March is Trisomy Awareness Month
You’ve probably heard of Down syndrome, but did you know:
- About one in every 700 babies in the U.S. is born with this condition?
- A 45-year-old woman is 10 times more likely to conceive a child with Down syndrome than someone who is 35 years old?
- Down syndrome is only one of several chromosome abnormalities called trisomies, and that two of the others, Trisomy 18 and Trisomy 13, are much more serious?
“Most women know very little about their risk of giving birth to a child with Down syndrome. Many know nothing at all about other trisomy conditions that cause the majority of miscarriages, and are much more life-threatening to the baby,” says Dr. Jill Hechtman, medical director of Tampa Obstetrics. “With today’s highly accurate, non-invasive prenatal genetic screening tests (NIPTs), they can find out as early as nine weeks from a simple blood draw if their unborn child is at risk.”
What is a trisomy?
A trisomy condition means that some or all of a person’s cells have an extra chromosome. How a trisomy affects a person will depend on which chromosome is affected and other factors. Health issues associated with the condition can range from mild intellectual and developmental disabilities and physical abnormalities (learning differences or infertility) to life-threatening problems with the heart or other organs.
What are the most common trisomies and their risks?
Trisomy can occur with any of a person’s 23 pairs of chromosomes, but the most well-known syndromes are:
Trisomy 21, more commonly known as Down syndrome.
About 400,000 Americans have Down syndrome and about 6,000 U.S. babies are born with this condition each year. People with Down syndrome usually have mild-to-moderate intellectual and developmental disability and heart abnormalities. They also are at risk for hearing and vision loss and other health conditions. Although children with Down syndrome will need extra medical care, most will live into their 60s.
The chance of having a child with Down syndrome increases as the age of the mother increases. At 35, a woman has about a one in 350 chance of conceiving a child with Down syndrome. But by 40, the chances are one in 100, and at 45, they go up to one in 30.
Learn more at National Down Syndrome Society
Trisomy 18, also called Edwards syndrome.
This is the second most common trisomy syndrome and occurs in about one in 7,000 live births each year. Babies with trisomy 18 have severe intellectual disabilities and birth defects that typically involve the heart, brain and kidneys. A small number of infants (more often girls) with the condition are able to live into their 20s and 30s, although they require full-time caregiving because of their significant developmental problems.
Only about 50 percent of babies who make it to term will live longer than one week and about 5-10 percent will live past one year. As with Down syndrome, trisomy 18 is more prevalent among older mothers.
Trisomy 13, also called Patau syndrome.
This condition occurs in about one in 10,000 live births. Trisomy 13 infants will have severe intellectual disabilities as well as physical disabilities that could include heart defects, brain and spinal cord problems, and extra fingers and/or toes.
Although about 5 percent will survive the first year. More than 80 percent of babies with Trisomy 13 have birth defects that may involve the heart, brain, kidneys and other organs. Survivors experience severe intellectual disability.
How can I find out if my child is at increased risk for Down syndrome or other trisomies?
Prenatal genetic screening tests from a simple blood draw that can be done in a physician’s office can determine your chance of having a baby with these conditions or other abnormal or missing chromosomes is increased or decreased.
Keep in mind, however, that not all NIPT tests are the same. For example, the Natera Panorama screening test is the only one currently available that can differentiate between mom and baby’s DNA.
Genetic screening tests are not replacements for diagnostic tests such as the CVS or amniocentesis. It is important to discuss all test results with your health care provider and obtain any recommended follow-up testing.
For more information on prenatal as well as other genetic tests, go to natera.com/awareness.