Prenatal screening gives parents-to-be information about whether their fetus has certain genetic disorders.
Genetic disorders are caused by changes in a person’s genes or chromosomes. Aneuploidy is a condition in which there are missing or extra chromosomes. In a trisomy, there is an extra chromosome. In a monosomy, a chromosome is missing. Inherited disorders are caused by changes in genes called mutations. Inherited disorders include sickle cell disease, cystic fibrosis, Tay–Sachs disease, and many others. In most cases, both parents must carry the same gene to have an affected child.
This testing can be done in conjunction with an elective 3D Ultrasound.
There are two general types of prenatal tests for genetic disorders:
- Prenatal screening tests: These tests can tell you the chances that your fetus has an aneuploidy and a few additional disorders.
- Prenatal diagnostic tests: These tests can tell you whether your fetus actually has certain disorders. These tests are done on cells from the fetus or placenta obtained through amniocentesis or chorionic villus sampling (CVS).
Both screening and diagnostic testing are offered to all pregnant women.
Eurofins NTD, LLC. First Trimester Screen | Fß® test reliably assesses a mother’s risk for having a baby with Down syndrome, trisomy 18 and 13 in the first trimester of pregnancy. Performed between 11 weeks, 1 day and 13 weeks, 6 days gestation, the First Trimester Screen |Fß uses data from a blood test (biochemistry) and an ultrasound examination (biophysical) which yields a risk assessment that physicians may present to their patients during the first trimester. The First Trimester Screen | Fß is now better than ever, with the addition of alpha fetoprotein (AFP) which increases the detection rate for Trisomy 21 (please select the PDF to the right for more information).
A maternal blood sample is analyzed for three biochemical markers: alpha fetoprotein (AFP), free beta human chorionic gonadotropin (free beta hCG) and pregnancy associated plasma protein-A (PAPP-A).
The ultrasound examination confirms the fetus’ gestational age and measures the nuchal translucency (NT), or the fluid accumulation behind the fetus’ neck. These combined biochemical and biophysical markers yield the most sensitive screening results possible at the earliest point during the pregnancy, achieving a 93% detection rate at a 5% false positive rate for Down syndrome (and a 95% detection rate at a 0.3% false positive for trisomy 18 and 13). When a Fetal Nasal Bone Assessment is added to the protocol, the detection rate for Down syndrome increases to 96% at a false positive rate of just 2%.
Primary benefits of First Trimester Screen | Fß
- 93% detection rate, 5% false positive rate for Down syndrome (95% detection rate, 0.3% false positive rate for trisomy 18 and 13)
- Safe, simple, non-invasive test
- 95% of all patients are shown to be at low risk for Down syndrome which means early reassurance for the vast majority of your patients
- Those shown to be at higher risk can receive immediate counseling regarding possible follow up options such as CVS (chorionic villus sampling) and amniocentesis
- High detection rates reduce the number of missed cases
- Separate twin reports provided
- Separate interpretations for Down syndrome and trisomy 18 and 13 provided
- Reduces the potential for iatrogenic losses of unaffected fetuses
The advantages of free Beta hCG:
The use of free beta hCG in screening for Down syndrome and other chromosomal abnormalities during the first trimester has been demonstrated to be more effective than other markers, including intact or total hCG. Intact/total hCG, while an effective second trimester marker, is not considered effective during the first trimester. Laboratories that lack the technology to measure free beta hCG have attempted to use total hCG as part of their first trimester screening. This practice results in significantly higher false positive rates for Down syndrome as compared to protocols that measure free beta hCG.
The Verifi® Prenatal Test safely and noninvasively screens for the most common chromosomal aneuploidies as early as 10 weeks gestation using a single maternal blood draw, offering the lowest test failure rate in the industry. The Verifi Prenatal Test uses sequencing technology to provide accurate information for pregnant women regardless of age or risk.
The leader in NIPT innovation
While there are different methods for performing noninvasive prenatal testing, sequencing is the most published method. It has demonstrated excellent detection rates and very low false positive rates.
The Verifi Prenatal Test from Illumina uses whole-genome sequencing (WGS) to screen for common fetal aneuploidies, with higher detection rates and significantly fewer false positives than traditional screening methods.
Why choose the Verifi Test?
- Proven superiority to traditional screening methods for the
- screening of common fetal aneuploidies, with reduced false
- positive rates (increased specificity) and increased positive
- predictive values (PPV)
- Comprehensive portfolio with expanded panel available
- Fast turnaround time
- Lowest published failure rate in the industry, 0.1%
NIPT vs traditional serum screening
- Offers the highest reported detection rate for
- Down syndrome6
- Offers the lowest reported false positive rate for
- Down syndrome
- Offers the broadest screening window (performed as
- early as 10 weeks gestation until term)
- Standard Verifi Test offering
- Trisomy 21 (Down syndrome)
- Trisomy 18 (Edwards syndrome)
- Trisomy 13 (Patau syndrome)
- Sex chromosome aneuploidies
- Monosomy X (MX/Turner syndrome)
- XXX (Triple X)
- XXY (Klinefelter syndrome)
- XYY (Jacob’s syndrome)
- Fetal Sex may be reported if no sex chromosome aneuploidies are detected
Clear, concise results
Results from the Verifi Prenatal Test are reported as “Positive: Aneuploidy Detected” or “Negative: No Aneuploidy Detected.” Results for chromosomes 21, 18, 13, X, and Y are reported individually.
