Hereditary coagulation factor XI deficiency: a rare or neglected disease? Results from a retrospective, single-centre cohort in northern Italy

To examine real-life clinical data regarding hereditary factor XI (FXI) deficiency from a secondary care centre. Retrospective review of clinical records for every FXI:C 0.7 IU/ml or less reported from 2012 to 2020. Seventy-nine patients were included. Six (7.6%) had a severe deficiency (FXI:C <0.2 IU/ml). Only 55 (69.6%) patients were referred to the Haemostasis Centre. Among them, six (15%) were subsequently not identified at increased haemorrhagic risk before a surgical/obstetrical procedure. Thirty-three (41.8%) experienced at least one bleeding event, minor (25 patients) and/or major (16 patients). Minor bleedings were predominantly spontaneous and more frequent in women, major events were mainly provoked. No correlation was found between FXI:C and risk of bleeding ( P  = 0.9153). Lower FXI:C, but not a positive bleeding history, was related with higher likelihood of being referred to the Haemostasis Centre ( P  = 0.0333). Hereditary FXI deficiency prevalence is likely underestimated, real-life clinical practices outside reference centres could be suboptimal.

Global epidemiology of factor XI deficiency: A targeted review of the literature and foundation reports

INTRODUCTION

Hereditary factor XI (FXI) deficiency is a rare coagulation disorder that may result in excessive bleeding requiring intervention to restore haemostasis.

AIM

The aim of this review was to report the current knowledge of the worldwide incidence and prevalence of FXI deficiency.

METHODS

A targeted PubMed search using terms related to FXI deficiency was conducted to identify studies published from April 2002 through April 2022. A manual search supplemented the electronic search. Studies were eligible for data abstraction if they reported population-based incidence proportions/rates or prevalence proportions for FXI deficiency.

RESULTS

The electronic and manual searches returned 253 publications. After applying exclusion criteria, seven publications were included in the analysis, including a global report from the World Federation of Haemophilia (WFH). Six publications provided information on the prevalence of FXI deficiency that included 74 countries and regions. The estimated prevalence of FXI in the WFH report ranged from 0/100,000 in several countries to 55.85/100,000 individuals in the United Kingdom. Prevalence estimates in the PubMed findings ranged from .1 to 246.2/1,000,000 inhabitants with varying methods of case identification and time periods of analysis. One study estimated the incidence of FXI deficiency in Yecla, Spain at 2% of blood donors and .09% of hospital inpatients/outpatients with activated partial thromboplastin time (aPTT) tests.

CONCLUSION

FXI deficiency is rare across the world, but additional steps could be taken to improve incidence and prevalence estimation, for example, development of a consistent FXI deficiency definition and incorporating genetic testing into a clinical routine to better identify and characterise cases.

The prevalence of hemophilia in mainland China: a systematic review and meta-analysis

The prevalence of hemophilia in mainland China was unclear; therefore, we can conducted a meta-analysis using existing data to evaluate the prevalence of hemophilia and its subtypes hemophilia A (HA), hemophilia B (HB), hemophilia C (HC) and Von Willebrand disease (VWD) in mainland China. We conducted a systematic literature review during August, 2011 using PubMed, EMBASE, and Cochrane Library in English and CBMDISK, CNKI, VIP and Wanfang Database in Chinese. We also carried out a search of general and specific hemophilia related websites. Reference lists of key reviews were hand-searched for further relevant research. Studies providing data of the prevalence of hemophilia or its subtypes were included. Meta-analysis was done using the generic inverse variance model. Twenty-two studies were included in the meta-analysis. The overall weighted prevalence of hemophilia was 3.6 per 100,000 and the prevalence among males was 5.5 per 100,000. The prevalence based on community studies was 2.9 per 100,000. The proportions of HA, HB, HC and VWD were 70.97%,16.13%,6.45% and 2.90%, respectively. The prevalences calculated in our study were higher than any previous studies in mainland China, but lower than the world-wide prevalences. The registration rate of hemophiliacs was extremely low. HA and HB were the major subtypes of hemophilia.

