Thromb Haemost 2006; 96(06): 711-716
DOI: 10.1160/TH06-07-0417
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

Combined partial exon skipping and cryptic splice site activation as a new molecular mechanism for recessive type 1 von Willebrand disease

Lisa Gallinaro
1   University of Padua Medical School, Department of Medical and Surgical Sciences, Second Chair of Internal Medicine, Padua, Italy
,
Francesca Sartorello
1   University of Padua Medical School, Department of Medical and Surgical Sciences, Second Chair of Internal Medicine, Padua, Italy
,
Elena Pontara
1   University of Padua Medical School, Department of Medical and Surgical Sciences, Second Chair of Internal Medicine, Padua, Italy
,
Maria Grazia Cattini
1   University of Padua Medical School, Department of Medical and Surgical Sciences, Second Chair of Internal Medicine, Padua, Italy
,
Antonella Bertomoro
1   University of Padua Medical School, Department of Medical and Surgical Sciences, Second Chair of Internal Medicine, Padua, Italy
,
Lucia Bartoloni
1   University of Padua Medical School, Department of Medical and Surgical Sciences, Second Chair of Internal Medicine, Padua, Italy
,
Antonio Pagnan
1   University of Padua Medical School, Department of Medical and Surgical Sciences, Second Chair of Internal Medicine, Padua, Italy
,
Alessandra Casonato
1   University of Padua Medical School, Department of Medical and Surgical Sciences, Second Chair of Internal Medicine, Padua, Italy
› Author Affiliations

Financial support: This work was supported by grants from the Telethon Foundation and MURST (60%, 2003).
Further Information

Publication History

Received 31 July 2006

Accepted after resubmission 09 October 2006

Publication Date:
29 November 2017 (online)

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Summary

We describe the complex picture associated with a mutated splice junction in intron 13 of von Willebrand factor (VWF) gene. The proband, characterized by a marked decrease in plasma and platelet VWF and near normal multimer organization, was classified as recessive type 1 von Willebrand disease (VWD). Genetic analysis demonstrated that he was homozygous for the 1534–3C>A mutation in the consensus sequence of the acceptor splicing site of intron 13 of the VWF gene. Platelet mRNA analysis documented three VWF transcripts: a wild type generated by the correct recognition of the mutated splice site, a smaller transcript not containing exon 14, and a longer one that, in addition to exons 13 and 14, included a 62bp fragment corresponding to the end of intron 13. The small transcript derives from the skipping of exon 14, the long one from the activation of a cryptic splice site in intron 13; both show a premature stop codon inVWF propeptide, so the probandVWF derives entirely from the correct splice site recognition. Combined incomplete exon skipping and cryptic splice site activation are first recognized in VWD. Since the 1534–3C>A mutation does not abolish the normal processing of mRNA, it is unlikely to be found in type 3VWD. This mutation therefore appears to be peculiar to type 1 VWD.