About Down Syndrome

Down syndrome is a naturally occurring chromosomal arrangement that has always existed and is universal across racial, gender and socio-economic lines.


Types of Down Syndrome

There are 3 types of Down syndrome:

Trisomy 21

  • 95% of people with Down syndrome have Trisomy 21
  • Three copies of chromosome 21, instead of two, which occurs during cell division


  • 2-3% of people with Down syndrome have a translocation pattern
  • Part of chromosome 21 breams off and attaches itself to another chromosome (often the chromosome 14)
  • Two-thirds of translocation occurrences are spontaneous while the other third is inherited from a parent


  • 2% of people with Down syndrome have Mosaic Down syndrome
  • Cell division occurs in one of the early cell divisions after conception, resulting in some cells having three copies of chromosome 21 instead of two
  • Like their peers, a person with Down syndrome has diverse abilities. An individual’s level of functioning is not dependent upon the determination of one of these types of Down syndrome.

Physical characteristics of Down syndrome

People with Down syndrome can have similar physical characteristics. Some of these include:

  • Small, flat nose
  • Almond-shaped eyes that have an upward slant
  • Smaller limbs and body frame
  • A gap between the first and second toes that is larger than that of a typically developed individual
  • Low muscle tone
  • Single deep crease across the palm of the hand

How To Talk About Down Syndrome

Make sure you are using appropriate language when referring to any group of people. Correct terminology helps reduce prejudice, misconceptions, and stereotypes. This guide will help you when talking about Down syndrome.

    Down syndrome is named after John Langdon Down. He didn’t have Down syndrome, so it is not possessive (as in Down’s). Some countries still refer to “Down’s syndrome”, but in North America, we do not.
    A person should not be defined by their disability. Emphasize the person. It’s not “Down’s kid.” It’s not “Down syndrome person.” It’s “person with Down syndrome.”
    A person is not “suffering from” or “afflicted with” Down syndrome. A person “has” Down syndrome. People with Down syndrome can lead fulfilling lives; they can go to university, get married, and have careers!
    The r-word is often used in every day speech in a derogatory, offensive, and hateful way. If you stop using it, you help promote the acceptance of people with all disabilities, including Down syndrome.

For more information about Down syndrome: