dyslexia vs learning disability

dyslexia and learning disability both are nouns.

Word	Noun	Adjective	Verb	Adverb
dyslexia	Yes	No	No	No
learning disability	Yes	No	No	No

As nouns, learning disability is a hypernym of dyslexia; that is, learning disability is a word with a broader meaning than dyslexia:

dyslexia: impaired ability to learn to read
learning disability: a disorder found in children of normal intelligence who have difficulties in learning specific skills

Other hypernyms of dyslexia include learning disorder.

dyslexia (noun)	learning disability (noun)
impaired ability to learn to read	a disorder found in children of normal intelligence who have difficulties in learning specific skills