In patients with a severe ADAMTS13 deficit, overwhelming exposure of the thrombosis-prone ULMW-vWF on damaged endothelial cells leads to progressive aggregation of platelets and thrombus formation, which results in widespread microvascular ischemia also known as thrombotic microangiopathy or TMA, and subsequently all clinical symptoms of TTP1,2,6. This evidence concerns the gene VWF and thrombotic microangiopathy.