Genetic mutations in von Willebrand disease identified by DHPLC and DNA sequence analysis

Abstract

Von Willebrand disease (VWD) is a common inherited bleeding disorder caused by quantitative (types 1 and 3) and qualitative (type 2) defects in von Willebrand factor (VWF). The VWF gene is a large gene containing 52 exons; except for type 2 VWD, the majority of mutations causing VWD are not localized to specific exons. We have used denaturing high performance liquid chromatography (DHPLC) to scan the coding region of the VWF gene for sequence variations. Primers were designed to amplify all 52 exons while avoiding amplification of the VWF pseudogene. Exon-specific primers were designed with sequencing primers, allowing direct sequencing of each VWF exon. Sequence variations in 33 previously characterized von Willebrand disease (VWD) samples were all detected using DHPLC demonstrating the high sensitivity of this technique. In addition, we analyzed 42 patients or family members with VWD. Thirty-two novel sequence variations were identified (2 deletions, 2 nonsense, 15 missense, 6 silent, and 7 intronic), some with clear functional consequences. A previously described deletion in exon 18, 2435delC, was also found in two unrelated type 3 patients. This DHPLC and DNA sequencing technique will enable the full length assessment of the VWF gene necessary to detect mutations causing types 1 and 3 VWD.