ATXN3 Gene Spinocerebellar ataxia type 3, autosomal dominant NGS Genetic Test
Short Name: ATXN3 Gene SCA3 NGS Test
Also known as: SCA3, Machado-Joseph Disease, MJD, ATXN3 Gene Test, Spinocerebellar Ataxia Type 3 Genetic Test
ATXN3 Gene Spinocerebellar ataxia type 3, autosomal dominant NGS Genetic Test test available at DNA Labs India for ₹20,000. Uses Next-Generation Sequencing (NGS) on Blood or Extracted DNA or One drop Blood on FTA Card samples. Results in Results are typically available within 3 to 4 weeks from the date of sample receipt at the laboratory.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr SULOCHANA HEMCHANDRA HOLLA
Consultant Medical Geneticist · Reg: 8532
Last reviewed: September 7, 2026
Overview
The purpose of the ATXN3 Gene NGS Genetic Test is to confirm or rule out a molecular diagnosis of Spinocerebellar Ataxia Type 3 (Machado-Joseph Disease) in individuals presenting with clinical features suggestive of hereditary ataxia. This test detects CAG trinucleotide repeat expansions in the ATXN3 gene, enabling definitive diagnosis, presymptomatic carrier identification in at-risk family members, and informed genetic counseling and family planning.
- Test Code
- 1844
- CPT Code
- 81405
- ICD Code
- G11.8
- Price
- ₹20,000
- Sample Type
- Blood or Extracted DNA or One drop Blood on FTA Card
- Result Time
- Results are typically available within 3 to 4 weeks from the date of sample receipt at the laboratory.
- Fasting Required
- No
- Method
- Next-Generation Sequencing (NGS)
Sample Collection
No fasting is required. A pre-test genetic counseling session is strongly recommended to discuss the implications of testing, potential outcomes, and family impact. Provide complete clinical history and a detailed family pedigree chart.
Method: Venipuncture
Laboratory Analysis
A trained phlebotomist will collect 3–5 mL of venous blood in an EDTA (lavender top) tube. Alternatively, a blood sample may be applied to an FTA card. The procedure typically takes less than 10 minutes.
Report Delivery
Apply gentle pressure to the venipuncture site with sterile gauze for 3–5 minutes. No specific post-collection restrictions are necessary. The sample will be transported under controlled ambient conditions to the testing laboratory.
Timeline: Results are typically available within 3 to 4 weeks from the date of sample receipt at the laboratory.
Patient Instructions
About This Test
Who Should Get This Test
The purpose of the ATXN3 Gene NGS Genetic Test is to confirm or rule out a molecular diagnosis of Spinocerebellar Ataxia Type 3 (Machado-Joseph Disease) in individuals presenting with clinical features suggestive of hereditary ataxia. This test detects CAG trinucleotide repeat expansions in the ATXN3 gene, enabling definitive diagnosis, presymptomatic carrier identification in at-risk family members, and informed genetic counseling and family planning.
How to Prepare
- Collect 3–5 mL of venous blood in an EDTA (Lavender Top) tube
- Alternatively, apply one drop of blood to an FTA card and allow it to dry completely
- Ensure the tube is gently mixed 8–10 times immediately after collection to prevent clotting
- Label the sample accurately with patient name, date of birth, and unique identifier
- Transport the sample at ambient room temperature to the laboratory
- Do not freeze the blood sample prior to DNA extraction
Doctor's Notes
Reviewed by Dr SULOCHANA HEMCHANDRA HOLLA — MBBS, MD (Medical Genetics) · Reg. No. 8532
"Spinocerebellar Ataxia Type 3 is one of the most prevalent hereditary ataxias globally, and a confirmed molecular diagnosis through NGS is essential for accurate clinical management. Early genetic identification allows presymptomatic carrier detection within at-risk families, supports informed family planning decisions, and enables timely enrollment in emerging therapeutic trials. I recommend that any patient presenting with progressive cerebellar ataxia, pyramidal signs, or a positive family history of ataxia undergo ATXN3 gene testing alongside appropriate genetic counseling."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Hemolyzed, clotted, or insufficient volume samples
- Samples collected in incorrect anticoagulant tubes (e.g., heparin, citrate)
- Unlabeled or mislabeled samples
- Contaminated FTA cards or cards not fully dried before packaging
- Samples received without accompanying clinical history or test requisition form
Understanding Your Results
Normal result. No pathogenic ATXN3 expansion detected. SCA3 is unlikely to be the cause of symptoms; consider alternative diagnoses.
Negative for SCA3
Pathogenic expansion detected. Confirms a molecular diagnosis of Spinocerebellar Ataxia Type 3 (Machado-Joseph Disease). Genetic counseling is strongly recommended for the patient and at-risk family members.
Positive for SCA3
Intermediate or reduced penetrance range. The clinical significance may be uncertain. Genetic counseling is advised. Some individuals in this range may develop symptoms later in life or may remain unaffected.
Uncertain clinical significance; requires counseling
The test could not determine the exact repeat length. A repeat test with a fresh sample or an alternative methodology (such as repeat-primed PCR) may be recommended.
Inconclusive; repeat testing advised
Consult a neurologist if you or a family member experience progressive difficulty with balance and coordination, slurred speech, difficulty swallowing, muscle stiffness, involuntary eye movements, or limb weakness — particularly if there is a known family history of ataxia. Individuals identified as presymptomatic carriers through genetic testing should seek neurological follow-up and genetic counseling to discuss surveillance, family planning, and potential participation in clinical trials.
Limitations
- ⚠This test specifically targets CAG repeat expansions in the ATXN3 gene and does not assess other spinocerebellar ataxia subtypes
- ⚠Sequence variations or structural rearrangements outside the CAG repeat region may not be fully characterized
- ⚠The test cannot predict the exact age of onset, rate of disease progression, or severity of symptoms
- ⚠Results in the intermediate repeat range (45–54 repeats) may be classified as uncertain clinical significance and require genetic counseling
- ⚠Somatic mosaicism of repeat length may not be fully captured by standard peripheral blood analysis
Risks & Considerations
- ●Minor bruising or discomfort at the venipuncture site
- ●Very rare risk of fainting during blood draw
- ●Psychological impact of genetic results, particularly for predictive or presymptomatic testing
- ●Potential implications for insurance and employment; consult a genetic counselor regarding genetic non-discrimination protections in your jurisdiction
Interfering Factors
- ●Heavily hemolyzed blood samples may compromise DNA quality and affect sequencing accuracy
- ●Recent blood transfusion (within the preceding 4 weeks) may introduce donor DNA and interfere with genotyping
- ●Contaminated or improperly stored samples may yield inconclusive results
- ●Low DNA yield due to insufficient sample volume can impact NGS library preparation
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Frequently Asked Questions
What is the ATXN3 Gene Spinocerebellar Ataxia Type 3 NGS Genetic Test?
What is Spinocerebellar Ataxia Type 3 (SCA3)?
Who should consider getting this genetic test?
What sample is required for the ATXN3 Gene NGS Test?
What does a positive test result mean?
Is Spinocerebellar Ataxia Type 3 an inherited condition?
What is the cost of the ATXN3 Gene NGS Genetic Test at DNA Labs India?
Is home sample collection available for this test?
How long does it take to receive the test results?
Can this test detect if I am a carrier of SCA3 before symptoms appear?
What is the difference between NGS and repeat-primed PCR for SCA3 testing?
Is there a cure for Spinocerebellar Ataxia Type 3?
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