1. National Clinical Guideline Centre; Royal College of Physicians of London; 11 St Andrews Place; London; NW1 4LE; U.K
2. Symmetron Ltd; Kinetic Centre; Theobald St, Borehamwood; WD6 4PJ; U.K
3. Faculty of Health and Social Care; University of Hull; Hull; HU6 7RX; U.K
4. Division of Medicine and Molecular Genetics; St John's Institute of Dermatology; Guy's Hospital; London; SE1 9RT; U.K