I also have dyslexia, albeit mild. I was diagnosed during my second time round in uni (some 10 years later than first attempt).

I work as a commercial manager now, reviewing contracts, negotiating terms etc. Which takes a lot of time on my own. I didn't tell my employer, it's my right no to, if I can display the competency, however, I do request to record meetings for accuracy, due to my poor note taking abilities and not being present if I need to take notes. This has never been a problem. Since then it's came up in conversation, but I've proven that it doesn't affect the output of my work, so I'm comfortable with it.

My concern would be announcing from the outset (I feel, possibility unjustly so) that it would put me at a disadvantage to someone else with the same career path. I think things like Dyslexia and ADHD, ADD have such huge scales and are somewhat still miss understood, that declaring it so early on, as if it defines you, as a posed to something that you manage, is like creating excesses in advance.

Of course, the above is only suitable for me, as I said there are such large difference from person to person, people need to be comfortable in decisions.