We have evaluated the position of the Platelet Function Analyzer PFA‐100TM in the management of 41 patients with von Willebrand disease (VWD) receiving either desmopressin (23 patients with type 1, five with type 2M, three with type 2A and three with type 2B) or von Willebrand factor (VWF) concentrates (four patients with type 3, two with type 2M ‘type B’, two with type 2A and one type 1 ‘platelet low’). In all patients the following were studied before and 30 min after infusion of desmopressin and/or VWF concentrates: VWF ristocetin cofactor activity (VWFRCo), bleeding time (BT) and closure time with the PFA‐100 using ADP (CT‐ADP) as well as epinephrine (CT‐Epi) cartridges. After the infusion of desmopressin, the CT was modified in the same way as the VWFRCo levels, being always normalized in patients with type 1 and not constantly corrected in those with type 2. Thus, our results indicated that the measurement of the CT enabled a quick and accurate evaluation of the response to desmopressin which, in fact, measured the releasable VWF cellular compartment containing the highly multimerized forms of VWF. For patients with type 2 or 3 VWD who were non‐responsive to desmopressin, VWF concentrates corrected the VWFRCo defect but not the CT as none of these patients had a normal platelet VWF content and the VWF concentrates did not contain the ultralarge VWF multimers. In conclusion, the very high shear conditions in the PFA‐100 make it very sensitive to the contribution of platelet VWF and to the ultralarge VWF multimers, indicating that the evaluation of the CT is a very simple and rapid tool to discriminate between good and non‐responders to desmopressin.
To cite this article: Trossaë rt M, Regnault V, Sigaud M, Boisseau P, Fressinaud E, Lecompte T. Mild hemophilia A with factor VIII assay discrepancy: using thrombin generation assay to assess the bleeding phenotype. J Thromb Haemost 2008; 6: 486-93.
To cite this article: Que  lin F, Trossae È rt M, Sigaud M, Mazancourt PDE, Fressinaud E. Molecular basis of severe factor XI de®ciency in seven families from the west of France. Seven novel mutations, including an ancient Q88X mutation. J Thromb Haemost 2004; 2: 71±6.Summary. Inherited factor (F)XI de®ciency is a rare disorder in the general population, though it is commonly found in individuals of Ashkenazi Jewish ancestry. In particular, two mutationsÐa stop mutation (type II) and a missense mutation (type III)Ðwhich are responsible for FXI de®ciency, predominate. The bleeding tendency associated with plasma FXI de®-ciency in patients is variable, with $50% of patients exhibiting excessive post-traumatic or postsurgical bleeding. In this study, we identi®ed the molecular basis of FXI de®ciency in 10 patients belonging to six unrelated families of the Nantes area in France and one family of Lebanese origin. As in Ashkenazi Jewish or in French Basque patients, we have identi®ed a new ancient mutation in exon 4 resulting in Q88X, speci®c to patients from Nantes, that can result in a severely truncated polypeptide. Homozygous Q88X was found in a severely affected patient with an inhibitor to FXI and in three other unrelated families, either as homozygous, heterozygous or compound heterozygous states. Other identi®ed mutations are two nonsense mutations in the FXI gene, in exon 7 and 15, resulting in R210X and C581X, respectively, which were identi®ed in three families. A novel insertion in exon 3 (nucleotide 137 G), which causes a stop codon, was characterized. Finally, sequence analysis of all 15 exons of the FXI gene revealed three missense mutations resulting in G336R and G350A (exon 10) and T575M (exon 15). Two mutations (T575M and G350A) with discrepant antigen and functional values are particularly interesting because most of the described mutations are associated with the absence of secreted protein.
To cite this article: Trossaë rt M, Boisseau P, Qué mé ner A, Sigaud M, Fouassier M, Ternisien C, Lefranç ois-Bettembourg A, Tesson C, Thomas C, Bezieau S. Prevalence, biological phenotype and genotype in moderate/mild hemophilia A with discrepancy between one-stage and chromogenic factor VIII activity. J Thromb Haemost 2011; 9: 524-30. Summary. Background: In most laboratories, the severity of hemophilia A is assessed by the factor VIII activity (FVIII:C) one-stage assay. However, comparisons of these results with those of two-stage assays can reveal discrepancies and suggest misdiagnosis. Patients/Methods: In this monocentric study, we measured FVIII:C with two methods (one-stage chronometric and chromogenic assays) in 307 (173 families) patients with moderate/mild hemophilia A. To compare results, we used a chronometric/chromogenic ratio. Discrepancy was defined as a ratio < 0.5 or > 1.5. We studied their putative involvement at known FVIII functional sites, their interspecies conservation status, and their spatial position within the FVIII structure. Results: Thirty-six patients from 17 families exhibited a discrepancy between the two assays: 12 (6.9%) families had a low ratio (< 0.5), and five (2.9%) families had a high ratio (> 1.5). Qualitative deficiency was diagnosed in about 16% of the families. Molecular studies were performed in 15 of these 17 families, resulting in each case in the identification of missense mutations, including three novel mutations. We were further able to propose a pathophysiologic explanation. Conclusions: In this monocentric study, we have demonstrated a discrepancy between FVIII:C assay results in 10% of families with moderate/mild hemophilia A. The prevalence of ÔinverseÕ discrepancy (i.e. low chronometric/chromogenic ratio) is high as compared with previous reports. We suggest that both FVIII:C assays are recommended in patients with moderate/mild hemophilia A for a complete biological phenotype. This could also improve our knowledge of the FVIII structure-function relationships.
Thirty per cent of patients with mild haemophilia A (MHA) present markedly different FVIII: C level when assayed by one-stage clotting and two-stage chromogenic assays. It is, therefore, a real clinical challenge to predict the individual bleeding risk of these patients. The aim of the present work was to study the relationship between the bleeding tendency of these patients with the results of a panel of phenotypic and genotypic tools. Thirty-six patients with MHA were included in this multicentre prospective clinical study. The severity of bleeding symptoms was evaluated using the ISTH/SSC score. FVIII:C levels were measured using an activated partial thromboplastin time-based one-stage FVIII assay (FVIII: C1) and three commercial chromogenic kits (FVIII:CR). FVIII antigen levels, thrombin generation measurement and FVIII gene mutation analysis were also performed. Our results showed that a one-stage FVIII: C assay cannot rule out the diagnosis of MHA, a combined use of FVIII:C1 with a FVIII:CR is suitable for detecting MHA. We observed that FVIII:CR results better reflected the clinical bleeding tendency of patients compared to FVIII:C1. We also observed a relationship between thrombin generation (TG) capacity and FVIII:CR of these patients. FVIII gene mutation analysis showed mutations previously reported in MHA patients with discrepant FVIII:C measurements, but with no predictive value of the individual bleeding phenotype of patients. Overall, we observed a relationship between chromogenic FVIII:C results, TG assay and bleeding tendency of patients with discrepant FVIII:C measurements, while FVIII:C1 was not well correlated with clinical bleeding phenotype in this particular population.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.