According to one school of thought, factors secreted by hypertrophied mature adipocytes (within white adipose tissue (WAT))/the intraexocrine fat [35] (Figure 1(g)) could be one such causative agent or it could be due to chemokines secreted by fat cells (monocyte chemoattractant protein- 1, leptin, etc.,) normally overexpressed in obesity [38, 39]. The gene discussed is CCL2; the disease is obesity due to melanocortin 4 receptor deficiency.