A search for susceptibility loci for anorexia nervosa: Methods and sample description

Background: Eating disorders have not traditionally been viewed as heritabl e illnesses; however, recent family and twin studies lend credence to the p otential role of genetic transmission. The Price Foundation funded an inter national, multisite study to identify genetic factors contributing to the p athogenesis of anorexia nervosa (AN) by recruiting affective relative pairs . This article is an overview of study methods and the clinical characteris tics of the sample. Methods: All probands met modified DSM-IV criteria for AN; all affected fir st, second, and third degree relatives met DSM-IV criteria for AN, bulimia nervosa (BN), or eating disorder not otherwise specified (NOS). Probands an d affected relatives were assessed diagnostically with the Structured Inter view for Anorexia and Bulimia. DNA was collected from probands, affected re latives and a subset of their biological parents. Results: Assessments were obtained from 196 probands and 237 affected relat ives, over 98% of whom are of Caucasian ancestry. Overall, there were 229 r elative pairs who were informative for linkage analysis. Of the proband-rel ative pairs, 63% were AN-AN, 20% were AN-BN, and 16% were AN-NOS. For famil y-based association analyses, DNA has been collected from both biological p arents of 159 eating-disordered subjects. Few significant differences in de mographic characteristics were found between proband and relative groups. Conclusions: The present study represents the first large-scale molecular g enetic investigation of AN. Our successful recruitment of over 500 subjects , consisting of affected probands, affected relatives, and their biological parents, will provide the basis to investigate genetic transmission of eat ing disorders via a genome scan and assessment of candidate genes. Biol Psy chiatry 2000;47:794-803 (C) 2000 Society of Biological Psychiatry.