ADAMTS 13 (a disintegrin and metalloprotease with thrombospondin type I motif, member 13) is a protease that cleaves multimeric VWF (von Willebrand factor) into smaller units10, thereby preventing development of thrombotic thrombocytopenic purpura, a life-threatening disease characterized by the formation of microvascular thrombi11. This evidence concerns the gene VWF and thrombotic thrombocytopenic purpura.