1. Department of Reproductive Biology (S.B., S.J., I.T.H.), Medical Research Council, Clinical Sciences Center
2. Division of Epidemiology (E.P.), Public Health and Primary Care
3. Physiological Genomics and Medicine Group (E.P., A.G., T.J.A., J.M.M.), Medical Research Council, Clinical Sciences Center
4. Section of Molecular Genetics and Rheumatology (T.J.A.), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom