ADAMTS13 and thrombotic thrombocytopenic purpura: Thrombotic thrombocytopenic purpura, caused by an acquired or inherited deficiency of the von Willebrand factor–cleaving protease ADAMTS‐13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif member 13), results in spontaneous aggregation of platelets and ultralarge von Willebrand multimers to form platelet‐rich thrombi throughout the microvasculature 8.