Congenital fibrinogen disorders: a retrospective clinical and genetic analysis of the Prospective Rare Bleeding Disorders Database.

ABSTRACT: Congenital fibrinogen deficiency (CFD) is a rare bleeding disorder caused by mutations in FGA, FGB, and FGG. We sought to comprehensively characterize patients with CFD using PRO-RBDD (Prospective Rare Bleeding Disorders Database). Clinical phenotypes, laboratory, and genetic features were investigated using retrospective data from the PRO-RBDD. Patients were classified from asymptomatic to grade 3 based on their bleeding severity. In addition, FGA, FGB, and FGG were sequenced to find causative variants. A total of 166 CFD cases from 16 countries were included, of whom 123 (30 afibrinogenemia, 33 hypofibrinogenemia, 55 dysfibrinogenemia, and 5 hypodysfibrinogenemia) were well characterized. Considering the previously established factor activity and antigen level thresholds, bleeding severity was correctly identified in 58% of the cases. The rates of thrombotic events among afibrinogenemic and hypofibrinogenemic patients were relatively similar (11% and 10%, respectively) and surprisingly higher than in dysfibrinogenemic cases. The rate of spontaneous abortions among 68 pregnancies was 31%, including 86% in dysfibrinogenemic women and 14% with hypofibrinogenemia. Eighty-six patients received treatment (69 on-demand and/or 17 on prophylaxis), with fibrinogen concentrates being the most frequently used product. Genetic analysis was available for 91 cases and 41 distinct variants were identified. Hotspot variants (FGG, p.Arg301Cys/His and FGA, p.Arg35Cys/His) were present in 51% of dysfibrinogenemia. Obstetric complications were commonly observed in dysfibrinogenemia. This large multicenter study provided a comprehensive insight into the clinical, laboratory, and genetic history of patients with CFDs. We conclude that bleeding severity grades were in agreement with the established factor activity threshold in nearly half of the cases with quantitative defects.

Little discrepancy between one-stage and chromogenic factor VIII (FVIII)/IX assays in a large international cohort of persons with nonsevere hemophilia A and B.

BACKGROUND: Accurate measurements of coagulation factor activity form an essential part of hemophilia management and are performed by the one-stage or chromogenic assay. Current literature suggests that approximately one-third of persons with nonsevere hemophilia A exhibit assay discrepancy, albeit with a high variability between studies. Such data are scarce in nonsevere hemophilia B. OBJECTIVES: To investigate the extent of factor VIII/IX one-stage and chromogenic assay discrepancy in moderate and mild hemophilia A and B. METHODS: Persons with previously diagnosed nonsevere hemophilia A and B with a factor level of 2 to 35 IU/dL were included from the international DYNAMO cohort study. Central measurements of the factor VIII and IX activity levels were performed by the one-stage and chromogenic assay. Relative and absolute discrepancy definitions were used, with the International Society on Thrombosis and Haemostasis-Scientific and Standardization Committee proposed ratio of >2.0 or <0.5 being the primary outcome. Discrepancy was also evaluated in a subgroup of 13 persons with mutations previously associated with discrepancy (≥3 cases reported in literature). RESULTS: A total of 220 persons were included, of whom 3 (1%) showed assay discrepancy: 2/175 hemophilia A and 1/45 hemophilia B. Six persons (3%) exhibited an absolute difference >10 IU/dL between the assay results. In addition, with more lenient definitions, over 90% of participants (n = 197) had no discrepant results. Only 1 out of 13 persons with a mutation previously associated with discrepancy had significant assay discrepancy. CONCLUSION: Little assay discrepancy was observed despite the presence of mutations previously associated with discrepancy, suggesting that the presence and magnitude of assay discrepancy are largely determined by laboratory variables.

Desmopressin for bleeding in non-severe hemophilia A: Suboptimal use in a real-world setting.

