[Nature history and genetics of type 2 diabetes]

The nature history of type 2 diabetes is characterized by the interaction between beta-cells function and insulin sensitivity. Normal glucose tolerance could be maintained when there is a balance between insulin sensitivity and beta-cells function. For most of type 2 diabetic patients, both defects in insulin secretion as well as insulin action are needed for the development of diabetes. In addition, there is abundant evidence indicating the importance of genetic factors in the development of type 2 diabetes, including data from the twin studies, family studies, studies among different ethnic groups living in the same environment and admixture studies. In the last two decades, that genetic defects affecting both beta-cells function and insulin sensitivity has been identified. But those defects can only explain a very small portion of etiology of type 2 diabetes, and the gene defects contributing to the cause of most type 2 diabetes are still at large. We have learned, from the past experience that type 2 diabetes is a very heterogeneous and complex disease. The complexity of type 2 diabetes is related to factors such as genetic heterogeneity, interactions between genes, and the modulating role played by the environment.