[Appropriate laboratory investigation in women with menorrhagia]

Inherited bleeding disorders are potentially causes of menorrhagia and must be investigated if no specific cause is identified. The reported prevalence of inherited bleeding disorders is high in women with menorrhagia compared to the general population. The most frequent disorders reported are von Willebrand's disease and Factor XI deficiency. Menorrhagia is, also, a frequent finding in women with congenital bleeding disorders. Morever, menorrhagia represents the major cause of iron-deficiency anemia among women of reproductive age. Primary evaluation for an underlying disorder of hemostasis in a woman wih menorrhagia is a focused history for familiy and personal history of bleeding symptoms and a complete blood cell count. This will rule out thrombocytopenic bleeding and also assesses for the degree, if any, of anemia. Those women with a positive screen and normal platelet count should be evaluated with laboratory investigation including prothrombin time, activated partial thromboplastin time, factor VIII, VWF ristocetin cofactor and antigen. If initial hemostasis testing above is normal, then further hemostasis testing can be considered, especially in terms of platelet aggregation, in a multidisciplinary clinic.

Factor XI deficiency in humans

Factor XI (FXI) deficiency is an autosomal recessive injury-related bleeding tendency, which is common in Jews particularly of Ashkenazi origin. To date, 152 mutations in the FXI gene have been reported with four exhibiting founder effects in specific populations, Glu117stop in Ashkenazi and Iraqi Jews and Arabs, Phe283Leu in Ashkenazi Jews, Cys38Arg in Basques, and Cys128stop in the United Kingdom. Severe FXI deficiency does not confer protection against acute myocardial infarction, but is associated with a reduced incidence of ischemic stroke. Inhibitors to FXI develop in one-third of patients with very severe FXI deficiency following exposure to blood products. Therapy for prevention of bleeding during surgery in patients with severe FXI deficiency consists of plasma, factor XI concentrates, fibrin glue and antifibrinolytic agents. In patients with an inhibitor to FXI, recombinant factor VIIa is useful.

Carrier rate of Factor XI deficiency in stunted Japanese black cattle

Blood examinations and genotyping of Factor XI (F11) were performed in growth retardation Japanese Black cattle and their dams. Genotyping of F11 revealed that the recessive homozygous and heterozygous genotype frequencies were 5.2% and 50.0% in the Claudin-16 (CL-16) deficiency group (n=58), 0% and 14.2% in the renal dysplasia group (n=7), 0% and 26.1% in the non-CL-16 deficiency nephritis group (n=23), 8.9% and 46.7% in the hypogenesis syndrome group (n=45), 6.2% and 25.0% in the neonatal weak calf syndrome group (n=32), 9.1% and 38.6% in the respective dams group (n=44), 0% and 23.1% in the normal cattle group (n=13), and 5.9% and 38.2% in total (n=222), respectively. These results showed that the carrier rate of F11 deficiency was high in Japanese Black cattle, and that the CL-16 deficiency, hypogenesis syndrome, neonatal weak calf syndrome, and dams groups had a large amount of recessive homozygous genotype than the other groups. No abnormal bleeding was observed clinically in the present study, and 4 of the recessive homozygous dams showed normal growth and parturition.

United States' factor XI-deficiency patients need a safer treatment

A replacement factor for Factor XI with is virally inactivated is not available in the U.S. Elsewhere an inactivated concentrate has been used. A review of the experience over 15 years suggests that this product is safe and effective and suggests its potential use in the U.S. The most serious complication of the factor was a slight increase in DIC and thrombotic events.

Prevalence, causes, and characterization of factor XI inhibitors in patients with inherited factor XI deficiency

Factor XI deficiency, an injury-related bleeding disorder, is rare worldwide but common in Jews in whom 2 mutations, Glu117Stop (type II) and Phe283Leu (type III), prevail. Mean factor XI activities in homozygotes for Glu117Stop and for Phe283Leu are 1 and 10 U/dL, respectively. Inhibitors to factor XI in patients with severe factor XI deficiency have been reported in a small number of instances. This study was undertaken to determine the prevalence of acquired inhibitors against factor XI in patients with severe factor XI deficiency, discern whether these inhibitors are related to specific mutations, and characterize their activity. Clinical information was obtained from unrelated patients with severe factor XI deficiency, and blood was analyzed for factor XI activity, inhibitor to factor XI, and causative mutations. Immunoglobulin G purified from patients with an inhibitory activity was tested for binding to factor XI, effects on activation of factor XI by factor XIIa and thrombin, and activation of factor IX by exogenous factor XIa. Of 118 Israeli patients, 7 had an inhibitor; all belonged to a subgroup of 21 homozygotes for Glu117Stop who had a history of plasma replacement therapy. Three additional patients with inhibitors from the United Kingdom and the United States also had this genotype and were exposed to plasma. The inhibitors affected factor XI activation by thrombin or factor XIIa, and activation of factor IX by factor XIa. The results imply that patients with a very low factor XI level are susceptible to development of an inhibitor following plasma replacement.

