Although we still have a lot to learn about the causes of eating disorders, we do know that genetic factors play a substantial role risk. In regard to anorexia nervosa specifically, individuals who have a family member with anorexia nervosa are up to 11-times more likely to develop an eating disorder themselves. Additionally, 40-60% of the risk of developing an eating disorder is attributable to genetic factors—meaning that genes play a substantial role. But genes do not act alone. Environment also plays a role.
Genetic factors are important in determining who may or may not get an eating disorder, but we don’t yet know precisely which genes are implicated.
Secondly, somewhat paradoxically, unlocking the genetic code will tell us more about how environmental risk factors for eating disorders operate. Many individuals in the world are exposed to the cultural thin ideal, but comparatively few people ever develop an eating disorder. Genetic factors may help us identify why some individuals are more vulnerable to environmental triggers. For example, many people go on weight loss diets, but only those with a greater genetic predisposition to anorexia may go on to develop the illness. Similarly, just about everyone overeats at some point in their life, but those with higher genetic risk may be the ones for whom overeating can trigger recurrent binge eating episodes.
Identifying the genes involved in eating disorders can ultimately help us find both the cause and a cure.
Anorexia Nervosa Genetics Initiative (ANGI)
The Anorexia Nervosa Genetics Initiative (ANGI), funded by the Klarman Family Foundation, is the largest genetic study ever conducted on anorexia nervosa, and our goal is to identify the genes involved in anorexia nervosa so that we can understand the biology of the illness and ultimately develop targeted treatment approaches based on genetic information. ANGI represents an international collaboration cross the US, Australia and New Zealand, Denmark and Sweeden to collect blood samples and clinical information from over 13,000 individuals who have ever had anorexia nervosa as well as individuals who have never suffered from an eating disorder. Our goal is to unlock the genetic code of anorexia, but to do so; we need volunteers so that we can reach our ambitious goals.
Some people ask why we require blood samples from so many individuals in order to achieve this goal. The reason is that, based on research on other conditions like schizophrenia and bipolar disorder, we expect that there are hundreds of genes that influence risk for anorexia nervosa and that each of them alone only has a small effect. In order to identify all of these small effects and their interactions, we need large sample sizes. Genome-wide studies for some traits have now collected samples from tens and even hundreds of thousands of people!
You can find out more about the study and results at Anorexia Nervosa Genetics Initiative (ANGI) study.
About The Author:
Dr. Baker is Associate Research Director for the Center of Excellence for Eating Disorders in the Department of Psychiatry at the University of North Carolina (UNC). Broadly, her research focuses on the biological and genetic vulnerability for eating disorders and how these factors may change across the lifespan and between the sexes. Dr. Baker is also the onsite UNC coordinator for the Anorexia Nervosa Genetics Initiative (ANGI).
Written – 2015