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.

---

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

Alistair also takes an interest in the intellectual and developmental disabilities community, writing about the effects of the Covid-19 pandemic and war in Ukraine on people with autism, Down syndrome and other conditions.

From The Wall Street Journal • Feb. 16, 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

New research suggests that disrupted brain circuits in Down syndrome may be linked to a shortage of a specific molecule that the nervous system relies on to develop and work properly.

From Science Daily • Dec. 17, 2025

Later pregnancies have a higher risk of complications such as miscarriage, high blood pressure and chromosomal abnormalities such as Down syndrome.

From Los Angeles Times • May 3, 2025

She leans down, handing her baby with Down syndrome chunky plastic blocks from the toy basket.

From "Rules" by Cynthia Lord