Let's start with the current hopeful (and the one I'm rooting for), James Durbin. After being rejected for his audition in season 8, James returned in 2011 with a set of pipes that has currently landed him in the top 11 spot to become the next American Idol. He was diagnosed with Tourettes and Aspergers when he was 9 years old but per sued his dream of performing and starred in Broadway shows and was the lead singer of a band called The Hollywood Scars.
Jonathan Jayne has a mild form of autism and appeared briefly in season 6 of American Idol. While he did not make it very far on the show, he did appeared on several television programs such as "Jimmy Kimmel Live!".
Heather Kuzmich was one of the final five contestants on America's Next Top Model, Cycle 9. Having been diagnosed with Aspergers at the age of 15, she dreamed of becoming a model, despite her difficulties with communicating with others. Although she did not win the competition, she did win nine CoverGirl of the Week awards and appeared on 'Top Models in Action' of ANTM cycle 12.
A big thank you for each of these individuals for showing America that each one of us are unique in our way!