Background: Desmopressin is an important treatment option in nonsevere hemophilia A because it has several benefits compared with factor (F) concentrates, including no inhibitor risk and much lower costs. Despite these advantages, data are limited on the real-world use of desmopressin in the treatment of bleeds. Objective: To describe the clinical use of desmopressin in relation to other therapeutic modalities in the treatment of bleeding episodes in patients with nonsevere hemophilia A. Methods: Patients with nonsevere hemophilia A aged 12-55 years were included from the DYNAMO cohort study. Data on the desmopressin test response and treated bleeding events in the period January 2009 to July 2020 were retrospectively collected from medical files. An adequate desmopressin test response was defined based on a peak FVIII level of ≥30 IU/dl. Results: A total of 248 patients with a median age of 38 years (interquartile range 25-49) were included. An adequate desmopressin test response was documented in 25% and 73% of patients with moderate and mild hemophilia, respectively. In adequate responders, 51% of bleeds were exclusively treated with FVIII concentrates, 24% exclusively with desmopressin, 21% with a combination of both and 4% with other treatments. In 54% of bleeds treated with a single dose of factor concentrates, the expected FVIII level after desmopressin exceeded the level targeted. Conclusion: Most bleeds in patients with an adequate response to desmopressin are treated with factor concentrates. These findings may indicate a suboptimal use of desmopressin and that barriers to the use of desmopressin should be explored.

Von Willebrand disease type 2M: Correlation between genotype and phenotype.

BACKGROUND: An appropriate clinical diagnosis of von Willebrand disease (VWD) can be challenging because of a variable bleeding pattern and laboratory phenotype. Genotyping is a powerful diagnostic tool and may have an essential role in the diagnostic field of VWD. OBJECTIVES: To unravel the clinical and laboratory heterogeneity of genetically confirmed VWD type 2M patients and to investigate their relationship. METHODS: Patients with a confirmed VWD type 2M genetic variant in the A1 or A3 domain of von Willebrand factor (VWF) and normal or only slightly aberrant VWF multimers were selected from all subjects genotyped at the Radboud university medical center because of a high suspicion of VWD. Bleeding scores and laboratory results were analyzed. RESULTS: Fifty patients had a clinically relevant genetic variant in the A1 domain. Median bleeding score was 5. Compared with the nationwide Willebrand in the Netherlands study type 2 cohort, bleeding after surgery or delivery was reported more frequently and mucocutaneous bleedings less frequently. Median VWF activity/VWF antigen (VWF:Act/VWF:Ag) ratio was 0.32, whereas VWF collagen binding activity/VWF antigen (VWF:CB/VWF:Ag) ratio was 0.80. Variants in the A3 domain were only found in two patients with low to normal VWF:Act/VWF:Ag ratios (0.45, 1.03) and low VWF:CB/VWF:Ag ratios (0.45, 0.63). CONCLUSION: Genetically confirmed VWD type 2M patients have a relatively mild clinical phenotype, except for bleeding after surgery and delivery. Laboratory phenotype is variable and depends on the underlying genetic variant. Addition of genotyping to the current phenotypic characterization may improve diagnosis and classification of VWD.

Acrophyseal growth arrest in a long-term survivor of acute lymphoblastic leukemia.

Growth arrest at the secondary growth plate, also known as the acrophysis, is a rare phenomenon with only very few known published case reports. We report on a case of formation of ghost secondary ossification centers at the acrophyses of the knee joint in a 14-year-old female, who survived early childhood acute lymphoblastic leukemia. The patient suffered from severe side effects from both disease and subsequent treatment strategies with a 10-month immobilization period as a consequence at the age of 3 years. The ghost secondary ossification centers were encountered on radiographs and MRI 10 years later, when she presented for evaluation of chronic pain in her left knee related to sports activities, due to a meniscal cyst. Awareness of this phenomenon is nevertheless important, because it seems that endochondral bone growth recovery at the acrophyses might be different from recovery in physes, because we found no concomitant sequelae of growth arrest in the metaphyses.

Discontinuation of imatinib in children with chronic myeloid leukaemia in sustained deep molecular remission: results of the STOP IMAPED study.

