scholarly journals Assessment of the F9 genotype-specific FIX inhibitor risks and characterisation of 10 novel severe F9 defects in the first molecular series of Argentinian patients with haemophilia B

2013 ◽  
Vol 109 (01) ◽  
pp. 24-33 ◽  
Author(s):  
Liliana Carmen Rossetti ◽  
Miguel Martín Abelleyro ◽  
Miguel Candela ◽  
Raúl Pérez Bianco ◽  
Miguel de Tezanos Pinto ◽  
...  
Keyword(s):  
Point Mutations ◽  
Bioinformatic Analysis ◽  
Factor Ix ◽  
Causative Mutation ◽  
Control Analysis ◽  
Missense Mutations ◽  
Novel Mutations ◽  
Haemophilia B ◽  
Large Deletions ◽  
Genotype Frequencies

SummaryIn haemophilia B (HB) (factor IX [FIX] deficiency), F9 genotype largely determines clinical phenotype. Aimed to characterise Argentinian families with HB, this study presents F9 genotype frequencies and their specific FIX inhibitor risk and 10 novel F9 mutations. Ninety-one DNA samples from HB patients and relatives were subjected to a new scheme: a primary screen for large deletions, a secondary screen for point mutations using conformation sensitive gel electrophoresis, DNA-sequencing and bioinformatic analysis. Our unbiased HB population (N=52) (77% with severe, 11.5% moderate and 11.5% mild HB) showed 32 missense (61.5%), including three novel mutations predicting specific structural/functional defects in silico, seven nonsense (13.5%) (one novel), five large deletions, four splice including three novel mutations affecting predicted splicing scores, three indels (two novel) and one Leiden mutation. Our comprehensive HB population included five patients with long-lasting FIX inhibitors: three nonsense (p.E35* (novel), p.R75*, p.W240*) and two entire-F9 deletions. Another patient with an indel (p.A26Rfs*14) developed transient inhibitors. A case-control analysis, based on our global prevalence of 3.05% for developing inhibitors in HB revealed that missense mutations were associated with a low risk odds ratio (OR) of 0.05 and a prevalence of 0.39%, whereas nonsense and entire-F9 deletions had significantly higher risks (OR 11.0 and 32.7) and prevalence (14.3% and 44.5%, respectively). Our cost-effective practical approach enabled identification of the causative mutation in all 55 Argentine families with HB, analysis of the molecular pathology of novel F9 defects and determination of mutation-associated FIX inhibitor risks.

Six Novel and Three Recurrent Mutations in Nine Austrian Patients with Hemophilia B

1994 ◽  
Vol 72 (01) ◽  
pp. 074-077 ◽  
Author(s):  
J Walter ◽  
I Pabinger-Fasching ◽  
H H Watzke
Keyword(s):  
Direct Sequencing ◽  
Point Mutations ◽  
Factor Ix ◽  
Hemophilia B ◽  
Causative Mutation ◽  
Genetic Defects ◽  
Missense Mutations ◽  
Enzymatic Amplification ◽  
Recurrent Mutations ◽  
Polymerase Chain

SummaryIn this report we describe the molecular basis of the factor IX (FIX) deficiency in nine patients with severe (n = 6), moderate (n = 1) or mild (n = 2) hemophilia B. The following genetic defects were identified by enzymatic amplification with the polymerase chain reaction (PCR) and subsequent direct sequencing of all exons and exon-intron-junctions: patient B.B. (FIX “Vienna I”): deletion of nucleotides 6343 to 6362; patient M.H. and W. J. (FIX “Vienna II”): nucleotide 17704 (C to G), Gin 97 to Glu; patient L. K. (FIX “Vienna III”): nucleotide 17761 (C to T), Arg 116 to stop; patient U. A. (FIX “Vienna IV”): nucleotide 10415 (C to G), Pro 55 to Ala; patient H.G. (FIX “Vienna V”): nucleotide 6488 (C to T), Thr 38 to lie; patient H. M. (FIX “Vienna VI”): nucleotide 31276 (G to C), Trp 385 to Cys; patient L. C. (FIX “Vienna VII”): deletion of nucleotide 6700; patient S.F. (FIX “Vienna VIII”): nucleotide 10392 (A to T), Asp 47 to Val. The causative mutation was detected in the FIX gene in each of the nine patients with hemophilia B. There was one small deletion, one point deletion and seven point mutations. The latter include six missense mutations and one nonsense mutation. The mutations in Vienna III, IV and V have already been described in previous studies. The two deletions, Vienna I and Vienna VII have not been reported previously. The genetic defects observed in Vienna II, VI and VIII are novel missense mutations which result in amino acid changes at residues 97,47 and 385, respectively.

