diabetes vs polygenic disease

diabetes and polygenic disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
diabetes	Yes	No	No	No
polygenic disease	Yes	No	No	No

As nouns, polygenic disease is a hypernym of diabetes; that is, polygenic disease is a word with a broader meaning than diabetes:

diabetes: a polygenic disease characterized by abnormally high glucose levels in the blood; any of several metabolic disorders marked by excessive urination and persistent thirst
polygenic disease: an inherited disease controlled by several genes at once

Other hypernyms of diabetes include polygenic disorder.

diabetes (noun)	polygenic disease (noun)
a polygenic disease characterized by abnormally high glucose levels in the blood; any of several metabolic disorders marked by excessive urination and persistent thirst	an inherited disease controlled by several genes at once