Genome-wide association studies have shown that melatonin receptor 1B variation is also associated with insulin and glucose concentrations; the risk genotype of this SNP predicts future type 2 diabetes suggesting that blocking the melatonin ligand-receptor system in the endocrine pancreas could be a therapeutic avenue for type 2 diabetes [265,266]. This evidence concerns the gene MTNR1B and type 2 diabetes mellitus.