Genes linked to anorexia show deadly disease isn't just psychiatric

Scientists have identified the first genetic locus – the position on a chromosome – associated with anorexia. Their study suggests that this life-threatening psychiatric disease might have metabolic underpinnings.

Anorexia nervosa is a rare disease, but with a high death rate. A number of studies have shown that genetic factors are involved in the development of anorexia, but scientists had failed to pinpoint specific variants associated with the illness.

"Family and twin studies have shown that anorexia can run in the family and that the disease is heritable. They didn't point to which genes are implicated but their results encouraged us to do larger, genome-wide association studies," Cynthia Bulik, from the University of North Carolina and lead investigator of the new study, told IBTimes UK.

The complete findings of her investigation are published in the American Journal of Psychiatry.

Psychiatric and metabolic underpinnings

The team analysed the genome of 3,495 anorexia patients and 10,982 controls. This is the largest genome-wide association study with anorexia sufferers to date, but the scientists hope to obtain more data from patients over the next year and to increase the size of their sample.

For now, their analyses have led them to uncover the first genome-wide significant locus on chromosome 12 - an area of the genome previously associated with type 1 diabetes.

They also established that anorexia nervosa has large and significant genetic correlations with other psychiatric disorders as well as with metabolic traits. This is perhaps the most important take-away from this study and opens up an avenue of research into the metabolic underpinnings of anorexia.

"Genetic variations that underlie anorexia are shared with other psychiatric disorders but are also protective against high body mass index (BMI). In other words, the genetic variants that predispose to anorexia may also perhaps predispose to having low BMI and low insulin resistance", study author Dr Gerome Breen, from King's College London, told IBTimes UK.

"That's an important side of the story because it indicates that anorexia has equally strong genetic correlations with psychiatric disorders and metabolic traits. Conceptually, it is a change in the way we think about the disorder and it will take some time for clinicians to come around to this view", he added.

If scientists continue to do this type of research, it could in the long run lead to the development of new treatments to help anorexia patients. At present, clinicians focus mostly on re-nourishing and performing psychological interventions.

"We are hopeful that if we keep doing these kind of studies with larger samples we can identify single genes that are important in the risk of developing anorexia and their associated biological pathways. That's important because it may give us potential therapeutic targets. We hope our work will stimulate a wave of evidence-based research into the biology of anorexia in a way that has not happened so far", Breen said.

Offering adequate psychiatric care remains a priority to treat anorexia patients, but as this study indicates, working to understand metabolic underpinnings and to find therapeutic alternatives could also be step forward.