Factor IX Gene Analysis In 70 Unrelated Patients with Haemophilia B: Description of 13 New Mutations

1999 ◽  
Vol 82 (11) ◽  
pp. 1437-1442 ◽  
Author(s):  
M. C. Trzeciak ◽  
A. Durin ◽  
G. Pernod ◽  
V. Gay ◽  
C. Ménart ◽  
...  
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Direct Sequencing ◽  
Point Mutations ◽  
Factor Ix ◽  
Coagulation System ◽  
Molecular Defect ◽  
Missense Mutations ◽  
Nucleotide Substitutions ◽  
Haemophilia B ◽  
Gradient Gel Electrophoresis

SummarySeventy unrelated patients suffering from haemophilia B have been screened for determining the molecular defect and for evaluating the spectrum of factor IX mutations in the Rhône Alpes region in France. Most patients were characterized with respect to factor IX antigen and factor IX coagulant activity. We have used denaturing gradient gel electrophoresis to obtain a full scanning of the whole coding, promoter, and exon flanking sequences of the factor IX gene. This technique enabled us to determine the molecular defect in 68 out of 70 families (97%), and the mutation was further identified in the two last patients with a direct sequencing of the gene. A total of 2 complete gene deletions in patients with antifactor IX inhibitor, 6 small insertions/ deletions and 62 point mutations were found. Two of these nucleotide substitutions (Arg145His and Ala233Thr) were detected in 21 patients (30%) suggesting the existence of a local founder effect. Thirteen mutations were previously undescribed, including 7 missense mutations. The detection of mutations in patients affected with haemophilia B may shed some light in the structure-function relationship of factor IX molecule within the coagulation system.

scholarly journals Mutations causing hemophilia B in Algeria: Identification of two novel mutations of the factor 9 gene

2018 ◽  
Vol 19 (1) ◽  
pp. 52-58 ◽  
Author(s):  
ZIDANI ABLA ◽  
YAHIA MOULOUD ◽  
EL MAHMOUDI HEJER ◽  
GOUIDER EMNA ◽  
ABDI MERIEM ◽  
...  
Keyword(s):  
Direct Sequencing ◽  
Point Mutations ◽  
Coagulation Factor ◽  
Factor Ix ◽  
Hemophilia B ◽  
Causative Mutation ◽  
Novel Mutations ◽  
Mutation Database ◽  
Wide Range ◽  
The Family

Abla Z, Mouloud Y, Hejer El, Emna G, Abdi Meriem A, Ouarhlent Yamina O, Naouel S. 2018. Mutations causing hemophilia B in Algeria: Identification of two novel mutations of the factor 9 gene. Biodiversitas 19: 52-58. Hemophilia B (HB) (also known as Christmas disease; Christmas is the family name of the first patient.) is an X linked recessive hemorrhagic disorder caused by mutations in factor 9 (F9: is used for the gene) gene that leads to deficient or defective coagulation factor IX (FIX: is used for the protein). The variable phenotype of HB results from wide range of mutations affecting the F9 gene. Our study was aimed at molecular analysis of HB to identify the causative mutation in known patients with HB in a part of Algeria. For genotyping, polymerase chain reaction (PCR) and direct sequencing have been applied to all the essential regions of the F9 gene from 39 Algerian HB patients belonging to 13 unrelated families. We identified 10 different mutations. The identified mutations included 1 duplication and 9 substitutions. In total 9 point mutations were identified, of which 5 are located in exon 8, the hotspot region in the F9 gene. Among the 10 mutations, 2 are novel and not deposited in database sites nor described in recently published articles. The results of this study emphasize the heterogeneity of HB. In summary, our preliminary results will be used to build an Algerian mutation database which would facilitate genetic counseling.

scholarly journals Identification of 31 novel mutations in the F8 gene in Spanish hemophilia A patients: structural analysis of 20 missense mutations suggests new intermolecular binding sites

