The Korean undiagnosed diseases program phase I: expansion of the nationwide network and the development of long-term infrastructure

Soo Yeon Kim, Seungbok Lee, Hyewon Woo, Jiyeon Han, Young Jun Ko, Youngkyu Shim, Soojin Park, Se Song Jang, Byung Chan Lim, Jung Min Ko, Ki Joong Kim, Anna Cho, Hunmin Kim, Hee Hwang, Ji Eun Choi, Man Jin Kim, Jangsup Moon, Moon Woo Seong, Sung Sup Park, Sun Ah ChoiJi Eun Lee, Young Se Kwon, Young Bae Sohn, Jon Soo Kim, Won Seop Kim, Yun Jeong Lee, Soonhak Kwon, Young Ok Kim, Hoon Kook, Yong Gon Cho, Chong Kun Cheon, Ki Soo Kang, Mi Ryoung Song, Young Joon Kim, Hyuk Jin Cha, Hee Jung Choi, Yun Kee, Sung Gyoo Park, Seung Tae Baek, Murim Choi, Dong Sung Ryu, Jong Hee Chae

Research output: Contribution to journalArticlepeer-review


Background: Phase I of the Korean Undiagnosed Diseases Program (KUDP), performed for 3 years, has been completed. The Phase I program aimed to solve the problem of undiagnosed patients throughout the country and develop infrastructure, including a data management system and functional core laboratory, for long-term translational research. Herein, we share the clinical experiences of the Phase I program and introduce the activities of the functional core laboratory and data management system. Results: During the program (2018–2020), 458 patients were enrolled and classified into 3 groups according to the following criteria: (I) those with a specific clinical assessment which can be verified by direct testing (32 patients); (II) those with a disease group with genetic and phenotypic heterogeneity (353 patients); and (III) those with atypical presentations or diseases unknown to date (73 patients). All patients underwent individualized diagnostic processes based on the decision of an expert consortium. Confirmative diagnoses were obtained for 242 patients (52.8%). The diagnostic yield was different for each group: 81.3% for Group I, 53.3% for Group II, and 38.4% for Group III. Diagnoses were made by next-generation sequencing for 204 patients (84.3%) and other genetic testing for 35 patients (14.5%). Three patients (1.2%) were diagnosed with nongenetic disorders. The KUDP functional core laboratory, with a group of experts, organized a streamlined research pipeline covering various resources, including animal models, stem cells, structural modeling and metabolic and biochemical approaches. Regular data review was performed to screen for candidate genes among undiagnosed patients, and six different genes were identified for functional research. We also developed a web-based database system that supports clinical cohort management and provides a matchmaker exchange protocol based on a matchbox, likely to reinforce the nationwide clinical network and further international collaboration. Conclusions: The KUDP evaluated the unmet needs of undiagnosed patients and established infrastructure for a data-sharing system and future functional research. The advancement of the KUDP may lead to sustainable bench-to-bedside research in Korea and contribute to ongoing international collaboration.

Original languageEnglish
Article number372
JournalOrphanet Journal of Rare Diseases
Issue number1
StatePublished - Dec 2022
Externally publishedYes


  • Data sharing
  • Rare disease
  • Translational research
  • Undiagnosed disease program


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