Do you capitalize dyslexia in a sentence?

Yes, "dyslexia" should be capitalized when it is used as a proper noun to refer to the specific learning disability characterized by difficulty in reading and writing. For example:

"My son has Dyslexia and struggles with reading."

However, if "dyslexia" is used in a more general sense or as a common noun, it can be written in lowercase. For example:

"Some people with dyslexia also have difficulty with math."