Study implicates IGF2 gene in pathology of eating disorders

The results of a recent study suggest that the ApaI polymorphism in the insulin-like growth factor 2 (IGF2) gene may contribute to the pathology of eating disorders. Previous research has shown that the IGF2 ApaI polymorphism has a modest influence on body mass index (BMI) and an inherited predisposition to weight gain.In this latest study, researchers in Israel recruited non-clinical subjects from 376 families to test the association between three IGF2 single nucleotide polymorphisms (SNPs) and eating behaviour.Siblings in participating families completed two self-report questionnaires: the Eating Attitudes Test and the Eating Disorder Inventory-2 subscales. DNA samples were obtained from all family members.The researchers found that the two self-report measures were strongly correlated among siblings included in the study (n=845). Significant correlation was observed between the Eating Attitudes Test score and the body dissatisfaction and drive for thinness subscales of the Eating Disorder Inventory-2 (pAnalysis with the family-based association test identified a highly significant association between the IGF2 ApaI G allele and Eating Attitudes Test scores overall as well as for each of its subscales (bulimia, dieting and oral control).A significant association between the IGF2 ApaI G allele and scores on the body dissatisfaction and drive for thinness subscales of the Eating Disorder Inventory-2 was also observed. Subjects with the G allele had higher scores.Testing for an association between the three IGF2 SNPs and BMI revealed a highly significant association between the IGF2 ApaI G allele and BMI.The researchers state that their findings support the notion that the association between the IGF2 ApaI G allele and various measures of eating behaviour and BMI are "driven" by the G allele's effect on body mass and composition."Our results suggest the hypothesis that some individuals predisposed to modest increases in BMI due to common polymorphisms in the IGF2 gene, and perhaps unduly influenced by the media message that thin is better, embark on a course of constant dieting that slowly evolves into a pattern of abnormal eating behaviour and, in a small percentage of such individuals, the full-blown clinical syndromes," they conclude.Reference...