| 1. |
- Eikenboom, J, et al.
(författare)
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Linkage analysis in families diagnosed with type 1 von Willebrand disease in the European study, molecular and clinical markers for the diagnosis and management of type 1 VWD
- 2006
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Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 4:4, s. 774-782
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Tidskriftsartikel (refereegranskat)abstract
- Background: von Willebrand disease (VWD) type 1 is a congenital bleeding disorder caused by genetic defects in the von Willebrand factor (VWF) gene and characterized by a reduction of structurally normal VWF. The diagnosis of type 1 VWD is difficult because of clinical and laboratory variability. Furthermore, inconsistency of linkage between type 1 VWD and the VWF locus has been reported. Objectives: To estimate the proportion of type 1 VWD that is linked to the VWF gene. Patients and methods: Type 1 VWD families and healthy control individuals were recruited. An extensive questionnaire on bleeding symptoms was completed and phenotypic tests were performed. Linkage between VWF gene haplotypes and the diagnosis of type 1 VWD, the plasma levels of VWF and the severity of bleeding symptoms was analyzed. Results: Segregation analysis in 143 families diagnosed with type 1 VWD fitted a model of autosomal dominant inheritance. Linkage analysis under heterogeneity resulted in a summed lod score of 23.2 with an estimated proportion of linkage of 0.70. After exclusion of families with abnormal multimer patterns the linkage proportion was 0.46. LOD scores and linkage proportions were higher in families with more severe phenotypes and with phenotypes suggestive of qualitative VWF defects. About 40% of the total variation of VWF antigen could be attributed to the VWF gene. Conclusions: We conclude that the diagnosis of type 1 VWD is linked to the VWF gene in about 70% of families, however after exclusion of qualitative defects this is about 50%.
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| 2. |
- Lanke, E., et al.
(författare)
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Genetic analysis of 31 Swedish type 1 von Willebrand disease families reveals incomplete linkage to the von Willebrand factor gene and a high frequency of a certain disease haplotype
- 2005
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Ingår i: Journal of Thrombosis and Haemostasis. - : Wiley-Blackwell. - 1538-7933 .- 1538-7836. ; 3:12, s. 2656-2663
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The most common type of von Willebrand disease (VWD), type 1, has in only a few cases been explained by an identified causative mutation in the von Willebrand factor (VWF) gene. The ABO blood group and other modifier loci outside the VWF gene may contribute to the development of type 1 VWD. OBJECTIVES AND METHODS: Our aim was to determine whether there was genetic linkage to the VWF gene in 31 Swedish type 1 VWD families. Stringent diagnostic criteria in accordance with ISTH guidelines were used. Genetic linkage was investigated by using two highly informative dinucleotide microsatellite markers, which we have recently identified, located in introns six and 15 of the VWF gene. We also investigated the existence of common disease haplotypes and the relation between type 1 VWD and ABO blood group. RESULTS: We found genetic linkage to the VWF gene in 27 (87%) of the families. However, in four (13%) of the families, there was clearly no genetic linkage. We found the 4751A>G (Tyr1584Cys) sequence variation in exon 28, which is a common mutation in the Canadian VWD population (14.3%), in only one of the 31 families (3.2%). A possible common mutation was identified in six of the 27 (22%) families with genetic linkage. Blood group O was over-represented among type 1 VWD patients. CONCLUSION: We conclude that there is linkage between the VWF gene and hereditary type 1 VWD in a majority of families.
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| 3. |
- Lanke, E., et al.
(författare)
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Co-segregation of the PROS1 locus and protein S deficiency in families having no detectable mutations in PROS1
- 2004
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Ingår i: Journal of Thrombosis and Haemostasis. - : Wiley-Blackwell. - 1538-7933 .- 1538-7836. ; 2:11, s. 1918-1923
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Tidskriftsartikel (refereegranskat)abstract
- Inherited deficiency of protein S constitutes an important risk factor of venous thrombosis. Many reports have demonstrated that causative mutations in the protein S gene are found only in approximately 50% of the cases with protein S deficiency. It is uncertain whether the protein S gene is causative in all cases of protein S deficiency or if other genes are involved in cases where no mutation is identified. The aim of the current study was to determine whether haplotypes of the protein S gene cosegregate with the disease phenotype in cases where no mutations have been found. Eight protein S-deficient families comprising 115 individuals where previous DNA sequencing had failed to detect any causative mutations were analyzed using four microsatellite markers in the protein S gene region. Co-segregation between microsatellite haplotypes and protein S deficiency was found in seven of the investigated families, one family being uninformative. This suggests that the causative genetic defects are located in or close to the protein S gene in a majority of such cases where no mutations have been found.
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