Myths on Down syndrome abound.

You may have heard these myths, or even shared them yourself: People with Down syndrome are always sick, always happy or born to older mothers. And these are just a few.

Marshfield Clinic Genetic Counselors Anna Cisler and Kyle Salsbery teamed up to demystify five of these myths.

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Myth: Down syndrome is a rare genetic disorder.

Down syndrome, also known as trisomy 21, is more common than one might think.

Each year, around 6,000 babies in the U.S. are born with Down syndrome, according to the National Down Syndrome Society.

In fact, it’s the most common chromosomal abnormality, said Cisler. Other chromosomal abnormalities occurring less frequently are Turner syndrome and Trisomy 18 and 13.

Trisomy 18 and 13 are like Down syndrome in that they are also trisomies – there is a presence of three chromosomes rather than the usual pair of chromosomes. Both genetic disorders include a combination of birth defects, like intellectual disability and health problems in nearly every organ system in the body.

Turner syndrome is a monosomy – there are 45 chromosomes in each cell of the body, rather than 46. This genetic disorder occurs in girls and causes them to be shorter than others.

Myth: Children with trisomy 21 are born to older mothers.

“The process of producing an egg is more prone to mistakes as a woman ages,” Salsbery said, “but this does not mean most children with Down syndrome are born to older mothers.”

Actually, the opposite is true. Cisler said nearly 80 percent of babies with trisomy 21 are born to women younger than 35.

“Every maternal age is at risk,” Cisler said. “It’s just that the degree of risk changes each year.”

The error that results in an extra chromosome can happen in sperm cells too.

Myth: People with Down syndrome are always sick.

People with trisomy 21 are at an increased risk for certain illnesses, like heart disease and eye problems, among others, said Salsbery.

But, they don’t spend the majority of their time in health care facilities, as most of these illnesses are treatable.

“Advancements to address these health concerns are always improving,” Salsbery said. “People with Down syndrome have a lot better quality of life than most may assume.”

Myth: Those living with trisomy 21 are always happy.

Just like everyone else, people with Down syndrome feel a range of emotion.

“They also get sad, angry, frustrated, happy,” Cisler said.

Salsbery added that many parents comment how their child with trisomy 21 behaves much like any other child: They, too, misbehave and have likes and dislikes.

Myth: Down syndrome is hereditary.

A majority of the time – nearly 99 percent – trisomy 21 is sporadic. This means that the genetic disorder occurs by chance and is not carried by either parent.

The lesser percent usually happens from a translocation, occurring when a parent has a rearrangement of chromosomes such that two can become stuck together. That parent is then at risk of passing on two copies of chromosome 21 to a child, causing the child to receive three copies of chromosome 21 in total – two from the parent with the translocation and one from the other parent.

Let’s spread the word

Share these mythbusters with your family and friends to educate each other on the truths of Down syndrome.

“In all reality, people with Down syndrome are more alike other individuals than they are different,” Salsbery said.