People with Williams syndrome are some of the friendliest people you’ll ever meet. They are incredibly sociable, almost unnervingly so, and they approach strangers with the openness that most people reserve for close friends.
Their sociable streak is the result of a genetic disorder caused by the loss of around 26 genes. This missing chunk of chromosome leaves people with a distinctive elfin face, a risk of heart problems, and a characteristic lack of social fear. They don’t experience the same worries or concerns that most of us face when meeting new people. And now, Andreia Santos from the University of Heidelberg has suggested that they have an even more unique trait – they seem to lack racial bias.
http://blogs.discovermagazine.com/notrocketscience/2010/04/12/williams-syndrome-children-show-no-racial-stereotypes-or-social-fear/