Is there actually a test for it available? Most of what I can find in the literature is experimental. The genetic testing seems so far to be more accurate for determining med regimens once one has been diagnosed rather than providing the actual diagnosis, let alone diagnosing it in someone who's asymptomatic.
Because she's a bright kid who likes to read. You can't make a kid like to read any more than you can make them like liver, and you can't coach her to be smart any more than you can coach her to be world class in a sport for which she has no aptitude.
Come on, don't steal the poor kid's thunder.
Please remember that this is Madison's accomplishment, not yours. It's great that you provide her with a supportive environment for reading, but a kid either reads, or they don't. You were lucky - you got a reader.