In humans, elevated circulating copeptin levels have been independently associated with increased risk of type 2 diabetes mellitus (T2DM), cardiovascular morbidity and mortality [7–14], and clinical signatures of metabolic syndrome (MS), such as hyperinsulinemia [7], visceral fat deposition, systemic hypertension, high triglycerides, and impaired glucose regulation, independently from obesity [15, 16]. This evidence concerns the gene AVP and obesity due to melanocortin 4 receptor deficiency.