What is the family connection in autoimmune diseases?
The ability to develop an autoimmune disease is determined by a dominant genetic trait that is very common (20 percent of the population) that may present in families as different autoimmune diseases within the same family. The genetic predisposition alone does not cause the development of autoimmune diseases. It seems that other factors need to be present as well in order to initiate the disease process. It is important for families with members who have an autoimmune disease to mention this fact when another member of the family is experiencing medical problems that appear to be difficult to diagnose.