Down Syndrome Information

What Is Down Syndrome

In every cell in the human body there is a nucleus, where genetic material is stored in genes.
Genes carry the codes responsible for all of our inherited traits and are grouped along rod-like structures called chromosomes.
Typically, the nucleus of 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.

Facts About Down Syndrome

  • Down syndrome occurs when an individual has a full or partial extra copy of chromosome 21. This additional genetic material alters the course of development and causes the characteristics associated with Down syndrome.
  • There are three types of Down syndrome: trisomy 21 (nondisjunction) accounts for 95% of cases, translocation accounts for about 4%, and mosaicism accounts for about 1%.
  • Down syndrome is the most commonly occurring chromosomal condition. One in every 691 babies in the United States is born with Down syndrome, about 6,000 each year.
  • There are approximately 400,000 people living with Down syndrome in the United States.
  • Down syndrome occurs in people of all races and economic levels.
  • The incidence of births of children with Down syndrome increases with the age of the mother. But due to higher fertility rates in younger women, 80% of children with Down syndrome are born to women under 35 years of age.
  • People with Down syndrome have an increased risk for certain medical conditions such as congenital heart defects, respiratory and hearing problems, Alzheimer's disease, childhood leukemia and thyroid conditions. Many of these conditions are now treatable, so most people with Down syndrome lead healthy lives.
  • 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. Every person with Down syndrome is a unique individual and may possess these characteristics to different degrees or not at all.
  • Life expectancy for people with Down syndrome has increased dramatically in recent decades – from 25 in 1983 to 60 today.
    People with Down syndrome attend school, work, participate in decisions that affect them, have meaningful relationships, vote and contribute to society in many wonderful ways.
  • 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.
    Quality educational programs, a stimulating home environment, good health care and positive support from family, friends and the community enable people with Down syndrome to lead fulfilling and productive lives.

Down Syndrome Myths and Truths

Today there are still many misconceptions about Down syndrome and those who have it. 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. One in every 691 babies in the United States is born with Down syndrome, or around 6,000 births per year. Today, there approximately 400,000 people with Down syndrome living in the United States.

  • MYTH: Down syndrome is hereditary and runs in families.

    TRUTH: Translocation, a type of Down syndrome that accounts for 3 to 4% of all cases, is the only type of Down syndrome known to have a hereditary component. Of those, one third (or 1% of all cases of Down syndrome) are hereditary.

  • MYTH: Most children with Down syndrome are born to older parents.

    TRUTH: Most children with Down syndrome are born to women younger than 35 years old simply because younger women have more children. However, the likelihood of having a child with Down syndrome increases with the age of the mother, especially after age 35.

  • MYTH: Parents will not find community support in bringing up their child with Down syndrome.

    TRUTH: In almost every community of the United States there are parent support groups and other community organizations directly involved in providing services to families of individuals with Down syndrome. You can find a list of groups at http://www.ndss.org/Resources/Local-Support.

  • MYTH: All people with Down syndrome have a severe cognitive disability.

    TRUTH: Most people with Down syndrome have a mild to moderate cognitive disability, or intellectual disability. This is not indicative of the many strengths and talents that each individual possesses. Be considerate of the extra time it might take a person who has a disability to get things done or said.

  • MYTH: People with Down syndrome are always sick.

    TRUTH: Though people with Down syndrome are at an increased risk for certain medical conditions such as congenital heart defects, respiratory and hearing problems, and thyroid conditions, advances in health care and treatment of these conditions have allowed for most individuals with Down syndrome to lead healthy lives.

  • MYTH: Scientists know everything there is to know about Down syndrome.

    TRUTH: Though we know that an extra full or partial copy of chromosome 21 causes the characteristics of Down syndrome, researchers are making great strides in identifying how individual genes on chromosome 21 affect a person with Down syndrome. Scientists now feel strongly that it will be possible to improve, correct or prevent many of the problems associated with Down syndrome in the future.

  • MYTH: Segregated special education programs are the only option for students with Down syndrome.

    TRUTH: 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. Sometimes students with Down syndrome are included in specific courses, while in other situations students are fully included in the typical classroom for all subjects. Increasingly, individuals with Down syndrome graduate from high school with diplomas, and participate in postsecondary academic and college programs.

