ADAMTS13 and Genetic thrombotic microangiopathy: Also, thrombotic microangiopathies, disseminated intravascular coagulopathy and chronic liver diseases are well known with decreased ADAMTS-13 levels.10 In immune thrombotic thrombocytopenic purpura (TTP), patients have anti-ADAMTS-13 immunoglobulin G antibodies that inhibit ADAMTS-13 activity or increase ADAMTS-13 clearance.