"Cure" here means any treatment that can change someone's personality such that they're no longer diagnosed as autistic, or can prevent a newborn from being diagnosed. (Must be an actual change to the person, not a change to the diagnosis criteiria.)

Doesn't need to be widely available or approved by any regulatory agency, just needs to exist and be shown to work without any significant doubt on the matter.

An active brain device would count. Embryo selection would not count, since that's just "choosing a different person".