Anorexia and Bulimia: Cracking the Genetic Code
New research suggest a person's genes may point to a propensity for developing an eating disorder.
Not so long ago, doctors and therapists blamed anorexia, bulimia, and other eating disorders on overly controlling parents. When they first gained attention in the late 1970s and early 1980s, the diseases were often seen as psychosomatic -- the willful behavior of often-spoiled, privileged teenagers.
Today, a growing body of research indicates that you can indeed get anorexia from your parents, but not in the way previously thought. Eating disorders appear to be as strongly genetically linked as many other major psychiatric disorders, like schizophrenia, depression, bipolar disorder, or obsessive-compulsive disorder.
"I know a woman in Massachusetts who lost three sisters to an eating disorder. One of our board members has three generations of eating disorders in her family," says Lynn Grefe, CEO of the National Eating Disorders Association. "I meet elderly women who have had eating disorders who whisper to me, 'My mother cooked all day long, but she never ate.'"
"I think what we're learning is that the genetic predisposition interacts with the culture to bring about anorexia and other eating disorders," she says.
"You're born with the gun, and society -- your cultural and environmental circumstances -- pulls the trigger," says Grefe.
In 1996, a private European foundation called the Price Foundation began to fund research into the genetics of anorexia and bulimia. During the next several years, an international group of scientists collected an astounding amount of data: first, on some 600 families with two or more members who have anorexia or bulimia, and later, on another group of 700 families with three members who have anorexia or bulimia along with 700 "control" women for comparison studies.
Their early results found a couple of "likely suspects": areas on chromosomes 1 and 10 that appear to be significantly linked with anorexia and bulimia. Follow-up studies of candidate genes have identified several genes that may increase a person's vulnerability to these disorders.
The research proved so promising that in 2002, the National Institute of Mental Health awarded a $10 million grant to this group of investigators. This is the first-ever U.S. government-funded genetic study of anorexia. It aims to find regions of the human genome that contain genes influencing risk for anorexia. (Ten sites in the U.S., Canada, and Europe are now recruiting families for the study. You can find out more at http://www.wpic.pitt.edu/research/angenetics/.)
"I don't think any of us feel that we're going to find a single gene that will account for anorexia nervosa and bulimia, such as with the gene for Huntington's disease," says Craig Johnson, PhD, director of the Eating Disorders Program at Laureate Psychiatric Clinic and Hospital in Tulsa, Oklahoma, and one of the study's co-investigators. "We're convinced that instead there will be a number of genes that, to small effect, line up to create susceptibility."