What Causes Thrombotic Thrombocytopenic Purpura (TTP)?

It is caused by a deficiency of the enzyme ADAMTS13, which is responsible for breaking von Willebrand factor (vWF), a protein involved in blood clotting. Inherited TTP is caused by genetic mutations that reduce ADAMTS13 activity. Acquired TTP is more common and usually occurs when the body produces antibodies that inhibit ADAMTS13.