Thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening blood disease caused by severe deficiency of a disintegrin and metalloprotease with thrombospondin type I repeats-13 (ADAMTS-13) enzyme, a von Willebrand factor (VWF)-cleaving protease [1]. The gene discussed is ADAMTS13; the disease is thrombotic thrombocytopenic purpura.