1. Department of Obstetrics and Gynaecology, Royal Free and University College Medical School, London, WC1E 6HX, United Kingdom
2. Department of Histopathology, Imperial College School of Medicine, London, W12 0HS, United Kingdom
3. Gene Therapy Research Group, Section of Cell and Molecular Biology, Division of Biomedical Sciences, Imperial College School of Medicine, London, SW7 2AZ, United Kingdom
4. Gene Therapy Research Group, Section of Cell and Molecular Biology, Division of Biomedical Sciences, Imperial College School of Medicine, London, SW7 2AZ, United Kingdom; Childrens Hospital, University of Erlangen, Loschgestr. 15, D-91054 Erlangen, Germany
5. The Royal Veterinary College, Hatfield, AL9 7TA, United Kingdom
6. Childrens Hospital, University of Erlangen, Loschgestr. 15, D-91054 Erlangen, Germany