All of this.
When a person has cancer, if you fight the cancer what remains is the person. If we could fight Alzheimer’s and reverse the damage, what would be left would be the original person.
Suppose we can fight autism. What we’re left with afterwards is…this is a trick question. There is no non-autistic person inside that would be left over.
Most autistic people and people with Down Syndrome will also tell you that they are grateful that, if they were given the chance, their parents did not terminate them in the womb. Observe how this might be different if, say, we could interview someone with Tay Sachs.