a disorder caused by the presence of an extra chromosome 21 and characterized by mental retardation and distinguishing physical features.
出典:Wiktionary
出典:『Wiktionary』 (2026/03/29 23:13 UTC 版)
Named after English physician John Langdon Haydon Down (1828–1896), who first described the condition as a distinct form of mental disability in the 1860s.
Down syndrome (uncountable) (chiefly US, Ireland, Australia, New Zealand, usually Canada)