Factor X Friuli Coagulation Disorder

Girolami, Antonio; Molaro, G; Falomo, R

doi:10.1159/000208061

Cited by 7 publications

(1 citation statement)

References 18 publications

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“…Their firnction is however adversely affected. The best studied CRM + factor X variant is undoubtedly factor X Friuti which, in the hornozygous state, is associated with a moderate bleeding tendency (81)(82)(83)(84)(85). This dysfunctional factor X is only marginally activated by the intrinsic and extrinsic pathways [3 Vo rnfirnl activation; (86)] but is much more readily by Russell's viper venom 125% activation; (86,87)].…”

Section: Dysfunctioral Variants Grm:) Crm+ Variant Proteinsmentioning

confidence: 99%

Inherited Factor X Deficiency: Molecular Genetics and Pathophysiology

et al. 1997

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Factor X deficiency is a haemorrhagic condition of variable severity. Over 50 families have been reported (1-4), transmission being normally incompletely autosomal recessive. The most severely affected patients often exhibit haemarthroses. Heterozygotes sometimes exhibit abnorrnal bleeding during surgery but in the absence of a haemostatic challenge, they are clinically asymptomatic. Cases of homozygous factor X deficiency ile frequently found to be associated with consanguinity. Factor X is the rymogen of factor Xa, a serine protease which occupies a pivotal position in the clotting process. It is activated either by the contact-activated (intrinsic) pathway or by the tissue factor (extrinsic) pathway. Factor Xa, in combination with factor V then activates prothrombin to form the effector ewnyme of the coagulation cascade. A continuous low-level generation of factor Xa occurs in the quiescent state and may provide the initial activator for coagulation after injury. Despite the availability of crystal stnrcture data, the regrons of factor X involved in factor V binding are only just beginning to be defined. One way of shedding light on structure-firnction relationships is through the study of naturally occurring variants. These are reviewed here together with a resum6 of the structure, function and molecular genetics of factor X. Physiology, Structure and Function Factor X synthesis occurs in the liver (5-7) and is vitarrin K-dependent; Warfarin, which antagonizes vitamin K action, causes a marked fall in the level of factor X activity and a moderate fall in factor X antigen (8). Factor X occurs in plasma [concentration-10 pE ml-t] as a two chain glycoprotein of Mr 59 kD (Fig. 1). The light chain (Mr 17kD) is cleaved from the heavy chain (Mr 42 kD) during or after secretion. Plasma levels ilre lower in women as compared to men and lower in premenopausal women as

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Section: Dysfunctioral Variants Grm:) Crm+ Variant Proteinsmentioning

confidence: 99%

Inherited Factor X Deficiency: Molecular Genetics and Pathophysiology

et al. 1997

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Discrepant ratios of arterial versus venous thrombosis in hemophilia A as compared with hemophilia B

Girolami¹,

Bertozzi²,

Marinis³

et al. 2013

J Thromb Thrombolysis

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The occurrence of thrombosis in patients with congenital bleeding disorders represents an exceptional event. Hemophilia A and hemophilia B patients have been showed to present both arterial and venous thrombosis (85 cases of arterial thrombosis and 34 cases of venous thrombosis). The great majority of arterial thrombosis are myocardial infarction or other acute coronary syndromes, whereas the majority of venous thrombosis are deep vein thrombosis and/or pulmonary embolisms. However there are discrepancies in the proportion of arterial and venous thrombosis seen in hemophilia A versus hemophilia B. The ratio of arterial versus venous thrombosis in hemophilia A is 3.72 whereas that for hemophilia B is 1.12. This indicates that arterial thrombosis is more frequent in hemophilia A as compared to hemophilia B and the opposite is true for venous thrombosis. The potential significance of this discrepancy is discussed.

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