Rare bleeding disorders: Advances in management.

Inherited factor coagulation deficiencies and vascular bleeding disorders, associated with bleeding of various severity, are often classified as rare bleeding disorders (RBDs). These include inherited fibrinogen disorders, inherited platelet function disorders (IPFD) and hereditary haemorrhagic telangiectasia (HHT). In the last decades, there have been large increases in knowledge on the epidemiology, genetics, physiopathology, clinical features, and diagnosis of RBDs, but improvements in management have been more limited and remain challenging. The treatment mainstay of RBDs is based only on replacement of a few available coagulation factor concentrates or cryoprecipitates. There is growing interest in therapeutic agents that enhance coagulation or inhibiting anticoagulant pathways in RBDs. In severe IPFD, the optimal platelet transfusion strategy is not yet established. Moreover, data is scarce on the effectiveness and safety of desmopressin and/or antifibrinolytic drugs often used for milder IPFD treatment. The best fibrinogen replacement strategy (prophylaxis vs. on demand) in afibrinogenemia is still debated. Similarly, the optimal trough fibrinogen target level for treatment of acute bleeding, and the role of fibrinogen replacement during pregnancy in mild hypofibrinogenemia and dysfibrinogenemia, have not been properly evaluated. The therapeutic arsenal in HHT includes antifibrinolytics and a series of antiangiogenic agents whose potential efficacy has been tested in small studies or are under investigation for treatment of bleeding. However, there is need to address several issues, including the optimal dosing strategies, the potential emergent toxicity of longer-term use, and the impact of systemic antiangiogenic treatment on visceral arteriovenous malformations.

A novel mutation in the FGG gene causes hypofibrinogenemia in a Chinese family.

Congenital fibrinogen disorders are a group of coagulation deficiencies caused by fibrinogen defects and are divided into four types, including afibrinogenemia, hypofibrinogenemia, dysfibrinogenemia, and hypodysfibrinogenemia. In this study, we collected a family with hypofibrinogenemia, and genetics analysis identify a novel pathogenic variants (c.668G > C, p.Arg223Thr) in the FGG gene. And electron microscope observation revealed significant changes in the ultrastructure of fibrin of the proband. Our research expands the phenotypic and genetic spectrum associated with the FGG gene, which would facilitate in genetic counselling and prenatal genetic diagnosis.

Management of pregnancy and delivery in congenital fibrinogen disorders: communication from the ISTH SSC Subcommittee on Factor XIII and Fibrinogen.

Congenital fibrinogen disorders (CFDs) are a heterogeneous group of rare congenital quantitative and/or qualitative fibrinogen deficiencies. The spectrum of molecular anomalies is broad, leading to several subtypes of fibrinogen disorders (ie, afibrinogenemia, hypofibrinogenemia, dysfibrinogenemia, and hypodysfibrinogenemia). Pregnancy in women with CFDs is a high-risk clinical situation, with an increased tendency for miscarriages, bleeding, and thrombosis. Even though it is well established that management of such pregnancies requires a multidisciplinary approach involving specialists (hematologists and maternal/fetal medicine experts with expertise in the management of inherited bleeding disorders), specific guidelines are lacking. In this International Society on Thrombosis and Haemostasis (ISTH) Scientific and Standardization Committee communication, we aim to propose an expert consensus opinion with literature evidence where available on the strategy for management of pregnancy, delivery, and puerperium in CFDs.

Interest in the new thromboelastometry device, Clot Pro®, for predicting thrombocytopenia and hypofibrinogenemia during lung transplantation.

