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Labarque V, Mancuso ME, Kartal-Kaess M, Ljung R, Mikkelsen TS, Andersson NG. F8/F9 variants in the population-based PedNet Registry cohort compared with locus-specific genetic databases of the European Association for Haemophilia and Allied Disorders and the Centers for Disease Control and Prevention Hemophilia A or Hemophilia B Mutation Project. Res Pract Thromb Haemost 2023; 7:100036. [PMID: 36798899 PMCID: PMC9926204 DOI: 10.1016/j.rpth.2023.100036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/11/2022] [Accepted: 12/17/2022] [Indexed: 01/11/2023] Open
Abstract
Background Hemophilia A and B are caused by variants in the factor (F) VIII or FIX gene. Selective reporting may influence the distribution of variants reported in genetic databases. Objectives To compare the spectrum of F8 and F9 variants in an international population-based pediatric cohort (PedNet Registry) with the spectrum found in the European Association for Haemophilia and Allied Disorders (EAHAD) and the Centers for Disease Control and Prevention Hemophilia A or Hemophilia B Mutation Project (CHAMP/CHBMP) databases. Methods All patients registered in the PedNet Registry on January 1, 2021 were included in this study. As comparators, data from patients with severe hemophilia included in the CHAMP/CHBMP registry (US center data) and EAHAD were used. Results Genetic information was available for 1941 patients. Intron 22 inversion was present in 52% of patients with severe hemophilia A; frameshift (36%), missense (28%), and nonsense (20%) were the most frequent variants in patients with severe hemophilia A who were inversion-negative. The most frequent variants in severe hemophilia B were missense (48%). In nonsevere disease, most variants were missense variants (moderate hemophilia A: 91%; mild hemophilia A: 95%, moderate and mild hemophilia B: 86% each). Comparison with the databases demonstrated a higher proportion of missense variants associated with severe hemophilia B in EAHAD (68%) than in PedNet (48%) and CHBMP (46%). Conclusion The PedNet population-based cohort provides an alternative to the established databases, which collect data by selective reporting, as it is a well-maintained database covering the full spectrum of pathogenic F8 and F9 variants, and indicates the number of patients affected by each particular variant.
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Affiliation(s)
- Veerle Labarque
- Department of Paediatrics, Paediatric Haematology and Oncology, University Hospitals Leuven, Leuven, Belgium,Correspondence Veerle Labarque, Department of Paediatrics, Paediatric Haematology and Oncology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium.
| | - Maria Elisa Mancuso
- Center for Thrombosis and Hemorrhagic Diseases, IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy,Humanitas University, Rozzano, Milan, Italy
| | - Mutlu Kartal-Kaess
- Division of Pediatric Hematology and Oncology, Department of Pediatrics, Inselspital, University Hospital, University of Bern, Bern, Switzerland
| | - Rolf Ljung
- Department of Clinical Sciences and Paediatrics, Lund University, Lund, Sweden
| | - Torben S. Mikkelsen
- Department of Paediatric Oncology and Haematology, University Hospital, Aarhus, Denmark
| | - Nadine G. Andersson
- Department of Clinical Sciences and Paediatrics, Lund University, Lund, Sweden,Centre for Thrombosis and Haemostasis, Skåne University Hospital, Lund, Sweden
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2
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McVey JH, Rallapalli PM, Kemball-Cook G, Hampshire DJ, Giansily-Blaizot M, Gomez K, Perkins SJ, Ludlam CA. The European Association for Haemophilia and Allied Disorders (EAHAD) Coagulation Factor Variant Databases: Important resources for haemostasis clinicians and researchers. Haemophilia 2020; 26:306-313. [PMID: 32166871 DOI: 10.1111/hae.13947] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/15/2020] [Accepted: 02/06/2020] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Advances in genomic sequencing have facilitated the sequencing of genes associated with disorders of haemostasis. The identification of variants within genes and access to curated data incorporating structural, functional, evolutionary as well as phenotypic data has become increasingly important in order to ascribe pathogenicity. AIM The European Association for Haemophilia and Allied Disorders (EAHAD) Coagulation Factor Variant Database Project aims to provide a single port of entry to a web-accessible resource for variants in genes involved in clinical bleeding disorders. RESULTS New databases have evolved from previously developed single gene variant coagulation database projects, incorporating new data, new analysis tools and a new common database architecture with new interfaces and filters. These new databases currently present information about the genotype, phenotype (laboratory and clinical) and structural and functional effects of variants described in the genes of factor (F) VII (F7), FVIII (F8), FIX (F9) and von Willebrand factor (VWF). CONCLUSION The project has improved the quality and quantity of information available to the haemostasis research and clinical communities, thereby enabling accurate classification of disease severity in order to make assessments of likely pathogenicity.
