I used to take care of a child with Asperger's syndrome and we never had any problem bonding. At the end of my time in that family the boy was quite social and he was going to a regular school. Unfortunately I lost contact with this family. I used to be their Au Pair.
My other case of special needs was another little boy who has a twin brother.
He had torticolis and a lot of other muscle issues. We did a lot of therapy. I used to take him to the sessions and I learned a lot of exercises and techniques that I adapted for the playground. This child, who wasn't suppose to walk any time soon started to have great speed on his development. Today he is 6 years old. He still is going to speech and vision therapy but he is the happiest boy on earth and I'm sure that the love and care that me and his family gave to him made a huge difference in this kid's life.
Maybe I don't have the most experience with special needs kids, but I'm willing to learn and research to help more and more kids in my life.