SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Factor XII deficiency has been reported to be a risk factor for thromboembolism as a result of inactivation of fibrinolysis. We describe a case of a huge left atrial thrombus with mitral stenosis, which was successfully removed surgically in a Factor XII deficient patient.
Factor XII Tenri (Y34C), a rare cross-reacting material (CRM)-negative factor XII deficiency, was identified in a 71-yr-old Japanese woman with angina pectoris. In the patient's plasma, factor XII activity and antigen levels were only 1.6% and 5.0%, respectively, of those seen in a normal subject. Immunoblot analysis showed that the secreted factor XII Tenri existed not only as a monomer (76 kDa), but also in complexes with apparent molecular weights of approximately 115, 140, 190, 215, and 225 kDa. After reduction with 2-mercaptoethanol, the factor XII Tenri contained in the complexes was completely converted to monomeric form on immunoblot patterns. It appeared that some of the secreted factor XII Tenri formed several types of disulfide-linked complexes, including a factor XII-alpha1-microglobulin complex, through a newly generated Cys residue. The monomeric form of factor XII Tenri, like normal factor XII, was degraded into 2 major fragments with molecular weights of approximately 45 kDa and 30 kDa following mixing with activated partial-thromboplastin-time measuring reagent (cephalin and ellagic acid), whereas the factor XII Tenri that formed the complexes was not. This indicates that the factor XII Tenri present in disulfide-linked complexes with other proteins (and itself) is not converted to active forms, suggesting that attached proteins obstruct or delay the activation of factor XII via an inhibition of its binding to a negatively charged surface in vitro.
Explore the source record for details and available documents.
Factor X deficiency constitutes one of the most uncommon congenital bleeding disorders. Here we report three families with Factor X deficiency, one of them with an associated deficit of Factor XII. Family I presented Red variant deficiency (low functional and antigenic activity, the latter in higher levels than the former). In Family II functional activity was low but antigenic one was normal (Prower defect). Besides, an heterozygous deficiency of factor XII was diagnosed. Although genetic analysis supports the hypothesis of combined deficiency, the study was possible in only two generations of the propositus, so a multiple familial deficiency could not be discarded. Finally, Family III suffered from a "classic" or Mr. Stuart deficiency (low levels in functional and immunological assays). Besides, crossed immunoelectrophoresis showed a grossly pathological pattern.
A family with a combined deficiency of factor XII and factor V Leiden is presented. The proposita is a 72-year-old who showed a mild to moderate thrombotic tendency characterized by two episodes of deep venous thrombosis and superficial phlebitis between the age of 50 and 71. She was shown to be carrier of homozygous factor XII deficiency and heterozygous FV Leiden mutation. A sister of the proposita showed the same pattern but remained asymptomatic. Other family members showed either isolated heterozygous factor XII deficiency or combined heterozygous factor XII deficiency and heterozygous FV Leiden mutation but were all asymptomatic. These data lend support to those who maintain that FV Leiden is a mild genetic determinant for thrombosis. The role of FXII deficiency as an additional risk factor remains questionable.
103 patients suffering from recurrent venous thrombosis, recurrent arterial thromboembolism and/or recurrent myocardial infarction and 50 healthy subjects were tested for Hageman factor (F XII) coagulant activity and antigen. Among the 103 patients we identified 15 subjects with F XII deficiency (15%), 3 with protein C deficiency (3%) and 3 with protein S deficiency (3%). Combined F XII and protein C, protein S or antithrombin III deficiency was not observed. The 103 patients were divided into subgroups according to the type of thrombotic complication. Among patients with exclusively recurrent venous thromboembolism 8% (p = 0.153) were deficient in F XII. Among patients suffering from recurrent arterial thromboembolism and/or myocardial infarction, the incidence of F XII deficiency was significantly higher (20%, p < 0.003). In 67% of the patients with F XII deficiency a positive family history of thrombosis could be established. In contrast, only 32% (p = 0.043) of all venous and 28% (p = 0.019) of all arterial thrombosis patients had a positive family history. We believe that reduced levels of F XII should be considered as a risk factor in the development of thromboembolism. Consequently, more attention should be payed to the measurement of F XII when evaluating thromboembolic risk factors especially in cases of recurrent arterial thromboembolism and/or myocardial infarction.
