Which factor is implicated in the pathophysiology of TTP?

The deficiency of vWF-cleaving protease, known as ADAMTS13, is a critical factor implicated in the pathophysiology of thrombotic thrombocytopenic purpura (TTP). This enzyme is responsible for cleaving von Willebrand factor (vWF) multimers into smaller, less active forms. When there is a deficiency or dysfunction of ADAMTS13, these larger vWF multimers accumulate, leading to excessive platelet aggregation. This platelet aggregation can result in the formation of microthrombi, which can occlude small blood vessels and lead to organ ischemia, hemolytic anemia, and thrombocytopenia, all hallmark features of TTP.

In contrast to other factors that might influence coagulation, such as gene mutations or increased thrombin activity, the specific role of ADAMTS13 highlights a unique mechanism of TTP. The deficiency in this protease allows for the unchecked activity of large vWF multimers, which is central to the disease's pathology and manifests clinically with the characteristic symptoms of TTP.