Interestingly, prior to the discovery of the association between severe ADAMTS13 deficiency and thrombotic thrombocytopenic purpura (TTP), intravenous administration of purified botrocetin has been claimed to mimic the laboratorial picture of acute TTP: thrombocytopenia, formation of platelet microthrombi in lungs and spleen, and depletion of circulating VWF, particularly of HMWM-VWF [52,53]. This evidence concerns the gene ADAMTS13 and thrombotic thrombocytopenic purpura.