CLOCK polymorphisms: associated with obesity, hyperglycemia and higher prevalence of T2DCLOCK mutation: Pancreatic β cell failure, leading to hypo-insulinemia and hyperglycemiaBmal1, PER1/2 mutation: Glucose intolerance and hyperglycemiaBMAL1 deficiency: β cell failure via oxidative stress-induced mitochondrial uncouplingBMAL1 disfunction: dyslipidemia. This evidence concerns the gene PER1 and metabolic syndrome.