Autodidact
Intentionally Blank
"Not Normal" would be a good candidate but I really think "unnatural" express my view adequately ("unnatural - 'at variance with what is normal or to be expected' - Unnatural | Define Unnatural at Dictionary.com)
Pretty much; I think that extremely gifted persons are unnatural, as with left-handed persons (gosh, forgot that I am a lefty ...).
O.K., well I'll agree that it's in the same category as being left-handed or a genius. I don't call that unnatural, and I don't think most people do, but in that (odd) sense of the word I don't have a problem.
Of course, that does not in any way mean there's something wrong with it.