Researchers using the world's largest twin registry found the risk of development of seven autoimmune diseases is largely pre-wired in the genes, but that some diseases are more closely related than others.

By using data on 116,320 twins from the Swedish Twin Registry, Dr. Jacob Skov and colleagues found that Addison's disease, celiac disease (gluten intolerance) and type 1 diabetes are strongly influenced by genes, with heritability greater than 85 percent. Addison's and vitiligo often overlap with other disorders, thereby marking autoimmune clusters for future research. Environmental factors contribute to disease for vitiligo, Hashimoto's hypothyroidism, Graves' disease and atrophic gastritis.