Down Syndrome Awareness Month: Trisomy 21 and its Effect on the Heart

October is Down Syndrome Awareness Month! Sibley Heart Center Cardiology’s pediatric cardiologist, Rachel McKay, MD, took a few minutes to discuss how Trisomy 21 (T21) affects the hearts of some patients.

Q: What is Trisomy 21?

A: Trisomy 21 refers to the most common form of Down syndrome, a genetic disorder associated with developmental delays, characteristic facial features, and intellectual disabilities. It is caused by the presence of a full or partial extra copy of chromosome 21 and can affect other systems such as the heart and gastroenterology system.

Q: What are the common causes and risk factors of Trisomy 21?

A: There is a known association with advanced maternal age and Trisomy 21. However, in most cases, doctors are unable to identify a cause for the disorder.

Q: How can Trisomy 21 affect the heart?

A: There are several different cardiac lesions that can be associated with trisomy 21. One is an atrial septal defect (ASD), which is a hole between the two top chambers of the heart. Another is a ventricular septal defect (VSD), or hole between the bottom two chambers of the heart. Another is a “canal” type defect,  where there are holes in the upper and lower chambers in the heart creating a large hole in the center of the heart, and this can lead to abnormalities in the valves in the heart. Another abnormality that can occur is when a fetal structure called the patent ductus arteriosus can stay open longer in patients with T21. All of these defects can cause congestive heart failure, or in other words, too much blood flow to the lungs. Smaller holes may close on their own as the baby grows but some require surgery.

Q: What do you want families to know about diagnosis and screening?

A: If there is a suspicion of Trisomy 21 in pregnancy, a fetal echocardiogram can confirm the diagnosis, allowing for early recognition and planning. All patients who have been identified as Trisomy 21 should have an echocardiogram within weeks of birth and should be followed by a cardiologist if a heart defect is diagnosed.

“A pediatric cardiologist will work with the family to determine whether the patient needs further observation, medication, or will require heart surgery,” Dr. McKay said. “Signs such as fast breathing, poor feeding, and poor weight gain can indicate that too much blood is flowing into lungs and that the patient may need surgery. We keep a watchful eye on these signs and discuss them with the family along the way. The surgical outcomes for these defects are very favorable and most patients require just a single heart surgery with excellent surgical outcomes.”

For more information about Sibley Heart Center Cardiology and our pediatric cardiology specialists, click here.