INTRODUCTION: Lung transplantation is associated with high proportion of transfusion. Monitoring of coagulopathy using viscoelastic tests could aid in the perioperative management of bleeding. The aim of the study was to assess the predictive cut-off values for thrombocytopenia and hypofibrinogenemia using the new thromboelastography analyzer, ClotPro. METHODS: We retrospectively enrolled 65 patients who underwent lung transplantation and were sampled for both viscoelastic assays and conventional coagulation assays simultaneously during the procedure. We characterized the correlation between the EX-test (extrinsic pathway) and platelet count as well as between the FIB-test (extrinsic pathway after platelet inhibition) and fibrinogen concentration. Then, we used ROC curve analysis to determine the optimal EX-test and FIB-test values for predicting thrombocytopenia and hypofibrinogenemia. RESULTS: All the amplitude values of the EX-test (A5, A10, A20, MCF) showed correlation with platelets count (Spearman's rank correlation coefficient ranging from 0.75 to 0.77, all p < 0.0001). We also observed a strong correlation between the amplitude values of the FIB-test (A5, A10, A20 and MCF) and the fibrinogen concentration (Spearman's rank correlation coefficient ranging from 0.68 to 0.71, all p < 0.0001). The AUCs of the EX-test values for thrombocytopenia <100 G/L and <80 G/L ranged from 0.80 to 0.93. Similarly, the AUCs of the FIB-test values for hypofibrinogenemia <1.5 g/L and <2 g/L ranged from 0.74 to 0.83. These results indicate that only the five-minute parameter of thromboelastometry is sufficient for detecting thrombocytopenia and hypofibrinogenemia in patients undergoing lung transplantation. The proposed cut off values for the EX-test to predict thrombocytopenia <80 G/L showed high sensitivity (>86 %), high specificity (>89 %) and high negative predictive value (>95 %). FIB-test cut off values predictive of fibrinogen below 1.5 g/L showed sensitivity (>78 %), specificity (>55 %) and negative predictive value (>88 %). CONCLUSIONS: Our study provided preliminary results that are useful for developing a ClotPro-based algorithm to guide transfusion in lung transplantation. Future interventional studies will be necessary to validate these cut-off values of ClotPro for guiding transfusion.

Absence of Missense Variant Detection in Inherited Dysfibrinogenemia May Result from a Poor Raw Data Analysis Algorithm or Mosaicism.

Variant identification underlying inherited dysfibrinogenemia quite exceptionally fails. We report on two dysfibrinogenemia cases whose underlying DNA variant could not be identified by Sanger analysis. These failures result from two distinct mechanisms. The first case involved raw signal overcorrection by a built-in software, and the second constituted the first description of mosaicism for one of the fibrinogen genes. This mosaicism was subsequently identified by next-generation sequencing reanalysis of the sample.

Dysfibrinogenemia: discrepant results following infusion of purified fibrinogen.

Inherited dysfibrinogenemias are molecular disorders of fibrinogen that affect fibrin polymerization. The majority of cases are asymptomatic, but a significant proportion suffer from increased bleeding or thrombosis. We present two unrelated cases of dysfibrinogenemia, both of whom showed a characteristic discrepancy between fibrinogen activity and the immunologic fibrinogen. In one patient, the dysfibrinogenemia was confirmed by molecular analysis; in the other case, the diagnosis was presumptive based upon laboratory studies. Both patients underwent elective surgery. Both received a highly purified fibrinogen concentrate preoperatively and demonstrated a suboptimal laboratory response to the infusion. Three methods for determining fibrinogen concentration (Clauss fibrinogen, prothrombin-derived fibrinogen, and the viscoelastic functional fibrinogen) were utilized in the case of one patient, and these techniques showed discrepant results with the classic Clauss method giving the lowest concentration. Neither patient experienced excessive bleeding during surgery. Although these discrepancies have been previously described in untreated patients, their manifestation after infusion of purified fibrinogen is less well appreciated.

[Placenta percreta management in a patient with a severe congenital hypofibrinogenemia]. / Gestion d'un placenta percreta chez une patiente atteinte d'une hypofibrinogénémie congénitale sévère.

