Naruto was one of my special interests when I was around age 14 or 15 (along with One Piece). Sai was still a fairly new character by the time I had moved on to my next set of interests, but I remember reading about him on the Naruto wiki and thinking that his behavior sounded a lot like AS.
I always thought that Hinata seemed kind of autistic-like too, though she had less symptoms than Sai.