1/10. Identification of a novel mutation in a non-Jewish factor XI deficient kindred.The role of factor XI (FXI) in blood coagulation has been clarified in recent years by descriptions of FXI-deficient patients who are prone to excessive bleeding after haemostatic challenge. We have studied a large kindred of an Italian FXI-deficient patient with a previously undescribed mutation. The propositus, a 68-year-old woman, presented with a cerebral thromboembolic event but had no history of bleeding (FXI activity 1.6 U/dl). A sensitive ELISA failed to detect FXI antigen in the propositus. sequence analysis of the entire FXI gene revealed a TGG to TGC transversion in codon 228 of exon 7 (FXI-W228C). This missense mutation results in a Trp to Cys substitution within the third apple domain of FXI. We conclude that this novel mutation occurred in a structurally conserved region and may therefore have interfered with either chain folding and secretion or stability of FXI and was responsible for the inherited abnormality seen in this kindred. It is unclear why this kindred does not exhibit a bleeding tendency but it may correlate with a FXI-like antigen and factor ix binding activity expressed on platelets.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/10. A novel type of factor xi deficiency showing compound genetic abnormalities: a nonsense mutation and an impaired transcription.We studied a 29-year-old Japanese male patient with factor xi deficiency; we also studied his parents and one sibling. Factor XI coagulation activity and antigen levels were extremely low (less than 1% of normal level) in both the patient and his brother, and they were half the normal levels in both parents. sequence analysis of all 15 exons and the exon-intron boundaries of the factor XI gene amplified by polymerase chain reaction revealed a nonsense mutation in exon 8 (Gln263-->Stop). Although the parents are first cousins, the mutation was unexpectedly heterozygous in all the family members except the father, who showed the homozygous wild type, indicating that this mutation alone was not sufficient to account for the factor xi deficiency. To explore the genetic abnormality in the father, we analyzed allele-specific expression of the platelet factor XI gene using reverse transcription-polymerase chain reaction and subsequent restriction enzyme digestion. As a result, gene expression from only one allele was severely impaired in the father. This result implies an additional mutation in some regulatory element of the factor XI gene from paternal inheritance. We concluded that the factor xi deficiency of the patient was caused by compound heterozygous genetic abnormalities.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
3/10. A novel congenital haemostatic defect: combined factor VII and factor xi deficiency.Isolated deficiencies of factors VII and XI are both rare. Not surprisingly, therefore, combined factor VII and XI deficiency has not been reported previously. We report here a kindred with a combined heterozygous deficiency for both factors VII and XI. The proposita is a 28-year-old woman who had both a prolonged prothrombin time (PT) and a prolonged activated partial prothrombin time (APTT) associated with a mild bleeding tendency. Coagulation studies were performed on the six available members of this kindred. The PT and APTT were normal or mildly abnormal in five of these individuals. Factor VII coagulant activity (VII:C) varied from 0.33 to 0.77 units/ml in affected subjects. In contrast, the concentration of factor VII-related antigen for the six individuals ranged from 0.68 to 2.10 units/ml. Comparable factor VII:C levels were obtained when each subject's plasma was tested with either a rabbit or a human thromboplastin reagent. Factor XI coagulant activity was less than 0.5 units/ml in three of the six subjects and normal (approximately 1.0 units/ml) in the other three. The concentrations of thrombin-antithrombin-III and prothrombin fragment 1.2 were within normal limits for all individuals. In addition to being associated with heterozygous factor xi deficiency, the abnormal factor VII molecule in the plasma of affected individuals in this kindred appears to represent a newly described mutation. This is suggested by the pattern of reactivity with thromboplastin from different species, the normal tissue factor binding and the bleeding tendency in heterozygous individuals in this kindred.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
4/10. Identification of a defective factor XI cross-reacting material in a factor XI-deficient patient.A homozygous factor XI-deficient girl, who appeared to be positive for cross-reacting material (CRM ) was studied for clarification. Factor XI antigen (F XI:Ag) was measured by radial immunodiffusion using monospecific, heterologous anti-factor XI antibodies. Factor XI coagulant activity (F XI:C) was determined in a modified activated partial thromboplastin time (APTT) test. The ratio of F XI:C to F XI:Ag was 0.04 for the proposita, as compared with 0.7 to 0.74 in the other family members. In contrast, 12 normal individuals had ratios of F XI:C to F XI:Ag of 1.04 /- 0.15. F XI esterolytic activity was clearly higher than F XI:C in the proband, but not in her relatives. immunoblotting studies demonstrated F XI CRM in the patient's plasma. chromatography on diethylaminoethanol (DEAE)-Sephadex at pH 8.4 led to an almost complete removal of F XI from the plasma. The defective F XI was not bound to a negatively charged kaolin surface due to an abnormal interaction with high-mol-wt kininogen (HMWK).- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
5/10. Hereditary plasma thromboplastin antecedent (PTA, FXI) deficiency in a Saudi family.A rare case of factor XI (PTA) deficiency was discovered in a Saudi family in the Riyadh area. Nine members of the family were studied. Two were found to have a severe PTA deficiency; levels of factor XI clotting activity were 0.01 i.u./ml and 0.02 i.u./ml respectively. Both plasmas were markedly deficient in factor XI antigen and appeared to be negative for cross-reactive material (CRM-). The parents were first cousins and both were found to have a minor PTA deficiency. Factor XI levels were: mother 0.048 i.u./ml and father 0.33 i.u./ml. Another sibling was found to have a FXI level of 0.47 i.u./ml. menorrhagia and bleeding for 1 day after tooth extraction were the main bleeding manifestations found in one member with severe PTA deficiency. Clinically this member presented with iron deficiency anaemia. Other family members had no significant history of bleeding tendency. This is the first report of a Saudi Arabian family with PTA deficiency.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
