SMN1-Spinal Muscular Atrophy Gene Deletion Test: Booking, Price, and Results
About SMN1-Spinal Muscular Atrophy Gene Deletion Test: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | SMN1 Exon 7 Deletion Test, SMA Gene Deletion Test, SMN Gene Deletion Test, SMA Carrier Test, Spinal Muscular Atrophy Molecular Test |
| Sample Type | Whole Blood (EDTA tube) |
| Fasting Required | No fasting required |
| Report Time | 21 days |
| Recommended For | Newborns, infants, children, and adults with suspected SMA; prospective parents for carrier screening; all ages |
| Price | Starting at ₹42,000 |
What Is a SMN1-Spinal Muscular Atrophy Gene Deletion Test?
The SMN1-Spinal Muscular Atrophy Gene Deletion test is a specialised genetic test that checks for deletions in the SMN1 gene, which is responsible for producing a protein essential for motor nerve cell survival. It is prescribed when a doctor suspects spinal muscular atrophy (SMA), a hereditary neuromuscular condition, or when prospective parents want to know if they carry the gene. Also called the SMA Gene Deletion Test or SMN1 Exon 7 Deletion Test, it uses a blood sample and is analysed using a method called MLPA (Multiplex Ligation-dependent Probe Amplification).
What Does a SMN1-Spinal Muscular Atrophy Gene Deletion Test Measure?
This test examines key aspects of the SMN1 and SMN2 genes. The following parameters are assessed:
| Parameter | What It Tells Us |
|---|---|
| SMN1 exon 7 copy number | Whether the SMN1 gene is present in normal, reduced, or absent quantities |
| SMN1 copy number interpretation | Determines if a person is unaffected, a carrier (1 copy), or affected with SMA (0 copies) |
| SMN2 copy number | Estimates how many backup copies of the SMN2 gene are present; more copies are linked to milder disease |
The SMN1 gene produces over 90% of the survival motor neuron (SMN) protein. When both copies are deleted, the motor nerve cells in the spinal cord gradually stop functioning, leading to muscle weakness.
Why Is a SMN1-Spinal Muscular Atrophy Gene Deletion Test Done?
Doctors order this test for several reasons, from confirming a suspected diagnosis to identifying carrier status before or during pregnancy.
Common Symptoms That May Require This Test
- Progressive muscle weakness, particularly in muscles closest to the centre of the body (shoulders, hips, thighs)
- Reduced muscle tone (hypotonia), often noticed in infants as "floppiness"
- Difficulty controlling or lifting the head in infants
- Breathing problems or recurrent respiratory infections
- Trouble swallowing or feeding in newborns and infants
- Delay in motor milestones such as sitting, standing, or walking
Conditions This Test Can Help Detect
- Spinal muscular atrophy (SMA), an autosomal recessive neuromuscular disease that causes degeneration of motor neurons in the spinal cord
- SMA subtypes (Type 0 to Type IV), which range from symptoms appearing before birth to muscle weakness appearing in adolescence or adulthood
- Carrier status in individuals or couples planning a family
SMN1-Spinal Muscular Atrophy Gene Deletion Test During Pregnancy
The American College of Obstetricians and Gynecologists (ACOG) recommends that all individuals who are pregnant or planning a pregnancy be offered carrier screening for SMA. Ideally, this screening is done before pregnancy so that couples have more time to understand their options. If both parents are carriers, there is a 1 in 4 chance that a child may be born with SMA.
How to Prepare and What to Expect
No special preparation is needed for the SMN1-Spinal Muscular Atrophy Gene Deletion test procedure. Below is everything you should know before your appointment.
Do You Need to Fast?
No, fasting is not required for this test. You can eat and drink normally before the sample is collected.
Practical Tips Before Your Test
- Bring a detailed clinical history, including your symptoms, previous test results, and family history, as this is required for the test.
- Inform the laboratory or your doctor if you have had a bone marrow transplant from another person (allogenic transplant), as this can interfere with the test result.
- Let your doctor know about any medications or supplements you are taking.
- Genetic counselling before the test is recommended, especially if you are being tested for carrier status or family planning purposes.
- Wear clothing with easy access to the arm for blood collection.
Step-by-Step Procedure
- You will be seated comfortably, and an elastic band (tourniquet) will be placed around your upper arm to make the vein easier to locate.
- The area on the inside of your elbow will be cleaned with an antiseptic solution.
- A trained phlebotomist will gently insert a sterile needle to collect approximately 5 mL of blood into an EDTA (lavender-top) tube.
