reviewed 8/9/2018

Down syndrome: True or false?

Down syndrome happens when a child is born with an extra chromosome—it is one of the most common genetic birth defects. In fact, it occurs in about 1 of every 700 babies in the U.S. How much do you know about Down syndrome?

True or false: Down syndrome is a hereditary disorder that runs in families.

False. There are three different types of Down syndrome. All are caused by an extra chromosome 21, but only one kind—called translocation—can sometimes be passed down from parent to child. However, only about 1 percent of all Down syndrome cases are hereditary.

True or false: People with Down syndrome all share the same physical features.

False. There are some physical features common to people with Down syndrome. These include eyes that slant upward, a small mouth and nose, small ears, a short neck, small hands and feet, and a below-average height. But not every person with Down syndrome will have all these qualities.

True or false: Down syndrome rarely causes severe intellectual disability.

True. The intellectual disability of people with Down syndrome can vary widely, but it usually is mild to moderate. Early intervention programs—in which very young children with Down syndrome work with special educators and therapists—can improve their communication and physical skills as well as their learning abilities.

True or false: The risk for having a baby with Down syndrome rises with the mother's age.

True. For example, the risk for a 25-year-old mother is 1 in 1,340. By age 35, the risk rises to 1 in 353. The risk that a 45-year-old mother will have a baby with Down syndrome is 1 in 35. Still, 80 percent of cases occur in births to women under 35 years old—as more children overall are born to this group.

True or false: People with Down syndrome often have other health conditions too.

True. Children with Down syndrome often are born with heart defects, some of which require surgical correction. Other common health conditions can include vision and hearing problems, thyroid deficiency, frequent ear and respiratory infections, and an increased risk for Alzheimer's disease.

Giving a child with Down syndrome the extra care he or she needs to be as healthy and active as possible can start on day one. Find out what you can do to help your child reach his or her full potential.

How to help

Sources: March of Dimes; National Down Syndrome Society; National Institutes of Health

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