First anorexia nervosa genes found
QUEENSLAND researchers have played a key role in identifying the first genes associated with the eating disorder anorexia nervosa, providing hope for the development of drug treatments.
Scientists at the QIMR Berghofer Medical Research Institute were part of a breakthrough international study of more than 72,000 people that found eight genes linked to the potentially fatal condition.
QIMR Berghofer geneticist Nicholas Martin said that surprisingly, the study identified as many genes associated with a person's metabolism as those related to mental health issues, suggesting anorexia nervosa is as much a physical as it is a psychiatric disorder.
"We really only expected to find psychiatric genes, but we're finding that equally important are metabolic genes," Professor Martin said.
"Everybody had thought that anorexia is a completely psychiatrically-driven disease and that the metabolic issues were a consequence of psychiatry. This is suggesting something rather more complex. It's a completely new insight into the disease that we need to explore more."
Professor Martin said studies of both identical and non-identical twins had found anorexia nervosa is about 60 per cent genetically driven.
"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," he said.
Another aim for the research is to provide the pharmaceutical industry with leads for the development of medications to treat the condition.
"You can give antidepressants but there are no specific drugs," Professor Martin said.
"Theoretically, if people wanted it, and if the ethics are in place, we could also identify people at birth who are at higher risk of anorexia so they could be monitored and get some early intervention, if necessary."
Anorexia, which affects up to 4 per cent of women and 0.3 per cent of men, is a life-impairing illness characterised by dangerously low body weight, an intense aversion to gaining extra kilos and an inability or unwillingness to recognise the seriousness of being so thin.
Why more women are affected than men is a medical mystery.
The researchers compared the DNA of almost 17,000 anorexia patients, including 3000 from Australia and New Zealand, to more than 55,000 people without the disorder.
About 10 per cent of the anorexia cases, recruited over six years, were men.
Professor Martin said the study, published today in the journal Nature Genetics, found strong genetic links between anorexia and other psychiatric conditions, such as obsessive compulsive disorder, depression, anxiety and schizophrenia.
Anorexia was also strongly genetically associated with having a university degree.
"They're more likely to be high-performing people," Professor Martin said.
Mum of two Cayetana Martinez, 31, joined the study three years ago after developing anorexia nervosa at age 15. At one stage, the 1.68m tall woman, weighed just 45kg.
"I lost my period for a year and a half," she said. "My hair was falling out. It was not a good place to be."
She began the slow journey to recovery in her mid-twenties with the help of a psychologist.
"I took part in the study because I was interested in the scientific side of things," Ms Martinez said. "I never considered, actually, that it could be genetic but it interested me. I wanted to know whether I could pass it on genetically to my kids."
With an estimated 40 per cent of the condition associated with environmental factors, Ms Martinez said she made sure she exposed her children to positive messages about their bodies.
"We don't talk about fat as something bad," she said.
Professor Martin said the researchers hoped to recruit more anorexia patients, and also people with other eating disorders such as bulimia, to expand the study.
"It's quite clear that there are many more genes to find," he said.
Those interested should visit the website edgi.qimr.edu.au or phone toll free on 1800 257 179.
For support: Butterfly Foundation helpline 1800 33 46 73
Lifeline: 13 11 14