1. Department of Medicine, University of Dresden and Center for Regenerative Therapies-Dresden, Dresden, Germany
2. First Department of Pediatrics, Athens University Medical School, Athens, Greece
3. Laboratory of Molecular Biology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
4. Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA