UNITY Screen™ NIPT for Edwards Syndrome (Trisomy 18)

What Is UNITY Screen™ for Edwards Syndrome?

Discussing Trisomy 18 prenatal testing with your doctor is recommended for all pregnant patients. UNITY Screen™ non-invasive prenatal testing (NIPT) is a type of screening for Edwards syndrome that doctors and expecting parents can use to find out if an unborn baby might be at high-risk for the genetic condition. It works by analyzing the baby's DNA from the placenta, which is found in the mother's blood. This test is non-invasive, which means it only requires a blood sample from the pregnant patient.

How UNITY for Edwards Syndrome Works?

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What Is Edwards Syndrome?

Trisomy 18 or Edwards syndrome is a genetic condition that happens when a baby inherits an extra copy of a chromosome called chromosome 18. This can cause serious health problems and birth defects, such as heart defects, and poor growth. Babies with Trisomy 18 usually pass away within the first year of life due to medical complications and those that do survive beyond one year typically have significant intellectual disability. Trisomy 18 testing during pregnancy allows couples to understand if their pregnancy is at high-risk for this condition.

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What Causes Edwards Syndrome?

Trisomy 18 is caused by inheriting an extra chromosome 18. This extra genetic material leads to differences in the development and growth of a pregnancy. Inheriting the extra chromosome is random, however the chance of having a baby with Edwards syndrome increases as the mother's age increases. It can happen to any baby, even in pregnancies to younger mothers.

For this reason, screening tests help assess a baby's risk for chromosome conditions such as Edwards syndrome which would otherwise not have been predicted by family or personal history.

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Signs and Symptoms of Edwards Syndrome

The extra genetic information from chromosome 18 can cause a wide range of medical and developmental concerns. Oftentimes there are signs of Trisomy 18 on prenatal ultrasounds during the second and third trimesters. Most commonly, pregnancies with Trisomy 18 can have:

• Heart defects
• Kidney problems
• Extra amniotic fluid (polyhydramnios)
• Characteristic facial features
• Poor growth

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Who Should Get Prenatal Screening for Edwards Syndrome?

The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant people be offered screening for chromosomal abnormalities, including Trisomy 18. However, it's especially important for pregnant patients who are older, or who have had a previous pregnancy with Trisomy 18.

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UNITY Screen™ Prenatal Screening for Trisomy 18 Workflow

Consult
The UNITY Screen™ NIPT is ordered through your healthcare provider. You can schedule a complimentary genetic counseling session to answer any questions about the test before or after your blood is drawn.

Test: As early as week 9
Your blood sample can be collected in the doctor’s office, at a local lab, or through our mobile services. Your blood sample is shipped to our CAP/CLIA certified laboratory in northern California.

aneuploidy NIPT + fetal antigen results: As early as week 10
Within about one week from lab receipt, your doctor will receive the baby’s risk score for aneuploidies (chromosome conditions) and fetal antigens (if added). You will receive a text or email indicating your results are available on our portal, or your healthcare provider may call you with the results.

carrier status + single-gene NIPT results: As early as week 11
Within about two weeks from lab receipt, your doctor will receive the results of your maternal carrier status testing and single-gene NIPT. If you were found to be a carrier for any of the recessive conditions, single-gene NIPT is automatically run to determine your baby’s risk of being affected. You will receive a text or email indicating your results are available on our portal, or your healthcare provider may call you with the results.

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How Accurate Is NIPT for Edwards Syndrome?

UNITY Screen™ results can tell you if there is a higher or lower chance that your baby might have Trisomy 18. This genetic testing for Trisomy 18 is a screening test and not a diagnostic test. If you receive a high-risk result, it does not mean that the baby has Edwards syndrome.

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However, it may indicate a need for diagnostic testing for Trisomy 18 in pregnancy or after birth. It's important to discuss the test results with a healthcare provider to understand what they mean and decide how you would like to move forward with possible next steps.

• Before Birth
  Testing during pregnancy can be performed by obtaining a sample of placenta (chorionic villus sampling or CVS) or fluid around your baby (amniocentesis) which both contain DNA that is representative of your baby.  A CVS is ideally performed between 10 to 13 weeks pregnancy while an amniocentesis is typically performed between 15 to 24 weeks pregnancy.  Both procedures are generally safe, but have a small risk for pregnancy complications, including miscarriage.  
• After Birth
  Infants with Edwards syndrome typically have physical features of the condition. However, if confirmatory testing during pregnancy is not done, the baby’s pediatrician should be informed of this result. The baby can have chromosome analysis performed after birth. Physical exam by a medical geneticist can also be considered.

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Resources

• Support Organization for Trisomy (SOFT)
• Trisomy 18 Foundation
• The National Organization for Rare Disorders (NORD)

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Frequently Asked Questions

Explore our additional resources and find answers to common questions.

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How is Edwards syndrome (Trisomy 18) treated?

At this time, there is no cure for Trisomy 18. Treatment for infants with Trisomy 18 usually involve supportive measures and comfort care to assist with breathing and other medical complications.

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Are there different types of Trisomy 18?

Most cases of Trisomy 18 are caused by every cell having an extra chromosome 18, this is commonly called “full Trisomy 18.” This type of Trisomy is not inherited and can happen to any pregnant person. Although rare, some cases of Trisomy 18 are called “partial Trisomy 18”. In these cases, a portion of chromosome 18 is duplicated. This means these pregnancies have two full copies of chromosome 18 plus a “partial” or extra piece from a third chromosome 18. Lastly, some pregnancies can have mosaic Trisomy 18. Mosaic Trisomy 18 occurs when some cells have an extra chromosome 18 and other cells do not. This is also very rare and happens spontaneously.

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How can I reduce my risk of having a child with Edwards syndrome (Trisomy 18)?

There is no way to reduce your risk of having a child with the condition since it is random.  Trisomy 18 typically happens randomly. Testing for Trisomy 18 in pregnancy is recommended for any pregnant person, and especially those over the age of 35 who have a higher chance to have a baby with a chromosome condition.