The documentation of elevated YKL-40 levels in patients with CVD[11], [12] and T2D[11] as well as the observation of higher YKL-40 levels in patients with obesity[16] has nourished our hypothesis that YKL-40 might be involved in the development of dyslipidemia. The gene discussed is CHI3L1; the disease is obesity due to melanocortin 4 receptor deficiency.