[Genetic causes of type 2 diabetes].

The characterisation of the intracellular signal transmission regulating the secretion of insulin from the beta cells of the pancreatic islets has enabled the initiation of massive effort to find the genetic causes of beta cell dysfunction in Type II diabetes. The search for genetic determinants began when several genes involved in the mechanisms of insulin secretion were cloned in the human genoma, and when informative polymorphism was described within or in the vicinity of these genes. The rational approach to identify the putative genes causing diabetes would be to examine genes which encode for proteins likely to be important in the beta cell control of insulin secretion. A large number of mutations which cause Type II diabetes have been found recently. Type II diabetes is therefore probably a heterogenous disease, with a polygenic inheritance of a combination of major and minor genes affecting obesity, insulin secretion, and insulin action. Thus, a genotypic classification of Type II diabetes will eventually be possible, and it might also be possible to explain the sometimes puzzling observations made in diabetes research by the heterogeneity of Type II diabetes and the interaction between environmental and genetic factors.