National Down Syndrome Society

What is Down Syndrome?

Learn more about the science behind Down syndrome, how it is diagnosed, its history and social impact.

What causes Down Syndrome?

Every cell contains a nucleus, where genetic material is stored in genes. They are responsible for all of our inherited traits and are grouped along rod-like structures called chromosomes. Each cell contains 23 pairs of chromosomes, half of which are inherited from each parent. Down syndrome occurs when an individual has a full or partial extra copy of chromosome 21.

Read more about - What is Down Syndrome?

Myths & Truths

This guide dispels some of the common myths about Down syndrome.

MYTH: Down syndrome is a rare disorder. TRUTH: Down syndrome is the most commonly occurring chromosomal condition.

Find out more about Myths & Truths here.

Local Support

NDSS has more than 375 local affiliates that provide an array of benefits.

Affiliate services and programs include: new parent support and education, partnerships with Down Syndrome Clinics and more.

Find your nearest support group here

Helpline - 800-221-4602 /info@ndss.org

NDSS responds to questions from parents, professionals, and self-advocates.

An NDSS Information & Referral Specialist is available to respond to email inquiries and phone calls between the hours of 9am and 5pm ET, Monday - Friday. The helpline is also supported by a translation service that can be accessed in over 150 languages.

Helpline

Our Mission

The National Down Syndrome Society is the leading human rights organization for all people with Down syndrome. NDSS envisions a world in which all people with Down syndrome have the opportunity to enhance their quality of life, realize their life aspirations and become valued members of welcoming communities.

Activity

National Down Syndrome Society has answered a question
On Feb 15, 2019

What causes Down syndrome?

All people with Down syndrome have an extra, critical portion of chromosome 21 in all or some of their cells that alters the course of development and causes the characteristics associated with Dow...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

When was Down syndrome discovered?

For centuries, people with Down syndrome have been alluded to in art, literature and science. It wasn’t until the late 19th century, however, that John Langdon Down, an English doctor, publis...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

Does Down syndrome run in families?

All three types of Down syndrome are genetic conditions (relating to the genes), but only one percent of all cases of Down syndrome have a hereditary component (passed from parent to child through ...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

What are the common physical traits associated with Down syndrome?

A few of the common physical traits of Down syndrome are low muscle tone, small stature, an upward slant to the eyes and a single deep crease across the center of the palm -- although each person w...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

What prenatal tests for Down syndrome are available?

There are two categories of tests for Down syndrome that can be performed before a baby is born: screening tests and diagnostic tests. Prenatal screens estimate the chance of the fetus having Down ...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

What are people with Down syndrome capable of?

Though people with Down syndrome are at an increased risk for certain medical conditions, advances in healthcare and treatment of these conditions have allowed for most individuals with Down syndro...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

What is the likelihood of having a child with Down syndrome?

Down syndrome occurs in people of all races and economic levels, although older women have an increased chance of having a child with Down syndrome. A 35-year-old woman has about a one in 350 chanc...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

How does Down syndrome affect cognitive delays?

All people with Down syndrome experience cognitive delays, but the effect is usually mild to moderate and is not indicative of the many strengths and talents that each individual possesses. Be cons...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

What is the likelihood of having a second child with Down syndrome?

Once a woman has given birth to a baby with trisomy 21 (nondisjunction) or translocation -- two of the three types of Down syndrome -- it is estimated that her chances of having another baby with t...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

How is the idea that people with Down syndrome are always happy misleading?

People with Down syndrome have feelings just like anyone else. They experience the full range of emotions. They respond to positive expressions of friendship and are hurt and upset by inconsiderate...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

How common is Down syndrome?

According to the U.S. Centers for Disease Control and Prevention (CDC), approximately one in every 700 babies in the United States is born with Down syndrome, making Down syndrome the most common c...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

How does maternal age affect the odds of having a baby with Down syndrome?

The likelihood of having a child with Down syndrome increases with the age of the mother, especially after age 35. That said, 80 percent of children with Down syndrome are born to women under 35 ye...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

What kind of education programs are best for students with Down syndrome?

Students with Down syndrome are included in typical academic classrooms in schools across the country. The current trend in education is for full inclusion in social and educational settings. Somet...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

How does having Down syndrome affect relationships and marriage?

People with Down syndrome socialize and have meaningful friendships. Some choose to date, maintain ongoing relationships and marry. Adults with Down syndrome are not children, and should not be con...
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National Down Syndrome Society has answered a question
On Feb 06, 2017

How can people with Down syndrome be active members in their communities?

People with Down syndrome are active participants in educational, social and recreational activities. They are included in the typical education system and take part in sports, music, art programs ...
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National Down Syndrome Society

What is Down Syndrome?

What causes Down Syndrome?

Myths & Truths

This guide dispels some of the common myths about Down syndrome.

Local Support

NDSS has more than 375 local affiliates that provide an array of benefits.

Helpline - 800-221-4602 /info@ndss.org

NDSS responds to questions from parents, professionals, and self-advocates.

Our Mission

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Associated Groups

National Down Syndrome Society's contact info

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