Su-Hyun Kim, Eun-Jae Lee, Young-Min Lim, Hyunjin Kim, Ju-Hong Min, Seung Ho Choo, Byoung Joon Kim, Sung-Min Kim, Dong Seok Ohn, Ha Young Shin, Ki Hoon Kim, Young Nam Kwon, S I Kim, Jae‐Joong Kim, Woojun Kim, Eunhee Sohn, Sooyoung Kim, Jin Myoung Seok, T. S. Nam, You-Ri Kang, Minsu Park, Kyong Jin Shin, Byung-Jo Kim, Seol‐Hee Baek, Jin-Woo Park, Sun‐Young Oh, Young Eun Park, Yoon‐Ho Hong, Suk-Won Ahn, Woohee Ju, Jeeyoung Oh, Hye Lim Lee, Tae-Kyeong Lee, Byeong-Jun Jeon, Nam-Hee Kim, Sunyoung Kim, Soonwook Kwon, Byeol‐A Yoon, Jong Kuk Kim, Jinseok Park, Jeong Bin Bong, Eun Bin Cho, Yoo Hwan Kim, Jong Seok Bae, Seong-il Oh, Yoon Sung Sang, Jiwon Yang, Do-Hyung Kim, Jae‐Joong Kim, Juhyeon Kim, Hyun-June Shin, O.M. Kwon, Ahwon Kim, Sa‐Yoon Kang, Jung Im Seok, Minsung Kang, Joo Hye Sung, Hung Youl Seok, J Shin, Jae-Hwan Choi, Dae-Seong Kim, Je Hong Min, In Soo Joo, Jung Min So, Jae-Won Hyun, Ho Jin Kim
OBJECTIVES: To provide the clinically validated, nationwide estimates of multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) in Korea, and to describe their relative proportions. METHODS: From January to March 2025, 47 referral hospitals participating in a nationwide hospital-based registry identified actively followed patients with MS, NMOSD, or MOGAD. Diagnoses followed international criteria, and antibody status was confirmed using validated CBAs. Actively followed patients had ≥1 outpatient visit in the prior 6 months. Centers provided demographics, treatments, and Expanded Disability Status Scale. Prevalence used national population data. RESULTS: A total of 4,196 patients were identified, 1,799 MS, 1,616 NMOSD, and 781 MOGAD (ratio 2.3:2.1:1). Mean age at onset was 33.4 ± 12.0 years for MS, 42.7 ± 14.7 for NMOSD, and 41.7 ± 17.8 for MOGAD, and the female-to-male ratios were 2.2:1 for MS, 5.1:1 for NMOSD (6.5:1 in aquaporin-4-IgG positive cases), and 1.5:1 for MOGAD. Crude prevalence estimates were 3.48, 3.13, and 1.51 per 100,000, respectively. DISCUSSION: This nationwide registry demonstrates a distinctive Korean CNS inflammatory demyelinating disease profile, with a relatively higher proportion of NMOSD and MOGAD reflecting the low prevalence of MS in East Asia.