It can't be largely European. It's gotta be worldwide. I think the particular dynamics of a culture either allow an aspie to blend in easier or be "outed" easier. In the Western world, the institution of Psychology is perhaps more entrenched, established, and more publicly disseminated than say in the East or in third world countries, so perhaps in the West, aspies are more likely to be "outed" and categorized.
I mean, I'm filipino. So unless I got the aspie gene from my European Spanish great-grandfather, then I'd probably come to the opinion that Aspergers is not localized in European genes and is a worldwide thing.
I wish I had data or be able to recommend literature, but I think it'll be awhile before there are significant research studies about Asperger's worldwide. The autism-sprectrum idea is only barely making a dent in the English-speaking mainstream--it's still largely misunderstood. Time will tell.