Limitations of the test
Noninvasive prenatal testing (NIPT) based on cell-free DNA analysis from maternal blood is a screening test; it is not diagnostic. False positive and false negative results do occur. Test results must not be used as the sole basis for diagnosis. Further confirmatory testing is necessary prior to making any irreversible pregnancy decision. A negative result does not eliminate the possibility that the pregnancy has a chromosomal or subchromosomal abnormality. This test does not screen for polyploidy (eg, triploidy), birth defects such as open neural tube defects, single gene disorders, or other conditions, such as autism. There is a small possibility that the test results might not reflect the chromosomal status of the fetus, but may instead reflect chromosomal changes in the placenta (confined placental mosaicism, CPM) or the mother that may or may not have clinical significance.
Panorama® is a market-leading noninvasive prenatal screening test (NIPT) that reveals your baby’s risk for genetic disorders as early as nine weeks. Panorama analyzes baby’s (placental) DNA through a simple blood draw from the mother’s arm.
Panorama screens for the most common genetic conditions and the baby’s gender (optional). Some conditions, such as Down syndrome, are caused by extra copies of a specific chromosome. Others, such as microdeletions, occur when a chromosome is missing a small piece of genetic information. Microdeletions affect women equally, regardless of age.
Panorama is a screening test. Genetic counseling and diagnostic testing are recommended to confirm positive findings.
A trisomy is a genetic condition caused by extra copies of a chromosome. Down syndrome, one of the most well-known genetic conditions, is caused by an extra copy of chromosome 21. Generally, the larger the extra chromosome is in size, the more severe problems it will cause. For instance, chromosome 21 is the second smallest autosomal chromosome, and babies with Down syndrome often lead healthy and productive lives. However, babies with Trisomy 13, or Patau syndrome, will typically pass away within the first few weeks of life.
Sex chromosome abnormalities occur when there is an extra or missing copy of one of the sex chromosomes. One type of sex chromosome abnormality that affects girls is called Turner syndrome. Girls with Turner syndrome are missing one X chromosome. Other common sex chromosome abnormalities are caused by an extra chromosome. Although most affected individuals have an IQ that is in the normal range, some but not all, have learning disabilities or delays. In general, presentation is less severe than what is seen in trisomies 18, 13, and 21. Children with sex chromosomes abnormalities typically do not have major birth defects. The risk of some sex chromosome abnormalities increase with maternal age.
Microdeletions are caused when a chromosome is missing a small piece. The severity of problems caused by a microdeletion is determined primarily by the size and location of the deletion. For instance, features of the 22q11.2 deletion syndrome tend to be different and may be less severe than Angelman syndrome, which is a microdeletion involving chromosome 15.
Panorama is currently the only NIPT that tests for triploidy.
Babies with triploidy have a complete extra set of chromosomes for a total of 69 chromosomes instead of the usual 46. At 10 weeks gestation, one in 1,000 pregnancies is affected by triploidy. It is extremely rare for these pregnancies to reach term as they typically spontaneously miscarry early in pregnancy. Those few liveborns usually pass away within days of delivery due to heart, brain, and kidney problems. Babies with triploidy also often have birth defects affecting the extremities and face.
Carrying a baby with triploidy can increase a mother’s risk for a variety of conditions: pre-eclampsia (which can lead to seizures) and excessive bleeding after delivery. In rare instances, triploid pregnancies can persist and progress to a type of cancer called choriocarcinoma. Knowing about triploidy allows the physician to monitor the health of the mother appropriately.
Among commercially available NIPTs, Panorama has the highest published accuracy in determining the baby’s gender.
Panorama’s ability to analyze SNPs unique to the Y chromosome and to detect the presence of vanishing twin pregnancies helps to overcome causes of inaccurate gender reporting common with other technologies.
If the mother is a known carrier, or if there is a known family history for an X-linked condition, (example Duchenne muscular dystrophy) fetal sex determination by NIPT can help determine the need for further diagnostic testing in the pregnancy.
Like most noninvasive prenatal tests (NIPTs), MaterniT GENOME® can tell you if you screen positive or negative for trisomies 21 (Down syndrome), 18 (Edwards syndrome), and 13 (Patau syndrome), and if you’re having a boy or a girl.
But it can also find other chromosomal changes that may go undiagnosed at birth. Having information about these chromosomal changes before birth can help ensure your baby receives the proper and necessary support.
Results delivered clearly and quickly
Results from the MaterniT GENOME test are typically available within five days after your sample has been received in the laboratory. And while some NIPTs give you a risk score, MaterniT GENOME ensures screening results are communicated clearly—as positives or negatives.
Whole chromosomes analyzed by most NIPTs
Most noninvasive prenatal tests (NIPTs) analyze information from select chromosomes. But changes can be found in all chromosomes—which is why MaterniT® GENOME analyzes them all.