1. Department of Endocrinology, Diabetes and Metabolism, Clinical Chemistry – Division of Laboratory Research, University Hospital Essen, University Duisburg-Essen, Essen, Germany
2. Endocrine Practice, Molecular Laboratory, Heidelberg, Germany
3. Endocrine and Nuclear Medicine Center Lüneburg, Lüneburg, Germany
4. Private Endocrine Practice, Essen, Germany
5. Endocrinology and Diabetes Department, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University Bochum, Bochum, Germany
6. Department of Nuclear Medicine, Medical Faculty, University Duisburg-Essen, Essen, Germany
7. Experimental and Clinical Endocrinology, Medical Clinic I, University of Luebeck, Luebeck, Germany
8. Institute for Genetics and Functional Genome Research, University of Greifswald, Greifswald, Germany
9. Department of Medical Endocrinology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark