Star Trek has lots of autistic characters, but Data's autistic because he's an android, Seven of Nine is autistic because she was raised Borg, and vulcans are literally just the autistic race. When Odo is introduced it's strongly implied that he's just a different autistic race, and only later do we realize that changelings are mostly pretty normal (as villains go) and Odo is just autistic for no reason other than that's who he is.
