Prader Willi Methylation/ Angelman Syndrome (AS-PWS) Methylation: Booking, Price, and Results
About Prader Willi Methylation/ Angelman Syndrome (AS-PWS) Methylation: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | PWS/AS Methylation Test, Prader-Willi/Angelman Syndrome DNA Methylation Analysis, SNRPN Methylation Test |
| Sample Type | Whole Blood (EDTA tube) |
| Fasting Required | No |
| Report Time | 8 Days |
| Recommended For | Infants, children, and adults of any gender with suspected Prader-Willi or Angelman syndrome |
| Price | Starting at ₹11,500 |
What Is a PWS/AS methylation test?
The AS-PWS test is performed specifically to examine methylation patterns on chromosome 15. Methylation refers to chemical tags attached to DNA that control which genes are switched on or off. The test is used to confirm a suspected diagnosis of either Prader-Willi syndrome (PWS) or Angelman syndrome (AS) in infants, children, or adults showing characteristic symptoms. It is also known as the PWS/AS methylation test or SNRPN methylation test. The whole blood sample collected in an EDTA tube is used for analysis.
What Does a Prader Willi Methylation/ Angelman Syndrome (AS-PWS) Methylation Measure?
The AS-PWS test procedure uses a method called 'methylation PCR' to analyse a specific region of chromosome 15 (15q11.2-q13). It evaluates two key aspects of this region.
| Component | What It Checks |
|---|---|
| SNRPN gene methylation pattern | Determines whether the methylation pattern on chromosome 15 reflects normal inheritance from both parents or only from one parent. |
| Copy number variations | Identifies deletions, duplications, or imprinting defects within the PWS/AS critical region of chromosome 15 |
Why Is a Prader Willi Methylation/ Angelman Syndrome (AS-PWS) Methylation Done?
Doctors request this test when a patient shows signs that suggest either Prader-Willi or Angelman syndrome. Both are neurodevelopmental genetic conditions that affect development, behaviour, and physical health.
Common Symptoms That May Require This Test
The following symptoms are among the most common reasons a doctor may recommend the AS-PWS test:
- Severe hypotonia (very low muscle tone) and feeding difficulties in early infancy
- Global developmental delay and intellectual disability
- Marked hyperphagia (excessive hunger) leading to obesity, short stature, and small hands and feet
- Severe speech impairment or absence of speech
- Unsteady walking (gait ataxia) and limb tremors
- Seizures and small head size (microcephaly)
- Frequent laughing, smiling, and excitability with an apparently happy demeanour (characteristic of Angelman syndrome)
Conditions This Test Can Help Detect
The Prader-Willi/Angelman Syndrome DNA Methylation Analysis test can help identify the following genetic conditions:
- Prader-Willi syndrome (PWS), caused by loss of function of paternally expressed genes in the 15q11.2-q13 region
- Angelman syndrome (AS), caused by loss of function of maternally inherited genes in the same region
- 15q11-q13 duplication syndrome, which can cause developmental delay, intellectual disability, hypotonia, and seizures
How to Prepare and What to Expect
No special preparation is needed before the AS-PWS test. However, a few practical steps will help ensure a smooth collection.
Do You Need to Fast?
No, fasting is not required for this test. You may eat and drink normally before sample collection.
Practical Tips Before Your Test
The following steps will help ensure your sample is suitable for testing:
- Bring a detailed clinical history including your symptoms, previous test results, and family history, as this is required for the test.
- Ensure the requesting doctor has noted the patient's clinical features and any relevant family history of PWS or AS.
- Inform the phlebotomist if the patient has recently received a blood transfusion, as transfused blood is not an acceptable sample.
- Do not allow the sample to freeze during transport, as frozen whole blood is unacceptable for this test.
- Label the sample clearly with the patient's name, date of birth, and the date and time of collection.
Step-by-Step Procedure
Here is what to expect during sample collection for the AS-PWS test:
- A trained phlebotomist (blood collection specialist) will explain the procedure briefly before starting.
- A 5 ml blood sample is drawn from a vein in your arm using a lavender-top EDTA tube.
- The sample is labelled with the patient's name, date of birth, and collection details.
- The sample is refrigerated at 2 to 8 degrees Celsius and sent to the laboratory.
