Epidemiological investigation of the prevalence of von Willebrand’s disease. Blood. 1987; 69:454. [PubMed: 3492222

To evaluate the prevalence of von Willebrand’s disease (vWd) we carried out an epidemiological investigation among school children of the Veneto region in northern Italy. A total of 1.21 8 of 1.281 possible children partici-pated in the study. They were 1 1 to 14 years of age. and all attended secondary schools in two distinct small areas. 70 km apart. between which there is no social contact. A blood sample was taken from each subject for determina-tion of the blood group and von Willebrand factor (vWf) level (measured as ristocetin cofactor and expressed in IIJ/dL after calibration of the internal pool against an international standard). and the parents were given a questionnaire concerning hemorrhagic symptoms in the members of the family in the last three generations. Separate normal ranges were calculated for blood group