The factor XII genes of two unrelated factor XII-deficient Japanese families were screened, and two novel mutations were identified. A heterozygous mutation (Q421K) was identified in the gene of a cross-reacting material (CRM)-negative patient with reduced FXII activity (entitled Case 1). No mutations were discovered in the other allele. Case 2 was a CRM-negative patient with severe FXII deficiency. In this case, a homozygous mutation (R123P) was discerned. Expression studies in Chinese Hamster Ovary (CHO) cells demonstrated accumulation of mutant Q421 K factor XII in the cell, and insufficient secretion, while the R123P mutant showed lower levels of accumulation than wild-type, and no evidence of secretion in culture supernatant. In the presence of proteasome inhibitor, all types of FXII (wild-type. Q421K, R123P) accumulated in the cells. Protease protection experiments using the microsomal fraction of these cell lines demonstrated that while 20% wild-type FXII (total wild-type:100%) and 10% R123P mutant (total R123P-type: 40%) were resistant to treatment with trypsin, 50% Q421K-type FXII (total Q421K-type:130%) remained resistant to digestion. From these results, we conclude that Q421K is less susceptible to proteasome degradation than wild-type, but is unable to exit the ER efficiently, resulting in insufficient secretion phenotype. In contrast, R123P is susceptible to proteasome degradation and is not secreted.
Explore the source record for details and available documents.
PURPOSE: Factor XII deficiency is among the coagulation disorders that have been implicated in major thromboembolic events. However, little is known about an association of this coagulation disorder and retinal vessel occlusion. In the current study, we investigated the prevalence of factor XII deficiency in patients with retinal vein occlusion (RVO) with reference to age and cardiovascular risk factors. DESIGN: Cross-sectional study. METHODS: A cohort of 150 consecutive patients with central or branch retinal vein occlusion and 135 subjects matched for age and gender were prospectively screened for factor XII deficiency. Both cohorts were divided into two subgroups (<= 45 or >45 years), depending on the patients' age at the time of the RVO or a previous thromboembolic event. RESULTS: Overall, factor XII deficiency was found to be present in 14 (9.3%) of 150 patients and in 1 (0.7%) of 135 controls (P =.0009). Patient age <= 45 years at the time of the RVO or a previous thromboembolic event was associated with a high prevalence of factor XII deficiency (18%). By contrast, only 5 (5%) of 100 patients >45 years (P =.016) and none of the young controls (P =.0001) tested positive for factor XII deficiency. The prevalence among patients >45 years was similar to that found in age-matched controls (2%; P =.66). CONCLUSIONS: Our results indicate that factor XII deficiency is highly prevalent in RVO patients <= 45 years of age. By contrast, the prevalence of factor XII deficiency in RVO patients older than 45 years appears to be similar to that seen in healthy individuals.
A 12-year-old girl with lifelong hemorrhagic episodes was found to have both a dys-form of homozygous factor XI deficiency and heterozygous factor XII deficiency. The heredity of the coagulation defects was confirmed by family studies. Severe bleeding after dental surgery occurred in spite of replacement therapy and local measures including fibrin glue. Our findings suggest that the risk of bleeding in patients with homozygous factor XI deficiency must not be underestimated and that the most effective measure is the transfusion of sufficient amounts of fresh frozen plasma until at least the 5th postoperative day.
Congenital factor XII deficiency is a rare condition. We report a case of aortic valve replacement (AVR) in a 63-year-old man with factor XII deficiency. On admission, the patient's activated partial thromboplastin time (aPTT) was prolonged (271 s), and activated clotting time was 500 s. His factor XII level was <3%. The Sonoclot signature showed an abnormal pattern. AVR with a prosthetic valve (St. Jude Medical) was performed safely after the normalization of aPTT and the Sonoclot signature by frozen plasma transfusion. The perioperative management in patients with factor XII deficiency is discussed.
