Have you heard of Stealth Dyslexia? I hadn't either until I read this article by The Dyslexia Initiative.
Here is a little excerpt;
"STEALTH DYSLEXIAPeople with stealth dyslexia have problems sounding out (or decoding) words just like those with "classic" dyslexia, yet typically their scores on tests where reading comprehension is measured are typically above average, or even quite strong."-The Dyslexia Initiative
Check out the full article, it short and a good informative read.