I lived in remote parts in North West Thailand for a decade and came across more people with 6 fingers then I thought normal. The Karen tribes people had more of this affliction then most. Albinism seemed more common amongst the Hmong. I recently came across a mention about polydactylism most common amongst the Aborigines in North Australia and what I have observed amongst the Hill tribes in NW Thailand, particularly amongst the Karen, a christian group and a religious sect in Amsterdam.....the Mennonites. We all know those missionaries are reputed to be of a nasty sort. Apparently this is another 'gift' provided with their christian charity.