Huntington Disease (HD) Mutation Screening Test: Booking, Price, and Results
About Huntington Disease (HD) Mutation Screening Test: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | HD mutation screening, huntington's chorea test, HTT gene analysis, CAG repeat expansion test |
| Sample Type | Whole blood/peripheral blood |
| Fasting Required | No fasting required |
| Report Time | 15 days |
| Recommended For | Adults (18 years and above) with symptoms or a family history of huntington disease |
| Price | Starting at ₹4,800 |
What Is a Huntington Disease Mutation Screening Test?
The huntington disease mutation screening test is a genetic blood test that detects changes in the HTT gene on chromosome 4. It counts the number of CAG trinucleotide repeats in the gene - an abnormally high number of these repeats is the known cause of huntington disease. It is also known as the CAG repeat expansion test or HTT gene analysis.The test is prescribed for adults who show symptoms of the condition or who have a family history of it.
What Does a Huntington Disease Mutation Screening Test Measure?
This test measures a single, specific genetic marker. Here is what it analyses:
| Parameter | What It Measures |
|---|---|
| CAG trinucleotide repeat count | The number of times a three-letter DNA sequence (CAG) repeats within the HTT gene. An unusually high repeat count indicates the presence of the HD-causing genetic change. |
The repeat count determines whether a person is at risk and at what level. Results fall into four categories based on how many repeats are found (see the results section below for details).
Why Is a Huntington Disease Mutation Screening Test Done?
This test is used in three main ways: to confirm a diagnosis in someone showing symptoms, to assess risk in a symptom-free person with a family history, and to check whether an inherited mutation is present in a specific at-risk individual.
Common Symptoms That May Require This Test
A doctor may recommend this test if a person is experiencing any of the following:
- Involuntary, jerky body movements (known as chorea).
- Difficulty with balance and walking.
- Slurred or hard-to-understand speech.
- Trouble swallowing
- Gradual decline in memory or thinking ability.
- Mood changes or unexplained depression.
- A known family history of Huntington disease, even without symptoms.
Conditions This Test Can Help Detect
The test is used to identify or rule out the following:
- Huntington disease (HD), a progressive brain disorder caused by the CAG repeat expansion in the HTT gene.
- Intermediate allele status, where the person is unaffected but may pass an expanded repeat to their children.
- Reduced penetrance, where a person may or may not develop symptoms over their lifetime.
How to Prepare and What to Expect
No special preparation is required for this test. However, because it is a genetic test with significant implications, there are important steps to follow before and during collection.
Do You Need to Fast?
No. Fasting is not required before the HD mutation screening test. You may eat and drink normally on the day of collection.
Practical Tips Before Your Test
Here are a few things to keep in mind before your appointment:
- Bring a detailed clinical history including your symptoms, previous test results, and family history, as this is required for the test.
- Seek genetic counselling before undergoing this test, particularly if you are having it done for predictive (presymptomatic) purposes.
- Inform the laboratory if you have had a recent blood transfusion or bone marrow transplant, as this can affect results.
- Ensure a completed consent form (signed by both you and your doctor) is in place before sample collection.
- Presymptomatic testing is generally not offered to individuals under 18 years of age.
Step-by-Step Procedure
The collection process is straightforward and takes only a few minutes:
- A trained phlebotomist will clean the skin at the inside of your elbow with an antiseptic swab.
- A small needle is used to draw 3 mL of whole blood into a lavender-top EDTA tube.
- The tube is labelled with your name and other identification details.
- The sample is stored at 2°C to 8°C and dispatched to the specialised genetics laboratory.
- In the lab, DNA is extracted from the blood and analysed using fragment analysis to count CAG repeats.
- If a very large expansion is detected (typically more than 80 repeats), southern blot analysis may be used to confirm the sizing.
Factors That Can Affect Accuracy
The following factors may influence the reliability of your results:
- Recent blood transfusions or bone marrow transplantation (donor DNA may be present in the sample).
- Severely haemolysed or frozen blood, which is not acceptable for this test.
