Suk-Kyun Yang^{1, #}, Myunghee Hong^{2, #}, Hyunjung Oh², Hui-Qi Low², Seulgi Jung², Seonjoo Ahn², Youngjin Kim², Jiwon Baek², Cue Hyunkyu Lee³, Eunji Kim^{3, 4}, Kyung Mo Kim⁵, Byong Duk Ye¹, Kyung-Jo Kim¹, Sang Hyoung Park¹, Ho-Su Lee¹, Inchul Lee⁶, Hyoung Doo Shin⁷, Buhm Han³, Dermot P.B. McGovern⁸, Jianjun Liu⁹, Kyuyoung Song<sup>2,*

1</sup> Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea
² Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736, Korea
³ Department of Convergence Medicine, University of Ulsan College of Medicine & Asan Institute for Life Sciences, Asan Medical Center, Seoul 138-736, Korea
⁴ Department of Chemistry, Seoul National University, Seoul 151-742, Korea
⁵ Department of Pediatrics, Asan Medical Center Children’s Hospital, University of Ulsan College of Medicine, Seoul 138-736, Korea
⁶ Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea
⁷ Department of Life Science, Sogang University, Seoul 121-742, Korea
⁸ The F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute; Cedars-Sinai Medical Center, Los Angeles, California, United States of America
⁹ Human Genetics Group, Genome Institute of Singapore, Singapore

^*Correspondence should be addressed to: Kyuyoung Song, Ph.D., Dept. of Biochemistry and Molecular Biology, Univ. of Ulsan College of Medicine, 88, Olympic-ro, 43-gil, Songpa-Gu, Seoul 138-736, Korea,

^# Authors named in bold designate shared co-first authoprship.

Abstract
Recent genome-wide association studies (GWAS) have identified more than 200 regions that affect susceptibility to inflammatory bowel disease (IBD). However, identified common variants account for only a fraction of IBD heritability and have largely been identified in populations of European ancestry. We performed a GWAS of susceptibility loci in Korean individuals, comprising a total of 1,505 IBD patients and 4,041 controls. We identified 2 new susceptibility loci for IBD at genome-wide significance: rs3766920 near PYGO2-SHC1 at 1q21 and rs16953946 in CDYL2 at 16q23. In addition, we confirmed associations, in Koreans, with 28 established IBD loci (P < 2.16 × 10^-4). Our findings support the complementary value of genetic studies in different populations.

Keywords : Crohn’s disease; ulcerative colitis; genetics; risk factor