Di-George Syndrome (Karyotyping+FISH) Test
About Di-George Syndrome (Karyotyping+FISH) Test
| Field | Value |
|---|---|
| Also Known As | 22q11.2 Deletion Syndrome Test, DiGeorge Syndrome FISH Test, Velocardiofacial Syndrome (VCFS) Test, CATCH 22 Syndrome Test, Shprintzen Syndrome Test, Chromosome 22q11.2 Microdeletion Analysis Test |
| Sample Type | Peripheral blood (sodium heparin tube) |
| Fasting Required | No fasting required |
| Report Time | 12 days |
| Recommended For | Infants, children, and adults with suspected DiGeorge syndrome |
| Price | Starting at ₹7,800 |
What is a Di-George Syndrome (Karyotyping+FISH) Test?
The Di-George Syndrome (Karyotyping+FISH) test is a specialised genetic test that checks for a tiny missing piece of chromosome 22, known as the 22q11.2 deletion. This deletion causes DiGeorge syndrome, a condition present from birth that can affect the heart, immune system, and development.
The test combines two laboratory techniques — karyotyping and FISH (Fluorescence In Situ Hybridisation) — to examine a sample of peripheral blood. It is also known as the 22q11.2 Deletion Syndrome test or the DiGeorge Syndrome FISH test.
What Does a Di-George Syndrome (Karyotyping+FISH) Test Measure?
This test uses two complementary methods on the same blood sample. Together, they provide a complete picture of the chromosomes.
| Method | What It Does |
|---|---|
| Karyotyping | Examines all 46 chromosomes for large structural problems such as rearrangements or deletions visible under a microscope |
| FISH (Fluorescence In Situ Hybridisation) | Uses fluorescent probes (glowing molecular markers) that attach specifically to the 22q11.2 region of chromosome 22 to detect tiny deletions too small for karyotyping alone |
Karyotyping rules out other chromosomal abnormalities, while FISH specifically targets the microdeletion that causes DiGeorge syndrome. Using both methods together improves diagnostic accuracy.
Why is a Di-George Syndrome (Karyotyping+FISH) Test Done?
A doctor may request this test when a patient shows signs that suggest a chromosomal problem affecting the heart, immune system, or development. Below are the common reasons for ordering this test.
Common Symptoms That May Require This Test
The following symptoms are among the most common reasons a doctor will request a Di-George Syndrome (Karyotyping+FISH) test:
- Congenital heart defects (structural problems with the heart present at birth)
- Recurrent infections suggesting a weakened immune system
- Low calcium levels (hypocalcemia) causing seizures or muscle spasms
- Cleft palate or nasal-sounding speech
- Delayed speech, learning, or developmental milestones
- Distinctive facial features such as low-set ears or a small jaw
- Feeding difficulties in infants
Conditions This Test Can Help Detect
The Di-George Syndrome (Karyotyping+FISH) test procedure can help identify the following:
- DiGeorge syndrome (22q11.2 deletion syndrome)
- Velocardiofacial syndrome (VCFS)
- CATCH 22 syndrome
- Conotruncal heart malformations associated with chromosome 22 deletion (e.g., ventricular septal defect, tetralogy of Fallot)
- Immune deficiency due to thymus underdevelopment
- Hypoparathyroidism and related calcium disorders
- Palatal abnormalities and renal anomalies linked to the 22q11.2 deletion
How to Prepare and What to Expect
No special preparation is needed before this test. The section below covers what to do before your appointment and what the collection process involves.
Do You Need to Fast?
No fasting is required for this test. You may eat and drink normally before your appointment.
Practical Tips Before Your Test
Keep the following points in mind before you go for sample collection:
- Bring a detailed clinical history, including your symptoms, previous test results, and family history
- Inform the collecting staff about any current medications or recent blood transfusions
- If the patient is an infant or young child, keep them calm and comfortable before the blood draw
- Wear clothing with easy access to the inner elbow area
- Bring any previous medical records or imaging reports that may be relevant
Step-by-Step Procedure
Here is what to expect during the Di-George Syndrome (Karyotyping+FISH) test procedure:
- The phlebotomist (person who draws blood) cleans the skin at the collection site, usually the inner elbow, with an antiseptic solution.
- A small amount of peripheral blood (approximately 3 ml) is drawn into a green-top sodium heparin tube.
- The sample is labelled clearly with your details and maintained at ambient room temperature (15°C to 25°C) for transport to the laboratory. Do not refrigerate or freeze the tube.
- In the laboratory, cells from the blood are cultured (grown in controlled conditions) for one to two weeks to obtain enough dividing cells for karyotyping.
