Morbidity and mortality in a large number of Iranian patients with severe congenital factor XIII deficiency

Novel Insights into Heterozygous Factor XIII Deficiency

The prevalence and clinical significance of heterozygous factor XIII (FXIII) deficiency has long been debated, with controversial reports emerging since 1988. In the absence of large epidemiologic studies, but based on a few studies, a prevalence of 1 per 1,000 to 5,000 is estimated. In southeastern Iran, a hotspot area for the disorder, a study of more than 3,500 individuals found an incidence of 3.5%. Between 1988 and 2023, a total of 308 individuals were found with heterozygous FXIII deficiency, of which molecular, laboratory, and clinical presentations were available for 207 individuals. A total of 49 variants were found in the F13A gene, most of which were missense (61.2%), followed by nonsense (12.2%) and small deletions (12.2%), most occurring in the catalytic domain (52.1%) of the FXIII-A protein and most frequently in exon 4 (17%) of the F13A gene. This pattern is relatively similar to homozygous (severe) FXIII deficiency. In general, heterozygous FXIII deficiency is an asymptomatic condition without spontaneous bleeding tendency, but it can lead to hemorrhagic complications in hemostatic challenges such as trauma, surgery, childbirth, and pregnancy. Postoperative bleeding, postpartum hemorrhage, and miscarriage are the most common clinical manifestations, while impaired wound healing has been rarely reported. Although some of these clinical manifestations can also be observed in the general population, they are more common in heterozygous FXIII deficiency. While studies of heterozygous FXIII deficiency conducted over the past 35 years have shed light on some of the ambiguities of this condition, further studies on a large number of heterozygotes are needed to answer the major questions related to heterozygous FXIII deficiency.

Traumatic intracranial hemorrhage in pediatrics: Implications of factor XIII deficiency and consumptive coagulopathy in abusive head trauma evaluation

For infants that present with intracranial hemorrhage in the setting of suspected abusive head trauma (AHT), the standard recommendation is to perform an evaluation for a bleeding disorder. Factor XIII (FXIII) deficiency is a rare congenital bleeding disorder associated with intracranial hemorrhages in infancy, though testing for FXIII is not commonly included in the initial hemostatic evaluation. The current pediatric literature recognizes that trauma, especially traumatic brain injury, may induce coagulopathy in children, though FXIII is often overlooked as having a role in pediatric trauma-induced coagulopathy. We report an infant that presented with suspected AHT in whom laboratory workup revealed a decreased FXIII level, which was later determined to be caused by consumption in the setting of trauma induced coagulopathy, rather than a congenital disorder. Within the Child Abuse Pediatrics Research Network (CAPNET) database, 85 out of 569 (15 %) children had FXIII testing, 3 of those tested (3.5 %) had absent FXIII activity on qualitative testing, and 2 (2.4 %) children had activity levels below 30 % on quantitative testing. In this article we review the literature on the pathophysiology and treatment of low FXIII in the setting of trauma. This case and literature review demonstrate that FXIII consumption should be considered in the setting of pediatric AHT.

The History of Factor XIII Deficiency

Despite the early discovery of factor XIII (FXIII) in 1944, the diagnosis of FXIII deficiency was not made until 1960, after all the other coagulation factor deficiencies, most likely due to the normality of routine coagulation testing in FXIII deficiency. Although the first case was detected by the clot solubility test and this test has long since been used to detect FXIII deficiency, the test is no longer recommended by experts. Over the past 60 years, knowledge about FXIII deficiency has expanded considerably, between 1992, when the first variant was identified, and 2022, 197 mutations have been reported. Almost all missense mutations have a similar effect on FXIII, leading to instability and faster degradation of mutant FXIII protein. Therapeutic options have evolved from historical fresh frozen plasma (FFP), old plasma, whole blood, and cryoprecipitate, to plasma-derived and recombinant FXIII concentrates, respectively available since 1993 and 2012. These concentrate products were respectively approved by the Food and Drug Administration in 2011 and 2013. This historical review covers various aspects of FXIII related disorders, including the discovery of the FXIII, associated disorders, molecular basis, diagnosis, and treatment of FXIII deficiency.

