1. Medical Faculty, Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center (DDZ), Heinrich Heine University , Duesseldorf D-40225 , Germany
2. German Center for Diabetes Research (DZD) , Partner Düsseldorf / Partner Potsdam, Munich-Neuherberg , Germany
3. Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics , Berlin D-14195 , Germany
4. Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke , Nuthetal D-14558 , Germany
5. Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig , Leipzig D-04103 , Germany