Down syndrome

/-dɹəm/

UK: /daʊn ˈsɪndɹəʊm/

Down syndrome

English Noun

Definition

A genetic disorder caused by the presence of all or part of a third copy of chromosome 21 (a chromosomal excess), whereby the patients typically have a delay in cognitive ability and physical growth, as well as a small head and tilted eyelids.

Etymology

Named after John Langdon Haydon Down (1828–1896), an English physician who first described the condition as a distinct form of mental disability in the 1860s.