This international study aimed to assess the effect of imatinib discontinuation in paediatric patients with chronic myeloid leukaemia (CML) after deep molecular remission (DMR) had been achieved and maintained for at least 2 years. The primary endpoint of this analysis was the molecular relapse-free survival, estimated by the non-parametric Kaplan-Meier method. Major endpoint was the estimated rate of patients without molecular relapse at 6 months. Fourteen patients were enrolled; 4 patients maintained DMR with a follow-up of 24 (two patients), 34 and 66 months, respectively, whereas 10 patients relapsed. All molecular relapses occurred within 6 months (median 3 months, range 1-6) after imatinib discontinuation. The overall probability of maintaining DMR at 6 months was 28·6%. No parameters associated with molecular relapse could be identified. Keeping in mind the rarity of paediatric CML, which contributed to the small size of the cohort, our findings illustrate that imatinib cessation after sustained DMR is successful in only limited numbers of patients, whereas much higher rates are reported in adult patients. Further research is needed to extend the cohort of paediatric CML patients who might achieve treatment-free remission with an ideal prerequisite of predicting the occurrence of molecular relapse l after imatinib cessation.

Whole exome sequencing in the diagnostic workup of patients with a bleeding diathesis.

INTRODUCTION: Bleeding assessment tools and laboratory phenotyping often remain inconclusive in patients with a haemorrhagic diathesis. AIM: To describe the phenotype and genetic profile of patients with a bleeding tendency. METHODS: Whole exome sequencing (WES) was incorporated in the routine diagnostic pathway of patients with thrombocytopenia (n = 17), platelet function disorders (n = 19) and an unexplained bleeding tendency (n = 51). The analysis of a panel of 126 OMIM (Online Mendelian Inheritance in Man) genes involved in thrombosis and haemostasis was conducted, and if negative, further exome-wide analysis was performed if informed consent given. RESULTS: Eighteen variants were detected in 15 patients from a total of 87 patients (17%). Causative variants were observed in MYH9 (two cases), SLFN14, P2RY12 and GP9. In addition, one case was considered solved due to combined carriership of F7 and F13A1 variants and one with combined carriership of F2, F8 and VWF, all variants related to secondary haemostasis protein aberrations. Two variants of uncertain significance (VUS) were found in two primary haemostasis genes: GFI1B and VWF. Eight patients were carriers of autosomal recessive disorders. Exome-wide analysis was performed in 54 cases and identified three variants in candidate genes. CONCLUSION: Based on our findings, we conclude that performing WES at the end of the diagnostic trajectory can be of additive value to explain the complete bleeding phenotype in patients without a definite diagnosis after conventional laboratory tests. Discovery of combinations of (novel) genes that predispose to bleeding will increase the diagnostic yield in patients with an unexplained bleeding diathesis.

Iron refractory iron deficiency anemia: a heterogeneous disease that is not always iron refractory.

TMPRSS6 variants that affect protein function result in impaired matriptase-2 function and consequently uninhibited hepcidin production, leading to iron refractory iron deficiency anemia (IRIDA). This disease is characterized by microcytic, hypochromic anemia and serum hepcidin values that are inappropriately high for body iron levels. Much is still unknown about its pathophysiology, genotype-phenotype correlation, and optimal clinical management. We describe 14 different TMPRSS6 variants, of which 9 are novel, in 21 phenotypically affected IRIDA patients from 20 families living in the Netherlands; 16 out of 21 patients were female. In 7 out of 21 cases DNA sequencing and multiplex ligation dependent probe amplification demonstrated only heterozygous TMPRSS6 variants. The age at presentation, disease severity, and response to iron supplementation were highly variable, even for patients and relatives with similar TMPRSS6 genotypes. Mono-allelic IRIDA patients had a milder phenotype with respect to hemoglobin and MCV and presented significantly later in life with anemia than bi-allelic patients. Transferrin saturation (TSAT)/hepcidin ratios were lower in IRIDA probands than in healthy relatives. Most patients required parenteral iron. Genotype alone was not predictive for the response to oral iron. We conclude that IRIDA is a genotypically and phenotypically heterogeneous disease. The high proportion of female patients and the discrepancy between phenotypes of probands and relatives with the same genotype, suggest a complex interplay between genetic and acquired factors in the pathogenesis of IRIDA. In the absence of inflammation, the TSAT/hepcidin ratio is a promising diagnostic tool, even after iron supplementation has been given. Am. J. Hematol. 91:E482-E490, 2016. © 2016 Wiley Periodicals, Inc.

