Anorexia nervosa is a serious eating disorder characterized by restriction of energy intake relative to requirements, resulting in abnormally low body weight. It has a lifetime prevalence of approximately 1%, disproportionately affects females (1, 2), and has no well replicated evidence of effective pharmacologic or psychological treatments, despite high morbidity and mortality (3, 4). Twin studies consistently support a genetic basis for the observed familial aggregation in anorexia nervosa, with heritability estimates of 48%-74% (5). Although initial genome-wide association studies (GWASs) were underpowered (6, 7), the available evidence strongly suggested that signals for anorexia nervosa would be detected with increased sample size (6).
