Abstract Genome-wide association studies have detected an associationbetweentype2diabetesriskandanon-codingSNP located in MTNR1B, the gene encoding melatonin receptor 2 (MT2). Melatonin regulates circadian rhythms and sleep and associateswithmetabolicdisorders.However,themechanisms underlying these actions are still unclear. Functional genomic, animal and clinical studies have not reached the same conclusions: while some studies have reported that decreased melatonin signalling increases type 2 diabetes risk, others have found the opposite. In this commentary, we have tried to provide an explanation for these contradictions and we suggest how the communitymayprogresstoreachaunifiedpictureoftheeffect of melatonin and its signalling on type 2 diabetes.
Keywords eQTL .Genome-wideassociationstudy .GWAS . Melatonin .Melatoninreceptor .MTNR1B/MT2 .Pancreatic islets .Rarevariants .Sequencing .SNP