Factor XI deficiency and its management

Factor XI deficiency has a more variable bleeding tendency than haemophilia A or B. Individuals with severe deficiency have only a mild bleeding tendency, which is typically provoked by surgery, but the risk of bleeding is not restricted to individuals with severe deficiency. The bleeding tendency varies between individuals with similar factor XI levels, and sometimes the bleeding tendency of an individual may vary. The reasons for this are not fully understood, although in cases of severe deficiency there is some correlation between phenotype and genotype.
Factor XI is activated by thrombin. The role of factor XI in physiological processes has become clearer since this fact was discovered, and the discovery has contributed to a revised model of blood coagulation. Factor XI deficiency occurs in all racial groups, but is particularly common in Ashkenazi Jews. The factor XI gene is 23 kilobases long. Two mutations are responsible for most factor XI deficiency in the Ashkenazi population, but a number of other mutations have now been reported in other racial groups.
Individuals with factor XI deficiency may need specific therapy for surgery, accidents, and dental extractions. Several therapies are available which include fresh frozen plasma, factor XI concentrates, fibrin glue, antifibrinolytic drugs, and desmopressin. Each has advantages and risks to be considered. Factor XI concentrate may be indicated for procedures with a significant risk of bleeding especially in younger patients with severe deficiency, but its use in older patients has been associated with thrombotic phenomena. If fresh frozen plasma is to be used it is preferable to obtain one of the virally inactivated products. Fibrin glue is a useful treatment which deserves further study.     

Factor XI deficiency and its management

The meeting offered participants, mostly interested in the manufacture or clinical application of factor XI concentrates, an opportunity to review evidence of their efficacy and some recent concerns about their safety.     

Factor XI: a review of its biochemistry and deficiency

The biochemistry and physiology of Factor XI have been reviewed. The clinical history of our 25 patients was reviewed and compared with others' experiences. Factor XI deficiency remains enigmatic in that there is no correlation between Factor XI levels and clinical manifestations. Approximately 40 to 50% of all persons lacking Factor XI are of Ashkenazi Jewish extraction, and the remainder are represented by nearly all populations. Persons may be found to lack Factor XI because of evaluation for hemorrhage, evaluation of a prolonged PTT, or through family or other genetic studies. Hemorrhage is not as severe as in patients with hemophilia A or B. Data are presented suggesting that hemorrhage may, in part, be associated with aspirin use.     

Factor XI deficiency in women

Factor XI (FXI) deficiency is an uncommon autosomally transmitted coagulopathy found predominantly in Jewish kindreds. It is associated with variable bleeding tendency that usually manifests after trauma, surgery, or other challenges to hemostasis. Therefore, women with FXI deficiency are at risk of excessive bleeding during their menstrual periods, childbirth, and after surgery. Increased awareness and close collaboration among hematologists, obstetricians, and gynecologists and availability of management guidelines is essential to minimize these risks. This review provides data from current research in FXI deficiency and pregnancy care, menstrual problems, and the role of screening for this disorder in women referred with menorrhagia. Am. J. Hematol. 60:48–54, 1999. © 1999 Wiley-Liss, Inc.     

Factor XI deficiency: genetic and clinical studies of a single kindred

A four-generation 25-member kindred with Factor XI:C deficiency is reported. Factor XI:C levels in heterozygotes varied from 15 to 58%, suggesting that Factor XI:C values for homozygote determination should be less than 15%. The frequency of bleeding was not correlated with Factor XI:C levels in this range. Individuals with joint pain had significantly lower Factor XI:C levels than members without joint pain and pain occurred more frequently in frequent bleeders. Lod scores showed no close genetic linkage of Factor XI:C deficiency with blood group MNSs (chromosome 4), complement components Bf and C4B (chromosome 6), or blood group P.     

Factor XI kinetics after plasma exchange in severe factor XI deficiency

Plasma exchange in a patient with factor XI deficiency allowed the determination of the factor XI disappearance time. The decay curve showed a biphasic pattern with a t1/2 of h. After a loading dose by means of plasma exchange with fresh frozen plasma (FFP) up to a factor XI level of 65%, administration of 0.5 liter FFP every 12 h was necessary to maintain the factor XI concentration between 40 and 60%. The clearances of factor XI, calculated from the results of plasma exchange and from the maintenance dose, correlated very well and showed that the t1/2 of factor XI did not change after surgery. The patient underwent major surgery uneventfully but ultimately died 3 1/2 weeks after operation from cerebral damage due to cardiac arrest, which occurred on the 2nd postoperative day.     

