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Factor VIII Gene (factor + viii_gene)
Selected AbstractsFactor VIII gene (F8) mutations as predictors of outcome in immune tolerance induction of hemophilia A patients with high-responding inhibitorsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2009A. COPPOLA Summary.,Background:, Immune tolerance induction (ITI) is the only therapeutic approach that can eradicate factor VIII (FVIII) inhibitors in patients with hemophilia A. Predictors of ITI outcome are still debated, and the role of F8 gene mutations in this is not well established. Objectives: To investigate the relationship between F8 genotype and ITI outcome in patients with severe hemophilia A and high-responding inhibitors. Patients and Methods:F8 mutations were identified in 86 patients recruited as part of the Italian ITI registry (the PROFIT study). ITI outcome was centrally reviewed according to the following definitions: success (undetectable inhibitor and normal FVIII pharmacokinetics), partial success (inhibitor titer < 5 BU mL,1 and/or abnormal FVIII pharmacokinetics), and failure. Results:F8 mutations known to be associated with a high risk of inhibitor development (large deletions, inversions, nonsense mutations and splice site mutations) were found in 70 patients (81%); among these, the intron 22 inversion was present in 49 patients (57%). In 16 patients (19%) lower-risk F8 defects (small insertions/deletions and missense mutations) were identified. The latter group of patients showed a significantly higher ITI success rate than those carrying high-risk mutations [13/16 (81%) vs. 33/70 (47%); risk ratio 1.7, 95% confidence interval (CI) 1.1,2.1, P = 0.01]. On multivariate analysis, the mutation risk class remained a significant predictor of success [adjusted odds ratio (OR) 6.2, 95% CI 1.1,36.0, P = 0.04], as were inhibitor titer at ITI start (< 5 BU mL,1, OR 11.8, 95% CI 3.5,40.2, P < 0.001), and peak titer during ITI (< 100 BU mL,1, OR 11.4, 95% CI 3.2,40.8, P < 0.001). Conclusions: ITI success is influenced by F8 genotype. This knowledge should contribute to the stratification of prognosis, and to the clinical choices made for ITI in patients with high-responding inhibitors. [source] Study of mutations in Jordanian patients with haemophilia A: identification of five novel mutationsHAEMOPHILIA, Issue 1 2010A. AWIDI Summary., Haemophilia A (HA) is an X-linked recessive bleeding disorder caused by mutations in the factor VIII gene (F8), which encodes factor VIII (FVIII) protein, a plasma glycoprotein, that plays an important role in the blood coagulation cascade. In the present study, our aim was to identify F8 gene mutations in HA patients from Jordan. One hundred and seventy-five HA patients from 42 unrelated families were included in this study. Among these patients, 117 (67%) had severe HA, 13 (7%) had moderate HA and 45 (26%) had mild HA. Severe patients were first tested for intron-22 inversion using long range polymerase chain reaction (PCR), then negative patients were tested for intron-1 inversion using PCR. Sequencing for the entire F8 gene was performed for all severe HA patients who were found negative for intron-22 and -1 inversions and it was also performed for moderate and mild HA patients. HA causative mutations were identified in all patients. Intron-22 and -1 inversions were detected in 52% and 2% of families respectively. Beside these two mutations, 19 different mutations were identified, which include 15 missense and four frameshift mutations. Five novel mutations were identified including one frameshift and four missense mutations. No large deletions or nonsense mutations were detected in patients who participated in this study. Only 17 patients with severe HA were found positive for FVIII inhibitors. The data presented will play an important role for genetic counselling and health care of HA patients in Jordan. [source] Spectrum of mutations in Albanian patients with haemophilia A: identification of ten novel mutations in the factor VIII geneHAEMOPHILIA, Issue 3 2007G. CASTAMAN Summary., Genetic analysis was carried out in 37 Albanian patients with haemophilia A. The factor VIII intron 22 inversion was detected only in 2/19 (10.5%) apparently unrelated patients with severe haemophilia A, while the intron 1 inversion was absent. A total of 19 different gene mutations were identified. Ten mutations were novel: four null mutations in severe haemophilia A patients (Gln1090X, Cys1832X, 2374delT, 5676insT) and six missense mutations (five in severe haemophilia A) (Ile76Thr, Leu299Pro, Asp525Glu, Cys692Tyr, His1755Leu and Trp1835Cys). None of these novel mutations occurred at CpG hotspots. These results further emphasize the extreme heterogeneity of the molecular basis of haemophilia A. The low prevalence of intron 22 inversion in Albanian patients with severe haemophilia A should be addressed by further studies. [source] A highly informative, multiplexed assay for the indirect detection of hemophilia A using five-linked microsatellitesJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2006J. R. HARRAWAY Summary.,Background:,Hemophilia A is a severe bleeding disorder caused by almost 1000 different known mutations in the F8C gene. Direct mutation analysis is sometimes difficult for this disorder. When a mutation cannot be found, linkage analysis can be used for prenatal and carrier diagnosis. Aim:,To develop a rapid and effective system for carrier detection and prenatal diagnosis of hemophilia A based on a single-multiplexed polymerase chain reaction (PCR) reaction utilizing five microsatellite markers. Patients and methods:,Two intronic microsatellites and three other markers flanking the factor VIII gene were ascertained, and primers were designed for multiplex