Clinical studies supporting genetic research in anorexia nervosa

Anorexia nervosa is a disorder of unknown etiology that occurs in young women and is associated with considerable morbidity and mortality. Several lines of evidence suggest that genetic and biologic factors contribute to the etiology of anorexia nervosa. Family study methods have shown that there is an increased occurrence of eating disorders in the relatives of probands with anorexia nervosa. Twin studies have found that proband concordance was significantly higher for monozygotic twins with anorexia nervosa than dizygotic anorexia nervosa pairs, which suggests a heritable factor. Finally, persistent serotonin abnormalities have been found in subjects who have been long-term recovered from anorexia nervosa. Subjects recovered from anorexia nervosa continue to have behaviors, such as inhibition, negative affect, and obsessions with exactness and perfectionism which could be related to serotonin activity. This international multi-center study has been sponsored by the Price Foundation. It will use an affected sibling paradigm to identify potential gene(s) that may contribute to the pathogenesis of anorexia nervosa. In this 2 year study, 7 sites will identify a total of 200 pairs of siblings. Probands will have anorexia nervosa and their affected siblings will have an eating disorder (anorexia nervosa, bulimia nervosa, or eating disorder NOS). Two strategies will be used to identify potential genetic factors in anorexia nervosa. First, a number of serotonin candidate genes will be investigated (e.g. various serotonin receptors, serotonin transporter, etc.) since considerable evidence supports a disturbance of seratonin in anorexia nervosa. Second, we will screen the genome using 400 known genetic markers to determine whether we can identify linkage between a genetic marker and the liability for an eating disorder. This study has the potential to discover gene(s) that may contribute to the pathogenesis of anorexia nervosa. Such findings may lead to new understandings and treatment for this often intractable illness.