I have a bunch of friends that aren't exactly "NT".
Me, my practical e-sister, two friends of mine, and my boyfriend all have diagnosed autism, with me and my e-ster having Asperger's. Though I would swear two of my other friends have some kind of HFA, as both of them have a few key traits. One even admitted to having a few "obsessions" in the past (the Titanic, funerary rites, gothic romantic writings a la Edgar Allan Poe, and the macabre) but he doesn't believe he does. I literally would bet my life he does have at least SOME form of HFA, and as him and my e-sister are a couple, maybe he'll work it out somehow.
Another one of my friends has ADD and psychosis issues, and a load of people are scared of him, but I think I'm the only person who isn't. Plus he admitted to fancying me, which is kinda awkward. His older brother in my year also has ADHD.
One has dyslexia, and enjoys annoying me. Out of my friendship group...I'd say maybe four or five are completely NT. The rest have all sorts, and we all fit in together pretty well.