04 October 2012
By Vesna Boraska
Eating disorders are common, complex psychiatric disorders thought to be caused by both genetic and environmental factors. They cover a variety of psychiatric diagnoses, with the most common being anorexia nervosa, bulimia nervosa and eating disorders not otherwise specified. They also share many symptoms, behaviours and personality traits, which may have overlapping heritability. The aim of our study was to identify genetic variants associated with eating disorders related symptoms, behaviours and traits derived from self-report instruments: drive for thinness, body dissatisfaction, bulimia, weight fluctuation, breakfast skipping and childhood obsessive compulsive personality disorder traits. Analysis of these eating disorder-related traits as potential intermediate traits may help in deciphering the genetic basis of eating disorders since it is believed that they share heritability but have less complex genetic architecture. In the published study we investigated 283,744 directly analysed genetic changes to individual letters of DNA sequence across six traits of interest in the TwinsUK dataset and followed-up 33 signals from various strata in two independent groups of people of European ancestry, analysing between 1360 and 2967 individuals (depending on the trait).
We did not identify associations strong enough to say they were conclusively linked to eating disorders, nevertheless, we identified several variants that could be related to eating disorders as they were previously associated with psychiatric disorders and eating disorder-related traits. Our results indicate that, even though the genetic basis of eating disorders-related traits may be less complex, the small-to-modest effect sizes of genetic variants with the strongest evidence of association in this study are comparable to those expected for psychiatric traits and could not be conclusively associated to eating disorders using the current sample size.
Our results suggest that multiple genetic regions contribute to the genetic complexity of eating disorder-related symptoms, behaviors and traits and that larger-scale collaborative studies will be needed to achieve the necessary power to detect them. Our findings will be of interest to a broad spectrum of scientists involved in genetic analysis of complex traits, and more specifically to those involved in the research of eating disorders and related psychiatric traits.
Vesna Boraska, Oliver S.P. Davis, Lynn F. Cherkas et al. (2012) ‘Genome-wide association analysis of eating disorder-related symptoms, behaviors, and personality traits’
American Journal of Medical Genetics. Volume 159B, Issue 7, pages 803–811. DOI: 10.1002/ajmg.b.32087