Scandanavia
The problem I see with your proposal (that Asperger’s originated in Scandinavia) is that it relies on a Lamarkian theory of evolution, i.e., that behaviors can be passed on through evolution. Lamarkianism was successfully challenged by Darwin.
If you have in mind Scandinavian’s who live in Scandanavia, then I would suggest you are referring to cultural, not neurological, traits. However, if you are referring to all persons of Scandinavian descent, no matter where they may currently live, that is Lamarkianism.
Whose proposal was this?
The only way I see behaviours being passed on through evolution is if they were wired that way or if they were memes.
And aren’t ‘cultural’ traits problematic to observe neutrally?