This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
ADAMTS13 defeciency is associated with which disease: 
Select and explain. 
A. ITP, B. TTP, C. HUS, D. PNH
B: TTP
Answer: B: TTP 
Explanation: The deficiency of ADAMTS13 can be inherited or acquired. In the acquired form, an autoantibody that inhibits the metalloprotease activity of ADAMTS13 is present. Less commonly, patients inherit an inactivating mutation in ADAMTS13. In those with hereditary ADAMTS13 deficiency, the onset is often delayed until adolescence and the symptoms are episodic. Thus, factors other than ADAMTS13 (e.g., some superimposed vascular injury or prothrombotic state) must be involved in triggering full-blown TTP. In contrast, HUS is associated with normal levels of ADAMTS13 and is initiated by several other distinct defects Ref: Robbins 8th edition Chapter 14.