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SCA-1 (Spinocerebellar Ataxia): ATXN1 Gene Mutation Test

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SCA-1 (Spinocerebellar Ataxia): ATXN1 Gene Mutation Test

Short Name: SCA-1 Test

Also known as: SCA-1 Test, ATXN1 Gene Mutation Test, Spinocerebellar Ataxia Type 1 Genetic Test

SCA-1 (Spinocerebellar Ataxia): ATXN1 Gene Mutation Test test available at DNA Labs India for ₹2,925. Uses PCR, Fragment Analysis on Whole Blood samples. Results in Reports are delivered within 10-12 days from sample receipt. You will receive a notification via email, WhatsApp, or the online portal once the report is ready.. Free home collection in 300+ cities across India.

Molecular Genetic TestingAll (typically adult onset; rare childhood onset)🏠 Home Collection

✍️ Written By

🩺 Medically Reviewed By

Dr SULOCHANA HEMCHANDRA HOLLA

Dr SULOCHANA HEMCHANDRA HOLLA

Consultant Medical Geneticist · Reg: 8532

Last reviewed: September 7, 2026

Overview

To confirm the clinical diagnosis of spinocerebellar ataxia type 1, to identify mutation carriers in families with a history of SCA-1, to assist in presymptomatic and prenatal genetic counseling, and to distinguish SCA-1 from other hereditary ataxias.

Test Code
3629
Price
₹2,925
Sample Type
Whole Blood
Result Time
Reports are delivered within 10-12 days from sample receipt. You will receive a notification via email, WhatsApp, or the online portal once the report is ready.
Fasting Required
No
Method
PCR, Fragment Analysis
Step 1

Sample Collection

No fasting is required. Please complete and sign the Genomics Clinical Information Requisition Form (Form 20) as it is mandatory. If you have any previous neurological imaging or family history records, share them with your doctor before the test.

Method: Venipuncture

Step 2

Laboratory Analysis

A trained phlebotomist will collect approximately 4 mL of venous blood into a lavender top (EDTA) tube. The procedure takes only a few minutes.

Step 3

Report Delivery

You can resume your normal activities immediately. The sample will be transported refrigerated to the laboratory. Do not freeze the sample.

Timeline: Reports are delivered within 10-12 days from sample receipt. You will receive a notification via email, WhatsApp, or the online portal once the report is ready.

Patient Instructions

1
Before the Test:No fasting is required. Complete and sign the Genomics Clinical Information Requisition Form (Form 20). A venous blood sample will be collected in an EDTA tube.
2
During the Test:A phlebotomist will collect a small blood sample from a vein in your arm. The process is quick and generally causes minimal discomfort.
3
After the Test:You can resume normal activities immediately. The blood sample is transported refrigerated to the laboratory for PCR and fragment analysis.

About This Test

Who Should Get This Test

To confirm the clinical diagnosis of spinocerebellar ataxia type 1, to identify mutation carriers in families with a history of SCA-1, to assist in presymptomatic and prenatal genetic counseling, and to distinguish SCA-1 from other hereditary ataxias.

How to Prepare

  • Ship refrigerated
  • Do not freeze
  • Duly filled Genomics Clinical Information Requisition Form (Form 20) is mandatory
  • Sample should be collected in a lavender top (EDTA) tube

Doctor's Notes

Reviewed by — MBBS, MD (Medical Genetics) · Reg. No. 8532

"Spinocerebellar ataxia is a challenging diagnosis for families. A confirmed ATXN1 result allows informed genetic counselling, reproductive planning and referral to neurology for symptom management."

Last medically reviewed: September 7, 2026

Test Parameters & Specifications

Sample TypeWhole Blood
Sample Volume4 mL (2 mL min.)
ContainerLavender top (EDTA) tube
Collection MethodVenipuncture

Sample Stability

Room Temperature6 hours
Refrigerator1 week
FrozenNot Acceptable
Sample Rejection Criteria:
  • Frozen sample
  • Clotted or haemolysed sample
  • Unlabelled or mislabelled sample
  • Incomplete or invalid Genomics Clinical Information Requisition Form (Form 20)
  • Sample received outside approved stability conditions

Understanding Your Results

The ATXN1 gene mutation test determines the number of CAG trinucleotide repeats present in both alleles of the ATXN1 gene. The result is classified as normal, intermediate, or pathogenic based on the repeat count.
📊

Normal

Fewer than 36 CAG repeats in both ATXN1 alleles. No increased risk of SCA-1 from this gene.

