Several lines of clinical evidence have shown that blood adropin levels are decreased in coronary artery disease (CAD), diabetes, metabolic syndrome, and obesity, and correlated negatively with the severity of CAD, body mass index, age, homeostasis model assessment of insulin resistance (HOMA-IR), insulin and homocysteine levels, and endothelial dysfunction in patients with diabetes, metabolic syndrome, and obesity [10,11,12,13,14,15,16,17,18,19,20,21]. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.