The obstetrical follow-up of patients with a severe hypofibrinogenemia requires a multidisciplinary collaboration because of potential maternal-fetal complications (recurrent miscarriages, intrauterine fetal demise, post-partum hemorrhage, thrombosis). We report the obstetrical management of a multiparous patient with a severe congenital hypofibrinogenemia associated with a platelet disorder (abnormal phospholipid externalization). A therapeutic strategy based on a biweekly administration of fibrinogen concentrates associated with enoxaparin and aspirin allowed the maintenance of pregnancy. But this last one got complicated by a placenta percreta requiring a salvage hysterectomy with an appropriate hemorrhage prophylaxis.

A new global fibrinolysis capacity assay for the sensitive detection of hyperfibrinolysis and hypofibrinogenemia in trauma patients.

BACKGROUND: Conventional clotting tests are not expeditious enough to allow timely targeted interventions in trauma, and current point-of-care analyzers, such as rotational thromboelastometry (ROTEM), have limited sensitivity for hyperfibrinolysis and hypofibrinogenemia. OBJECTIVES: To evaluate the performance of a recently developed global fibrinolysis capacity (GFC) assay in identifying fibrinolysis and hypofibrinogenemia in trauma patients. METHODS: Exploratory analysis of a prospective cohort of adult trauma patients admitted to a single UK major trauma center and of commercially available healthy donor samples was performed. Lysis time (LT) was measured in plasma according to the GFC manufacturer's protocol, and a novel fibrinogen-related parameter (percentage reduction in GFC optical density from baseline at 1 minute) was derived from the GFC curve. Hyperfibrinolysis was defined as a tissue factor-activated ROTEM maximum lysis of >15% or LT of ≤30 minutes. RESULTS: Compared to healthy donors (n = 19), non-tranexamic acid-treated trauma patients (n = 82) showed shortened LT, indicative of hyperfibrinolysis (29 minutes [16-35] vs 43 minutes [40-47]; p < .001). Of the 63 patients without overt ROTEM-hyperfibrinolysis, 31 (49%) had LT of ≤30 minutes, with 26% (8 of 31) of them requiring major transfusions. LT showed increased accuracy compared to maximum lysis in predicting 28-day mortality (area under the receiver operating characteristic curve, 0.96 [0.92-1.00] vs 0.65 [0.49-0.81]; p = .001). Percentage reduction in GFC optical density from baseline at 1 minute showed comparable specificity (76% vs 79%) to ROTEM clot amplitude at 5 minutes from tissue factor-activated ROTEM with cytochalasin D in detecting hypofibrinogenemia but correctly reclassified >50% of the patients with false negative results, leading to higher sensitivity (90% vs 77%). CONCLUSION: Severe trauma patients are characterized by a hyperfibrinolytic profile upon admission to the emergency department. The GFC assay is more sensitive than ROTEM in capturing hyperfibrinolysis and hypofibrinogenemia but requires further development and automation.

Etiology and management of hypofibrinogenemia in trauma.

PURPOSE OF REVIEW: Fibrin polymerization is essential for stable clot formation in trauma, and hypofibrinogenemia reduces hemostasis in trauma. This review considers fibrinogen biology, the changes that fibrinogen undergoes after major trauma, and current evidence for lab testing and treatment. RECENT FINDINGS: Fibrinogen is a polypeptide that is converted to fibrin by the action of thrombin. During trauma, fibrinogen levels are consumed and reduce within the first few hours because of consumption, dilution, and fibrinolysis. Fibrinogen levels usually rebound within 48 hours of injury and can contribute to thrombotic events. The Clauss fibrinogen assay is the gold standard test for fibrinogen levels, although viscoelastic hemostatic assays are often used when a lab delay is anticipated. An evidence-based threshold for fibrinogen replacement is not well established in the literature, but expert opinion recommends maintaining a level above 150 mg/dl. SUMMARY: Hypofibrinogenemia is an important cause of nonanatomic bleeding in trauma. Despite multiple pathologic causes, the cornerstone of treatment remains fibrinogen replacement with cryoprecipitate or fibrinogen concentrates.

Diagnostic utility of bleeding assessment tools in congenital fibrinogen deficiencies.