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Affiliation(s)
- John H McVey
- School of Bioscience and Medicine, University of Surrey, Guildford, UK
| | - Pavithra M Rallapalli
- Department of Structural and Molecular Biology, University College London, London, UK
| | - Geoffrey Kemball-Cook
- Katherine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, UK
| | | | | | - Keith Gomez
- Katherine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, UK
| | - Stephen J Perkins
- Department of Structural and Molecular Biology, University College London, London, UK
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3
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Mousavi SH, Mesbah-Namin SA, Zeinali S, Jazebi M, Dabbagh A, Hosseini SMR, Zafarghandi Motlagh F, Shiravand Y, Dorgalaleh A. A large deletion, spanning exons 1 to 25 of F8 gene, and a high-titer factor VIII inhibitor, in severe hemophilia A. Int J Lab Hematol 2020; 42:e138-e140. [PMID: 32125779 DOI: 10.1111/ijlh.13174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 01/27/2020] [Accepted: 01/31/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Sayed Hamid Mousavi
- Department of the Clinical Biochemistry, Faculty of Medical Sciences, Kateb University, Kabul, Afghanistan.,Afghanistan National Charity Organization for Special Diseases (ANCOSD), Kabul, Afghanistan
| | - Seyed Alireza Mesbah-Namin
- Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Sirous Zeinali
- Iranian Molecular Medicine Network, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mohammad Jazebi
- Iranian Comprehensive Hemophilia Care Center (ICHCC), Tehran, Iran
| | - Ali Dabbagh
- Anesthesiology Department, Anesthesiology Research Center, Shahid Beheshti University of Medicine, Tehran, Iran
| | | | | | - Yavar Shiravand
- Department of Hematology and Blood Transfusion, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Akbar Dorgalaleh
- Department of Hematology and Blood Transfusion, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
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4
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Key issues in inhibitor management in patients with haemophilia. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2013; 12 Suppl 1:s319-29. [PMID: 24333092 DOI: 10.2450/2013.0246-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 05/16/2013] [Indexed: 12/13/2022]
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5
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GOODEVE AC, PERRY DJ, CUMMING T, HILL M, JENNINGS I, KITCHEN S, WALKER I, GRAY E, JAYANDHARAN GR, TUDDENHAM E. Genetics of haemostasis. Haemophilia 2012; 18 Suppl 4:73-80. [DOI: 10.1111/j.1365-2516.2012.02832.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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Zhang AH, Skupsky J, Scott DW. Factor VIII inhibitors: risk factors and methods for prevention and immune modulation. Clin Rev Allergy Immunol 2009; 37:114-24. [PMID: 19199081 DOI: 10.1007/s12016-009-8122-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Patients with hemophilia A are deficient in coagulation Factor VIII. This bleeding disorder can be treated with Factor VIII replacement therapy, but close to a third of patients will be immunized to the treatment and begin to form inhibitory antibodies known as "inhibitors". These inhibitors will render the treatment ineffective and represent the most severe complication in the treatment of hemophilia A. In this review, we highlight factors involved in inhibitor development and emphasize research being done to modulate the immune response to this life-saving therapy.
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Affiliation(s)
- Ai Hong Zhang
- Department of Surgery, and Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, 800 West Baltimore Street, Room 319, Baltimore, MD 21201, USA
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7
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Brooks MB, Barnas JL, Fremont J, Ray J. Cosegregation of a Factor VIII Microsatellite Marker with Mild Hemophilia A in Golden Retriever Dogs. J Vet Intern Med 2005. [DOI: 10.1111/j.1939-1676.2005.tb02683.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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8
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Abstract
Factor VIII (FVIII) functions as a co-factor in the blood coagulation cascade for the proteolytic activation of factor X by factor IXa. Deficiency of FVIII causes hemophilia A, the most commonly inherited bleeding disorder. This review highlights current knowledge on selected aspects of FVIII in which both the scientist and the clinician should be interested.