Identification of a novel mutation in the factor XIII A subunit in a patient with inherited factor XIII deficiency

Inherited factor XIII (FXIII) deficiency is an extremely rare and under-diagnosed autosomal recessive inherited coagulopathy, which is caused by genetic defects in the F13A1 or F13B gene. More than 200 genetic mutations have been identified since the first case of inherited FXIII deficiency was reported. This study aimed to identify underlying gene mutations in a patient with inherited FXIII deficiency who presented with recurrent intracerebral hemorrhage. Levels of plasma FXIII-A antigen were measured, F13A1 and F13B genes were sequenced, mutation information was analyzed, and the mutated protein structure was predicted using bioinformatics methods. Molecular genetic analysis identified four mutations of FXIII-related genes in the proband, including three previously reported mutations inherited from his parents (c.631G>A, p.Gly210Arg and c.1687G>A, p.Gly562Arg of F13A1 gene and c.344G>A, p.Arg115His of F13B gene) and a novel spontaneous mutation of F13A1 gene (c.2063C>G, p.Ser687Cys). Molecular structural modeling demonstrated that the novel Ser687Cys mutation may cause changes in the spatial structure of FXIII-A and increase its instability. In conclusion, we identified a novel and likely pathogenic mutation of the F13A1 gene, which enriched the gene mutation spectrum of inherited FXIII deficiency. The findings may provide promising targets for diagnosis and treatment of inherited FXIII deficiency.

Genetic landscape in coagulation factor XIII associated defects – Advances in coagulation and beyond

Coagulation factor XIII (FXIII) acts as a fine fulcrum in blood plasma that maintains the balance between bleeding and thrombosis by covalently crosslinking the pre-formed fibrin clot into an insoluble one that is resistant to premature fibrinolysis. In plasma, FXIII circulates as a pro-transglutaminase complex composed of the dimeric catalytic FXIII-A encoded by the F13A1 gene and dimeric carrier/regulatory FXIII-B subunits encoded by the F13B gene. Growing evidence accumulated over decades of exhaustive research shows that not only does FXIII play major roles in both pathological extremes of hemostasis i.e. bleeding and thrombosis, but that it is, in fact, a pleiotropic protein with physiological roles beyond coagulation. However, the current FXIII genetic-epidemiological literature is overwhelmingly derived from the bleeding pathology associated with its deficiency. In this article we review the current clinical, functional, and molecular understanding of this fascinating multifaceted protein, especially putting into the same perspective its genetic landscape.

Evaluating for Suspected Child Abuse: Conditions That Predispose to Bleeding

Child abuse might be suspected when children present with cutaneous bruising, intracranial hemorrhage, or other manifestations of bleeding. In these cases, it is necessary to consider medical conditions that predispose to easy bleeding or bruising. When evaluating for the possibility of bleeding disorders and other conditions that predispose to hemorrhage, it is important for pediatricians to consider the child's presenting history, medical history, and physical examination findings before initiating a laboratory investigation. Many medical conditions can predispose to easy bleeding. Before ordering laboratory tests for a disease, it is useful to understand the biochemical basis and clinical presentation of the disorder, condition prevalence, and test characteristics. This technical report reviews the major medical conditions that predispose to bruising or bleeding and should be considered when evaluating for abusive injury.

The most common disease-causing mutation of factor XIII deficiency is corrected by CRISPR/CAS9 gene editing system

Factor XIII (FXIII) deficiency is one of the most severe congenital bleeding disorders, with an estimated incidence of one person per one million. Patients with severe FXIII deficiency present a wide range of clinical manifestations, including umbilical cord bleeding, intracranial haemorrhage and recurrent miscarriages. Due to the high rate of life-threatening bleeding, primary prophylaxis is mandatory from the time of diagnosis. Although replacement therapy is the most common therapeutic choice, gene therapy remains the only curative option. In the present study, we assessed the efficacy of the clustered regularly interspaced short palindromic repeats - CRISPR-associated protein 9 (CRISPR/Cas9) system in the correction of the most common FXIII disease-causing mutation (c.562 T > C). A dermal fibroblast was harvested from the human skin biopsy of a young patient with FXIII deficiency. Sanger sequencing was used to confirm the presence of c.562 T>C mutation in the patient and in the harvested fibroblasts. PX459 vector was digested with BbsI restriction enzyme, and after annealing and ligation of two 20-bp guide-RNAs (g-RNAs) close to the PAM (NGG) sequence, the constructed vectors were amplified in Escherichia coli Top 10. Transfection was performed by a nucleofector device, and DNA extraction was performed after puromycin selection and serial dilution from potentially transfected colonies. A 50-bp template oligonucleotide was used to aid homologous repair for correction of the underlying mutation and synonymous mutation as an internal control. The synonymous mutation (AAT to ACT) near the mutation site was used as internal control. Sanger sequencing was done in order to check the gene correction. The c.562 T > C mutation was detected in homozygote state in the primary fibroblasts of the patient and wild-type alleles were confirmed in the normal individual. Colony PCR and sequencing revealed successful cloning of the designed gRNAs. The detected mutation was corrected from a homozygote mutant state (c.562 T > C) to a homozygote wild type in transfected dermal fibroblasts of the patient. The control mutation, as an internal control, was also corrected in the same fibroblasts in the heterozygote manner. The result of the study shows that the CRISPR/CAS9 gene editing system is an effective tool for correction of point mutations in transfected fibroblasts of patients with congenital FXIII deficiency and represents a new, potentially curative, option.

