To understand the relationship between overweight, obesity, and serum Cu levels, it is important to keep in mind that most of the Cu levels in serum are associated with Cu-proproteins [35], of which, semicarbazide-sensitive amine oxidase (SSAO) and ceruloplasmin (Cp) are highly related to the pathophysiology of obesity [36,37]. The gene discussed is CP; the disease is obesity due to melanocortin 4 receptor deficiency.