Alopecia areata is known as a “polygenic disease.” This means that, unlike a single-gene disease, both parents must contribute a number of specific genes in order for a child to develop it. Because of this, most parents will not pass alopecia areata along to their children. With identical twins — who share all of the same genes — there’s only a 55% chance that if one has alopecia areata, the other will, too. This is why scientists believe that it takes more than just genetics to cause the disease and that other environmental factors also contribute to people developing alopecia areata. There are lots of factors that contribute to developing this complex condition. Alopecia areata is an autoimmune disease, which means your immune system mistakes the normal cells in your body as foreign invaders and attacks these cells.