Measuring Factor XIII Inhibitors in Patients with Factor XIII Deficiency: A Case Report and Systematic Review of Current Practices in Japan

Factor XIII (FXIII) deficiency is a rare but serious coagulopathy. FXIII is critical in blood coagulation, and FXIII deficiencies can lead to uncontrolled or spontaneous bleeding. FXIII deficiencies can be congenital or acquired; acquired FXIII deficiency can be categorized as autoimmune and non-autoimmune. Immunological tests to measure FXIII inhibitors are required to diagnose acquired FXIII deficiency; however, appropriate test facilities are limited, which increases the turnaround time of these tests. In the case of critical bleeding, delayed test results may worsen prognosis due to delayed treatment. Here, we report a case of acquired FXIII deficiency, followed by a review of FXIII deficiency cases in Japan. We performed a systematic review to investigate the present conditions of the diagnosis and treatment of FXIII deficiency, including the measurement of FXIII inhibitors in Japan. FXIII inhibitor testing was only performed in 29.7 of acquired FXIII deficiency cases. Clinical departments other than internal medicine and pediatrics were often involved in medical treatment at the time of onset. Therefore, it is important for doctors in clinical departments other than internal medicine and pediatrics to consider FXIII deficiency and perform FXIII inhibitor testing when examining patients with prolonged bleeding of unknown cause or persistent bleeding after trauma.

Risk and Management of Intracerebral Hemorrhage in Patients with Bleeding Disorders

Intracerebral hemorrhage (ICH) is the most dreaded complication, and the main cause of death, in patients with congenital bleeding disorders. ICH can occur in all congenital bleeding disorders, ranging from mild, like some platelet function disorders, to severe disorders such as hemophilia A, which can cause catastrophic hemorrhage. While extremely rare in mild bleeding disorders, ICH is common in severe coagulation factor (F) XIII deficiency. ICH can be spontaneous or trauma-related. Spontaneous ICH occurs more often in adults, while trauma-related ICH is more prevalent in children. Risk factors that can affect the occurrence of ICH include the type of bleeding disorder and its severity, genotype and genetic polymorphisms, type of delivery, and sports and other activities. Patients with hemophilia A; afibrinogenemia; FXIII, FX, and FVII deficiencies; and type 3 von Willebrand disease are more susceptible than those with mild platelet function disorders, FV, FXI, combined FV-FVIII deficiencies, and type 1 von Willebrand disease. Generally, the more severe the disorder, the more likely the occurrence of ICH. Contact sports and activities can provoke ICH, while safe and noncontact sports present more benefit than danger. An important risk factor is stressful delivery, whether it is prolonged or by vacuum extraction. These should be avoided in patients with congenital bleeding disorders. Familiarity with all risk factors of ICH can help prevent occurrence of this diathesis and reduce related morbidity and mortality.

Noninvasive prenatal diagnosis of congenital factor XIII deficiency in Iran

Congenital factor (F) XIII deficiency is a rare coagulation factor deficiency that is inherited in an autosomal recessive manner. FXIII deficiency presents various clinical manifestations, such as intracranial hemorrhage (ICH), which is the most common cause of morbidity and mortality. As ICH can occur in the neonatal period, prenatal diagnosis (PND) is an effective way to reduce neonatal ICH and its associated fatal consequences. In this study, we investigated a noninvasive prenatal diagnosis (NIPD) method, cell-free fetal DNA (cffDNA), for PND in FXIII deficiency. This study was conducted on seven pregnant women in the first trimester. After extraction of cffDNA from maternal plasma, PCR-restriction fragment length polymorphism (PCR-RFLP) was performed to find the underlying F13A gene mutations previously identified in the family members. PCR-RFLP was also performed on postnatal DNA samples. Sanger sequencing was performed to confirm the results. Four cases were heterozygous for F13A gene mutations, whereas three were unaffected. PCR-RFLP results for cffDNA and postnatal DNA samples were identical, and Sanger sequencing confirmed the results. cffDNA is a noninvasive and effective method for PND in congenital FXIII deficiency.