  • MYTH: People with Down syndrome cannot be active members of their community.

    TRUTH: 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 and any other activities in the community. People with Down syndrome are valued members of their families and communities, and make meaningful contributions to society.

  • MYTH: People with Down syndrome are always happy.

    TRUTH: 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 behavior.

  • MYTH: Adults with Down syndrome are the same as children with Down syndrome.

    TRUTH: Adults with Down syndrome are not children, and should not be considered children. They enjoy activities and companionship with other adults, and have similar needs and feelings as their typical peers.

  • MYTH: Adults with Down syndrome are unable to form close interpersonal relationships leading to marriage.

    TRUTH: People with Down syndrome socialize and have meaningful friendships. Some choose to date, maintain ongoing relationships and marry.

  • MYTH: Adults with Down syndrome are unemployable.

    TRUTH: Businesses employ adults with Down syndrome for a variety of positions – in banks, corporations, hotels, hospitals, nursing homes, offices and restaurants. They work in the music and entertainment industry, in clerical positions, childcare, the sports field and the computer industry, to name a few. Like anybody else, people with Down syndrome want to have a job where their work will be valued.

  • MYTH: It is ok to use the “r-word” if you don’t really mean it.

    TRUTH: It is never acceptable to use the word “retarded” in any derogatory context. Using this word is hurtful and suggests that people with disabilities are not competent.

Preferred Language Guide

  • People with Down syndrome should always be referred to as people first.
  • Instead of "a Down syndrome child," it should be "a child with Down syndrome." Also avoid "Down's child" and describing the condition as "Down's," as in, "He has Down's.”
  • Down syndrome is a condition or a syndrome, not a disease.
  • People "have" Down syndrome, they do not "suffer from" it and are not "afflicted by" it.
  • “Typically developing” or “typical” is preferred over “normal.”
  • “Intellectual disability" or "cognitive disability” has replaced “mental retardation” as the appropriate term.
  • NDSS strongly condemns the use of the word "retarded" in any derogatory context. Using this word is hurtful and suggests that people with disabilities are not competent.
  • NDSS uses the preferred spelling, Down syndrome, rather than Down's syndrome.
  • Down syndrome is named for the English physician John Langdon Down, who characterized the condition, but did not have it. An "apostrophe s" connotes ownership or possession.
  • While Down syndrome is listed in many dictionaries with both popular spellings (with or without an apostrophe s), the preferred usage in the United States is Down syndrome. The AP Stylebook recommends using "Down syndrome," as well.

Health Care Information

Down syndrome is a common condition caused by having “extra” copies of genes on the 21st chromosome. Those
extra genes change development during pregnancy, and they continue to have effects after birth and throughout
a person’s life. Each person with Down syndrome is unique, having some of the many possible health, learning,
and related differences that can occur with this condition.


Some of the differences in people with Down syndrome are common and visible, like the facial appearance.
Other changes are less common or less visible but can still cause problems or may need special treatments. The
“special treatments” may include medicines, surgeries, or changes in what you should expect. There are no
medicines or therapies that are needed by all people with Down syndrome. There are also no medicines or
therapies that can “cure” Down syndrome.


Your child’s doctor should be your starting point. Your child needs regular doctor visits and a few special tests.
Medical specialists may also need to be involved.


The medical issues for a child with Down syndrome change with age. For this reason, this document is divided
into several age groups. Each age group includes a list of issues that may be important to your child at that age.
Your doctor can check the full AAP guideline for more details (the web address is given below).
The information within each age group is sorted by the parts of the body that are affected (heart, ears, etc).
Many tests only need to be done once. Some areas might need to be looked at again, or even many times, as
the child grows to an adult.


This document focuses on medical topics that affect physical health. Other issues can affect social and school
success, which may not need doctors or other medical resources but are still important issues for children with
Down syndrome. Many people with Down syndrome understand more than they can say. They may need help
to communicate in other ways. Most have good social skills, especially if they have friends with typical behavior
as models. Respect for and attention to their abilities are often important missing pieces and may be enough to
make a big difference in performance and behavior.