Summary
The genetic defects causing recessive type 1 and type 3 von Wille-brand disease (VWD)
in eight families from the northern part of Italy have been investigated. Mutations
were identified in 14 of the 16 disease-associated von Willebrand factor (VWF) genes.
Only one mutation, a stop codon in exon 45, was previously reported. Several new mutations
were identified: one cytosine insertion in exon 42, one guanine deletion in exon 28,
one probably complete VWF gene deletion, one substitution in the 3’ splice site of
intron 13, one possible gene conversion, and three candidate missense mutations. One
missense mutation, the substitution of a cysteine in exon 42, was identified in all
type 3 VWD patients that were previously characterized as a subgroup with significant
increase of factor VIII procoagulant activity after desmopressin infusion. This paper
demonstrates again that the molecular defects of quantitative VWD are diverse and
located throughout the entire VWF gene.