Factor XIII Deficiency: A Review of Clinical Presentation and Management

Factor XIII (FXIII) deficiency is a rare autosomal recessive disorder that can result in life-threatening bleeding and early fetal loss. FXIII not only is responsible for cross-linking fibrinogen to stabilize and strengthen clot formation but also facilitates wound healing and angiogenesis and plays an important role in fetal vitality. Modern therapeutics allow for prophylactic treatment that can prevent most major bleeding and increasing fetal viability. Early diagnosis is paramount due to the high risk of intracranial bleeding.

Retinal hemorrhage and bleeding disorders in children: A review

BACKGROUND

Retinal hemorrhages (RH) are a common manifestation of abusive head trauma (AHT) resulting from acceleration-deceleration injury with or without blunt impact. Evaluation of a child with RH requires careful consideration of these differential diagnoses. The extent to which coagulopathy alone can cause RH would be useful to understand as coagulopathy may accompany AHT.

OBJECTIVE

In this systematic review, we sought to identify whether coagulopathies have been reported with RH similar to those of AHT.

METHODS

We performed a literature search for ocular manifestations of bleeding disorders in children less than 18 years old. We included clotting factor deficiencies, vitamin K deficiency, platelet function abnormalities, thrombocytopenia, disseminated intravascular coagulation (DIC), and trauma induced coagulopathy (TIC). We included only pediatric reports of intraocular bleeding or documented eye examinations that indicated no hemorrhages. We then re-examined cases for ocular and systemic findings that could potentially mimic abuse.

RESULTS

Our initial search yielded 816 results. Sixty-one articles met our inclusion criteria. Of these, there were 32 children within the AHT age range (less than 5 years old) who had RH and concomitant coagulopathy. Only 5 cases might potentially be confused for abuse. Of these, no classic characteristics of RH from abuse such as retinoschisis or retinal folds were found. Systemic features were inconsistent with AHT.

CONCLUSIONS

The presence of coagulopathy alone does not rule out the possibility that the child has been abused. Coagulopathy alone has not been reported as an etiology of RH that are consistent with AHT, especially when other findings are present.

Cost Efficacy of Rapid Whole Genome Sequencing in the Pediatric Intensive Care Unit

The diagnostic and clinical utility of rapid whole genome sequencing (rWGS) for critically ill children in the intensive care unit (ICU) has been substantiated by multiple studies, but comprehensive cost-effectiveness evaluation of rWGS in the ICU outside of the neonatal age group is lacking. In this study, we examined cost data retrospectively for a cohort of 38 children in a regional pediatric ICU (PICU) who received rWGS. We identified seven of 17 patients who received molecular diagnoses by rWGS and had resultant changes in clinical management with sufficient clarity to permit cost and quality adjusted life years (QALY) modeling. Cost of PICU care was estimated to be reduced by $184,846 and a total of 12.1 QALYs were gained among these seven patients. The total cost of rWGS for patients and families for the entire cohort (38 probands) was $239,400. Thus, the net cost of rWGS was $54,554, representing $4,509 per QALY gained. This quantitative, retrospective examination of healthcare utilization associated with rWGS-informed medicine interventions in the PICU revealed approximately one-third of a QALY gained per patient tested at a cost per QALY that was approximately one-tenth of that typically sought for cost-effective new medical interventions. This evidence suggests that performance of rWGS as a first-tier test in selected PICU children with diseases of unknown etiology is associated with acceptable cost-per-QALY gained.

A retrospective study on clinical manifestations of neonates with FXIII-A deficiency

We assessed clinical presentations and the rate of central nervous system (CNS) bleeding in neonates with FXIIID who exhibited bleeding diathesis in the early days of their lives. A total of 27 neonates presented bleeding or abnormal clinical symptoms, diagnosed with FXIII deficiency were evaluated. Factor XIII concentrate was initiated as the first-line of treatment, and prophylactic therapy was given to all patients. Umbilical cord bleeding, delayed detachment of umbilical stunt, seizure, hematoma, and ecchymosis were concurrent complications in 27 (100%), 5 (18.5%), 5 (18.5%), 3 (11.1%), and 1 (3.7%) of the patients, respectively. History of having CNS bleeding was detected in 13 (48.1%) patients. There was no significant association between CNS bleeding and gender, familial history of FXIIID, or other clinical presentations. Also, there was no significant difference in the mean age of the patients who had CNS bleeding (3.4 ± 0.9 days) and without CNS bleeding (2.9 ± 0.7 days). However, a near significant threshold difference between the patients with and without CNS bleeding was found regarding the mean number of suspicious FXIIID death in their family (1.8 ± 0.5 and 0.7 ± 0.1, respectively, P = 0.05). Therefore, a suggested diagnostic algorithm based on prenatal diagnosis could be useful for timely detection of FXIII deficiency in neonates.

