Within the last decade, clinical implications of this type-O associated VWF deficiency have been illuminated: BG O as a determinate for lower VWF levels has been found to be protective against venous and arterial thrombotic and thrombembolic events such as myocardial infarction, deep vein thrombosis, cerebral ischemia and peripheral vascular disease [9–13]. The gene discussed is VWF; the disease is deep vein thrombosis.