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Down syndrome

This page is about the eponym Down syndrome


a condition caused by an extra or partial copy of chromosome 21, resulting in mild to severe intellectual and physical impairment

For example

  • People with Down syndrome often have a small stature.

  • Down syndrome is the most common genetic condition in the USA.

Many people incorrectly assume that "Down" refers to "delayed".

Origin: John Langdon Down (1828-1896) was a Cornish physician who worked in an asylum for people who were mentally impaired. He discovered that a certain group of his patients shared the same characteristics. Dr. Down classified these patients as Mongoloids, because he felt that they resembled people from Mongolia. Though he isolated this condition in 1862, it wasn't identified as a chromosomal condition until 1959. The condition was renamed Down syndrome in 1965. The name change came at the request of geneticists who felt the condition was inaccurately associated with the genes of people from Asia. Some people feel it should not have been named after John Langdon Down.

Quick Quiz

Which is true about Down syndrome?

a. It is present at birth.

b. It is only present in certain cultures.

c. Its presence is uncommon in America.

Contributor: Tara Benwell