Factor XI activity and factor XI antigen in homozygous and heterozygous factor XI deficiency

A relatively potent antiserum against highly purified, unactivated human factor XI antigen was raised in a rabbit. This antiserum, after concentration, neutralized 50% of the factor XI clotting activity of a standard normal plasma at an antiserum dilution of 1/900. The antiserum was used in a neutralization-inhibition assay to study the relation between factor XI clotting activity and factor XI antigen in plasma from ten unrelated patients with homozygous factor XI deficiency and from 12 heterozygous family members of these patients. No evidence of factor XI antigen significantly in excess of factor XI activity was found in either group. All data to date have been consistent with the hypothesis that hereditary factor XI deficiency represents a genetic disorder resulting from the absence of factor XI molecule. Severity of bleeding in factor XI deficiency could not be correlated with the level of factor XI activity or factor XI antigen.     

Factor XI deficiency in the French Basque Country

Thirty-nine patients with factor XI deficiency were diagnosed in our general hospital, which serves all the French Basque Country (about 290 000 inhabitants), between 1985 and 1995. Biological and clinical data of these cases are reported herein. Factor XI deficiency seems significantly more frequent in Basques than in the other non-Ashkenazi populations. Molecular studies should be performed for typing these cases in the view of population genetics.     

Factor XI deficiency: two novel mutations in asymptomatic Italian patients

Summary. Factor XI (FXI) deficiency is a rare bleeding disorder, resulting in a wide range of bleeding manifestations, from asymptomatic bleeding to injury‐related bleeding. To identify mutations in FXI‐deficient patients and to establish a possible relationship between clinical phenotype and genotype, we studied two patients from Southern Italy with FXI deficiency. They were identified by presurgical or routine laboratory screening. None of them showed bleeding. Three different mutations were detected (Glu117Stop, Cys118Arg and Trp497Gly); two of them were novel (Cys118Arg and Trp497Gly). One patient (with severe FXI levels) showed a compound heterozygosity (Glu117Stop with Cys118Arg). Two novel missense mutations were highly conserved among different species. In our patients, bleeding tendency did not appear to be correlated with FXI levels or with a single mutation in heterozygosis. On the other hand, the compound heterozygosis might explain low FXI levels, but it is not associated with bleeding. Our data confirm that a severe FXI deficiency is not necessarily associated with bleeding.     

The changing prognosis of classic hemophilia (factor VIII "deficiency")

OBJECTIVE: To estimate relative risk of mortality and median life expectancy for patients with classic hemophilia by a life-table analysis, taking into account deaths that may have occurred in infancy or childhood before the onset of symptoms. DESIGN: Retrospective chart review of clinical series. SETTING: Referral-based university medical center. PATIENTS: Seven hundred one patients with classic hemophilia (hemophilia A; factor VIII "deficiency") were studied for the years from 1900 to 1990; patients were identified in 289 families. MEASUREMENTS AND MAIN RESULTS: Relative risk for mortality and median life expectancy among hemophiliacs were compared with those among normal U.S. males. Overall, mortality (relative to that of contemporaneous U.S. males) was increased about sixfold among severely affected patients, more than twofold among moderately affected patients, and was equivalent to that of U.S. males among mildly affected patients. Median life expectancy at 1 year of age had reached almost 68 years in the decade 1971 to 1980, but declined to only 49 years in the decade 1981 to 1990. CONCLUSIONS: After improvement in survival from 1971-1980 (corresponding to widespread treatment with lyophilized concentrates of antihemophilic factor [factor VIII]), relative mortality is now increasing, especially among severely affected patients, in large measure because of the acquired immunodeficiency syndrome (AIDS).     

Acquisition of antibody to lymphadenopathy-associated virus in patients with classic hemophilia (factor VIII deficiency)

Antibody to lymphadenopathy-associated virus (LAV) was assayed in 461 serum and plasma samples that had been obtained from 149 patients with classic hemophilia and 64 controls and stored for periods as long as 18 years. No control or patient samples obtained before 1980 contained antibody to this retrovirus. The prevalence of antibody to LAV in the patient samples rose from 15% (2 of 13) in 1980 to 62% (18 of 29) in 1984. During this time, none of 8 untreated hemophiliacs and none of 26 hemophiliacs treated solely with cryoprecipitates had antibody to LAV. In contrast, the prevalence of antibody to LAV among hemophiliacs treated with lyophilized antihemophilic factor rose from 25% (2 of 8) in 1980 to 78% (18 of 23) in 1984. These seropositive hemophiliacs had fewer OKT4 helper cells and lower proliferative responses to mitogen than similarly treated seronegative patients. Treatment with locally prepared cryoprecipitates was not associated with serologic evidence of virus exposure.     

Primary pulmonary hypertension in patients with classic hemophilia

Five patients with classic hemophilia were found to have primary pulmonary hypertension, a disorder not previously recognized in this population. All patients had had their coagulation disorder treated for 10 years or more with self-administered lyophilized concentrates of factor VIII, and all had antibodies to human immunodeficiency virus (HIV). Primary pulmonary hypertension was confirmed by histologic means at autopsy in one patient and by lung biopsy findings in another. In the other three patients, the findings are in agreement with this diagnosis. No patient had underlying cardiac or pulmonary disease, or clinical or pathologic evidence of collagen-vascular disease, vasculitis, parasitic disorders, hemoglobinopathy, or exposure to anorexigenic agents. Whether the primary pulmonary hypertension was related to treatment with lyophilized factor VIII, or to the presence of antibodies to HIV, or both, is unknown.     

