Genetics in gestational diabetes mellitus: association with incidence, severity, pregnancy outcome and response to treatment.

Constant advances in gene mapping technology have allowed research to focus from rare monogenic disorders on common complex diseases involving multiple susceptibility genes-environment interactions. Gestational diabetes mellitus (GDM) is a heterogeneous pathogenic condition affecting 2-5% of all pregnant women during pregnancy. GDM is considered to result when genetic predisposition is triggered by increased insulin resistance during pregnancy leading to what seems to be one of the primary characteristics of GDM, the pancreatic b-cell impairment. Genetic predisposition to GDM has been suggested given the occurrence of the disease within family members. Furthermore, GDM is reported to be often present in women with maturity onset diabetes of the young (MODY) gene mutations. In addition, candidate susceptibility gene variants have been suggested to increase the risk of GDM. These genes include glucokinase (GCK), HLA antigens, insulin receptor (INSR), insulin-like growth factor-2 (IGF2), HNF4A, insulin gene (INS-VNTR), plasminogen activator inhibitor 1 (PAI-1), potassium inwardly rectifying channel subfamily J, member 11 (KCNJ11), hepatocyte nuclear factor-4a (HNF4A). Identification of the possible underlying genetic factors of GDM would eventually enrich our knowledge on the pathophysiologic mechanism of the disease and contribute to the individualization of both prevention and treatment of complications for the mother and fetus. However, so far, little is known about the genetic basis of GDM and its potential clinical significance. This review focuses on possible gestational diabetes mellitus susceptibility genes and their association with the disease incidence and severity as well as the pregnancy outcome and the response to treatment.