📊

Intermediate

36-38 CAG repeats. May not cause disease, but there is a small risk of expansion in future generations. Clinical correlation is advised.

📊

Pathogenic

39 or more CAG repeats in one allele. Consistent with a molecular diagnosis of spinocerebellar ataxia type 1.

⚠️ When to Consult a Doctor:

Consult a neurologist or clinical geneticist if you or a family member have progressive balance problems, slurred speech, tremors, swallowing difficulties, or a known family history of spinocerebellar ataxia. Genetic counselling is recommended before and after testing.

Limitations

  • ⚠This test detects ATXN1 CAG repeat expansion only and does not exclude other causes of spinocerebellar ataxia
  • ⚠A positive result does not predict exact age of onset, rate of progression, or disease severity
  • ⚠Intermediate alleles may show incomplete penetrance and must be interpreted with clinical and family context
  • ⚠Presymptomatic testing should always include formal genetic counselling before and after the test

Risks & Considerations

  • ●Mild bruising at the blood collection site
  • ●Dizziness or fainting during sample collection
  • ●Rare psychological distress following predictive genetic test results

Interfering Factors

  • ●Poor DNA quality from clotted, haemolysed, or degraded blood samples
  • ●Recent allogeneic bone marrow transplant can affect DNA analysis
  • ●Rare somatic mosaicism for CAG repeat size may affect result interpretation
  • ●Incomplete patient identification or requisition form errors

Compare With Similar Tests

TestSCA-1 (Spinocerebellar Ataxia): ATXN1 Gene Mutation Test
ComparisonSCA-1 (Spinocerebellar Ataxia): ATXN1 Gene Mutation Test

Frequently Asked Questions

What is SCA-1?
SCA-1 is a genetic disorder caused by a CAG repeat expansion in the ATXN1 gene. It affects the cerebellum and leads to progressive problems with coordination, balance, and speech.
What is the cost of the SCA-1 ATXN1 gene mutation test?
The test costs INR 2925 at DNA Labs India. For online bookings, a special discounted price of INR 2925 applies and free home sample collection is provided across several cities in India.
Is fasting required for this test?
No, fasting is not required. You only need to submit a duly filled Genomics Clinical Information Requisition Form (Form 20) with your sample.
What type of sample is needed?
About 4 mL (minimum 2 mL) of whole blood is collected in a lavender top (EDTA) tube.
How should the sample be transported?
The sample should be shipped refrigerated. Do not freeze. The completed Form 20 must accompany the sample.
What method is used for ATXN1 gene mutation testing?
The test uses PCR followed by fragment analysis to measure the CAG repeat number in the ATXN1 gene.
How long does it take to get reports?
Reports are generally available in 10-12 days after the sample reaches the laboratory.
What is the normal range for ATXN1 CAG repeats?
Normal alleles have fewer than 36 CAG repeats. Alleles with 36-38 repeats are considered intermediate, and 39 or more repeats are classified as pathogenic.
Who should get this test?
It is recommended for individuals with symptoms suggesting spinocerebellar ataxia, people with a family history of SCA-1, and those undergoing genetic counseling for presymptomatic or reproductive planning.
What does a positive ATXN1 mutation result mean?
A pathogenic expansion of 39 or more CAG repeats confirms the molecular diagnosis of SCA-1. It does not predict exact age of onset or severity, and should be interpreted with clinical findings.
Is SCA-1 inherited?
Yes, SCA-1 is inherited in an autosomal dominant pattern. A person with the mutation has a 50% chance of passing it on to each child.
Can SCA-1 be cured?
There is currently no cure for SCA-1. Management focuses on supportive therapies to improve coordination, speech, swallowing, and quality of life. Genetic testing helps in diagnosis and early planning.
Worried about the process? Our certified phlebotomists collect thousands of samples every month across India. The process takes under 5 minutes and is virtually painless. Questions? Message us on WhatsApp — we're here 7 days a week.

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