Inherited factor XI deficiency confers no protection against acute myocardial infarction

BACKGROUND AND PURPOSE

Factor XI (FXI) contributes to thrombin generation thereby affecting fibrin formation and to down regulation of fibrinolysis by activation of thrombin-activatable fibrinolysis inhibitor (TAFI). The purpose of this study was to evaluate whether patients with severe FXI deficiency are protected against acute myocardial infarction (AMI).

METHODS

The incidence of AMI in patients with severe FXI deficiency (FXI activity less than 15 U dL(-1)) whose age was 35 years or more was compared to the incidence of AMI in age and gender matched persons of the general population. Atherosclerotic risk factors were assessed in FXI deficient patients and blood was tested for prothrombotic parameters such as FV Leiden, prothrombin G20210A, lupus anticoagulant, and platelet membrane polymorphisms. The common mutations causing FXI deficiency in Jews were also examined.

RESULTS

Of 96 patients with severe FXI deficiency (55 women and 41 men) 16 had a history of AMI (6 women and 10 men). The median age at the time of AMI was 64.5 for women and 58 for men. The calculated annual rate of AMI in men was similar to the expected in the general Israeli population, whereas in women it was almost 2-fold higher, but this difference did not reach statistical significance. One or more atherosclerotic risk factors were observed in 13 of 16 patients (81.3%) with AMI compared to 44 of 79 patients (55.7%) without AMI (P < 0.001). The frequency distributions of platelet polymorphisms and of prothrombotic polymorphisms were not different between patients with severe FXI deficiency who experienced or not an AMI. None of the patients had lupus anticoagulant. The common genotypes which cause FXI deficiency in Jews were similarly distributed in patients with and without AMI.

CONCLUSIONS

Severe FXI deficiency does not confer protection against AMI.

Factor XI deficiency in Iranians: its clinical manifestations in comparison with those of classic hemophilia

BACKGROUND AND OBJECTIVES

In patients with factor XI(FXI) deficiency the bleeding tendency is poorly correlated with plasma factor levels. The purpose of this study was to evaluate whether or not this discrepancy is also present in a large series of patients from Iran, a previously unexplored ethnic group.

DESIGN AND METHODS

In 28 FXI - deficient patients bleeding symptoms and their relation to FXI levels were compared with those of 100 patients with factor VIII (FVIII)deficiency (classic hemophilia), matched for severity of factor deficiency.

RESULTS

Spontaneous bleeding was definitely less frequentin FXI deficiency than in hemophilia, whereas postoperative and post-traumatic bleeding occurred with comparable frequencies. Among FXI-deficient patients the severity of symptoms was poorly correlated with FXI levels, mildly deficient patients bleeding almost as frequently as those severely deficient. In contrast, in patients with classic hemophilia there was a close relation between the severity of bleeding and degree of FVIII deficiency.

INTERPRETATION AND CONCLUSIONS

As in other ethnic groups, in Iranians factor XI deficiency is less severe than classic hemophilia and the bleeding tendency is poorly correlated to plasma factor levels.

Age estimates of two common mutations causing factor XI deficiency: recent genetic drift is not necessary for elevated disease incidence among Ashkenazi Jews

The type II and type III mutations at the FXI locus, which cause coagulation factor XI deficiency, have high frequencies in Jewish populations. The type III mutation is largely restricted to Ashkenazi Jews, but the type II mutation is observed at high frequency in both Ashkenazi and Iraqi Jews, suggesting the possibility that the mutation appeared before the separation of these communities. Here we report estimates of the ages of the type II and type III mutations, based on the observed distribution of allelic variants at a flanking microsatellite marker (D4S171). The results are consistent with a recent origin for the type III mutation but suggest that the type II mutation appeared >120 generations ago. This finding demonstrates that the high frequency of the type II mutation among Jews is independent of the demographic upheavals among Ashkenazi Jews in the 16th and 17th centuries.

Frequency of inherited bleeding disorders in women with menorrhagia

BACKGROUND

Although menorrhagia is a common gynaecological symptom, a specific cause is identified in less than 50% of affected women. We investigated the frequency of inherited bleeding disorders in women with menorrhagia.

METHODS

Women referred for investigation of menorrhagia whose pelvis was normal on clinical examination and who had an estimated menstrual blood loss of more than 80 mL were studied. A detailed menstrual history and history about other bleeding symptoms was taken. The activated partial thromboplastin time, factor VIII activity, von-Willebrand-factor antigen and activity, and factor XI (FXI) were measured in all patients; further tests were done when results were at or outside the limits of the assays.

