1. Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
3. Division of Endocrinology, Department of Internal Medicine, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea.
4. Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
5. Department of Transplantation Surgery, Yonsei University Health System, Seoul, Korea.
6. Institute of Endocrine Research, Yonsei University College of Medicine, Seoul, Korea.