A major international study has for the first time identified eight genes associated with an increased risk of developing the eating disorder anorexia nervosa.

Key points: The six-year-long project involved the study of 17,000 anorexia nervosa cases from around the world

The six-year-long project involved the study of 17,000 anorexia nervosa cases from around the world Researchers found the disease has "very strong" links with metabolism

Researchers found the disease has "very strong" links with metabolism More patients are being recruited for an expanded study

Head of the QIMR Berghofer genetic epidemiology laboratory Nick Martin said the research had taken six years and involved the study of 17,000 anorexia nervosa cases from around the world.

"We've known for quite a long time that there are genetic factors influencing anorexia," Professor Martin said.

"The problem has been — do we know what the specific genes are … and that's what's taken us so long."

Anorexia is an illness characterised by restricted energy intake, intense fear of gaining weight, and disturbed body image.

Professor Martin said the study had found unexpected links with metabolic function, which may explain why patients struggle to maintain a healthy weight, even after undergoing treatment.

"What we expected was to find genes that are clearly implicated in the psychiatric mental and health aspects of the disease, which is obviously important," he said.

"But what has taken us by surprise is finding that there seem to be very strong links with metabolism as well.

Professor Martin said a stigma was often attached to eating disorders, and the parents of sufferers often blamed themselves.

"I'm hoping that the results of this study will change that perception and alleviate that guilt," he said.

June Alexander, 68, said she had felt "incarcerated" by anorexia nervosa for more than 40 years, and she had worried about passing the disorder on to her children and grandchildren.

June Alexander (centre) has worried about passing on the disorder to her daughter and grandchildren. ( Supplied )

"It's an illness that can wreck families, it can wreck lives," Dr Alexander said.

"This is certainly not an illness of choice and definitely not something that we can prevent."

She participated in the research by submitting a blood sample, and said she was excited by the results.

"While there's no immediate answer, we're well on the way on the way to finding answers, and that gives everybody hope," Dr Alexander said.

Her family is very mindful of disordered eating and they keep a close eye on her two young granddaughters.

"We know the signs to look for," she said.

Dr Alexander first developed anorexia nervosa at the age of 11 while growing up on a farm in regional Victoria, but she did not recover until she was in her 50s.

"Since I recovered 12 years ago, I've had such an amazing life," Dr Alexander said.

"I've been travelling the world and I'm writing books and I love every minute of every day."

Professor Martin said the findings could lead to screening for high-risk groups, and help pharmaceutical companies develop medications to target the disorder.

"There's nothing specifically for anorexia because people don't really understand its causes," he said.

The international study involved researchers from Sweden, Denmark, and the United States, and has been published in the journal Nature Genetics.

More patients are being recruited for an even larger project, which will look for more genes linked to anorexia nervosa and also investigate the genetic basis of bulimia and binge eating disorder.