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Genetic origins of anorexia both psychiatric, metabolic

Results from a genome-wide association study published in Nature Genetics implicated metabo-psychiatric origins of anorexia nervosa, supporting the reconceptualization of the disorder as both metabolic and psychiatric.

"Metabolic abnormalities seen in patients with anorexia nervosa are most often attributed to starvation, but our study shows metabolic differences may also contribute to the development of the disorder,” Gerome Breen, PhD, from the Institute of Psychiatry, Psychology & Neuroscience at King's College London, said in a press release. “Furthermore, our analyses indicate that the metabolic factors may play nearly or just as strong a role as purely psychiatric effects.”

The researchers combined data from the Anorexia Nervosa Genetics Initiative and the Eating Disorders Working Group of the Psychiatric Genomics Consortium, then conducted a genome-wide association study of 16,992 cases of anorexia nervosa and 55,525 controls.

In total, eight significant loci were identified in the study. The results showed that the genetic architecture of anorexia nervosa mirrored its clinical presentation, indicating significant genetic associations with psychiatric disorders. Specifically, the genetic basis of anorexia overlapped with obsessive-compulsive disorder, depression, anxiety and schizophrenia, according to the press release.

There were also significant genetic correlations between anorexia and physical activity and metabolic (including glycemic), lipid and anthropometric traits. This was independent of the effects of common variants tied to BMI, the researchers reported.

The investigators also found metabolic factors associated with anorexia nervosa that were more pronounced than in other psychiatric disorders, reporting significant negative single nucleotide polymorphisms genetic correlations with fat mass, fat-free mass, BMI, obesity, type 2 diabetes, fasting insulin, insulin resistance and leptin as well as a significant positive correlation with HDL cholesterol.

Janet Treasure

“Over time there has been uncertainty about the framing of anorexia nervosa because of the mixture of physical and psychiatric features. Our results confirm this duality and suggest that integrating metabolic information may help clinicians to develop better ways to treat eating disorders,” Janet Treasure, PhD, from the eating disorders research group at King's College London, said in the release. – by Savannah Demko

Disclosures: Treasure reports honorarium for participation in an EAP meeting and royalties from several books from Routledge, Wiley and Oxford University Press. Please see the study for all other authors’ relevant financial disclosures.