Hereditary protein S deficiency: clinical manifestations

To analyze the clinical manifestations of protein S deficiency, we evaluated 136 members of 12 families with the disorder. Seventy-one persons were found to be heterozygous for protein S deficiency, which is inherited as an autosomal dominant trait. Venous thrombotic events occurred in 39 patients (55%) and were recurrent in 77%. Most symptomatic patients had various combinations of deep venous thrombosis (74%), superficial thrombophlebitis (72%), and pulmonary embolism (38%), either in succession or simultaneously. On five occasions thrombosis was found at unusual sites, like the axillary, mesenteric, and cerebral veins. The age at the first thrombotic event ranged from 15 to 68 years (mean, 28 years), and at age 35 the probability to be still free of thrombosis was only 32%. Fifty-six percent of the thrombotic events were not preceded by a precipitating condition. In these respects protein S deficiency is similar to protein C deficiency.     

Factor XI deficiency in an Arab Moslem family in Israel

An arab moslem family with members affected by PTA deficiency is described. 3 children were found to have major deficiency, factor XI procoagulant activity being 3, 3 and 4 units/dl. 8 members, including parents, paternal grandparents and 4 siblings, were found to have minor deficiency of factor XI (40 to 68 units/dl). Assays of immunoreactive material in 4 members corresponded to the level of procoagulant activity. In this family, gene expression is autosomal recessive. The only bleeding episode reported was haematuria in the propositus. No other spontaneous, post-trauma or post-operative bleeding was noted. The PTA deficiency was reported until now, mainly in ashkenazi jews. This family is the first case of PTA deficiency ever reported in arab moslems.     

Factor XI deficiency in Southern Iran: identification of a novel missense mutation

Factor XI (FXI)-deficiency is a rare coagulation disorder inherited as an autosomal recessive trait, which is most common in Ashkenazi Jews, but also found in other groups like Moslems. We have reviewed for the first time cases of FXI deficiency in southern Iran in order to analyze their mutations related to factor XI, the main clinical and biological features, levels of circulating factor XI, and bleeding history. All 15 exons and exon–intron boundaries of F11 were polymerase chain reaction amplified using sets of primers designed on the basis of the known genomic sequence of the gene. Among bleeding disorder cases, five were FXI-deficient. FXI clotting activity ranged 0.39–16%. All were severely deficient. In all analyzed patients, functional level of FXI was markedly reduced, confirming the diagnosis of quantitative FXI deficiency. Sequencing of F11 identified three mutations: (1) a highly prevalent type II nonsense mutation (Glu117stop) in a homozygous patient, (2) a previously reported missense (Glu547Lys), and (3) novel missense (Gly372Ala) mutation. No causative mutation was found in the sequenced regions of other patients. One novel mutation and two previously described mutations were identified in patients living in southern Iran. No recurrent mutation was found, perhaps because there is a more intense population mixing in southern Iran. Screening a higher number of FXI-deficient patients will also be necessary to reveal the existence of a founder effect for these mutations in the Iranian population.     

GHRH-test in short children with "non classic" GH deficiency. A comparison with "classic" GH deficiency and short normal stature

In this study GHRH-test has been performed (2 micrograms/Kg of an iv bolus of GHRH 1-44) sampling for GH measurement every 15 min over 2 hours in three groups of short children. Group 1 consisted of 10 subjects with classic GH deficiency (CGHD): GH response less than 10 ng/ml to two conventional tests and 24-h mean GH concentration (MGHC) less than 3 ng/ml; group 2 consisted of 16 subjects with non-classic GH deficiency (NCGHD): response greater than 10 ng/ml to at least one conventional test and MGHC less than 3 ng/ml; group 3 consisted of 18 subjects with short normal stature: GH response greater than 10 ng/ml to at least one conventional test and MGHC greater than 3 ng/ml. GH peak and area under the curve (AUC) values were significantly lower in group 1 than groups 2 and 3 and in group 2 than group 3. GH peak and AUC values statistically correlated with height, height velocity, bone age/chronological age ratio and MGHC. Six children in group 1, 14 children in group 2 and all 18 children in group 3 showed after GHRH a GH peak greater than 10 ng/ml and were considered as 'responders'. Considering only the responders, GH peak and AUC values were significantly lower in group 1 than groups 2 and 3 and in group 2 than group 3. In conclusion, our data have shown that 87% of children with NCGHD responded to a single bolus of GHRH with an increase in GH levels greater than 10 ng/ml and that their responses were intermediate compared to those of CGHD and short normal subjects.