BACKGROUND: The assessment of clinical history is crucial before referring a patient for further laboratory testing. Bleeding assessment tools (BAT) are developed to standardize clinical evaluation. A small number of patients with congenital fibrinogen deficiencies (CFDs) have been evaluated with these tools without definitive results. AIMS: We compared the adequacy of the ISTH-BAT and the European network of rare bleeding disorders bleeding score system (EN-RBD-BSS) to identify patients with CFDs. The correlation between the two BATs and fibrinogen levels and patient clinical grade severity was further analyzed. METHODS: We included 100 Iranian patients with CFDs. Routine coagulation and fibrinogen-specific tests (fibrinogen antigen [Fg:Ag] and activity [Fg:C]) were performed. The ISTH-BAT and EN-RBD-BSS were used to assess the bleeding score (BS) of all patients. RESULTS: The ISTH-BAT and EN-RBD-BSS median (range) were 4 (0-16) and 2.21 (-1.49 to 6.71), with a statistically significant moderate correlation between the two systems (r = .597, P < .001). In patients with quantitative deficiencies (afibrinogenemia and hypofibrinogenemia), the correlation between Fg:C and the ISTH-BAT was moderately negative (r = -.4, P < .001), while the correlation between Fg:C and the EN-RBD-BSS was weakly negative (r = -.38, P < .001). Overall, 70% and 72% of patients with fibrinogen deficiencies were correctly identified by both the ISTH-BAT and EN-RBD-BSS, respectively. CONCLUSION: These results suggest that in addition to the ISTH-BAT, the EN-RBD-BSS may also be useful in identifying CFD patients. We found a significant level of sensitivity for detecting fibrinogen deficiency in the two BATs, and bleeding severity classification correctly identified severity grades in almost two-thirds of patients.

Two Novel Heterozygous Mutations (p.γPhe230Val and p.AαAsn839Thr) Cause Hereditary Hypodysfibrinogenemia in Two Chinese Independent Families.

The objective of this study was to explore the molecular defects in two Chinese families with hypodysfibrinogenemia. The coagulation method and immunoturbidimetric method were used to detect plasma fibrinogen activity and plasma fibrinogen antigen. The fibrinogen genes were amplified by PCR, and suspected mutations were confirmed by reverse sequencing. Bioinformatics and model analysis were used to study the conservatism and harm of the mutations. Study showed that the Fg:C and Fg:Ag of the probands of the two families were reduced, respectively, to 0.80g/L, 0.92g/L and 1.35g/L, 1.42g/L; gene analysis revealed that the proband 1 had a heterozygous missense mutation of c.688T>G (p.γPhe230Val) in exon 7 of the FGG gene; the c.2516A>C (p.AαAsn839Thr) heterozygous missense mutation in exon 6 of the FGA gene was got by the proband 2. These mutations found in this study might be related to the hypodysfibrinogenemia.

Acute obstetric coagulopathy during postpartum hemorrhage is caused by hyperfibrinolysis and dysfibrinogenemia: an observational cohort study.

BACKGROUND: Postpartum hemorrhage (PPH) may be exacerbated by hemostatic impairment. Information about PPH-associated coagulopathy is limited, often resulting in treatment strategies based on data derived from trauma studies. OBJECTIVES: To investigate hemostatic changes associated with PPH. PATIENTS/METHODS: From a population of 11 279 maternities, 518 (4.6%) women were recruited with PPH ≥ 1000 mL or placental abruption, amniotic fluid embolism, or concealed bleeding. Routine coagulation and viscoelastometric results were collated. Stored plasma samples were used to investigate women with bleeds > 2000 mL or those at increased risk of coagulopathy defined as placenta abruption, amniotic fluid embolism, or need for blood components. Procoagulant factors were assayed and global hemostasis was assessed using thrombin generation. Fibrinolysis was investigated with D-dimer and plasmin/antiplasmin complexes. Dysfibrinogenemia was assessed using the Clauss/antigen ratio. RESULTS: At 1000 mL blood loss, Clauss fibrinogen was ≤2 g/L in 2.4% of women and 6/27 (22.2%) cases of abruption. Women with very large bleeds (>3000 mL) had evidence of a dilutional coagulopathy, although hemostatic impairment was uncommon. A subgroup of 12 women (1.06/1000 maternities) had a distinct coagulopathy characterized by massive fibrinolysis (plasmin/antiplasmin > 40 000 ng/mL), increased D-dimer, hypofibrinogenemia, dysfibrinogenemia, reduced factor V and factor VIII, and increased activated protein C, termed acute obstetric coagulopathy. It was associated with fetal or neonatal death in 50% of cases and increased maternal morbidity. CONCLUSIONS: Clinically significant hemostatic impairment is uncommon during PPH, but a subgroup of women have a distinct and severe coagulopathy characterized by hyperfibrinolysis, low fibrinogen, and dysfibrinogenemia associated with poor fetal outcomes.