Four generations of a kin with congenital Factor XII deficiency were examined for coagulation and fibrinolysis, with the homozygous female carrier of features with a Factor XII below 1% also revealing certain indications of a disturbed fibrinolysis. The other members of the family had to be evaluated as heterozygous ones, showing values of Factor XII between 40 and 60%. The findings are discussed by referring to data from literature.
Factor XII initiates the intrinsic coagulation cascade and may affect the fibrinolytic system. Routine coagulation tests used during cardiopulmonary bypass (CPB) are abnormal in factor-XII-deficient patients and are useless for monitoring anticoagulation in these patients. A factor-XII-deficient patient requiring CPB is described. The baseline celite activated clotting time (ACT) was greater than 1400 seconds and the thrombin time was 12.4 seconds (control, 11.9 seconds). Two units of plasma were given resulting in an ACT of 173 seconds. Following 300 units/kg of heparin and during CPB, the ACT ranged from 670-596 seconds with the thrombin time greater than 200 seconds. Plasma provides exogenous factor XII allowing an endpoint on the ACT test and may protect against possible postoperative hypofibrinolytic complications. A commercially available modified thrombin time may also be useful and provide an endpoint during high-dose heparinization.
The case of an 18-year-old girl with a moderately severe Hageman factor deficiency (Factor XII 2.5%) is described. In this girl, an osteotomy of the pelvis after Chiari was carried out. Both the operation itself and the postoperative healing process were without complications and no signs of any abnormal tendency to haemorrhage were observed. Blood transfusions were not necessary. On the basis of this observation and a review of the literature for the attempt is made to establish general guide lines the procedure to be adopted for surgery in cases of Hageman factor deficiency.
A 19-year-old primigravida with known factor XII deficiency (prepregnant factor XII level of 21%) presented with placental abruption and preterm labor at 26 weeks' gestation. A healthy 925-g female infant was born by spontaneous vaginal delivery. The mother had no postpartum hemorrhage or further complications, and the infant demonstrated no intracranial or other forms of hemorrhage up to 70 days of age. The infant's factor XII level was 34% (normal for her age). There are only two previous reports of factor XII deficiency in pregnancy cited in the English literature, and both were uncomplicated. In view of the risk of thromboembolic complications in nonpregnant individuals with factor XII deficiency, pregnant women with a prolonged activated partial thromboplastin time and no lupus anticoagulant or anticardiolipin antibody syndrome should also be investigated for deficiencies of factors VIII, IX, and XII. These patients should be given the appropriate counseling and should be monitored for features of thromboembolism if factor XII deficiency is confirmed.
A patient with known factor XII deficiency underwent extraction of four impacted third molars. Significant preoperative laboratory values included a partial thromboplastin time (PTT) of greater than 100 seconds and a factor XII level of less than 1%. The third molars were removed without any significant intraoperative or postoperative bleeding. Factor XII not only has an important function in the initiation of the intrinsic pathway of the coagulation cascade, but it also plays a significant role in complement activation, kinin generation, and fibrinolysis. It would seem that a deficiency in this factor would have widespread clinical implications. In fact, the only clinical significance seems to be a predisposition to thromboembolism in factor XII deficient patients.
Explore the source record for details and available documents.
A patient with factor XII deficiency, gout, and angioimmunoblastic lymphadenopathy (AIL) was seen initially for an acute myocardial infarction, gout, and unexplained urticaria. The patient eventually was found to have AIL and a prolonged partial thromboplastin time. There was no evidence of a circulating anticoagulant. A factor XII deficiency (Hageman factor) was discovered. The coexistence of a factor XII deficiency, AIL, and gout in the same person raises some interesting questions regarding the basic mechanisms of the inflammatory process.