Deletion 7q11.23 WilliamS Syndrome Blood Test
About Deletion 7q11.23 WilliamS Syndrome Blood Test
| Field | Value |
|---|---|
| Also Known As | Williams-Beuren syndrome deletion test, Williams syndrome FISH test, 7q11.23 microdeletion test, Elastin gene deletion test |
| Sample Type | Peripheral blood (sodium heparin tube), bone marrow, Chorionic Villus Sampling (CVS), amniotic fluid, cord blood |
| Fasting Required | No |
| Report Time | 8 days |
| Recommended For | All ages; most commonly infants and children with suspected developmental delays, distinctive facial features, or heart anomalies |
| Price | Starting at ₹5,400 |
What is a Deletion 7q11.23 WilliamS Syndrome Blood Test?
The Deletion 7q11.23 WilliamS syndrome blood test is a specialised genetic test that checks for a missing segment of genetic material on chromosome 7. This deletion causes Williams syndrome, a rare condition that affects development, heart function, and physical features. The test is most often ordered for infants and children who show signs such as developmental delays, unusual facial characteristics, or heart problems. It is also known as the Williams syndrome FISH test or the 7q11.23 microdeletion test.
What Does a Deletion 7q11.23 WilliamS Syndrome Blood Test Measure?
This test uses a method called FISH (fluorescent in situ hybridisation), which attaches fluorescent probes to specific parts of the chromosomes to detect whether a segment is present or absent. The key targets examined are listed below.
| Parameter | What it Checks |
|---|---|
| 7q11.23 chromosomal deletion | Detects whether a segment of approximately 26 to 28 genes is missing from chromosome 7 |
| Elastin (ELN) gene | The primary marker gene for Williams syndrome; its absence confirms the deletion |
| Deletion size | Determines whether the deletion covers the typical range or is smaller or larger than usual |
Why is a Deletion 7q11.23 WilliamS Syndrome Blood Test Done?
Doctors order this test when a child's clinical picture suggests Williams syndrome. The following sections outline the symptoms and conditions that may prompt a referral.
Common Symptoms That May Require This Test
Several signs may lead a doctor to recommend the Deletion 7q11.23 WilliamS Syndrome blood test procedure. These include:
- Developmental delay or mild intellectual disability
- Distinctive facial features (wide forehead, full cheeks, small upturned nose)
- Heart problems such as narrowing of the aorta (the main blood vessel from the heart)
- Unusually sociable or overly friendly personality
- High blood calcium levels (hypercalcaemia), particularly in infants
- Poor growth or short stature
- Joint problems or unusually soft, loose skin
Conditions This Test Can Help Detect
This test can help identify the following conditions:
- Williams syndrome, a neurodevelopmental disorder caused by a deletion of multiple genes on chromosome 7
- Supravalvular aortic stenosis (SVAS), a narrowing of the aorta linked to the elastin gene deletion
- Connective tissue abnormalities, including joint hypermobility and loose skin
- Endocrine conditions such as hypercalcaemia, excess calcium in the urine, and an underactive thyroid gland
How to Prepare and What to Expect
No special preparation is needed for this test. The sections below explain what you should know before sample collection.
Do You Need to Fast?
No fasting is required. You may eat and drink normally before the test.
Practical Tips Before Your Test
Keep the following points in mind before going for the Deletion 7q11.23 WilliamS Syndrome blood test:
- Bring a detailed clinical history, including your child's symptoms, previous test results, and family history, as this is required for the test
- Inform the phlebotomist if the patient is a newborn, as a smaller blood volume (1 to 2 ml) is drawn for infants
- Wear clothing with easy access to the arm for a straightforward blood draw
- Ensure the sample reaches the laboratory on the same day it is collected, or the following day at the latest
- If the test involves bone marrow, CVS, amniotic fluid, or cord blood, the collection will be arranged by your doctor at a hospital
Step-by-Step Procedure
The Deletion 7q11.23 WilliamS Syndrome blood test procedure varies depending on the sample type. The process for each is described below.
Peripheral Blood (Sodium Heparin Tube) — Home or Centre Collection
- A certified phlebotomist cleans the skin over a vein, usually on the arm (or the heel for newborns).
- A small blood sample of approximately 3 ml is drawn into a green-top sodium heparin tube.
- The sample is labelled with the patient's details and stored at 2 to 8 degrees Celsius for transport.
- The sample is dispatched to the cytogenetics laboratory for FISH analysis.
- Results are processed and delivered within 8 days.
