Genes and metabolism have a great influence on anorexia
Anorexia is not only a psychological disorder – it is also a metabolic disorder. This is suggested by a new genetic discovery which researchers from iPSYCH have contributed to.
In the new study, researchers have identified eight DNA variations which appear to be significant for the development of the eating disorder anorexia. Perhaps unsurprisingly, some of these variants are connected with other psychological disorders such as anxiety, OCD, schizophrenia and depression. But more noteworthy is the fact that there are some incidents in the metabolism that are not caused by the disease, but which could contribute towards causing anorexia.
"This is the first step on the path to a better understanding of the genetic background for anorexia. The study shows that the development of the disorder is not only psychological, but that it also originates in DNA variations which help to regulate the body's metabolism. This is an entirely new realisation, says Liselotte Vogdrup Petersen, senior researcher and statistician at the National Centre for Register-based Research at Aarhus University and co-author of the new study.
The results, which have been published in Nature Genetics, stem from a comprehensive genetic study of approx. 72,500 people from 17 different countries, including Denmark. In the study, more than one hundred researchers compared the genes of 16,992 people suffering from anorexia and 55,525 control subjects.
High mortality rate
Anorexia is one of the psychological disorders with the highest mortality rate. The disorder is characterised by a deliberate and excessive weight loss and it affects markedly more women than men. There is currently no standard treatment that works for all patients. Liselotte Vogdrup Petersen emphasises that hundreds of DNA variations can probably be found and that they have significance for the development of anorexia in combination with environmental factors.
“Taken together the results give us the opportunity to redefine anorexia as a psychiatric and metabolic disease. The genetic findings can lead to a better understanding of the biological mechanisms which lie behind the disease and in the long term to better treatment of the disease. But patients and relatives can already now benefit from knowing that there is a genetic and biological background for anorexia,” explains the researcher.
Researchers have already begun a large follow-up study in the field. An additional 2,500 case subjects are participating in the new study. The aim is to see a doubling of the size of the population involved in the recently published study – as a minimum. This time the researchers will also include other eating disorders such as bulimia.
Background for the results:
- The study is a GWAS (Genome-Wide Association Study) in which researchers scan through frequently occurring genetic variations in the complete genome and find the variants which separate cases and control subjects. The current study is the largest GWAS study of anorexia.
- At the suggestion of the project's collaborative partner, Cynthia M. Bulik, and with funding from the Klarman Family Foundation, a collaboration with iPSYCH has made the Danish contribution possible, involving almost 5,000 of the total 17,000 anorexia sufferers and thousands of control subjects.
- The Lundbeck Foundation has financed the control elements for the current study and the Danish part of the follow-up study
- The scientific article “Genome-wide association study identifies eight risk loci and implicates metabo-psychiatric origins for anorexia nervosa” can be read here.