The relevance of the secondary factor related to adiposity (% body fat, visceral fat area, etc.)may be attributed to the adipose tissue not only serving as an energy reservoir but also as a secretory organ of certain molecules that have endocrine, paracrine, and autocrine actions, which are involved in the regulation of body weight (leptin, adiponectin), in the local inflammation generated in obesity (tumour necrosis factor α, interleukin (IL)-6, and IL-1β), or in vascular function (angiotensin II and plasminogen activator inhibitor-1) [63,64]. The gene discussed is IL1B; the disease is obesity due to melanocortin 4 receptor deficiency.