agraphia vs brain disorder

agraphia and brain disorder both are nouns.

Word	Noun	Adjective	Verb	Adverb
agraphia	Yes	No	No	No
brain disorder	Yes	No	No	No

As nouns, brain disorder is a hypernym of agraphia; that is, brain disorder is a word with a broader meaning than agraphia:

agraphia: a loss of the ability to write or to express thoughts in writing because of a brain lesion
brain disorder: any disorder or disease of the brain

Other hypernyms of agraphia include brain disease, encephalopathy.

agraphia (noun)	brain disorder (noun)
a loss of the ability to write or to express thoughts in writing because of a brain lesion	any disorder or disease of the brain