Blood ◽  
2008 ◽  
Vol 111 (7) ◽  
pp. 3468-3478 ◽  
Author(s):  
Adoración Venceslá ◽  
María Ángeles Corral-Rodríguez ◽  
Manel Baena ◽  
Mónica Cornet ◽  
Montserrat Domènech ◽  
...  
Keyword(s):  
Hemophilia A ◽  
Low Density Lipoprotein ◽  
Scavenger Receptor ◽  
Density Lipoprotein ◽  
Missense Mutations ◽  
Factor X ◽  
Novel Mutations ◽  
Large Deletions ◽  
Function Relationship ◽  
The Impact

Abstract Hemophilia A (HA) is an X-linked bleeding disorder caused by a wide variety of mutations in the factor 8 (F8) gene, leading to absent or deficient factor VIII (FVIII). We analyzed the F8 gene of 267 unrelated Spanish patients with HA. After excluding patients with the common intron-1 and intron-22 inversions and large deletions, we detected 137 individuals with small mutations, 31 of which had not been reported previously. Eleven of these were nonsense, frameshift, and splicing mutations, whereas 20 were missense changes. We assessed the impact of the 20 substitutions based on currently available information about FV and FVIII structure and function relationship, including previously reported results of replacements at these and topologically equivalent positions. Although most changes are likely to cause gross structural perturbations and concomitant cofactor instability, p.Ala375Ser is predicted to affect cofactor activation. Finally, 3 further mutations (p.Pro64Arg, p.Gly494Val, and p.Asp2267Gly) appear to affect cofactor interactions with its carrier protein, von Willebrand factor, with the scavenger receptor low-density lipoprotein receptor–related protein (LRP), and/or with the substrate of the FVIIIapi•FIXa (Xase) complex, factor X. Characterization of these novel mutations is important for adequate genetic counseling in HA families, but also contributes to a better understanding of FVIII structure-function relationship.

Detection of Ten New Mutations by Screening the Gene Encoding Factor IX of Danish Hemophilia B Patients

1995 ◽  
Vol 73 (05) ◽  
pp. 774-778 ◽  
Author(s):  
Marianne Schwartz ◽  
Jørgen Ingerslev ◽  
Elma Scheibel ◽  
Lise Rud Nielsen
Keyword(s):  
Point Mutations ◽  
Splice Site Mutation ◽  
Factor Ix ◽  
Hemophilia B ◽  
Missense Mutations ◽  
Coding Region ◽  
Site Mutation ◽  
Gene Encoding ◽  
Base Pair Deletion ◽  
Wide Range

SummaryHemophilia B is caused by a wide range of mutations. In order to characterize the mutations among patients in Denmark, we have systematically screened the entire coding region, the promoter region and exon flanking sequences of the gene encoding factor IX using single strand conformation and heteroduplex analyses. Patients from 32 different families were examined, and point mutations (23 different) were found in all of them. Ten of the mutations have not been reported by others; they include a splice site mutation, a single base pair deletion, and missense mutations. Notably, the study contains a female patient and a previously described Leyden mutation. In ten families with sporadic cases of hemophilia B, all 10 mothers were found to be carriers. The origin of two of these mutations was established.

MOLECULAR GENETICS OF HAEMOPHILIA

1987 ◽  
Author(s):  
B F Giannelli
Keyword(s):  
Signal Peptide ◽  
Point Mutations ◽  
Factor Ix ◽  
Indirect Detection ◽  
Gene Deletions ◽  
Gene Markers ◽  
Haemophilia B ◽  
Familial Cases ◽  
Number Of Patients ◽  
Gene Defects

