ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13)—also known as von Willebrand factor-cleaving protease (VWFCP)—is a zinc-containing metalloproteaseenzyme that cleaves von Willebrand factor (vWf), a large protein involved in blood clotting. It is secreted in blood and degrades large vWf multimers, decreasing their activity. The ADAMTS13 gene maps to the ninth chromosome (9q34).
ADAMTS13 deficiency was discovered in Upshaw Schulman Syndrome, the recurring familial form of thrombotic thrombocytopenic purpura (TTP). By that time it was already suspected that TTP occurred in the autoimmune form as well, owing to its response to plasmapheresis and characterization of IgG inhibitors. Since the discovery of ADAMTS13, specific epitopes on its surface have been shown to be the target of inhibitory antibodies.