explaining the benefits and potential psychological impact of the results.
Procedure Description
- Sample Collection: A healthcare provider collects a blood sample or a cheek swab from the patient.
- DNA Extraction: The DNA is extracted from the collected sample in the laboratory.
- Genetic Analysis: Using techniques such as PCR (Polymerase Chain Reaction) and Southern blotting, the DNA is analyzed to detect expansions in CAG trinucleotide repeats within the ATXN3 gene.
- Result Interpretation: Geneticists interpret the results to determine the presence of abnormal alleles.
Duration
The sample collection takes about 5-10 minutes. The analysis and interpretation of results typically take a few weeks.
Setting
The sample can be collected in an outpatient clinic, hospital, or a specialized genetic testing center. The analysis is performed in a specialized genetics laboratory.
Personnel
- Phlebotomist or nurse for sample collection.
- Geneticists and laboratory technicians for DNA analysis.
- Genetic counselors to discuss the results and implications with the patient.
Risks and Complications
- Minor discomfort or bruising at the blood draw site.
- Psychological impact of test results, which may necessitate counseling.
- Rare chance of sample contamination or incorrect results, mitigated by proper laboratory procedures.
Benefits
- Accurate diagnosis of spinocerebellar ataxia type 3 or Machado-Joseph disease.
- Informative for family planning and early intervention strategies.
- Clarity on symptoms and proper management plan.
Recovery
There is no recovery period as the procedure is non-invasive besides the minor discomfort from blood collection, if applicable. Normal activities can be resumed immediately.
Alternatives
- Clinical diagnosis based on symptoms and family history.
- Imaging studies such as MRI to observe brain changes.
- Other genetic tests to rule out different types of ataxia. Alternatives can be less definitive compared to direct genetic analysis.
Patient Experience
- The sample collection process is quick and involves minimal discomfort.
- Potential anxiety while awaiting results, which can be managed with support from healthcare providers.
- Clear communication of results and compassionate counseling are crucial for patient comfort and understanding.