Acquired thrombotic thrombocytopenic purpura is the non-hereditary form of thrombotic thrombocytopenic purpura (TTP), characterized by profound peripheral thrombocytopenia, microangiopathic hemolytic anemia (MAHA) and single or multiple organ failure of variable severity. The disease is Monarch Disease Ontology identifier MONDO_0019740 (acquired thrombotic thrombocytopenic purpura). Also known as: acquired ADAMTS13 deficiency, acquired TTP, autoimmune thrombotic thrombocytopenic purpura.