Association between a vasopressin receptor AVPR1A promoter region microsatellite and eating behavior measured by a self-report questionnaire (Eating Attitudes Test) in a family-based study of a nonclinical population.

OBJECTIVES: Considerable evidence including twin and family studies suggests that biologic determinants interact with cultural cues in the etiology of anorexia and bulimia nervosa. A gene that makes "biologic sense" in contributing susceptibility to these disorders, and to our knowledge not previously investigated for this phenotype, is the vasopressin receptor (AVPR1A), which we have tested for association with eating pathology.

METHODS: We genotyped 280 families with same-sex siblings for two microsatellites in the promoter region of the AVPR1A gene. Siblings completed the 26-item Eating Attitudes Test (EAT) and the Drive for Thinness (DT) and Body Dissatisfaction (BD) subscales of the Eating Disorders Inventory (EDI). The Quantitative Transmission Disequilibrium Test program (QTDT), which employs flexible and powerful variance-components procedures, was used to test for an association between EAT scores and the two AVPR1A promoter region microsatellites, RS1 and RS3.

RESULTS: A significant association (p = .036) was detected between the RS3 microsatellite and EAT scores. The strongest association was between RS3 and the Dieting subscale of the EAT (p = .011). A significant association was also observed between the EDI-DT and the RS3 microsatellit (p = .0450).

CONCLUSIONS: We demonstrate for the first time an association between a microsatellite polymorphism in the AVPR1A promoter region and scores on the EAT as well as with the EDI-DT. The strongest association was observed between the RS3 microsatellite and the Dieting subscale of the EAT. The relevant phenotype appears to tap severe dietary restriction for weight loss purposes.