biostudies-literatureKim SYKorea Centers for Disease Control and Prevention372https://www.ebi.ac.uk/biostudies/studies/S-EPMC9548182biostudies-literatureUnknown17(1)<h4>Background</h4>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.<h4>Results</h4>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 phenotOrphanet journal of rare diseasesThe Korean undiagnosed diseases program phase I: expansion of the nationwide network and the development of long-term infrastructure.PMC95481822018-ER6901-022020-ER6903-012021-ER0701-00Lee SKim SYLee JEKook HKim KJKim HPark SSCho AKo JMRyu DSChoi MKang KSKim YOCheon CKKim YJLim BCKim WSChoi JEPark SGKim MJSohn YBCha HJShim YJang SSWoo HKwon SCho YGChoi HJHwang HSeong MWChoi SALee YJChae JHPark SKim JSKee YHan JSong MRKwon YSBaek STKo YJMoon JfalseThe Korean undiagnosed diseases program phase I: expansion of the nationwide network and the development of long-term infrastructure.<h4>Background</h4>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.<h4>Results</h4>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 phenot2022-01-01T00:00:00Z2022 Oct2026-04-08T18:18:49.791Z2025-02-19T01:28:00.353ZS-EPMC95481823620918710.1186/s13023-022-02520-5