A recent study released by the University of North Carolina and Sweden's Karolinska Institute shows that genes may cause a risk for anorexia, a serious and potentially life-threatening eating disorder characterized by significant weight loss and self-starvation.

Evidence shows that anorexia can run in families.

"Recent studies have found that those with anorexic relatives are much more likely to develop the condition themselves and particularly if they are identical twins," Mary Anne Knapp, clinical social worker at the Center for Counseling and Psychological Services (CAPS), said. "But at the same time, there are also people who develop the disorder who are the first person in their family to struggle with the condition."

Richard Levine, professor of pediatric psychiatry and chief of the adolescent and eating disorder division at the Hershey Medical Center, said finding out if someone has a predisposition to anorexia is very complex.

"It's not simple," he said. "It's not just one gene or one chromosome."

In the studies, patients with anorexia or bulimia have their genes compared with the control group's genes -- those without the diseases, Levine said.

"This is a linkage study," he said. "You look at the studies in families with more than one member who has anorexia and compare the genes."

The brain chemical serotonin is also linked to anorexia, Levine said.

Serotonin is a transmitter in the nervous system and is related to feelings.

"The genes in [the nervous system] might make one more susceptible [to anorexia]," Levine said.

Also, serotonin is linked to other diseases that are a risk to developing anorexia, Knapp said.

"Other risk factors include family history of depression, obsessive compulsive disorder and alcoholism," she said. "Serotonin is implicated in many of these conditions."

Levine said anorexia may not be hereditary, but the tendency to develop it may be passed down from parent to child.

Genetics is not the only factor in developing this disease -- physiological factors, family issues and culture play a role in the development of anorexia.

"Not every girl that reads Glamour magazine develops anorexia," Levine said. "Predisposition, family and culture are all factors. It's not just one thing."

Environmental factors can change how genes act, George Vogler, professor of bio-behavioral health, said.

"Identical twins share 100 percent of the same genes," he said. "They may be more alike because they grow up in the same environment: eating the same food, sharing the same family problems, all of which are an influence [on anorexia], not just genetics."