Gene-environment interaction and the metabolic syndrome.

The metabolic syndrome, which has been shown to affect as many as 20% of the general adult US population, is generally described as a cluster of cardiovascular risks factors, most notably obesity, type 2 diabetes or resistance to insulin-stimulated glucose uptake (insulin resistance), dyslipidaemia and hypertension. All these risk factors are under both genetic and environmental control; they are considered individually as complex genetic diseases. Prior to pharmacological interventions for hypertension, diabetes and dyslipidaemia, lifestyle changes, in particular weight loss (or weight maintenance) and physical activity, were prioritized and constituted an effective first-line intervention strategy. Here we want to focus on three clinical components of the metabolic syndrome and the environmental factors that are considered to be the most significant targets for primary interventions: type 2 diabetes and exercise, obesity and diet, and hypertension and salt. Our experimental approach is to go from candidate gene strategy to genome-wide association. The identification of the genetic component of these risk factors is a major challenge, and it is hoped that this would help unravel mechanistic pathways that can ultimately serve as new targets for therapeutic intervention.