F2 and obesity due to melanocortin 4 receptor deficiency: In 8 of the 9 patients, risk factors for DVT, that is, obesity, malignant disorders such as Hodgkin's lymphoma, thrombotic predispositions (antiphospholipid antibody syndrome, prothrombin disturbance, and factor V dysfunction), and preoperative driving for a long duration, were present (Table 1) [3–9].