[1] Barts & London, Queen Marys Sch Med & Dent, Dept Haematol, UKHCDO von Willebrands Dis Working Party, London E1 2AD, England
[2] Hammersmith Hosp, Imperial Coll, Dept Haematol, London, England
[3] Royal Free Hosp, Dept Haematol, London NW3 2QG, England
[4] Univ Wales Hosp, Dept Haematol, Cardiff CF4 4XN, S Glam, Wales
[5] Manchester Royal Infirm, Dept Haematol, Manchester M13 9WL, Lancs, England
[6] Birmingham Childrens Hosp, Dept Haematol, Birmingham, W Midlands, England
[7] Churchill Hosp, Dept Haematol, Oxford OX3 7LJ, England
[8] Royal Hallamshire Hosp, Div Genom Med, Sheffield S10 2JF, S Yorkshire, England