VWF and thrombotic thrombocytopenic purpura: TTP, typically characterized by a deficit in the activity (< 10%) of ADAMTS13 leading to the accumulation of ultra‐large VWF multimers platelet aggregation, endothelial damage, and microvascular thrombosis and ischemia, shows an incidence of < 1/100 000/year [13, 14, 15].