[1] Univ Helsinki, Cent Hosp, Dept Dermatol, FIN-00250 Helsinki, Finland
[2] Great Ormond St Hosp Sick Children, London WC1N 3JH, England
[3] Royal Free Hosp, London NW3 2QG, England
[4] Univ Amsterdam, Acad Med Ctr, NL-1105 AZ Amsterdam, Netherlands
[5] Univ Oulu, Cent Hosp, SF-90220 Oulu, Finland
[6] Radboud Univ Nijmegen, Med Ctr, Nijmegen, Netherlands
[7] Alder Hey Childrens Hosp, Liverpool L12 2AP, Merseyside, England
[8] St Thomas Hosp, St Johns Inst Dermatol, Skin Therapy Res Unit, London, England
[9] Tampere Univ Hosp, Tampere, Finland
[10] Univ Szeged, Szeged, Hungary