my grandpa has done a lot of research on it, and supposedly it is not a highly genetic disorder, however, there also isn't a lot of information about what actually causes it (so i'm crossing my fingers that that is true.. its supposedly prominent in people that are scandanavian and seems to be triggered by people moving from a cold environment to a warm or more moderate environment.. something to do with the equator).
It is so sad though how many people have awful diseases and disorders that are so debilitating. youd' think with all the new innovative things in this world there would be a lot more cures!