Higher circulating of coagulation factors such as Von Willebrand Factor (VWF), thrombomodulin (TM), plasminogen activator type-1 (PAI-1) together with membrane-bound intercellular adhesion molecule-1 (ICAM-1), E-selectin levels or circulating angiogenic factors, as for example, VEGF and ang-2, have been documented in patients with SOS. This evidence concerns the gene VEGFA and spondylo-ocular syndrome.