Maturation toward neuronal tissue in a Ewing sarcoma of bone after chemotherapy.

BACKGROUND: Ewing sarcoma is the second most common bone tumor, occurring mainly in children and young adults. It shows a typical primitive, small round cell morphology and a characteristic fusion oncogene involving EWSR1 and members of the ETS family in most of the cases. Neuronal maturation after chemotherapy is a rare phenomenon and we herein describe such an exceptional case. CASE PRESENTATION: An 8-year old boy was diagnosed with a Ewing sarcoma in the left femur. On biopsy the morphology was typical and there was an EWSR1-FLI1 gene fusion. He underwent neo-adjuvant chemotherapy and resection of the tumor. On microscopic evaluation, part of the tumor showed ganglioneuroblastoma-like differentiation with expression of neuronal markers. The continued presence of EWSR1 rearrangement in both the blue round cell component and the ganglioneuroblastoma-like component was shown by FISH analysis. CONCLUSIONS: In conclusion, this case describes the possibility of a Ewing sarcoma to differentiate into a ganglioneuroblastoma-like lesion after neo-adjuvant chemotherapy treatment; the prognostic value of this phenomenon remains questionable.

Bleeding spectrum in children with moderate or severe von Willebrand disease: Relevance of pediatric-specific bleeding.

The bleeding phenotype of children with von Willebrand disease (VWD) needs to be characterized in detail to facilitate diagnosis during childhood and aid in the planning and assessment of treatment strategies. The objective was to evaluate the occurrence, type, and severity of bleeding in a large cohort of children with moderate and severe VWD. We included 113 children (aged 0-16 years) with Type 1 (n = 60), 2 (n = 44), and 3 (n = 9) VWD with von Willebrand factor (VWF) antigen and/or VWF ristocetin cofactor levels ≤ 30 U/dL from a nation-wide cross-sectional study ("Willebrand in the Netherlands" study). Bleeding severity and frequency were determined using the International Society on Thrombosis and Hemostasis-Bleeding Assessment Tool (ISTH-BAT) with supplementary pediatric-specific bleeding symptoms (umbilical stump bleeding, cephalohematoma, cheek hematoma, conjunctival bleeding, postcircumcision and postvenipuncture bleeding). We found that all 26 postmenarche girls experienced menorrhagia. Other common bleedings were cutaneous (81%), oropharyngeal (64%), prolonged bleeding from minor wounds (58%), and epistaxis (56%). Pediatric-specific bleeding symptoms were present in 44% of patients. ISTH-BAT bleeding score was higher in index cases than in affected family members (median, 12.0 vs. 6.5, P < 0.001), higher in Type 3 VWD than in Type 2 or 1 (17.0 vs. 10.5 or 6.5, P < 0.001) and higher in children with severe (<10 U/dL) than moderate VWD (10-30 U/dL) (11.0 vs. 7.0, P < 0.001). Frequency of any bleeding, epistaxis, and oral cavity was higher in types 2 and 3 than in Type 1 VWD and was associated with VWF levels. We conclude that pediatric-specific bleeding symptoms occurred in a large proportion of children with moderate or severe VWD and should be included when evaluating children for VWD.

Practice guidelines for the diagnosis and management of microcytic anemias due to genetic disorders of iron metabolism or heme synthesis.

