Scientists have discovered two gene mutations that they believe are associated with an increased risk of eating disorders.

Anorexia nervosa and bulimia often run in families, but these eating disorders are complex, and it has proved difficult  to identify the paths. But, using two families with very high incidences of eating disorders, scientists say they found rare mutations, one in each family, that were associated with the people who had the disorders.

The study suggests that mutations that decrease the activity of a protein that turns on the expression of other genes – called a transcription factor – increase the risk. That transcription factor is estrogen-related receptor alpha, or ESRRA.

Anorexia nervosa and bulimia are debilitating and occur in 1% to 3% of women, less frequently among men. They are among the deadliest of psychiatric diseases. They are thought to occur as a result of a combination of genetic predisposition and environmental factors.

The scientists reported their results in Tuesday’s Journal of Clinical Investigation.

“It’s basically a matter of finding out what the people with the disorder share in common that people without the disease don’t have,” Michael Lutter, the senior author of the study and an assistant professor of psychiatry at the University of Iowa, said in a statement. One challenge, he said, is finding families large enough to provide “statistical power.”

Full story of gene mutations and eating disoders at the Los Angeles Times