One of my sons has substantial measured cognitive disabilities including base IQ and a range of social functions. By most recent evaluations he's borderline "mentally retarded". (A nasty phrase that's enshrined by legal statutes. Of course there's no true binary state, this is all continua.)
Which is why our titanic struggles over his misuse of internet resources are puzzling. This ought to be the mismatch of the decade. In every measure of knowledge and cognitive measurement there should be no contest between him and me.
And yet it is a struggle. Mostly I win, but he wins some too. He's proven OS X Parental Controls, for example, are utterly broken. (I have more to write about iPhone for special needs adolescence. There's more promise there, starting with disabling Safari and YouTube.)
Yes, he has a knack for software. It's not savant level, but he might be 60% for age -- that's far beyond his other cognitive skills. It's not only that however. He can be very inventive in solving the problems I create for him.
It has something, I think, to do with his alien motivations. He's not particularly motivated by neurotypical concerns like parental approval or even peer approval. This means he barely exerts himself in measurement settings where most people would at least make a go of it. Where he is motivated, therefore, he performs significantly better than his testing would suggest possible.
Of course in most domains he can't perform in the neurotypical range no matter his motivation, but the reality of his peculiar (and highly problematic) motivational structure does mean most testing will underestimate his maximal abilities (though they do predict his performance in the settings we care about).
I suspect he is not unique.