Comparative retrospective study on the validity of point-of-care testing device for massive obstetrical hemorrhage: dry hematology vs thromboelastography.

BACKGROUND: Early recognition of hypofibrinogenemia and prompt initiation of transfusion therapy in patients with massive obstetrical hemorrhage can improve prognosis. There are reports on the usefulness of point-of-care testing, which provides quicker test results compared with fibrinogen measurements using the conventional Clauss method. OBJECTIVE: This study aimed to compare and investigate the diagnostic accuracy of dry hematology and thromboelastography in point-of-care testing for the diagnosis of hypofibrinogenemia. STUDY DESIGN: A single-center, retrospective study of 126 massive obstetrical hemorrhage cases with point-of-care testing before treatment was initiated. The correlation of fibrinogen values with the Clauss method and the diagnostic accuracy for hypofibrinogenemia were compared between dry hematology and thromboelastography. RESULTS: Fibrinogen value in dry hematology showed a strong positive correlation with values measured by the Clauss method, and the diagnostic accuracy for hypofibrinogenemia was high, but there were many residuals above 100 mg/dL, and the distribution of these residuals was not uniform. Although thromboelastography cannot be used to directly measure fibrinogen values, maximum amplitude citrated functional fibrinogen, amplitude-10 citrated rapid thromboelastography, and amplitude-10 citrated functional fibrinogen showed a strong positive correlation with fibrinogen values using the Clauss method, and no significant difference in correlation or diagnostic accuracy was observed relative to dry hematology. CONCLUSION: Dry hematology and thromboelastography were equally accurate in diagnosing hypofibrinogenemia, with results correlating well with fibrinogen values measured by the Clauss method.

Diagnostic Tests for Hypofibrinogenemia Resulting from Green Pit Viper (Trimeresurus albolabris) Envenomation: A Simulated In Vitro Study.

INTRODUCTION: The green pit viper (GPV) Trimeresurus albolabris is found in Southeast Asia. Its venom has a thrombin-like activity that can cause hypofibrinogenemia. Fibrinogen measurement is not always available. We aimed to establish a more available diagnostic tool indicating hypofibrinogenemia caused by GPV envenomation. METHODS: This was an in vitro study, in which healthy subjects aged 20 to 45 y were enrolled. There were 2 experiments. In Experiment 1, blood samples from 1 subject had varying amounts of T albolabris venom added to determine its effect on the fibrinogen level (FL). In Experiment 2, 3 sets of blood samples were obtained from another 25 subjects. The 2 venom doses established in Experiment 1 were used on 2 sets of the samples to simulate severe (FL <1.0 g·L-1) and mild hypofibrinogenemia (FL 1.0-1.7 g·L-1). The third set of samples was venom-free. All samples were used for platelet counts, prothrombin time (PT)/international normalized ratio (INR)/activated partial thromboplastin time (aPTT), and 2 bedside clotting tests. Diagnostic parameters were calculated against the target FL of <1.0 g·L-1 and <1.7 g·L-1. RESULTS: Twenty-five subjects were enrolled in Experiment 2. On referencing normal cutoff values (platelet count >150,000 cells/mm3, venous clotting time <15 min, normal 20-min whole blood clotting time, INR <1.2, aPTT <30), we found abnormalities of 5, 0, 0, 3, and 22%, respectively. The highest correlation with hypofibrinogenemia was provided by PT/INR. For an FL of <1.0 g·L-1, PT and INR revealed the highest areas under the receiver operating characteristic curve, 0.76 (95% CI, 0.55-0.97) and 0.76 (95% CI, 0.57-0.97), respectively. The highest accuracy and the highest sensitivity were provided by PT/INR. CONCLUSIONS: PT/INR could be used as a diagnostic test for severe hypofibrinogenemia in GPV envenomation because of its high accuracy and area under the receiver operating characteristic curve.

