Huh, there's an opposite of autism...

I never even knew this existed. Obviously it's extremely rare, even more so than autism, but it seems pretty interesting. Basically rather than being anti-social, those who have Williams syndrome are drawn to people. That's an oversimplification of course, there are also some cognitive impairment issues and other stuff but overall it seems like the kind of thing that more illustrates what's wrong with "healthy" folks than the sufferers. It also makes people really trusting, to the point that they get taken advantage of and robbed unfortunately. It makes one think really, a niceness disease that puts people who have it at an evolutionary disadvantage compared to all the jerks and morons who have no trouble at all reproducing.

http://www.bbc.com/news/health-26888280