factor XI


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Related to factor XI: factor IX, factor XII

factor XI

[′fak·tər ə′le·vən]
(biochemistry)
A procoagulant present in normal blood but deficient in hemophiliacs. Also known as plasma thromboplastin antecedent (PTA).
References in periodicals archive ?
Chung, (1987).Organization of the gene for human factor XI. Biochemistry.
Spontaneous thrombosis in a patient with factor XI deficiency homozygous for the p.Cys398Tyr mutation.
[14.] Berrebi A, Malnick SDH, Vorst EJ, et al High incidence of factor XI deficiency in Gaucher's disease.
Factor XI deficiency results in a lower incidence of thromboembolic events with minimal increase in bleeding risk.
There are many enigmas regarding the etiology and treatment of factor xi deficiency.
Of the 30 genes used on our array, six genes were found to be upregulated by [E.sub.2], including Vtgs 1 and 2, choriogenins 2 and 3, ER[alpha], and coagulation factor XI. Three genes found to be downregulated by [E.sub.2] were transferrin, [beta]-actin, and AMBP.
Dutch researchers now report in the March 9 NEW ENGLAND JOURNAL OF MEDICINE that people who have had a major blood clot in a vein--a condition called deep venous thrombosis--are about twice as likely as healthy people to harbor high concentrations of factor XI. Comparing 473 clot patients with 474 healthy participants matched for age and other characteristics, the researchers found that 92 of the patients but only 47 of the volunteers had factor XI concentrations exceeding 121 percent of normal.
The medicine inhibits the production of Factor XI, a coagulation factor produced in the liver that is involved in the formation of blood clots.
Importantly, factor VIII and factor IX deficiencies or severe factor XI deficiencies are associated with an increased risk of bleeding, whereas even drastic reductions of factor XII or rarely occurring high molecular weight kininogen and prekallikrein deficiencies do not cause excessive bleeding (4).
Factor XI deficiency was found in nine families (n=10), 2.5% of the total.
Genetic polymorphisms with either a positive or negative association with thrombosis and arterial vascular disease have been found in many of the procoagulant proteins, including factor V, prothrombin, fibrinogen, factor VII, factor XI, and factor XIII (Figure 3).
Of 150 women referred to one clinic, 26 (17 per cent) were found to have either lack of clotting factor XI or abnormal blood platelets, which is easily diagnosed with blood tests.