When my wife and I were planning to marry (many years ago) I found a book that listed genetic diseases by country of origin. For England there were none. For those of Jewish origin there were a few. For (white) South Africa there was a list of about fifty! I later became persuaded it's not because there are more genetic diseases among South Africans, it's because the genealogy is so well documented that the genetic lines have been traced. Iceland is another country where the gene pool is concentrated and relatively isolated. In my own tree I have many instances of the tree collapsing due to marriages between relatives. You can see the same thing in my trees of dead presidents on e-family.co.za In the words of the old hillbilly joke, I'm related to myself! ;-) Keith