By: Kathy Hubbard
“I gave birth to a beautiful baby girl with almond shaped eyes,” a woman named Sarah wrote on Cincinnati Children’s Hospital’s website. “The doctors and nurses didn’t notice, but I did. After days of waiting and watching, we were given a diagnosis that we were expecting but were silently praying would be negative: our daughter had Down syndrome.”
Down syndrome is one type of trisomy and trisomy is a genetic condition where there is an extra copy of a chromosome. Our bodies have 23 pairs of chromosomes, half we inherited from our fathers and half from our mothers, making a total of 46.
However, those with trisomy have a full or partial extra chromosome in most or all of his or her cells for a total of 47 chromosomes. Trisomy disorder is based on which chromosome has a third copy, resulting in a numbered diagnosis.
Cleveland Clinic’s website explains that “since each chromosome has a different role in your body’s blueprint, where the third copy attaches can affect what genetic the baby will have. The most common trisomy conditions include trisomy 13, Patau syndrome; trisomy 18, Edward syndrome, and trisomy 21, Down syndrome.”
The National Institute of Child Health and Human Development says that an extra copy of some chromosomes will be lethal. For example, an embryo with three copies of chromosome 1 will not develop. But, if cells include only a partial extra chromosome, symptoms are usually milder than if cells have a complete extra chromosome.
“Health conditions and problems associated with trisomy include physical abnormalities, such as extra fingers or toes; physiological issues, such as irregular heartbeat patterns; and problems related to intellectual and developmental functioning,” they say.
Trisomy 21, Down syndrome, is the most common. It occurs in one in 691 live births in the United States. “People with Down syndrome usually have mild-to-moderate intellectual and developmental disability (IDD), heart abnormalities, and are at risk for hearing and vision loss and a number of other health conditions,” NICHHD says.
“Trisomy 18, also called Edwards syndrome, occurs in about one in 5,000 live births each year in the U. Infants with Trisomy 18 often have severe IDD, as well as serious heart problems and other life-threatening issues that make them less likely to live past their first birthday.
“And, Trisomy 13, also called Patau syndrome, occurs in about one in 10,000 to 16,000 live births each year worldwide. Trisomy 13 is associated with more severe IDD and multiple physical problems, including serious heart problems.”
Cleveland Clinic explains that in our genetic code, the 23rd pair of chromosomes are the sex cells. “Designations for sex cells are XX for female or XY for male, instead of as a number. When the cells divide, the sex cells can copy abnormally, causing a trisomy. Types of sex cell
trisomies include Trisomy X (XXX), Klinefelter syndrome (XXY), and Jacob’s syndrome (XYY).”
Trisomy can occur in any pregnancy. “The risk is higher in those over 35 years old who become pregnant, but the majority of babies born with trisomy are to parents younger than 35 years of age because there are statistically more births in those under 35 years.”
During prenatal ultrasounds, the healthcare provider will look for signs such as excess amniotic fluid surrounding the baby; only one artery in the umbilical cord; small placenta; a less active baby, or one that’s small for its age; and physical abnormalities like heart problems or a cleft palate.
If there are suspicions, further genetic testing will be done. I won’t go into details, because I don’t have enough space, but they include blood tests, amniotic fluid test, and sample cells tests.
“Most of the time, trisomy conditions are not passed from one generation to the next but result from a random error that occurs during cell division very early on in development,” NICHHD says.
Sarah said that she and her family grieved the loss of what was “supposed” to be. But after a few weeks she realized that her “baby is the most amazing baby on earth! She makes our family complete. I look forward to this journey with her and have high aspirations for what she will do and become in this precious life she has been given.”
Kathy Hubbard is a member of the Bonner General Health Foundation Advisory Council. She can be reached at kathyleehubbard@yahoo.com. This article was written for publication in the Bonner County Daily Bee on March 19, 2025.
