FISH Prenatal Testing
Fluorescence In-Situ Hybridization (FISH) is a sophisticated cytogenetic test used in prenatal diagnosis to detect common chromosomal abnormalities like Trisomy 13, Trisomy 18, and Trisomy 21. FISH uses fluorescent probes that bind to specific chromosome regions, enabling the detection of genetic disorders with high precision and speed. This method is particularly valuable for expectant parents and healthcare professionals, as it allows for rapid decision-making regarding pregnancy management when a high risk of chromosomal abnormalities is suspected.
FISH testing employs fluorescently labeled DNA probes that are complementary to particular chromosome regions associated with known genetic disorders. These probes bind to the target areas, and under a microscope, the fluorescence reveals the presence or absence of specific chromosomal anomalies. For example, FISH can be used to detect trisomies—conditions where there is an extra copy of a chromosome, such as in Down syndrome (Trisomy 21), Patau syndrome (Trisomy 13), and Edwards syndrome (Trisomy 18).
Clinical Utility
FISH prenatal testing offers several key advantages for clinicians and patients alike, particularly when time-sensitive decisions need to be made during pregnancy. Here’s a closer look at its clinical utility:
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Rapid Turnaround Time: One of the major benefits of FISH is its ability to deliver results within 24-48 hours. This is crucial for pregnancies where rapid decision-making is required, such as in cases of suspected chromosomal abnormalities detected during routine ultrasounds or other prenatal screenings.
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High Sensitivity for Common Aneuploidies: FISH is highly effective at detecting common chromosomal aneuploidies, such as Trisomy 13, 18, and 21. These conditions are associated with significant developmental and intellectual disabilities, and early detection allows for better-informed pregnancy management.
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Targeted Testing: FISH is a targeted genetic test, focusing on specific chromosomal regions where abnormalities are most likely to occur. This precision minimizes the risk of overlooking important genetic issues, particularly in high-risk pregnancies.
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Guidance for Further Testing: FISH results can serve as a preliminary diagnostic tool, guiding the need for additional testing. If FISH results are positive for a chromosomal abnormality, confirmatory tests such as karyotyping or chromosomal microarray analysis (CMA) can be performed for a more comprehensive assessment of the fetal chromosomal profile.
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Valuable for Microdeletion/Microduplication Syndromes: Beyond common trisomies, FISH can be used to investigate chromosomal rearrangements, microdeletions, and microduplications that are associated with syndromes like DiGeorge syndrome or Prader-Willi syndrome. This targeted approach helps identify rare genetic conditions that may not be picked up through routine prenatal testing.
When to Consider FISH Prenatal Testing
FISH is recommended in several prenatal scenarios, particularly when there is a heightened risk or suspicion of specific chromosomal abnormalities. Below are the key situations when FISH should be considered:
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High-Risk Pregnancies: If the pregnancy is considered high-risk due to advanced maternal age, abnormal ultrasound findings, or abnormal results from non-invasive prenatal tests (NIPT), FISH can quickly confirm the presence of chromosomal anomalies.
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Suspicion of Specific Aneuploidies: When a doctor suspects common aneuploidies like Trisomy 13, 18, or 21, FISH testing offers a fast and accurate way to diagnose these conditions.
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Need for Rapid Results: In certain pregnancy management cases, timely decisions are critical. FISH is highly recommended when rapid genetic information is needed to guide clinical interventions, such as whether to continue with a pregnancy or prepare for specific medical care at birth.
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Microdeletion/Microduplication Syndromes: FISH is especially valuable in cases where syndromes related to microdeletions or microduplications are suspected, such as DiGeorge syndrome. These syndromes may not be detected by more routine prenatal tests.
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Follow-Up for Abnormal Ultrasound: If an ultrasound shows physical abnormalities that may be linked to chromosomal issues, FISH can offer targeted insight into the potential genetic cause.
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Parental Carrier of Chromosomal Rearrangements: In cases where one or both parents are carriers of chromosomal rearrangements, such as balanced translocations, FISH can help determine the risk of passing the rearrangement to the baby.
MapmyGenome Offerings
At MapmyGenome, we offer cutting-edge FISH prenatal testing designed to provide fast, accurate, and targeted results. Our laboratory uses advanced technology to ensure high sensitivity and specificity for detecting chromosomal abnormalities. Our FISH test can be used to investigate common aneuploidies as well as more complex genetic conditions, offering comprehensive care and support for expectant parents.
In addition to FISH testing, we offer the following complementary services:
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Chromosomal Microarray Analysis (CMA): If FISH results suggest a chromosomal abnormality, CMA can be performed to provide a detailed view of the entire genome, uncovering smaller genetic imbalances that may be missed by FISH.
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Karyotyping: For a full analysis of all chromosomes, karyotyping can be performed as a follow-up to FISH, providing a comprehensive assessment of the fetal chromosomal profile.
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Genetic Counseling: We provide genetic counseling services to help you understand your FISH results, offering support and guidance throughout your pregnancy journey. Our genetic counselors will walk you through the implications of the results, helping you make informed decisions about next steps.
With MapmyGenome’s FISH prenatal testing, you can expect fast and reliable results, enabling better-informed clinical decisions. Our goal is to support you every step of the way, providing the resources you need to manage your pregnancy with confidence.
Test specification
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Technique |
Variant types |
TAT |
Sample requirements |
|
FISH |
AS + SV |
6 - 7 days |
Amniotic Fluid, CVS(chorionic villus sample) |