- Incorrect sample labelling or incomplete patient identification.
- Somatic mosaicism, a rare condition where different cells carry different repeat counts.
Understanding Your HD Mutation Screening Test Results
Results are reported as a CAG repeat count, which is then classified into one of four categories. Always review your results with a qualified doctor or genetic counsellor who can explain what the findings mean for you and your family.
| Classification | CAG Repeat Count | Result |
|---|---|---|
| Normal | 10 to 26 repeats | No risk of developing HD; cannot pass an HD allele to children. |
| Intermediate (mutable) | 27 to 35 repeats | A person will not develop HD, but children may be at risk as repeats can expand across generations. |
| Reduced penetrance | 36 to 39 repeats | A person may or may not develop HD during their lifetime. |
| Full penetrance | 40 or more repeats | A person will almost certainly develop HD; adult onset is typically 36 to 55 repeats, and juvenile onset is usually above 55 repeats. |
These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
Certain situations can affect how results are interpreted:
- Blood transfusion or bone marrow transplant: Donor DNA may be present in the sample, potentially leading to incorrect results. Always inform the laboratory before testing.
- Genetic anticipation: The CAG repeat count can increase when passed from parent to child, particularly through the father. This means children may carry a higher repeat count than their affected parent.
How to Maintain Healthy Level
Because huntington disease is caused by a genetic mutation, lifestyle changes cannot alter the gene or prevent the condition. However, the following steps support overall wellbeing:
- Regular neurological and psychological follow-up is advisable for those who carry an expanded HTT gene mutation.
- Genetic counselling before and after testing provides emotional support and guidance for family planning decisions.
- Maintaining general mental and physical health through balanced nutrition, regular activity, and social support can contribute to quality of life.
Lupin Diagnostics Huntington Disease Mutation Screening Test Price and Home Collection
The HD test at Lupin Diagnostics is priced starting at ₹4,800, and home collection is available across multiple cities.
| City | Approximate Price (₹) |
|---|---|
| BHOPAL | 4800 |
| CHENNAI | 4800 |
| HYDERABAD | 4800 |
| KOLKATA | 4800 |
| NAVI MUMBAI | 4800 |
| PUNE | 4800 |
Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
- Select the huntington disease mutation screening test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
HD test home collection is available across cities through Lupin Diagnostics. A certified phlebotomist will visit your home at your chosen time to collect the blood sample. All samples are processed in NABL-accredited laboratories, and your digital report is shared directly via email or WhatsApp.
Frequently Asked Questions
The HD mutation screening test is used to confirm or rule out huntington disease in someone showing symptoms, to assess risk in asymptomatic individuals with a family history, and to determine whether an at-risk person has inherited the expanded HTT gene variant. It counts CAG repeats in the HTT gene to classify a person's risk level.
Adults aged 18 years and above who have symptoms of huntington disease or a confirmed family history of it may consider this test. A doctor or genetic counsellor will typically recommend it based on clinical presentation and family history.
No. The test can confirm whether you carry the expanded gene, but it cannot predict the age at which symptoms will appear, how severe they will be, or how quickly the condition will progress. Genetic counselling can help you understand what your result means.
Genetic counselling is strongly recommended, especially for presymptomatic testing. It helps you understand the implications of a positive or intermediate result before testing and provides support when receiving results.
Predictive (presymptomatic) testing is generally not offered to individuals under 18 years of age. This is due to ethical considerations and the absence of preventive treatment. Diagnostic testing in a symptomatic minor may be considered on a case-by-case basis.
Results are typically available within 15 days from the date the sample is received at the laboratory. The exact turnaround time may vary slightly depending on the testing workload.
An intermediate result means you will not develop huntington disease yourself. However, the CAG repeat count may expand during transmission to your children, which could place them at risk of inheriting a disease-causing expansion. A genetic counsellor can explain the implications for your family and discuss options for family planning.
Huntington Disease (HD) Mutation Screening Test: Booking, Price, and Results
