I do not know for sure, because the gene has not been found (or this one-). My husband and late brother in law both have/had it. My mother in laws family did not escape Russia (from the Czars) so we don't know. It would be very unusual for two brothers to get it from some environmental source since there was 8 years difference in their ages. I have entered my kids and nieces and nephews into a study. I don't think that phase of the study is still active. I will write them and see what is happening a little later. The study group certainly wanted them and there was no charge. If it is still open I will post it. complete with address and phone number. If any one knows of other studies, I would like to know. Nita