Furthermore, nondiabetic individuals carrying the risk G-allele showed increased expression of MTNR1B in pancreatic islets [5] and the MTNR1B risk G-allele has been suggested to increase risk of impaired fasting glycemia and type 2 diabetes through impaired insulin secretion [5,9,11,14]. This evidence concerns the gene MTNR1B and type 2 diabetes mellitus.