Summary
Von Willebrand disease type 2M “Vicenza” (VWD 2M V) is characterised by autosomal
dominant inheritance, low von Willebrand factor (VWF) and the presence of “supranormal”
multimers in plasma. This specific phenotype has been described in Italian and recently
also in German patients. The molecular defect is linked to the VWF gene. However,
no specific mutations have been identified until now. We analysed the complete coding
region and adjacent intron sequences of the VWF gene in Italian families in comparison
to German families with VWD 2M V by a PCR-based mutation screening, combined with
SSC-and heteroduplex-analysis of exons 2 through 52, followed by direct sequencing.
We identified the first heterozygous candidate mutation (G3864A; R1205H) in all affected
members of the 7 Italian families and in 1 German patient but not in the unaffected
family members nor on 100 chromosomes of normal subjects, suggesting a causal relationship
between the mutation and the phenotype. Haplotype identity, with minor deviations
in one Italian family, suggests a common but not very recent genetic origin of R1205H.
Keywords
Von Willebrand Disease Type 2M Vicenza - von Willebrand Factor Genetics