During recent years, our understanding of the pathogenesis of inherited microcytic anemias has gained from the identification of several genes and proteins involved in systemic and cellular iron metabolism and heme syntheses. Numerous case reports illustrate that the implementation of these novel molecular discoveries in clinical practice has increased our understanding of the presentation, diagnosis, and management of these diseases. Integration of these insights into daily clinical practice will reduce delays in establishing a proper diagnosis, invasive and/or costly diagnostic tests, and unnecessary or even detrimental treatments. To assist the clinician, we developed evidence-based multidisciplinary guidelines on the management of rare microcytic anemias due to genetic disorders of iron metabolism and heme synthesis. These genetic disorders may present at all ages, and therefore these guidelines are relevant for pediatricians as well as clinicians who treat adults. This article summarizes these clinical practice guidelines and includes background on pathogenesis, conclusions, and recommendations and a diagnostic flowchart to facilitate using these guidelines in the clinical setting.

Subcutaneous protein C concentrate in the management of severe protein C deficiency--experience from 12 centres.

Since the first description of subcutaneous protein C concentrate as treatment for severe protein C deficiency in 1996, further cases have been reported but there is no uniform approach to this form of treatment. In order to assess the safety and effectiveness of subcutaneous protein C concentrate and suggest recommendations for future use, patients who had received subcutaneous protein C concentrate were identified from the literature, by contacting the manufacturers and by personal communication. Treatment details were available from 14 cases. Apart from one case where the infusion interval was inadvertently increased, no thrombotic events occurred even when doses were subsequently reduced. Initially, a trough protein C level of >0·25 iu/ml should be aimed for. Subsequently, a smaller dose of subcutaneous protein C concentrate, especially if taken with an oral anticoagulant, may be protective maintenance treatment. The treatment was well tolerated with few side effects. Subcutaneous protein C concentrate on its own or combined with an oral anticoagulant appears to be safe and effective as maintenance treatment of severe protein C deficiency. A major advantage is the avoidance of central venous access devices. The incidence of neurodevelopmental handicap was high with blindness affecting the majority of patients.

Factor VIII gene (F8) mutation and risk of inhibitor development in nonsevere hemophilia A.

Neutralizing antibodies (inhibitors) toward factor VIII form a severe complication in nonsevere hemophilia A, profoundly aggravating the bleeding pattern. Identification of high-risk patients is hampered by lack of data that take exposure days to therapeutic factor VIII concentrates into account. In the INSIGHT study, we analyzed the association between F8 mutation and inhibitor development in patients with nonsevere hemophilia A (factor VIII 2-40 IU/dL). This analysis included 1112 nonsevere hemophilia A patients from 14 centers in Europe and Australia that had genotyped at least 70% of their patients. Inhibitor risk was calculated as Kaplan-Meier incidence with cumulative number of exposure days as the time variable. During 44 800 exposure days (median, 24 exposure days per patient; interquartile range [IQR], 7-90), 59 of the 1112 patients developed an inhibitor; cumulative incidence of 5.3% (95% confidence interval [CI], 4.0-6.6) after a median of 28 exposure days (IQR, 12-71). The inhibitor risk at 50 exposure days was 6.7% (95% CI, 4.5-8.9) and at 100 exposure days the risk further increased to 13.3% (95% CI, 9.6-17.0). Among a total of 214 different F8 missense mutations 19 were associated with inhibitor development. These results emphasize the importance of F8 genotyping in nonsevere hemophilia A.

The challenge of managing hemophilia A and STEC-induced hemolytic uremic syndrome.

BACKGROUND: The hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy leading to acute kidney injury in children. In most cases it is triggered by an infection caused by Shiga-like toxin-producing Escherichia coli (STEC). Endothelial damage plays a central role in the pathogenesis of disease. Hemophilia A is a genetic disorder leading to factor VIII (FVIII) deficiency, an important factor in the coagulation system. CASE: Here we describe a hemophilia A patient who developed HUS due to a STEC O26 infection. The patient developed not only acute kidney injury, but also severe gastro-intestinal and neurological complications. Increased amounts of recombinant FVIII (rFVIII) had to be administered during the acute phase of the disease to reach acceptable blood levels of FVIII, in order to control the hemorrhagic colitis and to prevent severe neurological complications. CONCLUSION: The patient's treatment schedule of rFVIII during the HUS period was a serious challenge, and we cannot exclude that it contributed to the severity of the HUS by enhancing the thrombotic microangiopathic process. The role of factor VIII administration in the severe outcome of this disease is discussed.

