Yes, people who are neurotypical both in the sense that they don't have an ASD and in the sense that they don't have ANY sort of neuropsych disorder can have synesthesia. I've read several case studies about neurotypicals with synesthesia.
-OddDuckNash99-
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Helinger: Now, what do you see, John?
Nash: Recognition...
Helinger: Well, try seeing accomplishment!
Nash: Is there a difference?