DNA methylation and microRNA-based biomarkers for risk of type 2 diabetes
The rapidly increasing prevalence of type 2 diabetes (T2D) is motivating an intensive search for biomarkers to identify individuals at risk for developing the disease. It has been established that both genetic and environmental factors are influential in the progression to T2D. Currently, the number of genetic loci implicated in T2D susceptibility is more than 65 and together, these factors explain only about 10% of the risk. At this time, prediction models using genetic information do not perform substantially better than models based on routine clinical measures. The search for new biomarkers must integrate new, independent factors beyond the static genome that are influenced by environmental conditions. This search must also recognize the heterogeneity of T2D and seek new biomarkers of potential subtypes and confounding conditions such as obesity. Modulation of gene expression by epigenetic modifications and the action of microRNAs are being recognized as critical processes affecting T2D risk. This review provides an update on the current state of genetic biomarkers of T2D susceptibility and examines how epigenetic modulation of some new and established diabetes susceptibility genes can identify increased risk and provide biomarkers for early detection and therapeutic monitoring.