Scientists from QIMR Berghofer Medical Research Institute are part of an international team that has identified the first eight genes associated with anorexia nervosa.
Almost 3000 Australians and New Zealanders living with the disorder contributed their DNA for the study, which included almost 17,000 cases worldwide.
Not just a psychological issue
Researchers say the discovery goes a long way in removing the stigma associated with the condition, dismissing the myth that anorexia nervosa is a lifestyle choice.
The study found other psychiatric disorders were closely genetically linked with the condition, including obsessive-compulsive disorder, depression, anxiety, and schizophrenia.
Associate Professor Warren Ward, the Director of the Queensland Eating Disorders Service says the research could help break down stigma.
"There is still some myth and misconception that people choose to have anorexia - that is not true. People are deprived of control once they catch it. And the treatment is re-nourishing their brains so they get some flexibility of thinking and psychotherapy."
The genetic link
Head of the QIMR Berghofer Genetic Epidemiology laboratory, Professor Nicholas Martin says the study also made an unexpected discovery on the role metabolism plays in the illness.
The research revealed an association with anorexia and low glucose levels.
The disorder has a high mortality rate of 10 to 20 per cent, with one of the causes, glucose levels dropping so low a person dies as a result.
Professor Martin says there is now genetic proof of the impact of metabolism on the disorder.
"What has taken us by surprise is finding quite a large genetic influence on metabolic factors as well, how people process carbohydrates and fats. This is not something we expected at all and quite frankly we don't quite know what to make of it. But what it does suggest is that you have to look at anorexia not just as a mental health problem but also as having a metabolic angle."
Professor Martin says the 17,000 DNA samples came from people of European ancestry purely for convenience because they were the populations more readily available for testing.
The genetic information of people with lived experience of the disorder was compared to DNA from others of European ancestry from 17 countries across North America, Europe, and Australasia.
He says researchers are acutely aware further studies with other ethnic groups are needed to fully understanding the global genetic footprint of the disorder.
"When you're doing this work you do have to keep the different ancestries separate or the statistical analysis get completely messed up. So what that means is the investigate this in Asians or Africans we would have to collect a sample size at least as big as we're doing for Europeans here. So the point is you can't do this in any half-hearted way. It's got to be done on a much bigger scale and I am hoping that another side product of our results is that it will spur those efforts in other ethnic groups."
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