mongolianism vs Down's syndrome

mongolianism and Down's syndrome both are nouns.

Word	Noun	Adjective	Verb	Adverb
mongolianism	Yes	No	No	No
Down's syndrome	Yes	No	No	No

As nouns, mongolianism and Down's syndrome are synonyms defined as:

mongolianism and Down's syndrome: a congenital disorder caused by having an extra 21st chromosome; results in a flat face and short stature and mental retardation

Other synonyms of mongolianism include Down syndrome, mongolism, trisomy 21.

mongolianism (noun)	Down's syndrome (noun)
a congenital disorder caused by having an extra 21st chromosome; results in a flat face and short stature and mental retardation	a congenital disorder caused by having an extra 21st chromosome; results in a flat face and short stature and mental retardation