[1] Manchester Royal Infirm, Dept Clin Haematol, Manchester M13 9WL, Lancs, England
[2] UCL Royal Free & Univ Coll Med Sch, Haemophilia Ctr, London, England
[3] UCL Royal Free & Univ Coll Med Sch, Haemostasis Unit, London, England
[4] Royal Hosp Sick Children, Yorkhill NHS Trust, Dept Haematol, Glasgow G3 8SJ, Lanark, Scotland
[5] Bradford Royal Infirm, Haemophilia Ctr, Bradford BD9 6RJ, W Yorkshire, England
[6] Univ Hosp Birmingham, Dept Haematol, Birmingham, W Midlands, England
[7] Birmingham Childrens Hosp, Dept Clin & Lab Haematol, Birmingham, W Midlands, England
[8] Univ Wales Hosp, Arthur Bloom Haemophilia Ctr, Cardiff CF4 4XW, S Glam, Wales
[9] Royal Hallamshire Hosp, Sheffield Haemophilia & Thrombosis Ctr, Sheffield S10 2JF, S Yorkshire, England
[10] Univ Nottingham Hosp, Queens Med Ctr, Dept Haematol, Nottingham NG7 2UH, England
[11] Bristol Haematol & Oncol Ctr, Bristol Haemophilia Ctr, Bristol, Avon, England