Sarah, it sounds like you're on the right track with looking for answers. Getting help to help your son achieve his full potential early is a key to a good outcome for him.

I've worked as a preschool teacher and have had a couple of kids in my class with their 'quirks' who I'm sure will be diagnosed with some PDD at some point but it's up to the parents. I've had my fair share of parents p***ed off at me for thinking I know their kid better than they do! In one case I actually spoke to the mum more dirrectly about it and she reqally appreciated it as she thinks she had been in denial that her son was anything other than quirky (not saying it's the case in your case). Her son is now getting the extra help he needs and is progressing marvelously. He should lead a really normal life whereas if his quirks had been allowed to continue and had just been accepted it may have been harder to 'change his ways' in the future to help him understand how society works.

She and I are now friends and can talk openly about it but it's hard when you're 'just' parent and teacher.

Good luck with it all!