Misdiagnosis of a patient with congenital dysfibrinogenemia: A case report and literature review.

BACKGROUND: We reported a patient with congenital dysfibrinogenemia who was misdiagnosed and reviewed relevant literature, in order to discuss the methods to reduce misdiagnosis. METHODS: A 23-year-old pregnant woman was found to be with low fibrinogen in antenatal examination at another province teaching hospital, who was misdiagnosed to have hypofibrinogenemia. Fibrinogen infusion or cryoprecipitation was recommended if necessary. The patient came to our hospital for further diagnosis and treatment considering the safety of herself and the fetus. We examined the coagulation function and gene sequencing of the pregnant woman and her family members. RESULTS: Fibrinogen (Clauss method) was significantly reduced in the patient and her mother, while the level of fibrinogen (PT-derived method) was normal. Thrombin time was prolonged. Heterozygous mutation site was found in exon 2 of the FGA gene, c.104G > A(p.Arg35His). CONCLUSION: When the fibrinogen (Clauss method) is significantly reduced and the thrombin time is prolonged, PT-derived method and the investigation of family coagulation function should be added, which can be used to diagnose and distinguish congenital dysfibrinogenemia from hypofibrinogenemia.

An audit of the diagnostic accuracy of the ROTEM®sigma for the identification of hypofibrinogenaemia in cardiac surgical patients.

The ROTEM®delta (TEM Innovations GmbH, Munich, Germany) has been used extensively worldwide for the assessment of coagulation in cardiac surgical patients. Recently, a new cartridge-based ROTEM device (ROTEM®sigma, TEM Innovations GmbH, Munich, Germany) has become available. In this paper we report an audit of the diagnostic accuracy of the ROTEM sigma for the identification of hypofibrinogenaemia in cardiac surgical patients. We hypothesised that the diagnostic accuracy of the ROTEMsigma for the identification of hypofibrinogenaemia would be in a similar range to that previously reported for the ROTEMdelta. Simultaneous blood samples for Clauss laboratory fibrinogen and ROTEMsigma FIBTEM measurements were obtained immediately after heparin reversal post-cardiopulmonary bypass in 200 adult cardiac surgical patients. The sensitivity, specificity, and positive and negative predictive values for FIBTEM A5 and A10 for the identification of hypofibrinogenaemia (Clauss fibrinogen <1.5 g/l) were calculated. The prevalence of hypofibrinogenaemia across the 200 patients was 8%. The mean sensitivity and specificity of FIBTEM A10 ≤8 mm for the identification of hypofibrinogenaemia were 0.75 and 0.90 respectively, which are in a similar range to that reported in several previous studies using the ROTEMdelta. For FIBTEM A5 ≤6 mm the values were 0.63 and 0.98 respectively. The predictive values were also in a similar range to those previously reported for the ROTEMdelta, with low false negative rates (2% for A10 ≤8 mm; 3% for A5 ≤6 mm). These findings support the use of the ROTEMsigma as an alternative to the ROTEMdelta for the identification of hypofibrinogenaemia post-cardiopulmonary bypass in cardiac surgical patients. However, further studies are required in other settings.

