I'm INTJ. I don't have just a casual understanding of Myers-Briggs, as its one of my special interests (typology in general; and more aptly Jung's 8 cognitive functions - so if you name a letter order I can spit out the stacked order of the cognitive functions being used by that type and how that influences their preferences). Probably not uncommon for any INTx's that find typology of interest.
I'm not sure I agree with the hypothesis that INTx's and INFx's are over-represented on the spectrum (I'll qualify that with: I'm not sure I DISAGREE, either). But, to play devil's advocate, you know what those types are likely to have in common? Struggling with outward social lives and instead coming to communities like this to find like-minded people (and voting on subsequent polls). So it kind of throws salt on survey as far as I'm concerned.
My rationale: I do not believe being on the spectrum has a significant effect on the perception (S/N) or judgement (T/F) cognitive preferences. It is likely to lead to an over-representation of introversion, but there are many extraverted auties, too. In lower numbers, yet assuredly E.
It would be interesting to do objective testing of groups of auties and comparing it to the general population statistics, though.