The Project


Coagulation factor XII, also known as Hageman factor, is part of the coagulation cascade and activates factor XI and prekallikrein in vitro. This is the starting point of the intrinsic pathway. Factor XII is used to start coagulation cascades in laboratory studies. Its roll in vivo is still unclear (1). However, Platelet polyphosphate-driven factor XII activation provides the link from primary hemostasis to secondary hemostasis (2). Factor XII deficiency is a rare disorder that is inherited in an autosomal recessive manner (3). Unlike other clotting factor deficiencies, factor XII deficiency is totally asymptomatic and does not cause excess bleeding. Mice lacking the gene for factor XII, however, are less susceptible to thrombosis (4). The exact physiological roll of factor XII is not fully known. Through the establishment of this registry, we hope to gain better understanding of the role of factor XII in humans.


To establish an international registry databse for patients with factor XII deficiency.


We propose that clinical data on patients with factor XII deficiency are registered, including:
1- The presence of any bleeding tendency
2- Previous arterial or venous thromboembolic events.
3- Recurrent infections.
4- Other concomitant medical illnesses


1. Renné T, Schmaler AH, Nickel KF, Blombäck M, Maas C (2012). "In vivo roles of factor XII.". Blood 120 (22): 4296–303.
2. Müller F, Mutch, NJ, Schenk WA, Smith SA, Esterl L, Spronk HM, Schmidbauer S, Gahl WA, Morrissey JH, Renné T (Dec 2009). "Platelet polyphosphates are proinflammatory and procoagulant mediators in vivo.". CELL 139 (6): 1143–56.
3. Wagenman, BL; Townsend, KT, Mathew, P, Crookston, KP (June 2009). "The laboratory approach to inherited and acquired coagulation factor deficiencies.". Clinics in laboratory medicine 29 (2)
4. Renné T, Pozgajová M, Grüner S, Schuh K, Pauer H-U, Burfeind P, Gailani D, Nieswandt B (Jul 2005). "Defective thrombus formation in mice lacking coagulation factor XII.". The Journal of Experimental Medicine 202 (2): 271–81.