Gawd, you've just described my own experience :) I'm so happy NOT to be the only socially inept gifted perfectionist in the world :D IQ = 140. EQ = infinitesimal :P
When you read popular science at the age of five and at six you explain daddy why the sun shines (and I mean nuclear fusion here :D), you're likely to be treated differently. And other kids won't like you because you 'know everything'. And when you're used to being the best at school and that's about the only sort of success you can claim, you might indeed be desperately afraid of not being the best at something...
And I have not the faintest idea of how to approach people. I can't chat with people, I simply get a mental block whenever I'm supposed to just talk. I can't make friends unless I absolutely must interact with people for a prolonged period of time.
This all may be the result of how people treated me during my childhood, but I certainly was socially inept when I went into kindergarten, so nature might well be similarly important to nurture.