Deficiency of ADAMTS13 activity, caused by either mutations in the ADAMTS13 gene or by inhibitory autoantibodies against ADAMTS13, results in the accumulation of ultra-large VWF (ULVWF) in plasma, leading to excessive platelet aggregation and disseminated VWF/platelet-rich thrombus formation, which is the characteristic feature of thrombotic thrombocytopenic purpura (TTP)[1, 4–7]. This evidence concerns the gene VWF and thrombotic thrombocytopenic purpura.