DETROIT, September 17, 1998 – A new study from researchers at the National Institutes of Health’s (NIH) Human Genome Project reports mapping hitherto unknown genes that may contribute to the onset of autoimmune diseases, such as Type 1 diabetes, multiple sclerosis and Crohn’s disease.

      The study findings, published recently in the Proceedings of the National Academy of Sciences (August 18, 1998), represent a significant step toward identifying many of the genes thay may increase susceptibility to autoimmune diseases (A.D.’s), bringing researchers closer to understanding what causes these diseases.

      A number of previous studies have shown that about half the risk of developing autoimmune diseases is inherited, while the other half is due to environmental factors that may include infectious organisms, chemicals or physical agents, but have not yet been established conclusively.

      Until now, most of the genes identified in the onset of autoimmune diseases have been part of the major histocompatibility complex (MHC), which is also referred to as HLA in humans. While researchers have been aware that there are many non-MHC genes that contribute to autoimmune susceptibility, to date they have not been able to identify them. However, the investigators involved in this new study have used research from the Human Genome Project to begin mapping these non-MHC genes.

      “As the only organization concerned with the overarching problems common to all autoimmune diseases, the American Autoimmune Related Diseases Association finds the approach taken by these researchers particularly promising,” said Noel R. Rose, M.D., Ph.D., Professor of Pathology and Molecular Microbiology and Immunology, Johns Hopkins University, and chairman of AARDA’s medical advisory committee.

      Using the large number of chromosomal markers available through the Genome Project, the researchers looked for linkage of several autoimmune diseases. Seven non-autoimmune diseases were used as controls. The researchers found that the autoimmune diseases were associated with 18 genetic markers, whereas such associations with the non-autoimmune diseases were random.

Family Clustering of A.D.s

      Autoimmune diseases tend to appear in families, with multiple autoimmune diseases occurring in the same individual and/or blood relatives within the same family. The finding that these non-MHC genes tend to cluster in 18 genetic complexes and that several of these complexes are common to multiple autoimmune diseases, provides, for the first time, some basis for understanding why A.D.s run in families.

      “By further pursuing this line of research, we may eventually be able to identify people who, for genetic reasons, are most susceptible to autoimmune diseases,” explained Dr. Rose.

      “In addition, if we can uncover the environmental triggers, we can advise individuals with the greatest genetic susceptibility to avoid those agents, in the same way we advise patients with allergies to avoid particular plants, animals, foods or drugs.

      According to AARDA, approximately 50 million Americans, 20 percent of the population or one in five people suffers from some 80 or so autoimmune diseases. Of these, the majority are women; some estimates say that 75 percent of those affected - some 30 million people - are women.

      Autoimmunity is the underlying cause of these diseases. It is the rpocess whereby the immune system mistakenly recognizes the body’s own proteins as foreign invaders and begins producing antibodies that attack healthy cells and tissues, causing a variety of diseases.

      AARDA is the nation’s only organization dedicated to raising awareness of the early warning signs of autoimmune diseases, bringing a national focus to autoimmunity as a major health issue, and promoting a collaborative research effort in order to find a cure for all autoimmune diseases.