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Affiliation(s)
- G M Bhopale
- Research and Development Division, Hindustan Antibiotics Ltd, Pimpri, Pune 411 018, India.
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9
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Freson K, Peerlinck K, Aguirre T, Arnout J, Vermylen J, Cassiman JJ, Matthijs G. Fluorescent chemical cleavage of mismatches for efficient screening of the factor VIII gene. Hum Mutat 2000; 11:470-9. [PMID: 9603440 DOI: 10.1002/(sici)1098-1004(1998)11:6<470::aid-humu8>3.0.co;2-a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The detection of mutations in large and complex genes represents a practical challenge in research and diagnostic laboratories. Available methods are either time-consuming or lack sensitivity. Mutation detection in the factor VIII gene, responsible for haemophilia A, is hampered by its large size, its many exons, and the high frequency of de novo mutations that result in different mutations in unrelated patients. For an exhaustive analysis of mutations in the factor VIII gene, we established a nonradioactive screening method based on chemical cleavage of mismatches (CCM). PCR-fragments of approximately 1 kb were generated from genomic DNA (exon 14) or after reverse transcription from mRNA isolated from blood cells. Some modifications have been made to improve the CCM strategy. First, using a fluorescent tag, the method gains safety and flexibility. Second, fluorescent detection allows an accurate sizing of digested fragments when measured on an automated DNA sequencer. Third, by labelling both 5' ends of the PCR-fragment, the detection rate is virtually 100%. Finally, in the case of an X-linked disease, samples from two patients can be mixed, which reduces the workload without losing information. In a pilot experiment, mutations were detected in 20 of 20 patients. In this series, three small insertions, two small deletions, one nonsense mutation, 13 missense mutations, and one splice mutation were found. Fifteen of these mutations are new. Thus virtually all kind of mutations are detectable by this method. Moreover, the analysis of the gene can be completed in 2 days.
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Affiliation(s)
- K Freson
- Center for Human Genetics, University of Leuven, Belgium
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10
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Maugard C, Tuffery S, Aguilar-Martinez P, Schved JF, Gris JC, Demaille J, Claustres M. Protein truncation test: detection of severe haemophilia a mutation and analysis of factor VIII transcripts. Hum Mutat 2000; 11:18-22. [PMID: 9450898 DOI: 10.1002/(sici)1098-1004(1998)11:1<18::aid-humu3>3.0.co;2-h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- C Maugard
- Laboratoire de Biochimie Génétique, CHU de Montpellier, CNS UPR 9008, France
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11
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Abstract
The aim of this study was to define the origin of mutation in sporadic cases of severe haemophilia A. The series was composed of 31 families with sporadic severe haemophilia A in the geographical catchment area of the Malmö haemophilia centre. The mutation was characterized in 29/31 families: inversion type 1 (n = 11), inversion type 2 (n = 3), other inversion (n = 1), small or partial deletion (n = 6), insertion (n = 2), non-sense mutation (n = 4) and mis-sense mutation (n = 2). Of 29 probands, eight carried a de novo mutation, whereas the proband's mother was found to carry the mutation in 21/29 families. Of the 21 carrier mothers, 16 had de novo mutations (i.e. the proband's maternal grandfather and grandmother were non-carriers). Owing to the lack of samples from the grandparents, origin could not be determined in the remaining five families. Polymorphisms of the FVIII gene were used to determine whether the de novo mutation of the carrier mother was of paternal or maternal origin. In 15/16 cases the mutation was of paternal origin and in 1/16 cases of maternal origin. In the series as a whole, mutation frequency was 6-fold higher in males than in females, but no differences in the ratio of sex-specific mutations rates was found among different types of mutation.
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Affiliation(s)
- R C Ljung
- Department of Paediatrics, University Hospital, Malmö, Sweden.