Medical Management of a Mural Thrombus Inducing Repeated Ischemic Strokes in a Patient with Congenital Afibrinogenemia.

OBJECTIVES: Congenital afibrinogenemia is an autosomal recessive inherited disorder that can cause thrombotic as well as hemorrhagic events. We describe a case of repeated mild ischemic strokes due to a mural thrombus in the carotid artery and our medical treatment. CASE DESCRIPTION: A 49-year-old woman with congenital afibrinogenemia developed two minor ischemic strokes in two months. Clinical images revealed scattered fresh infarcts in the right middle cerebral artery region and mild cervical carotid artery stenosis. The risk for surgical treatment was considered to be extraordinarily high. The patient was treated with 100 mg/day of aspirin and 3 g fibrinogen infusion every two weeks. After the one-year course of medication, the mural thrombus gradually decreased, and there were no bleeding or ischemic stroke events. CONCLUSION: This case report highlights the successful treatment of an ischemic stroke in a patient with a congenital afibrinogenemia with an antiplatelet agent and fibrinogen replacement. There are no guidelines for managing ischemic stroke in patients with congenital afibrinogenemia, and further studies are needed.

Structural and Functional Characterization of Four Novel Fibrinogen Mutations in FGB Causing Congenital Fibrinogen Disorder.

Congenital fibrinogen disorders are caused by mutations in genes coding for fibrinogen and may lead to various clinical phenotypes. Here, we present a functional and structural analysis of 4 novel variants located in the FGB gene coding for fibrinogen Bß chain-heterozygous missense BßY416C and BßA68S, homozygous nonsense BßY345*, and heterozygous nonsense BßW403* mutations. The cases were identified by coagulation screening tests and further investigated by various methods. Fibrin polymerization had abnormal development with decreased maximal absorbance in all patients. Plasmin-induced fibrin degradation revealed different lytic phases of BßY416C and BßW403* than those of the control. Fibrinopeptide cleavage measured by reverse phase high pressure liquid chromatography of BßA68S showed impaired release of fibrinopeptide B. Morphological properties, studied through scanning electron microscopy, differed significantly in the fiber thickness of BßY416C, BßA68S, and BßW403*, and in the fiber density of BßY416C and BßW403*. Finally, homology modeling of BßA68S showed that mutation caused negligible alternations in the protein structure. In conclusion, all mutations altered the correct fibrinogen function or structure that led to congenital fibrinogen disorders.

[Pedigree Analysis and Diagnosis of Congenital Dysfibrinogenemia: A Case Report].

OBJECTIVE: To improve the understanding and diagnosis and treatment of congenital dysfibrinogenemia (CD) through analyzing the clinical data of a pediatric patient and his pedigree. METHODS: The clinical manifestations, laboratory findings and treatment of a case of CD diagnosed at West China Second University Hospital, Sichuan University and those of its pedigree members were analyzed, and genetic tracing and follow-up were conducted on the patient and its pedigree. RESULTS: The child has no clinical manifestations at the time of admission. Coagulation function examination showed normal prothrombin time (PT), normal activated partial thrombin time (APTT), significantly prolonged thrombin time (TT), fibrinogen activity (Fg: C<0.5 g/L) measured with the Clauss method, and fibrinogen antigen (Fg: Ag) measured at 2.8 g/L with PT algorithm. Gene sequencing results showed that heterozygous missense mutation c.901C>T (p.Arg301Cys) in exon 8 of FGG gene. Combined with the family history, the child was diagnosed with CD. During the follow-up of 4 + months, the patient did not present bleeding, abnormal coagulation or thrombosis, and the coagulation function did not show significant changes compared with the findings obtained on admission. CONCLUSION: The diagnosis of CD is confirmed mainly based on genetic testing and the treatment is characterized by the principle of precise individualized treatment. No special treatment is needed for patients presenting no clinical manifestations. However, it is important to provide thorough prenatal diagnosis and follow-up services for female patients planning for pregnancy so as to prevent miscarriage and complications caused by postpartum coagulation dysfunction.