Haemophilia B, an X-linked recessive disease with an incidence of 1/30,000 newborn males, is due to defects in the gene for coagulation factor IX, which is on the long am of the X chromosome at band Xq27.1. This gene consists of approximately 34 Kb and contains 8 exons which specify a mRtfc of 2803 residues coding for a protein of 415 aa preceded by a prepro signal peptide of 46 aa. Coripanson of the functional domains of the factor IX protein with the exon structure of the gene supports the exon/protein domain hypothesis of gene evolution. The factor IX gene seems to be formed by a number of functionally and evolutionally independent modules. The signal peptide and the gla (γcarboxy-glutamic) region encoded in the first three exons are homologous to those of factor X, protein C and prothrombin. Thevfourth and fifth exons which code for the connecting peptide are homologous to one another and to the epidermal growth factor, a module that has been used in the construction of a great variety of proteins including different members of the coagulation and fibrinolytic pathways. The sixth exon encodes the activation peptide region, while the catalytic region of factor IX is coded by the seventh and eighth exon. This is at variance with other serine protease genes that have different exons for the segments containing the cardinal ami no-acids of the active centre (histidine, aspartic acid and serine).Natural selection acts against detrimental mutations of the factor IX gene and at each generation a proportion of haemophilia B genes is eliminated, as a significant number of patients does not reproduce. There appears to be no selective advantage to the heterozygote and therefore haemophilia B is maintained in the population by new mutations. Consequently, a significant proportion of patients should be born to non-carrier mothers, and unrelated patients should carry different gene defects, as recently verified by detailed analysis of individual haemophilia B genes.The defects of factor IX described so far comprise both point mutations and gene deletions. The latter affect either part or the whole of the gene and are often associated with the development of antibodies against therapeutically adninistered factor IX (the inhibitor complication). Since gene deletions may result in the complete absenceof factor IX synthesis or in the production of an extremely abnormal product, it has been suggested that mutationspreventing the synthesis of a factor IX gene product capable of inducing immune tolerance to normal factor IX is important in predisposing to the inhibitor complication.Among the point mutations described so far, those affecting the signal peptide are of particular interest. Substitutions of the arginine at positions -4 and -1 cause failure of propeptide cleavage. Thus they indicate that the propeptide consists of 18 aa an(lthat lts excision is necessary for factor IX function. It appears also that the propeptide contains a signal for γcarboxylation which has been conserved during the evolution of different γcarboxylated proteins.In spite of coagulant treatment, haemophilia B is a serious disease and one for which genetic counselling is required. Paramount for this is the detection of carriers and the diagnosis ofaffected male fetuses. DNA probes derived from the cloned factor IX gene have been used for this purpose. Carrier and first or second trimester prenatal diagnoses have been done using factors IX gene markers to follow the transmission of haemophilia B genes. Six sequence variations causing restriction fragment length polymorphisms (RFLP) in the factor IX gene have been detected and used as markers for such indirect diagnoses The efficiency of the above markers is reduced by linkage disequilibrium but, nevertheless, they offer definite carrier and nremtal diagnoses in 75-80% of the relatives of familial cases of haemophilia B.The indirect detection of gene defects is of modest help in the counselling of individuals from the families of isolated patients, but new methods for the direct detection of gene mutations promise better results in such families and also the attainment of % diagnostic success in relatives of familial cases.Finally the successful expression of recombinant factor IX genes in tissue culture and transgenic mammals raises hopes of therapeutic advances.

The spectrum of genetic changes in the RB1 gene in a group of Russian retinoblastoma patients

2021 ◽  
pp. 11-20
Author(s):  
Е.А. Алексеева ◽  
В.М. Козлова ◽  
О.В. Бабенко ◽  
Т.Л. Ушакова ◽  
Т.П. Казубская ◽  
...  
Keyword(s):  
High Throughput ◽  
Molecular Genetic ◽  
Genetic Diagnosis ◽  
Point Mutations ◽  
Missense Mutations ◽  
Rb1 Gene ◽  
Genetic Changes ◽  
Parallel Sequencing ◽  
Large Deletions ◽  
Efficient Detection

