Many brilliant classical composers have been suspected to be somewhat "atypical" mentally and/or to have learning differences. Beethoven and Chopin come to mind, people have remarked on their unusual mannerisms, particularly while composing.
I listen to the SF Bay Area's classical station KDFC while at work, and they mentioned a piece called the Mermaid Opera by a composer too shy to leave his home often and awkward in social settings. Didn't catch his/her name, and wasn't sure of the piece even after I looked at the KDFC playlist from last Thursday.
Playing the piano would require intense concentration, I could see someone with autism or Asperger's developing that or other instruments as a talent. Do you think it's easier for some people to communicate via music than verbally? That might be used as a way to help people on the autism spectrum communicate or express ideas.
Weird that I'm most likely Asperger's personally and can't carry a tune and don't have much rhythm, though.