- Once the sample is collected, the needle is removed, and a small cotton ball or bandage is placed over the site.
- The tube is labelled with your details and stored at a refrigerated temperature (2 to 8 degrees Celsius) before being sent to the laboratory.
- The sample is then processed using the MLPA method to analyse SMN1 and SMN2 gene copy numbers. Results are available within 21 days.
Factors That Can Affect Accuracy
- A previous allogeneic bone marrow transplant (donor DNA can affect results)
- Poor sample quality or insufficient DNA yield from the blood sample
- Rare SMN1 gene alterations that may not be detected by standard testing methods
- The specific laboratory methodology used for analysis
Understanding Your SMN1-Spinal Muscular Atrophy Gene Deletion Test Results
Results of this test should always be reviewed with a doctor or a qualified genetic counsellor. The table below explains how copy numbers are typically interpreted:
| Parameter | Result | Interpretation |
|---|---|---|
| SMN1 exon 7 copy number | 2 copies | Normal; person is unaffected and not a carrier |
| SMN1 exon 7 copy number | 1 copy | Carrier; unaffected but can pass the deletion to children |
| SMN1 exon 7 copy number | 0 copies | Affected with SMA (homozygous deletion) |
| SMN2 copy number | 2 copies | Associated with more severe SMA (Type I) |
| SMN2 copy number | 2 to 3 copies | Associated with intermediate severity (Type II) |
| SMN2 copy number | 3 or more copies | Associated with milder SMA (Type III) |
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
As this is a genetic test, the results reflect your inherited DNA and cannot be changed by diet or lifestyle. The following points, however, are worth keeping in mind:
- If you receive a positive or carrier result, seek genetic counselling promptly to understand what it means for you and your family.
- Early diagnosis of SMA, when confirmed, allows treatment to begin sooner, which can significantly improve outcomes.
- Family members of an affected individual may also benefit from carrier screening.
Lupin Diagnostics SMN1-Spinal Muscular Atrophy Gene Deletion Test Price and Home Collection
The SMN1-Spinal Muscular Atrophy Gene Deletion test cost at Lupin Diagnostics starts at ₹42,000, and home sample collection is available. The table below lists cities where the test can be booked:
| City | Approximate Price (₹) |
|---|---|
| BHOPAL | 42000 |
| CHENNAI | 42000 |
| HYDERABAD | 42000 |
| KOLKATA | 42000 |
| NAVI MUMBAI | 42000 |
| PUNE | 42000 |
Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
The SMN1-Spinal Muscular Atrophy Gene Deletion test online booking process at Lupin Diagnostics is straightforward:
- Select the 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
Lupin Diagnostics offers SMN1-Spinal Muscular Atrophy Gene Deletion test home collection across multiple cities in India, making it convenient to get tested without visiting a centre. All samples are processed in NABL-accredited laboratories by experienced professionals. Once ready, your digital report is shared securely via email or WhatsApp.
Frequently Asked Questions
This test is used to confirm a suspected diagnosis of spinal muscular atrophy and to identify carriers who may pass the condition to their children. It is one of the most reliable tests for detecting SMN1 gene deletions, achieving approximately 95% sensitivity and nearly 100% specificity.
The test is recommended for infants and children showing signs of muscle weakness or low muscle tone, individuals with a family history of SMA, and prospective parents who want to check their carrier status. ACOG guidelines suggest offering carrier screening to all individuals who are pregnant or planning a pregnancy.
No special preparation is needed. You do not need to fast, and there are no dietary restrictions. However, you should bring a detailed clinical history and inform the laboratory if you have had a bone marrow transplant from a donor.
A carrier has one working copy and one non-working copy of the SMN1 gene. Carriers are healthy and do not develop SMA themselves. If both parents are carriers, there is a 1 in 4 chance with each pregnancy that the child may be born with SMA. Genetic counselling is strongly advised in this situation.
The SMN2 gene partially compensates for the missing SMN1 protein. Patients with more SMN2 copies tend to have milder forms of SMA. This information helps doctors anticipate disease severity and plan care accordingly.
Yes. Prenatal testing for SMA can be done through amniocentesis (at 15 to 20 weeks of pregnancy) or chorionic villus sampling (from around 10 weeks). These procedures collect foetal genetic material to check whether the baby has inherited the SMN1 deletion.
SMN1-Spinal Muscular Atrophy Gene Deletion Test: Booking, Price, and Results
