Well, that is a lot of information to muse, especially the genetic questioning. I think that your premise of turning the flow chart upside down is quite interesting and might be applicable to many of the other diseases that you questioned. I have some questions about the concept of racial evolution and ethnicity of prophyria; but would need to do a bit more research before I could competently pose that question.
Otherwise, what you present are some very interesting ideas and thought provoking questions.
Peace and Blessings
Look For The Good and Praise It!