I've come to think that the issues are seldom genetic in origin. There's a simpler explanation. LWers are often intellectually gifted. This is conducive to early isolation.

Classic autism begins early, way earlier than a child becomes interested in social interactions (except for parents) or demonstrates being intellectually precocious. The frequent first symptom is loss of speech after starting to acquire it -- the child starts to use words but then stops. There are often associated issues like shifted sensory perception, repetitive movements, etc. Avoiding eye contact is standard. All this happens when the child is 2-3 years old.

And, of course, autistic kids usually have delayed mental development.

Instead, you are talking about nerds/geeks/otaku/etc. They might be on the spectrum in which case their symptoms feed into social isolation scenario -- but the causality is reversed from what you are proposing. Or they might not be autistic at all in which case what you are talking about is a possible explanation, but calling them autistic is pattern-botching.