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12
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Affiliation(s)
- S E Antonarakis
- Department of Genetics and Microbiology, University of Geneva Medical School, Geneva, Switzerland
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13
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Heimburger N. Faktor VIII: Biochemie und Physiologie. Hamostaseologie 1999. [DOI: 10.1007/978-3-662-07673-6_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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14
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El-Maarri O, Olek A, Balaban B, Montag M, van der Ven H, Urman B, Olek K, Caglayan SH, Walter J, Oldenburg J. Methylation levels at selected CpG sites in the factor VIII and FGFR3 genes, in mature female and male germ cells: implications for male-driven evolution. Am J Hum Genet 1998; 63:1001-8. [PMID: 9758623 PMCID: PMC1377497 DOI: 10.1086/302065] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Transitional mutations at CpG dinucleotides account for approximately a third of all point mutations. These mutations probably arise through spontaneous deamination of 5-methylcytosine. Studies of CpG mutation rates in disease-linked genes, such as factor VIII and FGFR3, have indicated that they more frequently originate in male than in female germ cells. It has been speculated that these sex-biased mutation rates might be a consequence of sex-specific methylation differences between the female and the male germ lines. Using the bisulfite-based genomic-sequencing method, we investigated the methylation status of the human factor VIII and FGFR3 genes in mature male and female germ cells. With the exception of a single CpG, both genes were found to be equally and highly methylated in oocytes and spermatocytes. Whereas these observations strongly support the notion that DNA methylation is the major determining factor for recurrent CpG germ-line mutations in patients with hemophilia and achondroplasia, the higher mutation rate in the male germ line is apparently not a simple reflection of sex-specific methylation differences.
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Affiliation(s)
- O El-Maarri
- Department of Molecular Biology, Bogazici University, Würzburg, Germany
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15
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Tavassoli K, Eigel A, Dworniczak B, Valtseva E, Horst J. Identification of four novel mutations in the factor VIII gene: three missense mutations (E1875G, G2088S, I2185T) and a 2-bp deletion (1780delTC). Hum Mutat 1998; Suppl 1:S260-2. [PMID: 9452104 DOI: 10.1002/humu.1380110183] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- K Tavassoli
- Institut für Humangenetik der Westfälischen, Wilhelms-Universität Münster, Germany
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16
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Kemball-Cook G, Tuddenham EG, Wacey AI. The factor VIII Structure and Mutation Resource Site: HAMSTeRS version 4. Nucleic Acids Res 1998; 26:216-9. [PMID: 9399839 PMCID: PMC147260 DOI: 10.1093/nar/26.1.216] [Citation(s) in RCA: 171] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Since 1996 the HAMSTeRS (Haemophilia A Mutation, Search, Test and Resource Site) WWW site has provided an online resource for access to data on the molecular pathology of haemophilia A, replacing previous text editions of the Haemophilia A Database published in Nucleic Acids Research . This report describes the continued development of the site (version 4), and in particular the expansion of factor VIII (FVIII) structure-related features. Access to the mutation database itself, both for searching the listings and for submission of new mutations, is via custom-designed forms: more powerful Boolean searches of the point mutations in the database are also available. During 1997 a total of 22 novel missense mutations were reported, increasing the total number of unique variants now described to 252 (238 in exonic sequences and 14 at intronic splice junctions). Currently, a total of 586 individual reports with associated phenotypic data are available for searching by any category including phenotype. The FVIII structure section now includes a download of a FVIII A domain homology model in Protein Data Bank format and a multiple alignment of the FVIII amino-acid sequencies from four species (human, murine, porcine and canine) in addition to the virtual reality simulations, secondary structural data and FVIII animation already available. Finally, to aid navigation across this site, a clickable roadmap of the main features provides easy access to the page desired. Our intention is that continued development and updating of the site shall provide workers in the fields of molecular and structural biology with a one-stop resource site to facilitate FVIII research and education. The HAMSTeRS URL is http://europium.mrc.rpms.ac.uk
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Affiliation(s)
- G Kemball-Cook
- Haemostasis Research Group, MRC Clinical Sciences Centre, Imperial College Medical School, Hammersmith Hospital, Du Cane Road, London W12 ONN, UK.
