Genotype-Phenotype Interaction Analyses in Hemophilia (original) (raw)
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J Mol Genet Med , 2016
Background: Hemophilia A is an X-linked bleeding disorder caused by mutations in the factor VIII gene (F8C). Molecular testing for the factor VIII gene is difficult due to its large size. More than 1000 different mutations have been described in factor VIII gene. In this study we have investigated the factor VIII gene mutations in Saudi Arabian population. Methods: For genotyping factor VIII cohorts of 110 samples from Saudi Arabian patients undergoing treatment for hemophilia A were collected. All patients were tested for factor VIII coagulant activity on Behring Coagulation System. Genomic DNA was isolated from blood on MagNapure system. Screening for inv-1 was done by multiplex PCR method, and inv-22 was done by ligation (inverse) PCR method. DNA sequencing was performed by Sanger method for all 26 exons of factor VIII gene. PCR products were sequenced on ABI 3500 Genetic analyzer. For molecular simulations we have used softwares such as CHARMM and GROMACS v4.0.527. In order to predict the possible impact of a variation on the function of factor VIII gene the online tools Polyphen 2, and SIFT were used. Results: Out of 110 cases screened, 2 patients were positive (affected) for inv-1 and 15 patients were positive (12 affected and 3 carriers) for inv-22. Out of 32 cases sequenced for coding exons, 2 novel mutations were found, one novel missense mutation c.355G>C, p. (A119P) in exon 3, and another novel frame shift mutation c.6482delC, p.(P2161Lfs*25) in exon 23. Also known mutations such as, c.409 A>C, p. (T137P) in 2 individual patients in exon 4, another known mutation c.1804C>T, p.(R602*) in 1 patient in exon 12 were found. Genotype-phenotype correlations and computer prediction analysis on these novel mutations and the secondary structure analysis of the factor VIII protein were performed, and compared with the predicted native proteins. Conclusions: These novel mutations in factor VIII gene and molecular dynamic simulation results to appropriately predict the deleterious effects of these mutations are presented in this study. In addition, for the native and mutant proteins models, the amino acid residues and its secondary structures were determined. Our In-silico study suggests that these mutations have significant impact on the structure and function of the factor VIII protein.
Molecular genetics of hemophilia A: Clinical perspectives
Egyptian Journal of Medical Human Genetics, 2010
Since the publication of the sequence of the factor VIII (F8) gene in 1984, a large number of mutations that cause hemophilia A have been identified and a significant progress has been made in translating this knowledge for clinical diagnostic and therapeutic purposes. Molecular genetic testing is used to determine the carrier status, for prenatal diagnosis, for prediction of the likelihood of inhibitor development, and even can be possibly used to predict responsiveness to immune tolerance induction. Phenotypic heterogeneity of hemophilia is multifactorial, mainly related to F8 mutation but other factors contribute especially to coinheritance of prothrombotic genes. Inhibitor development is mainly related to F8 null mutations, but other genetic and non genetic factors could contribute. This review will focus on the genetic aspects of hemophilia A and their application in the clinical setting and the care of patients and their families.
Recent scenario on the genetic abnormalities in patients suffering from Haemophilia A: A review
This review aims at compiling the different mutational changes undergone by the factor VIII gene leading to hemophilia A. It has been difficult to characterize completely a genetic disorder like hemophilia A where the gene of concerns is large, its tissue-specific expression, and all affected individuals have different mutational patterns. In this review, point mutational, insertional and deletional patterns are sited. The data are collected from all round the world, although "Western" sources are predominate.
Blood, 2013
Phenotypic variability is well recognized in severe hemophilia A. A few studies, mainly in adults treated lifelong on demand, suggest that bleeding phenotype correlates with factor VIII gene (F8) mutation type. Because treatment regimens influence outcomes to a large extent, examining bleeding phenotype during the first years of life may be the most suitable way to define this variability. We set out to analyze the very early phenotypic expression of severe hemophilia A in 621 consecutively enrolled, well-characterized previously untreated patients and to correlate this with patients' F8 mutation. Detailed information was collected on bleeds and treatment of the first 75 exposure days or until inhibitor development. F8 mutation type was known for 531 patients; 402 had null mutations and 129 had non-null mutations. Considering only patients who had not started prophylaxis or developed an inhibitor before select bleeding events, we found that patients with null mutations experienc...
2022
Hemophilia A is an X-linked bleeding disorder caused by mutations in the FVIII gene. Genetic factors have been shown to be a risk factor for the development of inhibitors. We aimed to identify the specific variations of the FVIII gene of patients with hemophilia A with inhibitors and their association with the inhibitor titer. Methods: Cross-sectional descriptive study. We included 12 Colombian patients from a health care provider, “Integral Solutions SD”, who underwent analysis of genetic material (DNA), which was reported by the Molecular Hemostasis Laboratory in Bonn, Germany. Results: All of these patients were diagnosed with severe hemophilia A with inhibitors; ages ranged between 6 and 48 years, with a median age of 13.5 years. Molecular analysis showed the inversion of intron 22 in six patients (50.0%), a small duplication in two patients (16.7%), the inversion of intron 1 in one patient (8.3%), a large deletion (8.3%), a nonsense mutation (8.3%) and a splicesite (8.3%), findings similar to those of other studies. A total of 58.3% of the patients presented inversion mutations with a high risk of developing inhibitors A total of 83.3% of the evaluated patients presented null mutations; however the presence of high inhibitor titers was 66.7%. The most frequent mutation was the inversion intron 22. Knowing the type of mutation and its association as a risk factor for generating inhibitors invites us to delve into other outcomes such as residual values of coagulation FVIII as well as its impact on the half-life of the exogenous factor applied in prophylaxis
Factor VIII Gene in Serbian Patients with Hemophilia a
2016
Hemophilia A (HA) is a common X-linked recessive bleeding disease caused by mutations of FVIII gene. Inversion of intron 1 (inv1) and intron 22 (inv22) are recurrent mutations in severe HA, causing 50 % of cases. Inv1 has been reported to occur in 2–5 % and inv 22 in 45 % of severe HA patients. Our objective was to determine, for the first time in Serbia, the frequency of inv1 and inv22 in a group of severe HA patients and to compare these data with those from other countries. Study subjects were 50 HA patients, diagnosed and treated from April 2009 to June 2012 at Mother and Child Health Care Institute of Serbia “Dr Vukan Cupic ” (IHS) and Institute for Child and Youth Health Care of Vojvodina (IHV).The presence of inv1 and inv22 was analyzed using Inverse shifting PCR (IS-PCR). Our results revealed that the frequencies of inv1 and inv22 in the cohort of Serbian patients were 6 % and 42 % (34 % of inv22 type I and 8 % of inv22 type II) respectively. These frequencies were in line w...