title: Identifying type Vicenza von Willebrand disease.
abstract: Increased clearance of von Willebrand factor (VWF) is one of the main features of type Vicenza von Willebrand disease (VWD), a variant with plasma and platelet VWF level discrepancies and unusually large VWF multimers. Diagnosing type Vicenza VWD may not be easy, due to its heterogeneous phenotype. Here we describe the criteria we adopted to identify type Vicenza in a large group of VWD patients. Emphasizing the contribution of platelet VWF by comparison with plasma values, a first step involved selecting the candidate Vicenza patients on the basis of low or very low plasma VWF and a normal platelet VWF content. After excluding type 2A and 2B VWD patients, who may have normal platelet VWF, 18 candidates were found to meet our selection criteria. Genetic analysis revealed that 15 patients (from 5 unrelated families) were type Vicenza VWD and that all carried both G2220A and G3614A type Vicenza mutations barring one, who only had the G3614A mutation. All patients had a reduced VWF survival, and all but the patient with the G3614A mutation alone had ultralarge VWF multimers. Thus, low-plasma VWF associated with a normal platelet VWF content may be a first useful indicator for identifying type Vicenza VWD patients.
authors.affiliation: Department of Medical and Surgical Sciences, University of Padua Medical School, Padua, Italy. sandra.casonato@unipd.it
authors.forename: Alessandra
authors.initials: A
authors.lastname: Casonato
authors.forename: Elena
authors.initials: E
authors.lastname: Pontara
authors.forename: Francesca
authors.initials: F
authors.lastname: Sartorello
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Cattini
authors.forename: Lisa
authors.initials: L
authors.lastname: Gallinaro
authors.forename: Antonella
authors.initials: A
authors.lastname: Bertomoro
authors.forename: Antonio
authors.initials: A
authors.lastname: Rosato
authors.forename: Roberto
authors.initials: R
authors.lastname: Padrini
authors.forename: Antonio
authors.initials: A
authors.lastname: Pagnan
mesh_terms: D001792:Blood Platelets / Q000378:metabolism; D005260:Female; D018740:Genetic Heterogeneity; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008297:Male; D010641:Phenotype; D017354:Point Mutation; D014842:von Willebrand Diseases / Q000145:classification / Q000175:diagnosis* / Q000235:genetics*; D014841:von Willebrand Factor / Q000235:genetics* / Q000378:metabolism
chemical_list: D014841:von Willebrand Factor