Novel Factor XIII variant identified through whole-genome sequencing in a child with intracranial hemorrhage

Pediatric stroke can be either hemorrhagic or ischemic, with ∼5% of hemorrhagic strokes being caused by genetic coagulopathies. We report an 8 mo old presenting with a hemorrhagic stroke caused by severe Factor XIII deficiency (OMIM # 613225) in whom rapid whole-genome sequencing identified a novel variant in the F13A1 gene c.1352_1353delAT (p.His451ArgfsTer29).

Long-term prophylaxis in patients with severe congenital factor XIII deficiency is not complicated by inhibitor formation

: Congenital factor XIII (FXIII) deficiency is a rare bleeding disorder accompanied by a variety of bleeding events. Severely deficient patients require regular replacement therapy. With development of FXIII concentrate, the risk of viral infections transmitted by fresh frozen plasma and cryoprecipitate is diminished, but the possibility of inhibitor development remains a challenging issue in the management of these patients. The aim of this study was to assess FXIII inhibitor development in Iranian patients with FXIII deficiency (FXIIID). This study enrolled 50 (30 women and 20 men) patients with severe congenital FXIIID from southeast Iran who underwent long-term (more than 4 years or more than 50 injections) prophylaxis with FXIII concentrate (Fibrogammin P, Dade Behring, Marburg, Germany). We evaluated plasma FXIII activity and FXIII inhibitor on day 28 after the last prophylaxis administration. The method for investigation of FXIII inhibitor was based on Bethesda assay. The mean age of the study population was 13.8 ± 8.3 years. The minimum and maximum FXIII activity levels were less than 1-4.5% (mean ± SD, 2.6 ± 0.7%). Our investigations showed that all patients with severe form of FXIIID were treated without inciting inhibitor development. Despite long-term prophylaxis in the studied patients, none was found to have developed FXIII inhibitors.

Prenatal diagnosis in rare bleeding disorders-An unresolved issue?

Intracranial haemorrhage (ICH) is the most dreadful complication, and the main cause of death among patients with rare bleeding disorders (RBD) and prenatal diagnosis (PND) is a preventative lifesaving program. A total of 39 PNDs were reported in the literature through a search on PubMed, EMBASE, SCOPUS and Web of Science databases, most often for congenital factor (F) XIII and FVII deficiencies and rarely in FX, FV deficiencies and afibrinogenemia. The main cause to request a PND is ICH and related morbidity and mortality. Different molecular methods including direct sequencing and linkage analysis as well as polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for a specific mutation are the most common used methods for PND, while factor assay and combination of molecular and factor assay also were used. In this research, 7 severely affected foetuses were identified during PND including 3 foetuses with FXIII deficiency, 3 with FVII deficiency and 1 with FX deficiency. Out of these 7 cases, intrauterine ICH occurred in 1 case with FXIII deficiency, 1 was electively aborted and 1 case with severe FVII deficiency received intrauterine factor transfusion. Postdelivery ICH was reported for 1 patient with severe FVII deficiency within the first month of life. All other pregnancies were uneventful.

Recombinant FXIII (rFXIII-A2) Prophylaxis Prevents Bleeding and Allows for Surgery in Patients with Congenital FXIII A-Subunit Deficiency

Recombinant factor XIII-A ₂ (rFXIII-A ₂ ) was developed for prophylaxis and treatment of bleeds in patients with congenital FXIII A-subunit deficiency. mentor™2 (NCT00978380), a multinational, open-label, single-arm, multiple-dosing extension to the pivotal mentor™1 trial, assessed long-term safety and efficacy of rFXIII-A ₂ prophylaxis in eligible patients (patients with severe [<0.05 IU/mL] congenital FXIII subunit A deficiency) aged ≥6 years. Patients received 35 IU/kg rFXIII-A ₂ (exact dosing) every 28 ± 2 days for ≥52 weeks. Primary endpoint was safety (adverse events including immunogenicity); secondary endpoints were rate of bleeds requiring FXIII treatment, haemostatic response after one 35 IU/kg rFXIII-A ₂ dose for breakthrough bleeds and withdrawals due to lack of rFXIII-A ₂ efficacy. Steady-state pharmacokinetic variables were also summarized. Elective surgery was permitted during the treatment period. Sixty patients were exposed to rFXIII-A ₂ ; their median age was 26.0 years (range: 7.0–77.0). rFXIII-A ₂ was well tolerated without any safety concerns. No non-neutralizing or neutralizing antibodies (inhibitors) against FXIII were detected. Mean annualized bleeding rate (ABR) was 0.043/patient-year. Mean spontaneous ABR was 0.011/patient-year. No patients withdrew due to lack of efficacy. Geometric mean FXIII trough level was 0.17 IU/mL. Geometric terminal half-life was 13.7 days. rFXIII-A ₂ prophylaxis provided sufficient haemostatic coverage for 12 minor surgeries without the need for additional FXIII therapy; eight procedures were performed within 7 days of the patient's last scheduled rFXIII-A ₂ dose, and four were performed 10 to 21 days after the last dose.

