Australian researchers help identify first genes linked to anorexia nervosa

QIMR Berghofer researchers have played a vital role in helping identify the first eight genes associated with the eating disorder anorexia nervosa.

The Australian scientists are part of an international study that has also shown the origins of anorexia nervosa appear to be both metabolic and psychiatric.

The results of the large-scale genome-wide association study have been published today in the prestigious journal Nature Genetics.

Anorexia nervosa is a life-impairing illness characterised by dangerously low body weight, an intense aversion to gaining weight, and an inability or unwillingness to recognise the seriousness of the low body weight.

Researchers from QIMR Berghofer recruited nearly 3,000 Australians and New Zealanders who had lived with the chronic eating disorder to contribute DNA for the study of 16,992 anorexia cases* from around the world.

The genetic information of people with lived experiences of the disorder was compared to DNA from 55,525 controls of European ancestry from 17 countries across North America, Europe, and Australasia.

QIMR Berghofer Senior Scientist and head of the Institute's Genetic Epidemiology laboratory, Professor Nicholas Martin, said it was a huge step forward in understanding the disorder.

"We've got the first eight genes, but we know there are hundreds more genes to find, and we can only do that by broadening the study and recruiting more participants. I am hoping that this success will encourage other Australians living with eating disorders to volunteer to help us find the responsible genes," Professor Martin said.

"By showing the role genetics plays in anorexia nervosa we should be able to remove any remaining stigma associated with the condition for patients and their families - especially parents.

"Australians and New Zealanders provided a fifth of the information needed to confirm the genetic basis of this potentially life threatening condition and I want us to continue to play a big role in expanding our knowledge of eating disorders.

"Our goal is to recruit 100,000 anorexia nervosa cases internationally with appropriate controls, and to also broaden our search beyond anorexia nervosa to include other eating disorders such as bulimia and binge eating disorder."

Principal investigator and Professor in the Department of Psychiatry at the University of North Carolina School of Medicine in the United States, Cynthia M. Bulik, said establishing the role metabolism played in anorexia nervosa would influence treatment.

"Until now, our focus has been on the psychological aspects of anorexia nervosa such as the patients' drive for thinness. Our findings strongly encourage us to also shine the torch on the role of metabolism to help understand why individuals with anorexia frequently drop back to dangerously low weights, even after therapeutic renourishment," Professor Bulik said.

"A failure to consider the role of metabolism may have contributed to the poor track record among health professionals in treating this illness."

Coordinator of QIMR Berghofer's Mental Health Program, Professor Sarah Medland, said the wide ranging research also uncovered other important information on the illness.

"The study found the genetic basis of anorexia nervosa overlapped with other psychiatric disorders such as obsessive-compulsive disorder, depression, anxiety, and schizophrenia, and this underscores the importance of taking a broad clinical focus in working with individuals who experience an eating disorder" she said.

The study also found the genetic basis of anorexia nervosa overlapped with metabolic (including glycemic), lipid (fats), and anthropometric (body measurement) traits, and that was not due to genetic effects that influence BMI.

Professor Martin is encouraging anyone who has lived with anorexia nervosa, bulimia or other eating disorders to sign up to the next stage of the study and provide a saliva sample from which DNA can be extracted.

Those interested in taking part in the study should visit the website: edgi.qimr.edu.au, or phone our toll-free number 1800 257 179.

The international research was funded by the Boston-based Klarman Family Foundation, the Australian National Health and Medical Research Council, the U.S. National Institute of Mental Health, the UK National Institute for Health Research, and the Foundation of Hope, Raleigh, NC.

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