Bone Marrow, CVS, Amniotic Fluid, or Cord Blood — Hospital Collection Only
- These samples must be collected by a qualified medical specialist at a hospital or clinical centre.
- For CVS and amniocentesis, the doctor uses imaging guidance to collect a small amount of tissue or fluid from around the foetus.
- Cord blood is collected at the time of delivery by the attending medical team.
- All samples are sent directly to the cytogenetics laboratory under appropriate storage conditions.
- Your doctor will explain the specific preparation and consent requirements before each procedure.
Factors That Can Affect Accuracy
The following factors may affect the quality or reliability of results:
- Delayed transport of the blood sample beyond 24 hours
- Use of an incorrect tube type (the sodium heparin tube is essential)
- Inadequate sample volume
- Poor sample storage conditions during transport
- Quality and experience of the cytogenetics laboratory
Understanding Your Deletion 7q11.23 WilliamS Syndrome Blood Test Results
Results from this test are reported by a genetics specialist and should always be discussed with your doctor. The table below shows how FISH signals are interpreted.
| Finding | Signal Pattern | Interpretation |
|---|---|---|
| Normal | 2 fluorescent signals (one on each chromosome 7) | No deletion detected; Williams syndrome unlikely |
| Abnormal | 1 fluorescent signal only | Deletion confirmed; consistent with Williams 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.
A negative result rules out Williams syndrome in most cases. However, a very small number of atypical presentations may require further testing even when no deletion is detected. A positive result will typically prompt a referral for cardiac evaluation, calcium monitoring, and specialist developmental support.
How to Maintain Healthy Levels
If a diagnosis of Williams syndrome is confirmed, the following general steps support ongoing well-being:
- Attend regular cardiac check-ups, as heart conditions such as aortic narrowing require consistent monitoring
- Keep track of blood calcium levels, which can be raised in children with this condition
- Enrol in early intervention programmes, as developmental therapy started early can significantly improve day-to-day functioning
Lupin Diagnostics Deletion 7q11.23 WilliamS Syndrome Blood Test Price and Home Collection
The Deletion 7q11.23 WilliamS Syndrome blood test cost at Lupin Diagnostics starts at ₹5,400. Home collection is available for peripheral blood samples. All other sample types (bone marrow, CVS, amniotic fluid, and cord blood) require collection at a hospital or clinical centre.
| City | Approximate Price (₹) |
|---|---|
| BHOPAL | 5400 |
| CHENNAI | 5400 |
| HYDERABAD | 5400 |
| KOLKATA | 5400 |
| NAVI MUMBAI | 5400 |
| PUNE | 5400 |
Disclaimer: 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 the Deletion 7q11.23 WilliamS Syndrome blood test online booking:
- Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist for peripheral blood, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
Lupin Diagnostics offers home collection for the peripheral blood sample across multiple cities. Samples are processed in NABL-accredited laboratories, ensuring quality at every step. Digital reports are shared via email or WhatsApp once ready.
Frequently Asked Questions
The Deletion 7q11.23 WilliamS Syndrome blood test detects a missing segment on chromosome 7 that causes Williams syndrome. It is ordered when a child shows signs such as developmental delays, distinctive facial features, or heart problems. It can be performed on peripheral blood, bone marrow, CVS, amniotic fluid, or cord blood, depending on clinical need.
This test is most commonly recommended for infants and children who show signs of Williams syndrome, such as a narrowing of the aorta, unusual facial features, or overly sociable behaviour. It may also be ordered when a family history of Williams syndrome exists or when prenatal imaging raises concerns.
FISH and chromosomal microarray testing are both highly reliable, with accuracy exceeding 95%. A deletion at 7q11.23 is detected in approximately 99% of patients with Williams syndrome. A very small number of atypical cases may require additional testing.
No fasting is needed. Your child may eat and drink as normal before the blood draw. No special dietary preparation is required for any of the sample types used in this test.
In most cases, Williams syndrome results from a new, spontaneous deletion on chromosome 7 that is not inherited. In rare instances, an affected parent can pass the deletion to a child. Each child of an affected parent has a 50% chance of inheriting the deletion.
Williams syndrome is estimated to occur in approximately 1 in every 7,500 live births. It affects males and females equally and occurs across all ethnic backgrounds.
Prenatal testing for the 7q11.23 deletion is possible through chorionic villus sampling or amniocentesis. It is generally offered only when there is a known family history of Williams syndrome or when findings on prenatal imaging suggest a possible diagnosis. Speak to your doctor or a genetic counsellor for guidance.
Deletion 7q11.23 WilliamS Syndrome Blood Test