Molecular diagnosis of factor XIII deficiency, data from comprehensive coagulation laboratory in Iran

: Diagnosis of factor XIII (FXIII) deficiency (FXIIID) as a rare bleeding disorder is a challenge worldwide. Thus, in the present study, we used different methods including two molecular methods for detection of FXIIID. This study was conducted on individuals suspected to FXIIID. All individuals were checked by two routinely used methods of clot solubility test in Iran and two other clot solubility tests as well as FXIII activity and antigen assays. Molecular analysis was performed by PCR-restriction fragment length polymorphism (PCR-RFLP) and tetra-primer amplification refractory mutation system (T-ARMS)-PCR for only FXIIID mutation in southeast Iran (p.Trp187Arg), previously associated with severe FXIIID. Out of 151 individuals, 26 had abnormal clot solubility test with all four methods. PCR-RFLP revealed that 27 patients were homozygotes for p.Trp187Arg, whereas 12 were heterozygotes. Molecular analysis revealed that in routinely used clot solubility combinations, two homozygotes (∼8%) were missed, whereas in two other combinations, one patient (∼4%) was missed. One false positive result was observed in routinely used methods, whereas further combinations don't have false positive. T-ARMS-PCR had three discrepancies with PCR-RFLP and sequencing confirmed that the results of T-ARMS-PCR were false. FXIII antigen assay diagnosed all homozygotes, whereas in FXIII activity assay, two homozygotes had higher than 5% FXIII activity that inconsistent with severe deficiency. It seems that clot solubility test is not enough sensitive and specific and molecular analysis is the most reliable method for detection of FXIIID in areas such Iran with one or few specific mutations.

Factor XIII deficiency diagnosis: Challenges and tools

Factor XIII deficiency (FXIIID) is a rare hereditary bleeding disorder arising from heterogeneous mutations, which can lead to life-threatening hemorrhage. The diagnosis of FXIIID is challenging due to normal standard coagulation assays requiring specific FXIII assays for diagnosis, which is especially difficult in developing countries. This report presents an overview of FXIIID diagnosis and laboratory methods and suggests an algorithm to improve diagnostic efficiency and prevent missed or delayed FXIIID diagnosis. Assays measuring FXIII activity: The currently available assays utilized to diagnose FXIIID, including an overview of their complexity, reliability, sensitivity, and specificity, as well as mutational analysis are reviewed. The use of a FXIII inhibitor assay is described. Diagnostic tools in FXIIID: Many laboratories are not equipped with quantitative FXIII activity assays, and if available, limitations in lower activity ranges are important to consider. Clot solubility tests are not standardized, have a low sensitivity, and are therefore not recommended as routine screening test; however, they are the first screening test in almost all coagulation laboratories in developing countries. To minimize the number of patients with undiagnosed FXIIID, test quality should be improved in less well-equipped laboratories. Common country-specific mutations may facilitate diagnosis through targeted genetic analysis in reference laboratories in suspected cases. However, genetic analysis may not be feasible in every country and may miss spontaneous mutations. Centralized FXIII activity measurements should also be considered. An algorithm for diagnosis of FXIIID including different approaches dependent upon laboratory capability is proposed.

Treatment with Recombinant Factor XIII (Tretten) in a Pregnant Woman with Factor XIII Deficiency

Patient: Female, 37

Final Diagnosis: Factor XIII deficiency

Symptoms: Bleeding • miscarriage

Medication: —

Clinical Procedure: —

Specialty: Hematology

Severe bleeding diatheses in an elderly patient with combined type autoantibody against factor XIII A subunit; novel approach to the diagnosis and classification of anti-factor XIII antibodies

INTRODUCTION

Acquired factor XIII (FXIII) deficiency due to autoantibody is a rare, severe bleeding diathesis. Its laboratory diagnosis and classification represents a difficult task.