- For FISH analysis, fluorescent probes targeting the 22q11.2 region are applied to the prepared cells; any deletion shows up as a missing signal under a fluorescence microscope.
- Both sets of results are reviewed by a cytogeneticist (a specialist in chromosome analysis) and compiled into your report.
Factors That Can Affect Accuracy
The following factors may affect the quality or reliability of results:
- Using the wrong collection tube (sodium heparin is required; other tube types are not acceptable)
- Insufficient blood volume in the sample
- Delay in transporting the sample to the laboratory
- Poor cell growth during culture, which may require recollection
- Deletion breakpoints that fall outside the fluorescent probe's target area (in rare cases, a microarray test may be needed for confirmation)
Understanding Your Di-George Syndrome (Karyotyping+FISH) Test Results
Results from this test are reviewed by a specialist and must always be discussed with your doctor. The table below shows how results are generally interpreted.
| Parameter | Normal Finding | Abnormal Finding |
|---|---|---|
| Karyotype | 46,XX (female) or 46,XY (male); no structural abnormalities | Structural rearrangements or other chromosomal abnormalities present |
| FISH for 22q11.2 | Two signals present on both copies of chromosome 22 | One signal absent, indicating a 22q11.2 deletion |
Disclaimer: 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
Standard karyotyping alone may not detect the 22q11.2 microdeletion, as it is often too small to be seen under a standard microscope. FISH is essential for accurate identification of this deletion. In rare cases where FISH does not detect a deletion but clinical suspicion remains high, your doctor may recommend a chromosomal microarray or targeted gene sequencing for further evaluation.
Long-Term Clinical Management
DiGeorge syndrome is a genetic condition, so no dietary or lifestyle change can alter the presence of a chromosomal deletion. However, the following steps are important for families:
- Seek early diagnosis so that a team of specialists (including cardiologists, immunologists, and speech therapists) can begin appropriate management
- Pursue genetic counselling to understand the inheritance pattern and implications for other family members
- Keep all follow-up appointments as recommended by your doctor to monitor associated health conditions
Lupin Diagnostics Di-George Syndrome (Karyotyping+FISH) Test Price and Home Collection
The Di-George Syndrome (Karyotyping+FISH) test cost at Lupin Diagnostics starts at ₹7,800, and home sample collection is available across cities in India.
| City | Approximate Price (₹) |
|---|---|
| BHOPAL | 7800 |
| CHENNAI | 7800 |
| HYDERABAD | 7800 |
| KOLKATA | 7800 |
| NAVI MUMBAI | 7800 |
| PUNE | 7800 |
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 your Di-George Syndrome (Karyotyping+FISH) 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
Lupin Diagnostics offers home collection for the Di-George Syndrome (Karyotyping+FISH) test across multiple cities in India. All samples are processed in NABL-accredited laboratories by experienced cytogenetics specialists. Your digital report is shared securely via email or WhatsApp once ready.
Frequently Asked Questions
DiGeorge syndrome is a genetic condition caused by a microdeletion on chromosome 22 at the 22q11.2 region. It can affect the heart, immune system, parathyroid glands, palate, and development. The severity and specific features vary from person to person.
Standard karyotyping cannot detect the 22q11.2 microdeletion on its own, as the deleted segment is too small to see under a conventional microscope. FISH uses fluorescent probes that target this specific region and can identify the deletion with over 95% accuracy. Using both methods together gives a more complete chromosomal assessment.
FISH detects the 22q11.2 deletion in more than 95% of individuals with the condition. In rare cases where the deletion falls outside the probe's target region, a chromosomal microarray may be recommended for further investigation.
Yes, prenatal testing for the 22q11.2 deletion is possible. It can be performed using chorionic villus sampling (CVS) between 10 and 13 weeks of pregnancy, or via amniocentesis after 15 weeks. A doctor or genetic counsellor will advise whether prenatal testing is appropriate based on your specific circumstances.
At Lupin Diagnostics, the report is delivered in 12 days. Karyotyping requires cells to be grown in the laboratory for one to two weeks before analysis, which accounts for the longer turnaround compared to routine blood tests.
In most cases, the 22q11.2 deletion occurs spontaneously and is not inherited from either parent. However, in some cases, it is passed down in an autosomal dominant pattern, meaning one parent carries the deletion. Genetic counselling is recommended for all affected families.
A positive result confirms the presence of a 22q11.2 deletion, consistent with DiGeorge syndrome. Your doctor will discuss the findings with you and refer you to the relevant specialists, such as a cardiologist, immunologist, or developmental pediatrician, based on the symptoms present. A genetic counsellor can also help you understand what the result means for your family.
Di-George Syndrome (Karyotyping+FISH) Test
