Autism/Intelligence

I have read in some cases autistics often become absolute genuises in later life. Any idea why, is it to do with their neurotransmitters being out of whack?

Also, is there anyway / supplements to take to become more intelligent? I.e. allow you to get that edge and learn things that before you couldnt have, new skills, new languages etc. I bet there are some minerals/vits/supps that can help somewhere.