Molecular study of Von Willebrand disease and its variants
Molecular study of Von Willebrand disease and its variants
Von Willebrand disease is an inherited bleeding disorder characterised by mucocutaneous bleeding and structural or functional defects of the Von Willebrand factor protein. Correct diagnosis and classification of patients is crucial as it predicts the bleeding risk and directs the clinical management.
Analysis of the Gp Ib alpha gene in five members of a British family with PT-VWD revealed a novel 27 bp in-frame deletion in the macroglycopeptide region (4373 - 4400). The deletion was detected in 3 affected and not found in 2 non-affected members. Stable transfected of wild type and mutant GPIb alpha co-transfected with pZeoSV2+ into CHO β/IX cells and flowcytometry showed the mutant GPIb alpha was expressed normally, bound significantly less to the mAb WM23 and showed higher VWF binding under low ristocetin concentration than the wild type. This deletion is the likely cause of the heightened platelet response and it supports the regulatory role of the macroglycopeptide region in receptor function.
Forty-six individuals of 10 families with type 1 von Willebrand disease were evaluated both phenotypically and genotypically. Using PCR, gene scanning and restriction enzyme analysis, an allelic association with the disease phenotype was revealed with three polymorphic markers in the VWF gene (VNTR I, II in intron 40, Rsa I 18) in 5 families. The association was likely in 2 and was ruled out in the remaining 3 families. Haplotype analysis may help in making a diagnosis in family members where the phenotype is less clear particularly in cases of high penetrance. However, phenotype and analysis remains the tool that provides the security and reliability in making the diagnosis of VWD.
We demonstrate the complexity of VNTR II locus of intron 40 of the VWF gene and showed by molecular cloning and sequencing two additional subloci (VNTR II ‘b’ and VNTR II ‘c’) with tetranucleotide repeats within the same amplified region containing the original VNTR II locus (VNTR II ‘a’). Fourteen configurations of VNTR II alleles were revealed instead of the known six. Thus, there is a necessary for a new nomenclature for VNTR II alleles to take into account these subloci.
University of Southampton
2003
Othman, Maha Ahmed
(2003)
Molecular study of Von Willebrand disease and its variants.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Von Willebrand disease is an inherited bleeding disorder characterised by mucocutaneous bleeding and structural or functional defects of the Von Willebrand factor protein. Correct diagnosis and classification of patients is crucial as it predicts the bleeding risk and directs the clinical management.
Analysis of the Gp Ib alpha gene in five members of a British family with PT-VWD revealed a novel 27 bp in-frame deletion in the macroglycopeptide region (4373 - 4400). The deletion was detected in 3 affected and not found in 2 non-affected members. Stable transfected of wild type and mutant GPIb alpha co-transfected with pZeoSV2+ into CHO β/IX cells and flowcytometry showed the mutant GPIb alpha was expressed normally, bound significantly less to the mAb WM23 and showed higher VWF binding under low ristocetin concentration than the wild type. This deletion is the likely cause of the heightened platelet response and it supports the regulatory role of the macroglycopeptide region in receptor function.
Forty-six individuals of 10 families with type 1 von Willebrand disease were evaluated both phenotypically and genotypically. Using PCR, gene scanning and restriction enzyme analysis, an allelic association with the disease phenotype was revealed with three polymorphic markers in the VWF gene (VNTR I, II in intron 40, Rsa I 18) in 5 families. The association was likely in 2 and was ruled out in the remaining 3 families. Haplotype analysis may help in making a diagnosis in family members where the phenotype is less clear particularly in cases of high penetrance. However, phenotype and analysis remains the tool that provides the security and reliability in making the diagnosis of VWD.
We demonstrate the complexity of VNTR II locus of intron 40 of the VWF gene and showed by molecular cloning and sequencing two additional subloci (VNTR II ‘b’ and VNTR II ‘c’) with tetranucleotide repeats within the same amplified region containing the original VNTR II locus (VNTR II ‘a’). Fourteen configurations of VNTR II alleles were revealed instead of the known six. Thus, there is a necessary for a new nomenclature for VNTR II alleles to take into account these subloci.
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Published date: 2003
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Local EPrints ID: 465018
URI: http://eprints.soton.ac.uk/id/eprint/465018
PURE UUID: 4f74635c-170f-4a9e-af7f-7475718c088a
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Date deposited: 05 Jul 2022 00:16
Last modified: 05 Jul 2022 00:16
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Author:
Maha Ahmed Othman
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