FINDINGS

150 women were screened. An inherited bleeding disorder was diagnosed in 26 (17%) patients: the disorders were von Willebrand's disease of mild (15) or moderate severity (three), mild FXI deficiency (four), mild von Willebrand's disease and FXI deficiency (one), combined von Willebrand's disease, FXI deficiency, and factor X deficiency (one), carriage of haemophilia-A gene (one), and platelet dysfunction (one). The frequency of von Willebrand's disease and FXI deficiency were 13% (95% CI 7.9-18.8%) and 4% (1.5-8.5%), respectively. Menorrhagia since menarche was noted in 11 (8.9%) of 123 women without a bleeding disorder compared with 13 (65%) of 20 women with von Willebrand's disease (p=0.001) and four (66.7%) of six women with FXI deficiency (p<0.001).

INTERPRETATION

Inherited bleeding disorders are found in a substantial proportion of women with menorrhagia and a normal pelvis examination. We suggest that such patients should be investigated for these disorders-especially von Willebrand's disease-before invasive procedures are done.

One of the two common mutations causing factor XI deficiency in Ashkenazi Jews (type II) is also prevalent in Iraqi Jews, who represent the ancient gene pool of Jews

In recent years four mutations causing factor XI deficiency have been identified in Jews of Ashkenazi (European) origin. Two of them, type II (a nonsense mutation) and type III (a missense mutation), were found to prevail among 125 unrelated Ashkenazi Jews with severe factor XI deficiency. A finding of type II mutation in four unrelated Iraqi-Jewish families raised the possibility that this mutation is also common in Iraqi Jews, who represent the ancient gene pool of the Jews. A molecular-based analysis performed in 1,040 consecutively hospitalized patients disclosed the following results: Among 531 Ashkenazi-Jewish patients, the type II allele frequency was 0.0217 and among 509 Iraqi-Jewish patients, 0.0167 (P = .50). The type III allele frequency in the Ashkenazi-Jewish patients was 0.0254, whereas none of 502 Iraqi-Jewish patients examined had this mutation. These data suggest that the type II mutation was present in Jews already 2.5 millenia ago. The data also indicate that the estimated risk for severe factor XI deficiency in Ashkenazi Jews (due to either genotype) is 0.22% and in Iraqi Jews, 0.03%, and that the estimated risk of heterozygosity in Ashkenazi Jews is 9.0% and in Iraqi Jews, 3.3%. As patients with severe factor XI deficiency are prone to bleeding after injury and patients with partial deficiency may have similar bleeding complications when an additional hemostatic derangement is present, the observed high frequencies should be borne in mind when surgery is planned for individuals belonging to these populations.

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.

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.

Congenital hemorrhagic disorders in Jordan

The results of a three year prospective study of inherited bleeding syndromes in Jordan is presented. There were 112 patients from 64 families. Of these there were 42 patients with hemophilia A, 23 with Glanzmann's thrombasthenia, 22 with von Willebrand's disease, 11 with Christmas disease, 6 with hypofibrinogenemia, 3 with afibrinogenemia, 2 with factor XIII deficiency, 2 with storage pool disease and 1 with factor XI deficiency. The pattern of inherited bleeding syndromes in Jordan is different from that seen in Europe and U.S.A. in that Glanzmann's thrombasthenia is very common. High proportion of hemophiliacs were severe. Arthropathy was common. A significant number of bleeders had fatal hemorrhage. In a high proportion of patients, no family history of bleeding was found.

Definition of the population at risk of bleeding due to factor XI deficiency in Ashkenazic Jews and the value of activated partial thromboplastin time in its detection

The previously found high gene frequency of hereditary Factor XI deficiency among Ashkenazic Jews, and the risk of bleeding following trauma in this disorder, prompted us to define the population at risk of bleeding and to evaluate the activated partial thromboplastin time (APTT) as a screening test for its detection. The APTT values of 30 patients with severe Factor XI deficiency (0 to 0.14 unit/ml) overlapped only minimally with the APTT of 56 healthy subjects with Factor XI levels greater than 0.5 unit/ml. In contrast, APTT values of partially deficient patients (Factor XI: 0.15 to 0.49 unit/ml) overlapped substantially with the APTT values of the healthy subjects. However, when only subjects at risk of bleeding were considered (Factor XI less than 0.3 unit/ml), the overlap of APTT values was much smaller. The apparent frequency of this population at risk in the general Ashkenazic population was found to be 3.05%. If a cutoff point of an APTT value at the 80th percentile of the normal range is taken for detection of subjects belonging to this group, one will miss only 4.4% of these cases, with confidence limits of 0.1 to 21%.