1. Department of Nephrology and Rheumatology, Georg-August University Goettingen, Robert-Koch-Strasse 40, D-37075 Goettingen, Germany, Institute of Human Genetics, Georg-August University Goettingen, Heinrich-Dueker-Weg 12, D-37073 Goettingen, Germany, Proteomics Group, Max-Planck-Institute of Experimental Medicine, Hermann-Rein-Strasse 3, D-37075 Goettingen, Germany, and Deutsche Forschungsgemeinschaft Research Center for Molecular Physiology of the Brain, Humboldtallee 23, D-37073 Goettingen, Germany