Analysis of von Willebrand Disease in the "Heart of Europe"

Authors: Vangenechten, I; Smejkal, P; Zavrelova, J; Zapletal, O; Wild, A; Michiels, JJ; Berneman, Z; Blatny, J; Batorova, A; Prigancova, T; Penka, M; Gadisseur, A

Affiliations: Haemostasis Unit, Antwerp University Hospital, Edegem, Belgium. Medicine and Health Sciences, Haemostasis Research Unit, Antwerp University, Antwerp, Belgium. Antwerp University, Antwerp, Belgium. Department of Clinical Haematology, University Hospital Brno, Brno, Czech Republic. Department of Laboratory Methods, Faculty of Medicine, Masaryk University, Brno, Czech Republic.

Publication: TH open; 2022; 6. e335-e346

Abstract: BACKGROUND von Willebrand disease (VWD) is a genetic bleeding disorder caused by defects of von Willebrand factor (VWF), quantitative (type 1 and 3) or qualitative (type 2). The laboratory phenotyping is heterogenic making diagnosis difficult. OBJECTIVES Complete laboratory analysis of VWD as an expansion of the previously reported cross-sectional family-based VWD study in the Czech Republic (BRNO-VWD) and Slovakia (BRA-VWD) under the name « Heart of Europe, » in order to improve the understanding of laboratory phenotype/genotype correlation. PATIENTS AND METHODS In total, 227 suspected VWD patients were identified from historical records. Complete laboratory analysis was established using all available assays, including VWF multimers and genetic analysis. RESULTS A total of 191 patients (from 119 families) were confirmed as having VWD. The majority was characterized as a type 1 VWD, followed by type 2. Multimeric patterns concordant with laboratory phenotypes were found in approximately 83% of all cases. A phenotype/genotype correlation was present in 84% (77% type 1, 99% type 2, and 61% type 3) of all patients. Another 45 candidate mutations (23 novel variations), not found in the initial study, could be identified (missense 75% and truncating 24%). An exon 1-3 gene deletion was identified in 14 patients where no mutation was found by direct DNA sequencing, increasing the linkage up to 92%, overall. CONCLUSION This study provides a cross-sectional overview of the VWD population in a part of Central Europe. It is an addition to the previously published BRNO-VWD study and provides important data to the International Society of Thrombosis and Haemostasis/European Association for Haemophilia and Allied Disorders VWD mutation database with identification of novel causal mutations.