1. Department of General Internal Medicine and Psychosomatics, University of Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany
2. Department of Gastroenterology, Infectious Diseases and Intoxications, University of Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany
3. Institute of Human Genetics, Department of Human Molecular Genetics, University of Heidelberg, Im Neuenheimer Feld 366, D-69120 Heidelberg, Germany
4. Department of Psychosomatic Medicine, Division of Internal Medicine, University Hospital Basel, Hebelstrasse 2, CH-4031 Basel, Switzerland
5. Faculty of Medicine, University of Basel, Klingelbergstrasse 61, CH-4056 Basel, Switzerland