The various mechanisms by which obesity may cause arterial and venous thrombosis include: the actions of adipocytokines from adipose tissue (e.g., leptin and adiponectin); increased activity of the coagulation factors (fibrinogen, factor VII, factor VIII, von Willebrand factor) and decreased activity of the fibrinolytic system (plasminogen activator inhibitor [PAI]); increased inflammation (tumor necrosis factor [TNFα], interleukin-6 [IL-6]); increased oxidative stress and endothelial dysfunction; disturbances of lipids and glucose tolerance in association with the metabolic syndrome [9]. This evidence concerns the gene TNF and obesity due to melanocortin 4 receptor deficiency.