Summary
Molecular diagnosis of von Willebrand Disease (VWD) is particularly complex. The autosomal
von Willebrand factor gene (VWF) is large and highly polymorphic, and there is a highly homologous (>96%) partial
pseudogene in chromosome 22. Because of these difficulties, application of molecular
study of VWD to the clinical routine has been considerably delayed. Recent advances
in sequencing technology and bioinformatics could convert direct sequencing of the
complete VWF into a routine diagnostic tool for VWD, which is especially desirable in types 1
and 3. This study describes a highly optimized procedure in which all the coding and
intronic flanking regions of VWF are amplified under identical thermocycling parameters in a ready-to-use PCR plate
format. The entire sequencing procedure, from blood extraction to mutation identification,
can be done within 24 hours, resulting in a simple, versatile, cost-effective strategy
with little hands-on time requirements. To validate the method, we performed full-length
VWF sequencing of 21 index cases including seven of each VWD type. A total of 30 VWF genetic variations were identified. Twelve of these sequence variations are new,
including four missense, one nonsense, one insertion, the first insertion-deletion
described in VWF, and 5 potential splice site mutations. To our knowledge, this is the fastest and
most efficient protocol designed to date for complete sequencing of the VWF coding region in the molecular diagnosis of VWD.
Keywords
Automated DNA sequencing - molecular diagnosis - mutation analysis - von Willebrand
disease - von Willebrand factor