Genetics of Eating Disorders

Family and twin studies have shown that eating disorders are moderately heritable. Newer methods, such as genome-wide association studies (GWASs), are guiding molecular genetic discoveries. The majority of evidence to date has emerged from studies of anorexia nervosa (AN). The most recent GWAS on AN implicated eight regions of the genome that contain genetic risk variants and provided evidence supporting the common disease–common variant theory. The role of rare variants has also been investigated, resulting in preliminary evidence for the role of structural variation and de novo mutations in AN. Evidence from cross-disorder GWASs and genetic correlations between AN and other traits points toward a shared genetic basis between AN and psychiatric traits, especially OCD, and physical activity, educational attainment, and anthropometric and metabolic traits. Other studies have shown that genetic risk scores for AN and early-onset AN significantly predict future onset of their respective phenotypes, albeit they are too premature for clinical use. Functional genomic studies have implicated subcortical appetitive and reward circuits and genes linked to food restriction in animal models. Animal models of AN have suggested that food can act as an addictive substance, and epigenetic studies have highlighted the role of global DNA methylation in AN, pointing toward differential methylation in genes relevant to metabolism, nutrition, and psychiatric status. We conclude with a brief discussion of the pitfalls of genetics research. Nonetheless, genetic research holds promise for new and improved treatment targets and for advancing our understanding of eating disorders.