AIM

Introduction of novel approaches into the diagnosis and characterization of anti-FXIII autoantibody and demonstration of their use in the diagnosis of a patient with autoimmune FXIII deficiency.

METHODS

Factor XIII activity, FXIII antigen levels and the titre of anti-FXIII-A antibody were monitored throughout the course of the disease. FXIII activity was measured by ammonia release assay; FXIII-A₂ B₂ complex, total and free FXIII-B concentrations were determined by ELISAs. The binding constant for the interaction of the autoantibody with recombinant FXIII-A₂ (rFXIII-A₂ ) and FXIII-A₂ B₂ was determined by surface plasmon resonance (SPR). The inhibitory capacity of IgG was expressed as the concentration exerting 50% inhibition of FXIII activation/activity (IC50). The truncation of FXIII-A by thrombin was monitored by western blotting. The inhibition of Ca²⁺ -induced FXIII activation and active FXIII (FXIIIa) were assessed by FXIII activity assay.

RESULTS

The antibody bound to rFXIII-A₂ and FXIII-A₂ B₂ with high affinity and accelerated the decay of supplemented FXIII concentrate. An IC50 value of 170.1 μg IgG·mL^-1 indicated effective FXIII neutralization. The main neutralizing effect of the autoantibody was the inhibition of FXIIIa. After 2 months, due to combined therapeutic modalities, the autoantibody disappeared and FXIII activity significantly elevated.

CONCLUSION

The anti-FXIII-A autoantibody exerted a combined effect including inhibition of FXIIIa and acceleration of FXIII decay in the plasma. IC50 and binding constant determinations added important information to the characterization of the autoantibody.

Agreement between factor XIII activity and antigen assays in measurement of factor XIII: A French multicenter study of 147 human plasma samples

INTRODUCTION

Factor XIII (FXIII) deficiency is a rare hemorrhagic disorder whose early diagnosis is crucial for appropriate treatment and prophylactic supplementation in cases of severe deficiency. International guidelines recommend a quantitative FXIII activity assay as first-line screening test. FXIII antigen measurement may be performed to establish the subtype of FXIII deficiency (FXIIID) when activity is decreased.

METHODS

The aim of this multicenter study was to evaluate the analytical and diagnostic levels of performance of a new latex immunoassay, K-Assay^® FXIII reagent from Stago, for first-line measurement of FXIII antigen. Results were compared to those obtained with the Berichrom^® FXIII chromogenic assay for measurement of FXIII activity. Of the 147 patient plasma samples, 138 were selected for analysis.

RESULTS

The accuracy was very good, with intercenter reproducibility close to 7%. Five groups were defined on FXIII activity level (<5% (n = 5), 5%-30% (n = 23), 30%-60% (n = 17), 60%-120% (n = 69), above 120% (n = 24)), without statistical differences between activity and antigen levels (P value >0.05). Correlation of the K-Assay^® with the Berichrom^® FXIII activity results was excellent (r = 0.919). Good agreement was established by the Bland and Altman method, with a bias of +9.4% on all samples, and of -1.4% for FXIII levels lower than 30%. One patient with afibrinogenemia showed low levels of Berichrom^® FXIII activity but normal antigen level and clot solubility as expected.

CONCLUSIONS

The measurement of FXIII antigen using the K-Assay^® is a reliable first-line tool for detection of FXIII deficiency when an activity assay is not available.

Disseminated intravascular coagulation with positive D-dimer: a controversial clinical feature in severe congenital factor XIII deficiency in southeast Iran

Disseminated intravascular coagulation (DIC) is an extremely rare coagulopathy in the rare factor XIII (FXIII) deficiency. Compensated DIC occurs because of injuries that lead to systemic coagulation activation that is amplified by impaired fibrinolysis. This challenge translates into the widespread deposition of fibrin degradation products in the circulation. The aim of this study is to report three cases with severe FXIII deficiency who presented with DIC and positive D-dimer. Here we describe three patients affected by both FXIII deficiency and DIC; two girls aged 17 and 45 days and a 3.5-year-old boy. All patients had a positive family history for FXIII deficiency. Umbilical cord bleeding was the first presentation of FXIII deficiency in all of them, who presented also with ecchymosis; two of them had delayed wound bleeding. DIC occurred simultaneously with intracranial haemorrhage in two patients, whereas the third experienced DIC following extensive haematoma. D-dimer measured in all patients ranged between 5 and 20 μg/ml, whereas fibrinogen degradation product was between 4 and 8 μg/ml.

