1. Musculoskeletal Research Group, Institute of Cellular Medicine, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
2. Department of Biology, The University of York, York YO10 5YW, UK
3. Department of Rheumatology, The James Cook University Hospital, Middlesbrough TS4 3BW, UK
4. Human Genetics Laboratory, SSEHS, Loughborough University, Loughborough LE11 3TU, UK
5. MRC Environmental Epidemiology Unit, University of Southampton, Southampton SO16 6YD, UK