I was thinking of more what happens in Wikipedia when you look at beliefs in God(s), and you end up with this list: Agnosticism, Apatheism, Atheism, Deism, Henotheism, Monolatrism, Monotheism, Panentheism, Pantheism, Transtheism. And don't ask me what they all mean because I don't know, but I do know that some of them inhabit various in-between zones.
As far as the question itself goes as to whether being on the spectrum relates to atheism, I think parts of the spectrum might make a person more likely to be, but other parts could well do the opposite.
I think the part of the spectrum that is most likely to create atheists is a particular sort of hyper-rational person that I see a lot of in the online autism community. OTOH I think my part of the spectrum might be more likely than usual to believe in some kind of spirituality, whether it involves (a) god(s) or not. There's one guy who keeps writing books on how autistic people are supposedly more spiritual (I have real problems with some of the things said in those books, but it shows a trend in some parts of the spectrum towards some form of religion or spirituality). And some parts would have no influence on the question whatsoever, and others would simply have more complex influence on it. So I don't think it's possible to generalize the entire spectrum. (Or to generalize from a poll here, since certain parts of the spectrum are over- and under-represented here. Generally if I do polls here it's only to find out what's common in this part of the autism community, not in autistic people as a whole.)
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"In my world it's a place of patterns and feel. In my world it's a haven for what is real. It's my world, nobody can steal it, but people like me, we live in the shadows." -Donna Williams