1. Department of Pathology, University of Geneva, 1211 Geneva 4, Switzerland
2. Rheumatology Section, Hammersmith Campus, Imperial College School of Medicine, London W12 0NN, United Kingdom
3. Department of Molecular Genetics, Chiba University Graduate School of Medicine, Chiba 260, Japan
4. Department of Human and Clinical Genetics, Leiden University Medical Center, 2300 RA Leiden, Netherlands
5. Center for Blood Research and Department of Pathology, Harvard Medical School, Boston, MA 02115