ADAMTS-13 (a metalloprotein) deficiency or inhibition by the blocking antibodies is found in:

Thrombotic Thrombocytopenic Purpura) ADAMTS13 and thrombotic thrombocytopenic purpura (TTP) -The etiology of thrombotic thrombocytopenic purpura (TTP) has been linked to abnormalities of the Von Willebrand factor-cleaving metalloprotease known as ADAMTS-13. Recent findings suggest that absent or low levels of ADAMTS13 (normally present in plasma) activity may allow the accumulation of ultra-large multimers of von Willebrand factor in plasma, which cause the intravascular platelet aggregation characteristic ofTTP. Although severe ADAMTS13 deficiency may be specific for TIP, the role of ADAMTS13 activity measurements for initial management decisions is unknown.