The influence of patient reported outcomes on the discussion of psychosocial issues in children with cancer.

BACKGROUND: This study investigates the effect of using patient reported outcomes (PROs) about health-related quality of life (HRQOL) in clinical practice on the type and amount of psychosocial topics discussed during a paediatric oncology consultation. PROCEDURE: Children (N = 193) with cancer participated in a sequential cohort intervention study, with a control (no PRO was used) and intervention group (a PRO was used). For each child three consecutive consultations with the paediatric oncologist were audio recorded in order to assess the discussed psychosocial topics. One third of the audio recordings were qualitatively analysed. RESULTS: The type of the discussed psychosocial topics in the control and intervention group did not differ from each other. However, the discussion of psychosocial topics increased in the intervention group compared to the control group. In both groups, topics within the social domain occurred most frequently and topics regarding the emotional domain had the lowest incidence. CONCLUSIONS: PROs do not change the psychosocial content of communication. Paediatric oncologists already address psychosocial issues during the consultation, regardless of the use of a PRO. However, with a PRO available they address these issues more systematically and more often.

A novel hemostasis assay for the simultaneous measurement of coagulation and fibrinolysis.

Thrombin and plasmin are the key enzymes involved in coagulation and fibrinolysis. A novel hemostasis assay (NHA) was developed to measure thrombin and plasmin generation in a single well by a fluorimeter. The NHA uses two fluorescent substrates with non-interfering fluorescent excitation and emission spectra. The assay was tested in vitro using modulators like heparin, hirudin, epsilon-aminocaproic acid, gly-pro-arg-pro peptide and reptilase and validated by measurement of prothrombin fragment 1+2 and plasmin-alpha2-antiplasmin levels. Intra- and inter-assay coefficients of variation were < 9% and 6-25%, respectively. Interplay between coagulation and fibrinolysis was demonstrated by the effect of tissue-type plasminogen activator on thrombin generation and by the different responses of activated protein C and thrombomodulin on fibrinolysis. The last responses showed the linkage between coagulation and fibrinolysis by thrombin activatable fibrinolysis inhibitor. In conclusion, this strategy allows detection of coagulation, fibrinolysis and their interplay in a single assay.

Long-term subcutaneous protein C replacement in neonatal severe protein C deficiency.

We describe here the case of a boy who presented 2 days after birth with purpura fulminans on his feet and scalp. Laboratory investigations revealed signs of disseminated intravascular coagulation. An underlying coagulation disorder was suspected, and therapy with recombinant tissue plasminogen activator, fresh-frozen plasma, and unfractionated heparin was started. On the basis of plasma protein C activity and antigen levels of 0.02 and 0.03 IU/mL, respectively, after administration of fresh-frozen plasma, a diagnosis of severe protein C deficiency was established, and therapy with intravenous protein C concentrate (Ceprotin [Baxter, Deerfield, IL]) was started. Because of difficulties with venous access, we switched to subcutaneous administration after 6 weeks. The precise dosing schedule for subcutaneously administered protein C concentrate is unknown. In the literature, a trough level of protein C activity at >0.25 IU/mL is recommended to prevent recurrent thrombosis. During 1 year of follow-up our patient frequently had protein C activity levels at <0.25 IU/mL. Clinically, however, there was no recurrent thrombosis, and we kept the dosage unchanged. This report highlights 2 important points: (1) subcutaneously administered protein C concentrate is effective in treating severe protein C deficiency; and (2) in accordance with previous studies, after the acute phase trough levels of protein C activity at >0.25 IU/mL may not be necessary to prevent recurrent thrombosis. However, further research on the dosing, efficacy, and safety of protein C concentrate for prophylaxis and treatment of severe protein C deficiency is needed.