Down syndrome

American  

Or Down's syndrome

noun

Pathology.

1. a genetic disorder, associated with the presence of an extra chromosome 21, characterized by mild to severe mental impairment, weak muscle tone, shorter stature, and a flattened facial profile.

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Sensitive Note

Down syndrome (or Down's syndrome ) has replaced earlier terms, such as mongolism to refer to the disease and Mongoloid or Mongol to refer to the affected person, all of which are now considered offensive.

Etymology

Origin of Down syndrome

First recorded in 1960–65; after John L. H. Down (1828–96), British physician

Example Sentences

We heard from a mother, Opal Foster, whose 18-year-old son has Down syndrome and lives at home as he strives to become a chef.

From Salon • Apr. 29, 2026

Previous additions include Barbie dolls with Type 1 diabetes, Down syndrome and blindness.

From Los Angeles Times • Jan. 12, 2026

The Eriksons also had a fourth child, Neil, who had Down syndrome and was sent to an institution immediately after birth.

From The Wall Street Journal • Dec. 18, 2025

The researchers also noted that pleiotrophin levels are reduced in Down syndrome.

From Science Daily • Dec. 17, 2025

He was probably about three or four years old and looked exactly like Ximena, except for the fact that it was very obvious he had Down syndrome.

From "Auggie & Me" by R. J. Palacio