1. Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom;
2. Department of Hematology, Herlev and Gentofte Hospital, Copenhagen, Denmark;
3. Van Creveldkliniek, Division of Internal Medicine and Dermatology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands;
4. Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands; and
5. National Institute of Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom