In obesity, fat hypertrophy increases the expression and release of the so-called adipocytokines, such as interleukin (IL) 1β, IL-6, resistin, leptin and tumor necrosis factor alpha (TNF-α), that are necessary for cell differentiation and hematopoiesis, among other functions. The gene discussed is TNF; the disease is obesity due to melanocortin 4 receptor deficiency.