About aTTP

Thrombotic thrombocytopenic purpura (TTP) is an ultra-rare, life-threatening disorder that is characterised by thrombocytopenia, haemolytic anaemia and organ ischaemia.1 The reported incidence in the UK is estimated to be at 6 per million and is more common in females than males.2,3

Acquired TTP (aTTP) is caused by autoantibody inhibition of the ADAMTS13 enzyme, also known as von Willebrand factor-cleaving protease, and it accounts for 95% of all TTP cases.2,4 The resulting decreased ADAMTS13 activity leads to the build up of the ultra-large von Willebrand factor multimers, which cause spontaneous and unrestrained platelet aggregation and subsequent microthrombi formation.4-6 aTTP episodes are associated with an acute mortality of up to 20%.7


    Download icon About aTTP
    Download icon Pathophysiology of aTTP
    Video icon Pathogenesis of aTTP
    Video icon Underlying cause of aTTP
    Video icon Role of ADAMTS13
    Video icon Role of vWF

   External resources

    Download icon TTP network

The formation of microthrombi results in a systemic effect including organ dysfunction, acute thrombotic events and death.6

Hour Glass


1. Joly B, Coppo P, Veyradier A. Blood. 2017;129(21):2836-2846.
2. Orphanet. Thrombotic thrombocytopenic purpura. https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=54057 Accessed: July 2020.
3. Orphanet. Acquired thrombotic thrombocytopenic purpura. https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=93585&epoch=1582298469736 Accessed: July 2020.
4. Scully M, Hunt B, Benjamin S, et al. Br J Haematol. 2012;158:323–335.
5. Saad J and Schoenberger L. Physiology, Platelet Activation. [Updated 2018 Feb 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2018 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482478/. Accessed: July 2020
6. Sadler JE. Blood. 2008;112(1):11–18.
7. Benhamou Y, Boelle PY, Baudin B, et al. J Thromb Haemost. 2015;13(2):293–302.

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