6/10. Pseudo-factor-XI deficiency: effect of an inhibitor of factor XI adsorption to surface.Recently we have described a normal plasma activity that modulates contact activation by inhibiting adsorption of factor XI to activating surfaces. Here we report the first identified case in which a patient has abnormal clotting tests due to an excess of a similar activity. The patient's plasma had a prolonged partial thromboplastin time and low apparent factor XI assay. His plasma prolonged the partial thromboplastin time of normal plasma and partially neutralized normal factor XI activity in vivo and in vitro. Analysis in dilute plasma revealed normal amounts of factor XI activity and antigen. Factor XI adsorption from plasma to activating surfaces was tested by adding a small amount of 125I-labeled purified factor XI to plasma, exposing the mixture to a glass tube or kaolin, and determining the amount of factor XI adsorbed to the surface. Whereas normal plasma and plasmas deficient in factor xii, factor XI, or Fletcher factor yielded about 4% adsorption to glass, factor XI adsorption from patient's plasma was less than 1%, indicating the presence of an adsorption inhibitor. This inhibitor did not affect factor XI activation or the activity of preformed factor xia. It was not adsorbed by AI(OH)3 and was present in serum and the macroglobulin peak on gel filtration of the plasma through Sephadex G-200. The patient's history does not allow a definitive conclusion as to whether this inhibitor was associated with abnormal bleeding.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
7/10. Combined hereditary factor XI (plasma thromboplastin antecedent) deficiency, von Willebrand's disease, and xeroderma pigmentosum in a Japanese family.We report a 28-year-old-Japanese male who had a skin tumor derived from variant type xeroderma pigmentosum (XP), combined with factor XI (FXI) deficiency and type IIB von Willebrand's disease (vWd). The patient had abnormal bleeding history on tooth extraction. FXI clotting activity (FXI:C) and antigen (FXI:Ag) were remarkably decreased (< 0.01 U/ml, < 0.02 U/ml, respectively). factor viii (FVIII) clotting activity, von willebrand factor antigen (vWf:Ag), and ristocetin cofactor (RCoF) were 0.43 U/ml, 45%, and 57%, respectively. ristocetin-induced platelet agglutination (RIPA) revealed hyper-aggregation compared with a normal control. Multimeric composition of vWf in plasma showed a reduction in high molecular weight forms. The family study revealed two other subjects with homozygous hereditary FXI deficiency and vWd, and five subjects with heterozygous FXI deficiency. The relationship between FXI deficiency and vWd is discussed and previously reported cases are reviewed.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
8/10. Decreased blood coagulation activities in carbohydrate-deficient glycoprotein syndrome.The carbohydrate-deficient glycoprotein (CDG) syndromes are a newly recognized group of inherited metabolic diseases. We report a Japanese brother and sister with a CDG syndrome. Both patients showed decreased activities of blood coagulation Factor XI and of the coagulation inhibitor protein c. In one of them there was also a somewhat decreased activity of factor ix and of antithrombin iii. isoelectric focusing of antithrombin iii revealed a decrease of negatively charged fractions and an increase of more cathodal bands. Furthermore, there was a discrepancy between activity and antigen level of factor viii and protein c. The patients had an incidental deficiency of factor xii. This is the first detailed report on blood coagulation systems in the CDG syndromes. These blood coagulation abnormalities may explain at least in part the thrombotic or haemorrhagic complications of the CDG syndromes.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
9/10. Clinical usefulness of desmopressin for prevention of surgical bleeding in patients with symptomatic heterozygous factor xi deficiency.Heterozygous factor XI (FXI) deficiency is sometimes associated with a significant bleeding tendency. Fresh frozen plasma of FXI concentrates are the mainstay of treatment in patients with a clear bleeding history, especially prior to surgery. However, these treatments are not completely free of risk. Furthermore, thrombosis has been reported in patients with FXI deficiency infused with FXI concentrate. No data are available on the possible efficacy of desmopressin in these patients. Two patients with a clear bleeding history associated with FXI deficiency and no additional haemostatic defects agreed to be treated with desmopressin before carpal tunnel surgery and dental extraction. The reduced basal FXI activity and antigen levels slightly increased after infusion, reaching borderline values. No bleeding was observed after surgical procedures. Desmopressin treatment seems a reasonable and useful choice in symptomatic, heterozygous FXI-deficient patients, thus reducing the cost of treatment, the risk of transmission of blood-borne viruses, and of thrombosis.- - - - - - - - - - ranking = 0.5keywords = antigen (Clic here for more details about this article) |
10/10. Combined deficiencies of factor viii (AHF) and Factor XI (PTA).Combined deficiencies of factor viii and Factor XI associated with moderate degree of bleeding symptoms were found in 3 brothers. Examination of factor viii activity and factor viii-related antigen revealed that the factor viii activity/factor viii-related antigen ratio was significantly decreased in their mother and maternal grandmother consistent with the carrier state of hemophilia. factor xi deficiency was found in 2 siblings, the father, and 2 of his sisters. The paternal grandmother was thought to carry the abnormal Factor X I gene, although her Factor XI level was normal, because of a significant bleeding history. It was concluded that the combined factor viii and XI deficiencies in the 3 brothers represent the coincidental inheritance of 2 separate and independent abnormal genes.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
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