RA GENES: ARE YOUR CHILDREN AT RISK?

Rheumatoid Arthritis, like many autoimmune diseases, has a genetic component. But so do most things these days. What does this really mean for your family? Your children are more likely to develop RA than the general population. Your family probably has a general susceptibility to autoimmune disorders (when the body mediates an immune attack against its own cellseither systemically, as in lupus, or against a particular group of cells, as in the beta cells of the pancreas in Type I diabetes). You may have an aunt with autoimmune thyroid disease, a mother with inflammatory bowel disease and a son with diabetes. Studies have indicated that there is a common genetic pathway underlying at least nine of the autoimmune disorders , including RA, that creates a propensity to develop the disease.

Thirty percent of the genetic risk comes from a part of the human genome (on chromosome 6) known as the Human Leukocyte Antigen (HLA) that helps your body to differentiate between what is part of it and what comes from a foreign attacker. The HLA has thousands of different alleles (sequences of genes that together produce a certain trait) at different locations. Several of these alleles are significantly associated with development of RA, while others have been found to be associated with other autoimmune or inf lammatory diseases.

Our study—in addition to examining clinical trends across the various symptoms you have described to us—is looking at this genetic component, trying to determine which parts of the genes might be associated with reactions to particular arthritis drugs. A certain location, for example, on the HLA might be associated with a positive response to methotrexate and another with arava-induced lung problems.

We have found some general associations between certain genes and negative response s to methotrexate and anti-TNF drugs. We hope that, through the identification of these and other genes, someday RA patients will be able to walk into the doctor’s office, receive a blood test for genetic markers and start on the right therapy.