Monarch Disease Ontology entry MONDO_0018896 (thrombotic thrombocytopenic purpura) (TTP) is an aggressive and life-threatening form of thrombotic microangiopathy (TMA) characterized by profound peripheral thrombocytopenia, microangiopathic hemolytic anemia (MAHA) and organ failure of variable severity and is comprised of congenital TTP and acquired TTP. Also known as: Moschcowitz disease, Moschcowitz's syndrome, Moschowitz disease, TTP.