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The Rational Basis of Thrombosis Models
Published in Josef Hladovec, Antithrombotic Drugs in Thrombosis Models, 2020
If the clinical experience is taken into account in only a portion of thrombosis patients, between 10 and 20%, a hereditary defect of a known blood clotting factor or inhibitor may be of such an important influence, or may have substantially contributed to the development of thrombosis.3–6 Antithrombin III deficiency, caused either by the lack of or a qualitative defect in the molecule, was found in about 2% of thrombosis cases. Deficiency of protein S was estimated in 10% of cases up to 40 years of age. The frequency of factor C defects is still difficult to assess. Other hereditary defects such as dysfibrinogenemias, factor XII deficiency, and sickle cell anemia are infrequently connected with the occurrence of thrombosis. Another portion of thrombosis patients may have inherited defects of the fibrinolytic system such as deficient or defective plasminogen, deficient tissue plasminogen activator (tPA) synthesis or release, as well as increased plasminogen activator inhibitor (PAI). This particularly concerns patients with recurrent attacks of deep vein thrombosis. Of course, not all possibly important factors and their hereditary defects have been properly identified as yet. Some factors inhibiting endothelial synthesis, accumulation or release of blood clotting or fibrinolytic factors or endothelial viability may exist as well, such as in homocysteinemia.7, 8 A special kind of a hereditary predisposition in thrombosis patients is suggested by the high freqency of some HLA antigens (Cw 4)9 and the prevalence of blood group A.10–14
Spontaneous (Unexplained) Thrombosis: The Inherited Basis for the Thrombohemorrhagic Balance
Published in E. Nigel Harris, Thomas Exner, Graham R. V. Hughes, Ronald A. Asherson, Phospholipid-Binding Antibodies, 2020
The potential importance for thrombophilia due to the parameters set out in the last line of Table 1 remains to be established, since so far no inherited anomaly, except for the intrinsic fibrinolytic pathway, has been found. Although some reports have suggested a relationship between thrombophilia and factor XII deficiency, the connection remains obscure.61,79
The Decision Process in the Laboratory Diagnosis and Management of Bleeding and Clotting Disorders
Published in Harold R. Schumacher, William A. Rock, Sanford A. Stass, Handbook of Hematologic Pathology, 2019
2. Are the abnormalities significant in that they can predict or result in clotting or bleeding? Certainly, a platelet count of 10,000 mm3 can pose an increased risk for spontaneous bleeding, but what about 25,000 mm3, 45,000 mm3, 80,000 mm3, or 120,000 mm3? The unique circumstances of the patient must be reviewed in concert with experience, the experience of others, and recommendations from the literature. What about an aPTT of 45 sec versus 55 sec versus 70 sec? Which will more likely bleed? This depends on why the aPTT is prolonged: Heparin? Factor VIII deficiency? Factor XII deficiency? A combination of factor deficiencies? Inhibitor? Factor VIII inhibitor? Lupus anticoagulant? The point is that a prolonged aPTT has no value unless you have an idea as to why it is prolonged. Degree of prolongation will mean different effects in different patients depending on one or multiple diseases, medications, and on and on. Take the time to learn the uniqueness of each patient, and understand how the patient’s coagulation system is responding to his or her disease, and what intervention has accomplished with the disease process as well as the patient’s coagulation system. These concepts may seem somewhat lofty, but to have any real impact on what is affecting the patient, you must know the patient.
Donor-to-recipient transmission of factor XII deficiency by orthotopic liver transplantation
Published in Baylor University Medical Center Proceedings, 2019
Hussien Elsiesy, Mohamed Shawakat, Waleed Alhamoudi, Mohamed Alsebayel, John Renz, Hany Elbeshbeshy, Mohamed Abdelfattah, Faisal Abaalkhail
Factor XII deficiency is a rare autosomal recessive trait presenting with prolongation of the aPTT, without increased risk of bleeding.1 Although thrombophilic tendency (venous thromboembolism and myocardial infarction) has been reported in patients with factor XII deficiency, this was not shown when studying families with factor XII deficiency.2–7 Therefore, the relation between factor XII deficiency and an increased risk of thrombosis is not well established.
Phenotypic and genetic analyses of four cases of coagulation factor XII deficiency
Published in Hematology, 2022
Shanshan Li, Kuangyi Shu, Fanfan Li, Xiao Yang, Wei Yang, Manli Ye, Xiaoou Wang, Minghua Jiang
In the study, we found six types of mutation, of which five were novel, which contributed to the pathogenesis of factor XII deficiency. However, the specific changes about the structure, function and metabolic processes of mutant proteins and their clinical significance warrant further study.