????
??21-?????????21????????????19?????????John Langdon Down
?
1866????????????Mongolism????mongolian idiocy???????????????????????
1959?????(Jerome LeJeune)???21???????????
1961????The Lancet???
1965?WHO??????
???????????660????????????????2024???1/149040?1/10649?1/11?????I?????80???35?35???? ?????????14??????????????
???????????????????60?????????????????????????????????40????????????????
??
??????????? ??????????????????????????????????????????????????????????????????????
...