Guidelines for laboratory diagnosis of factor XIII deficiency

Factor XIII (FXIII) deficiency is an extremely rare hemorrhagic disorder with an approximate worldwide incidence of one per two million. With current tests, diagnosis of this disease can be made more precisely. However, factors such as the number of patients with FXIII deficiency (FXIIID), available diagnostic coagulation tests and the number of molecular studies have affected the diagnosis of FXIIID in different parts of the world. Various laboratory approaches can be used, including screening and diagnosis of the disorder in countries with a relatively high rate of FXIIID and recurrent mutation(s) with a simple polymerase chain reaction-restriction fragment length polymorphism analysis or polymerase chain reaction-sequencing for detection of one or a few specific mutations. In other countries, two different laboratory approaches can be used, depending on available coagulation tests. In less-equipped coagulation laboratories, the clot solubility test remains the only diagnostic test for FXIIID. Even in these countries, at least one referral laboratory should perform FXIII activity and, if possible, confirmation of FXIIID by molecular analysis. In countries with well equipped coagulation laboratories, FXIII activity should be used to screen suspected FXIIID patients; more specific tests such as molecular analysis should be used for confirmation. This study suggests a simple, reliable and flexible algorithm for early diagnosis of FXIIID, and may, with one-time diagnosis of FXIIID, reduce the rate of morbidity and mortality in patients with the disorder.

Molecular Basis of Congenital Factor XIII Deficiency in Iran

Factor XIII deficiency (FXIIID) is an extremely rare autosomal recessive disorder that has the highest incidence in Iran. The FXIIID is primarily due to mutations in the FXIII-A gene, most of which are unique. In the current study, we report all identified mutations among Iranian patients. Among 483 patients, 366 (75.8%) were molecularly analyzed; 11 different mutations were observed. Of 11, 8 (72.7%) are missense, whereas the remaining 3 (27.3%) are deletion/insertion. Among these patients, 347 (94.9%) had the unique mutation of c.562T>C and 5 (1.4%) had the c.233G>A mutation. c.1226G>A, c.2111G>A, and c.1142T>A are also common, whereas other mutations, including 3 missense and 3 deletion/insertion, were observed only in single patient. Although, in most cases, FXIII mutations are unique and restricted to a specific family, this differs in Iran where a considerable number of identified mutations, recurrently observed, appear to be due to the high rate of consanguinity.

Recurrent Post Tonsillectomy Secondary Hemorrhage in Patients with Factor XIII Deficiency: A Case Series and Review of Literature

Case series

Patients: Male, 20 • Male, 4 • Male, 27 • Male, 25 • Female, 5 • Female, 26

Final Diagnosis: Post tonsillectomy secondary hemorrhage

Symptoms: Bleeding • bleeding per oral

Medication: —

Clinical Procedure: Control of post tonsillectomy secondary hemorrhage

Specialty: Otolaryngology

Laboratory Diagnosis of Factor XIII Deficiency in Developing Countries: An Iranian Experience

Factor XIII (FXIII) deficiency is an extremely rare bleeding disorder with an approximately 12-times higher than the rest of the world. The International Society for Thrombosis and Hemostasis (ISTH) suggested a standard algorithm for precise diagnosis and classification of FXIII deficiency (FXIIID). However, due to lack of investment in proper equipment and procedures in Iran, almost no part of this algorithm can be used to diagnose Iranian patients. Thus, this study proposes a guideline for accurate molecular and laboratory diagnosis of FXIIID based on the available tools. Because this study suggests a simple and reliable algorithm for early diagnosis, it can therefore, reduce the rates of morbidity and mortality of FXIIID patients with this condition.

Blood coagulation factor XIII and factor XIII deficiency

Factor XIII (FXIII) is a multifunctional pro-γ-transglutaminase that, in addition to its well-known role in hemostasis, has a crucial role in angiogenesis, maintenance of pregnancy, wound healing, bone metabolism, and even cardio protection. FXIII deficiency (FXIIID) is a rare bleeding disorder (RBD) with an estimated incidence of one per two million that is accompanied by life-threatening bleeding such as umbilical cord bleeding, recurrent spontaneous miscarriage, and intracranial hemorrhage (ICH). Today, the disease is successfully managed by FXIII concentrate and recombinant FXIII for prophylaxis, management of minor and major bleeding, treatment of ICH, and successful delivery in women with recurrent pregnancy loss. Molecular analysis of patients with FXIIID revealed a wide spectrum of mutations, most frequently missense mutations in the FXIII-A subunit, with a few recurrent mutations observed worldwide. In vitro expression studies revealed that most of the missense mutations cause intracellular instability of the FXIII protein and, subsequently, FXIIID.