Введение. Ретинобластома - злокачественная опухоль детского возраста, причиной которой является биаллельная инактивация гена RB1. Ранняя молекулярно-генетическая диагностика ретинобластомы необходима как для адекватного выбора алгоритма лечения пациента с такой опухолью, так и для медико-генетического консультирования семьи. Цель: охарактеризовать частоту и спектр мутаций в гене RB1 у российских больных с ретинобластомой. Методы. Исследование проведено на материале ДНК лимфоцитов крови, полученном от 492 больных с ретинобластомой. Скрининг точковых мутаций, малых инсерций/делеций в гене RВ1 осуществляли методом полупроводникового высокопроизводительного параллельного секвенирования. Исключение протяженных делеций в гене RВ1 проводили методом MLPA. Результаты. Исследовано 492 неродственных пациента с ретинобластомой, среди которых 38,2% (188/492) с билатеральной формой заболевания и 61,8% (304/492) - с унилатеральной. В группе больных с билатеральной формой ретинобластомы герминальная мутация обнаружена у 96,8% (182/188) пациентов, в группе больных с унилатеральной формой - у 16,4% (50/304). Суммарно в гене RB1 в исследованной группе пациентов обнаружено 339 мутаций: 232 - герминальных и 107 - соматических. Выявлен практически полный спектр молекулярных изменений, включающий нонсенс-мутации - 37,5% (127/339), миссенс-мутации - 5,3% (18/339), мутации, приводящие к сдвигу рамки считывания - 18,9% (64/339), мутации сайтов сплайсинга - 13,9% (47/339) и протяженные делеции - 24,5% (83/339). Выводы. Применение глубокого высокопроизводительного параллельного секвенирования и метода MLPA позволяет эффективно выявлять молекулярно-генетические изменения в гене RB1. Типы мутаций, обнаруженные в исследованной группе, их частота и распределение совпадают с результатами исследователей из других стран. Background. Retinoblastoma is a childhood malignant tumor caused by biallelic inactivation of the RB1 gene. Early molecular genetic diagnosis of retinoblastoma is necessary both for an adequate choice of an algorithm for treating a patient, and for competent medical genetic counseling of the family Objective. To establish the frequency and spectrum of mutations in the RB1 gene in the group of patients with retinoblastoma. Methods. The study was carried out on the DNA of blood lymphocytes from 492 patients with retinoblastoma. Screening of point mutations, small insertions/deletions in the RB1 gene was performed by semiconductor high-throughput parallel sequencing. Exclusion of gross deletions in the RB1 gene was performed by MLPA. Results. 492 unrelated patients with retinoblastoma were studied, including 38.2% (188/492) with bilateral form and 61.8% (304/492) with unilateral form. In the group of patients with bilateral retinoblastoma, germline mutation was found in 96.8% (182/188) patients, and in the group of unilateral patients, in 16.4% (50/304). In total, the RB1 gene in the studied group of patients 339 mutations were found, 232 germline and 107 somatic. An almost complete spectrum of molecular changes was revealed, including nonsense mutations, 37.5% (127/339); missense mutations, 5.3% (18/339); frame shift mutations, 18.9% (64 / 339); splice site mutations, 13.9% (47/339); and large deletions, 24.5% (83/339). Conclusion. The use of deep high-throughput parallel sequencing and the MLPA method allows efficient detection of molecular genetic changes in the RB1 gene. The types of mutations found in the studied group, their frequency and distribution are the same as the results of researchers in other countries.

Analysis of haemophilia B database and strategies for identification of common point mutations in the factor IX gene

Haemophilia ◽  
2003 ◽  
Vol 9 (2) ◽  
pp. 187-192 ◽  
Author(s):  
S. Mukherjee ◽  
A. Mukhopadhyay ◽  
K. Chaudhuri ◽  
K. Ray
Keyword(s):  
Point Mutations ◽  
Common Point ◽  
Factor Ix ◽  
Haemophilia B

Small and large PROS1 deletions but no other types of rearrangements detected in patients with protein S deficiency

2012 ◽  
Vol 108 (07) ◽  
pp. 94-100 ◽  
Author(s):  
Christina Lind-Halldén ◽  
Anna Dahlén ◽  
Andreas Hillarp ◽  
Bengt Zöller ◽  
Björn Dahlbäck ◽  
...  
Keyword(s):  
Point Mutation ◽  
Point Mutations ◽  
Protein S ◽  
Causative Mutation ◽  
Fish Analysis ◽  
Protein S Deficiency ◽  
Large Deletions ◽  
S Deficiency

SummaryProtein S deficiency is a dominantly inherited disorder that results from mutations in the PROS1 gene. Previous sequencing of the gene failed to detect mutations in eight out of 18 investigated Swedish families, whereas segregation analyses detected large deletions in three out of the eight families. The present study investigates more thoroughly for the presence of deletions but also for other types of rearrangements. FISH analysis confirmed the existence of the three previously identified large deletions, but failed to identify any other type of rearrangement among the eight analysed families. MLPA analysis of the PROS1 gene revealed two smaller deletions covering two and four exons, respectively. Thus, deletions could be found in five out of eight families where no point mutations could be found despite sequencing of the gene. Twelve additional, not previously analysed, families were subsequently analysed using MLPA. The analysis identified two smaller deletions (3 and 4 exons). Including all PS-deficient families, i.e. also the 10 families where sequencing found a causative point mutation, deletions were identified in seven out of 30 PS-deficient families. A strategy of sequencing followed by MLPA analysis in mutation-negative families identified the causative mutation in 15 out of 18 of Swedish PS-deficient families. Most deletions were different as determined by their sizes, locations and flanking haplotypes. FISH (8 families) and MLPA analysis (20 families) failed to identify other types of rearrangements.

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