Genetic link to anorexia ‘a great relief’ for patients

The study, published in Nature Genetics, examined DNA from 16,992 anorexia nervosa cases from around the world and compared it to genetic material from 55,525 controls. It identified eight genes with direct links to anorexia nervosa, which researchers say encourages a reconceptualisation of the illness as a metabo-psychiatric disorder.
 
Nearly 3000 Australians and New Zealanders were recruited as part of the study, which co-author and QIMR Berghofer Senior Scientist Professor Nicholas Martin said is a huge step forward in understanding the disorder.
 
‘That’s pretty exciting, it’s the first clue we’ve got as to what the genetic processes are behind anorexia,’ Professor Martin, said.
 
‘The results were interesting – we thought the genes would be mostly linked to behavioural genes and that’s true for some of them, there’s a strong [genetic] connection between anorexia and obsessive compulsive disorder, for example.
 
‘But the other part we hadn’t expected to see is strong links to metabolism, both in terms of body build, body weight and genes involved in diabetes.’
 
He went on to say this finding is likely to be the start of potentially more genetic links to the eating disorder.
 
‘I think there’ll be hundreds [more genes linked to anorexia], because for example, with schizophrenia, we’re already up to almost 200, while depression it’s around 100 and bipolar it’s around 30.
 
‘So we’re absolutely sure there’s a lot more to find, and it’s just a question of getting a large-enough sample size.’
 
He says this research can be a breakthrough in how we consider the disease.
 
‘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.
 
Dr Elizabeth Crouch, a GP with a special interest in eating disorders, told newsGP the findings ‘make a lot of sense’ as it’s common for patients with eating disorders to have a family history of the condition. She also agrees it may help ameliorate the guilt parents tend to feel about their children’s eating disorders.
 
‘Often when people have two or more children with anorexia they feel very much like people are judging them and saying, “There’s obviously something you’re doing wrong, because you’ve got a number of people in your family with anorexia nervosa”,’ Dr Crouch said.
 
‘It’s been hard up to now to understand why some people can diet and they’re fine, and in other people it can lead to anorexia. So I think it’s going to be a great relief.’
 
Dr Elizabeth Crouch is hopeful the research findings may help to reduce the stigma associated with an eating disorder where patients may feel responsible for their condition.

Dr Crouch says it might also shatter harmful beliefs that people with an eating disorder are in some way responsible for their condition.
 
‘I think a lot of people have an idea that eating disorders are a lifestyle choice and it so clearly isn’t,’ she said.
 
‘People always say, “You don’t see people with anorexia in Africa,” but of course you do.’
 
According to principal investigator Professor Cynthia Bulik, the research may not only affect how the condition is viewed; it may also influence further treatment.
 
‘Until now, our focus has been on the psychological aspects of anorexia nervosa such as the patients’ drive for thinness,’ she said.
 
‘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.
 
‘A failure to consider the role of metabolism may have contributed to the poor track record among health professionals in treating this illness.’
 
Dr Crouch says simply being aware of a genetic link to this condition can also help tailor future treatment.  
‘If you know that somebody’s at risk then I think it would be a really good thing to put a preventive program in place and also to educate the family, so people are aware of triggers,’ she said.
 
‘For example, if people start to lose weight that might be a problem that may go on to cause more problems. Knowing about it means we’re looking for it and we’re monitoring it more closely, so that would be a wonderful thing.’
 
Professor Martin believes further research is needed to confirm genetic links, and is calling on anyone with anorexia nervosa to participate in a follow-up study.
 
His goal is to recruit 100,000 participants from around the world and is encouraging more local participation after Australians and New Zealanders provided a fifth of the information needed to confirm the current study’s findings.
 
‘I want us to continue to play a big role in expanding our knowledge of eating disorders,’ he said.
 
According to the Department of Health, anorexia nervosa occurs in about 0.5% of girls and young women and is ‘very rare’ in men.
 
The condition has the highest death rate (20% in 20 years) of all mental illness.

anorexia nervosa eating disorder genetics