Physicians and scientists have known that the risk of having anorexia nervosa was at least 70 percent inherited but the exact cause of this genetic transfer has not been known until now. Dr. Michael Lutter, a neuroscientist at the University of Iowa’s Carver College of Medicine, and colleagues have found a genetic mutation in mice that produces behaviors that are very similar to the behaviors of humans that have anorexia nervosa.
The same group of scientists had previously found a mutation in the estrogen-related receptor alpha (ESRRA) gene or another gene that influences ESRRA’s expression that was common in people that inherited anorexia nervosa. The new research shows that levels of ESRRA protein in the brain are regulated by energy reserves. This accounts for the inheritability of anorexia nervosa and bulimia nervosa. The absence of proper energy utilization from sugar in the brain produces the characteristic behaviors of the diseases.
Mice were bred that lacked the ESRRA protein. The genetically altered mice exhibited the common behaviors that are associated with anorexia nervosa in people. The behaviors included obsessive-compulsive behaviors, social impairment, and a refusal to work to acquire high-fat food even when hungry or on the verge of starvation.
The discovery provides a target for improved treatment of anorexia nervosa in humans and possibly a cure. The research also shows that the “western ideal of thinness” plays a much lower role in causing anorexia nervosa than previously thought. Ten million women and one million men suffer from anorexia nervosa in the United States.