PCR amplification. A kindred with Hemophilia A was tested for linkage using the panel of primers, and informativity in the general population was ascertained by testing 50 unrelated females. Results:,Co-amplification of all microsatellites was optimized using DNA extracted by standard methods. Rapid detection and sizing of products were carried out using an automated DNA sequencer. The combined microsatellite panel was informative in each of the kindreds tested, and in 100% of the 50 unrelated females (95% CI 94.2,100%). Conclusions:,This method enables the indirect detection of hemophilia A for patients in whom mutations cannot be found, facilitating carrier testing and prenatal analysis. It is rapid and straightforward compared with many other published protocols, and offers a high degree of informativity. [source] Analysis of mRNA in hemophilia A patients with undetectable mutations reveals normal splicing in the factor VIII geneJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 2 2005O. EL-MAARRI Summary.,Background: haemophilia A (HA) is characterized by partial or total deficiency of factor VIII (FVIII) protein activity. It is caused by a broad spectrum of mutations in the FVIII gene. Despite tremendous improvements in mutation screening methods, in about 2% of HA patients no DNA change could be found, even after sequencing the whole coding part of the FVIII gene including the flanking splice sites, as well as the promotor and the 3, UTR regions. Objectives, patients and methods: In the present study we performed a detailed RNA analysis of three groups of patients. The first included control patients with known splicing defects, the second included two patients with already identified nucleotide changes close to splicing sites, that could potentially alter the normal splicing process, and a third group of 11 unrelated patients whose genomic DNA have already been screened for mutations by DHPLC and direct sequencing with no mutation being identified. Results: Both candidate splice site mutations were shown to result in either skipping or alternative splicing of at least one exon, therefore these DNA changes must be considered as causal for the patients' HA phenotype. In contrast, no abnormalities on the RNA level were observed in any of 11 unrelated patients without mutations in the FVIII gene. Conclusions: These findings exclude mutations that could be located deep in the introns and affecting either normal splicing or lead to mechanisms causing some unknown rearrangements of the FVIII gene. In fact, our results point to the presence of still unknown factor(s) causing HA, which might be either allelic or in the close proximity of the FVIII gene or non-allelic associated with other genetic loci that are involved in the processing of the FVIII protein. [source] Sustained transgene expression by human cord blood derived CD34+ cells transduced with simian immunodeficiency virus agmTYO1-based vectors carrying the human coagulation factor VIII gene in NOD/SCID miceTHE JOURNAL OF GENE MEDICINE, Issue 10 2004Jiro Kikuchi Abstract Background An Erratum has been published for this article in Journal of Gene Medicine 7(6), 2005, 836. Gene therapy is being studied as the next generation therapy for hemophilia and several clinical trials have been carried out, albeit with limited success. To explore the possibility of utilizing autologous bone marrow transplantation of genetically modified hematopoietic stem cells for hemophilia gene therapy, we investigated the efficacy of genetically engineered CD34+ cell transplantation to NOD/SCID mice for expression of human factor VIII (hFVIII). Methods CD34+ cells were transduced with a simian immunodeficiency virus agmTYO1 (SIV)-based lentiviral vector carrying the enhanced green fluorescent protein (eGFP) gene (SIVeGFP) or the hFVIII gene (SIVhFVIII). CD34+ cells transduced with SIV vectors were transplanted to NOD/SCID mice. Engraftment of transduced CD34+ cells and expression of transgenes were studied. Results We could efficiently transduce CD34+ cells using the SIVeGFP vector in a dose-dependent manner, reaching a maximum (99.6 ± 0.1%) at MOI of 5 × 103 vector genome/cell. After transducing CD34+ cells with SIVhFVIII, hFVIII was produced (274.3 ± 20.1 ng) from 106 CD34+ cells during 24 h in vitro incubation. Transplantation of SIVhFVIII-transduced CD34+ cells (5,10 × 105) at a multiplicity of infection (MOI) of 50 vector genome/cell into NOD/SCID mice resulted in successful engraftment of CD34+ cells and production of hFVIII (minimum 1.2 ± 0.9 ng/mL, maximum 3.6 ± 0.8 ng/mL) for at least 60 days in vivo. Transcripts of the hFVIII gene and the hFVIII antigen were also detected in the murine bone marrow cells. Conclusions Transplantation of ex vivo transduced hematopoietic stem cells by non-pathogenic SIVhFVIII without exposure of subjects to viral vectors is safe and potentially applicable for gene therapy of hemophilia A patients. Copyright © 2004 John Wiley & Sons, Ltd. [source] A missense mutation (p.Leu2153His) of the factor VIII gene causes cattle haemophilia AANIMAL GENETICS, Issue 5 2009M. Khalaj Summary Two cases of hereditary bleeding disorder diagnosed as haemophilia A were recently observed in Japanese Brown cattle. We sequenced the entire coding region of the factor VIII gene of the affected animals to find a causative mutation. A nucleotide substitution of T to A resulting in an amino acid substitution of leucine to histidine (p.Leu2153His) was identified in a highly conserved residue in the C1 domain of factor VIII. Genotyping of 254 normal animals including the pedigree of the affected animals and randomly sampled animals of different breeds confirmed that the substitution is the causative mutation of cattle haemophilia A. [source] | |||||||||||||