- In the laboratory, DNA is extracted from the blood sample and analysed using Methylation PCR to assess the chromosome 15 region.
- A specialist prepares an interpretive report, which is made available within 8 days.
Factors That Can Affect Accuracy
Certain factors may reduce the reliability of results. Be aware of the following:
- Recent whole blood transfusion (transfused blood gives inaccurate results).
- Severely haemolysed (damaged red blood cells) or heparinised blood samples.
- Poor DNA quality or quantity in the collected sample.
- Somatic mosaicism (a mix of normal and affected cells in the body), which may cause a false negative result.
- Mutations in the PCR primer binding sequences, which may affect the test's ability to read methylation patterns correctly.
- Samples older than 7 days may have reduced quality.
Understanding Your Prader Willi Methylation/ Angelman Syndrome (AS-PWS) Methylation Results
Results from this test show whether the methylation pattern on chromosome 15 is normal or points to a specific genetic syndrome. A specialist will review the findings alongside the patient's clinical features and family history.
| Result | Interpretation |
|---|---|
| Normal methylation pattern | Both maternal and paternal alleles are present; PWS and AS are effectively excluded. |
| Only maternal pattern was detected | Absence of paternal contribution is diagnostic for Prader-Willi syndrome |
| Only paternal pattern was detected | Absence of maternal contribution is diagnostic for Angelman syndrome. |
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.
This test detects more than 99% of PWS cases and approximately 80% of AS cases. A normal result does not entirely rule out Angelman syndrome, as around 11% of AS cases are caused by changes in the UBE3A gene, which this test does not assess.
How to Maintain Healthy Levels
The SNRPN Methylation test diagnoses a genetic condition and does not measure health markers that can be changed through lifestyle. The following general points apply after a diagnosis:
- Attend follow-up appointments with a specialist or genetic counsellor in order to understand next steps and family implications.
- Families are encouraged to seek genetic counselling to understand recurrence risks for future pregnancies.
- Connect with a paediatric specialist for an individualised care plan.
Lupin Diagnostics Prader Willi Methylation/ Angelman Syndrome (AS-PWS) Methylation Price and Home Collection
The AS-PWS test is available at Lupin Diagnostics starting at ₹11,500, with home sample collection available for your convenience.
| City | Approximate Price ( ₹) |
|---|---|
| BHOPAL | 11500 |
| CHENNAI | 11500 |
| HYDERABAD | 11500 |
| KOLKATA | 11500 |
| NAVI MUMBAI | 11500 |
| PUNE | 11500 |
Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
Follow these steps to book your AS-PWS test online:
- 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
The AS-PWS test home collection service is available across cities, allowing a trained phlebotomist to collect the blood sample at your preferred location. All samples are processed in NABL-accredited laboratories by experienced specialists. Your digital report is delivered securely via email or WhatsApp.
Frequently Asked Questions
The AS-PWS test examines chemical markers (methylation patterns) on chromosome 15 to diagnose two distinct genetic syndromes: Prader-Willi syndrome and Angelman syndrome. It is the first-line and most sensitive diagnostic test for both conditions.
Methylation analysis of chromosome 15 is the most sensitive single approach for diagnosing both conditions. It detects more than 99% of PWS cases and approximately 80% of AS cases, making it more informative than many other genetic tests used for these syndromes.
A 5 ml whole blood sample collected in a lavender-top EDTA tube is required. The sample must not be frozen or from a recently transfused patient, as this can make results unreliable.
The report is typically available within 8 days at Lupin Diagnostics. This timeline reflects the specialised nature of molecular genetic testing, which involves DNA extraction and detailed analysis.
Methylation testing may be performed on amniotic fluid samples from amniocentesis in families with a known risk. However, it is not recommended on chorionic villus samples, as incomplete methylation in early embryonic development can lead to uninterpretable results.
A normal result does not fully rule out Angelman syndrome, as about 11% of AS cases are caused by a change in the UBE3A gene, which this test does not detect. Your doctor may recommend UBE3A gene sequencing as a follow-up step.
No fasting or special preparation is needed. However, it is important to bring a detailed clinical history and to inform the phlebotomist about any recent blood transfusions before the sample is collected.
Prader Willi Methylation/ Angelman Syndrome (AS-PWS) Methylation: Booking, Price, and Results
