Scientists report finding eight new genetic markers for the eating disorder anorexia nervosa in a study published in Nature Genetics today (July 15). By analyzing the genomes of almost 17,000 patients—the largest genome-wide study of anorexia nervosa yet conducted—the researchers added to mounting evidence that the condition has both psychiatric and metabolic origins.
Anorexia nervosa, characterized by restrictive eating, unhealthy weight loss, distorted body image and fear of weight gain, claims more lives than any other psychiatric disorder. The condition affects up to 2 percent of women and 0.3 percent of men worldwide. Due to its dual effect on the body and mind, psychiatrists have struggled to define the disorder and treat its symptoms.
“Now, we know it's a complex mixture of aspects from the body and the mind that interact and cause this complex disorder,” says coauthor Janet Treasure, a psychiatrist at King's College London, in an interview with BBC News.
The genome-wide association study uncovered characteristic single-nucleotide polymorphisms (SNPs) that anorexia shares with several other psychiatric disorders, such as obsessive compulsive disorder, major depressive disorder and schizophrenia. Other gene variants that were more common in patients with anorexia than in the general population suggest that the disease is linked to the body’s ability to metabolize sugars and fats and to high levels of physical activity.
The variants may subvert physiological signals that would usually stimulate appetite in times of extreme weight loss or starvation, the study authors say. In other words, the mutations may “allow people to starve their bodies for longer,” the BBC explains.
“This is groundbreaking research that significantly increases our understanding of the genetic origins of this serious illness,” Andrew Radford, chief executive of the eating disorder charity Beat, tells the BBC. Radford was not involved in the study.
“Our findings strongly encourage us to shine the torch on the role of metabolism to help understand why some individuals with anorexia nervosa drop back to dangerously low weights, even after hospital-based refeeding,” says coauthor Cynthia Bulik, a clinical psychologist at the University of North Carolina at Chapel Hill, in an announcement.
Nicoletta Lanese is an intern at The Scientist. Email her at firstname.lastname@example.org.