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17
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Carrié A, Piccolo F, Leturcq F, de Toma C, Azibi K, Beldjord C, Vallat JM, Merlini L, Voit T, Sewry C, Urtizberea JA, Romero N, Tomé FM, Fardeau M, Sunada Y, Campbell KP, Kaplan JC, Jeanpierre M. Mutational diversity and hot spots in the alpha-sarcoglycan gene in autosomal recessive muscular dystrophy (LGMD2D). J Med Genet 1997; 34:470-5. [PMID: 9192266 PMCID: PMC1050969 DOI: 10.1136/jmg.34.6.470] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Sarcoglycanopathies are a genetically heterogeneous group of autosomal recessive muscular dystrophies in which the primary defect may reside in any of the genes coding for the different partners of the sarcolemmal sarcoglycan (SG) complex: the alpha-SG (LGMD2D at 17q21.2), the beta-SG (LGMD2E at 4q12), the gamma-SG (LGMD2C at 13q12), and the delta-SG (LGMD2F at 5q33). We report a series of 20 new unrelated families with 14 different mutations in the alpha-SG gene. Along with the mutations that we previously reported this brings our cohort of patients with alpha-sarcoglycanopathy to a total of 31 unrelated patients, carrying 25 different mutations. The missense mutations reside in the extracellular domain of the protein. Five of 15 missense mutations, carried by unrelated subjects on different haplotype backgrounds and of widespread geographical origins, account for 58% of the mutated chromosomes, with a striking prevalence of the R77C substitution (32%). The severity of the disease varies strikingly and correlates at least in part with the amount of residual protein and the type of mutation. The recurrent R284C substitution is associated with a benign disease course.
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Affiliation(s)
- A Carrié
- INSERM 129, Université Paris V, France
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18
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Fasman KH, Letovsky SI, Li P, Cottingham RW, Kingsbury DT. The GDB Human Genome Database Anno 1997. Nucleic Acids Res 1997; 25:72-81. [PMID: 9016507 PMCID: PMC146370 DOI: 10.1093/nar/25.1.72] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The value of the Genome Database (GDB) for the human genome research community has been greatly increased since the release of version 6. 0 last year. Thanks to the introduction of significant technical improvements, GDB has seen dramatic growth in the type and volume of information stored in the database. This article summarizes the types of data that are now available in the Genome Database, demonstrates how the database is interconnected with other biomedical resources on the World Wide Web, discusses how researchers can contribute new or updated information to the database, and describes our current efforts as well as planned improvements for the future.
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Affiliation(s)
- K H Fasman
- Division of Biomedical Information Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2236, USA.
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Kemball-Cook G, Tuddenham EG. The Factor VIII Mutation Database on the World Wide Web: the haemophilia A mutation, search, test and resource site. HAMSTeRS update (version 3.0). Nucleic Acids Res 1997; 25:128-32. [PMID: 9016520 PMCID: PMC146401 DOI: 10.1093/nar/25.1.128] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The HAMSTeRS WWW site was set up in 1996 in order to facilitate easy access to, and aid understanding of, the causes of haemophilia A at the molecular level; previously, the first and second text editions of the database have been published in Nucleic Acids Research. This report describes the facilities originally available at the site and the recent additions which we have made to increase its usefulness to clinicians, the molecular genetics community and structural biologists interested in factor VIII. The database (version 3.0) has been completely updated with easy submission of point mutations, deletions and insertions via e-mail of custom-designed forms. The searching of point mutations in the database has been made simpler and more robust, with a concomitantly expanded real-time bioinformatic analysis of the database. A methods section devoted to mutation detection has been added, highlighting issues such as choice of technique and PCR primer sequences. Finally, a FVIII structure section gives access to 3D VRML (Virtual Reality Modelling Language) files for any user-definable residue in a FVIII A domain homology model based on the crystal structure of human caeruloplasmin, together with secondary structural data and a sound+video animation of the model. It is intended that the general availability of this model will assist both in interpretation of causative mutations and selection of candidate residues forin vitromutagenesis. The HAMSTeRS URL is http://europium.mrc.rpms.ac.uk.
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Affiliation(s)
- G Kemball-Cook
- Haemostasis Research Group, MRC Clinical Sciences Centre, Royal Postgraduate Medical School, Hammersmith Hospital, Du Cane Road, London W12 ONN, UK.
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20
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Abstract
CpG dinucleotides are efficiently methylated in vertebrate genomes except in the CpG islands having a high C+G content. Methylated CpGs are the single most mutated dinucleotide. Sequences surrounding disease causing CpG mutation sites were analyzed from locus-specific mutation databases. Both tetra- and heptanucleotide analyses indicated clear overall sequence preference for having pyrimidines 5' and purines 3' to the mutated 5-methylcytosine. The most mutated tetranucleotides are TCGA and TCGG, the former being also a frequent restriction and modification site. The results will help in elucidating the still controversial mutation mechanism of CpG doublets.
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Affiliation(s)
- J Ollila
- Department of Biosciences, Division of Biochemistry, University of Helsinki, Finland
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