1.Age-Stratified Genetic Spectrum of Retinitis Pigmentosa in Korean Patients: Predominance of RPGR Variants in Early-Onset Disease
Youn-Ji HONG ; Sungsoon HWANG ; Ja-Hyun JANG ; Jong-Won KIM ; Sang Jin KIM ; Mi-Ae JANG
Annals of Laboratory Medicine 2026;46(2):200-209
Background:
Retinitis pigmentosa (RP) comprises a heterogeneous group of inherited retinal dystrophies. The genetic landscape of RP has been characterized; however, knowledge gaps regarding age-specific genetic variation trends in Korean patients remain. We comprehensively characterized the age-stratified genetic landscape of RP in Korean patients, with a focus on identifying novel mutational trends and clinically actionable insights.
Methods:
We performed targeted next-generation sequencing of 199 genes associated with RP and related disorders in a cohort of 403 unrelated patients clinically diagnosed as having RP. We analyzed the inheritance patterns, variation spectrum, and prevalence of pathogenic variants, stratifying the results by age, and conducted copy number variation (CNV) analysis.
Results:
A genetic diagnosis was achieved for 193 of the 403 patients (48%). The diagnostic yield was highest in patients diagnosed before 20 yrs of age (60%), with lower yields in older age groups. Although USH2A and EYS, the most common causative genes in autosomal recessive inheritance, were frequently identified, RPGR pathogenic variants accounted for a significantly larger proportion of genetically solved cases diagnosed before the age of 20 yrs (27%–28%) than in those with later-onset disease (9%–15%). CNVs were identified in 4% of genetically solved cases.
Conclusions
The results underscore distinct, age-related genetic contributions to RP in Korean patients, with RPGR variants demonstrating relevance in early-onset disease, and provide diagnostic insights to improve current practices. These findings can aid in prioritizing gene therapy targets and refining screening strategies.
2.Dynamics of T Cell-Mediated Immune Signaling Network During Pathogenesis of Chronic Obstructive Pulmonary Disease
Chae Min LEE ; Andrew Sehoon KIM ; Minki KIM ; Jae Woong JEONG ; Sugyeong JO ; Nahee HWANG ; Sungsoon FANG
Yonsei Medical Journal 2025;66(6):354-365
Purpose:
Chronic obstructive pulmonary disease (COPD) is characterized by alveolar destruction and increased inflammation, leading to respiratory symptoms. This study aimed to identify the traits for COPD progression from mild to severe stages. Additionally, we explored the correlation between coronavirus disease-2019 (COVID-19) and COPD to uncover overlapping respiratory patterns.
Materials and Methods:
Bulk RNA sequencing was conducted on data from 43 healthy individuals and 39 COPD patients across one dataset (GSE239897) to distinguish COPD characteristics. Single-cell RNA analysis was then performed on samples from seven mild patients, seven moderate patients, and three severe patients from three datasets (GSE167295, GSE173896, and GSE227691) to analyze disease progression. Finally, single-nuclei RNA analysis was applied to data from seven healthy individuals and 20 COVID-19 patients from one dataset (GSE171524) to compare the two conditions.
Results:
Bulk RNA sequencing revealed enhanced inflammatory pathways in COPD patients, indicating increased inflammation.Single-cell RNA sequencing showed a stronger inflammatory response from mild to moderate COPD with a decrease from moderate to severe stages. COVID-19 displayed similar biological patterns to moderate COPD, suggesting that stage-specific COPD analysis could enhance COVID-19 management.
Conclusion
The analysis found that immune responses increased from mild to moderate stages but declined in severe cases, marked by reduced pulmonary T cell activation. The overlap between moderate COPD and COVID-19 suggests shared therapeutic strategies, warranting further investigation.
3.Dynamics of T Cell-Mediated Immune Signaling Network During Pathogenesis of Chronic Obstructive Pulmonary Disease
Chae Min LEE ; Andrew Sehoon KIM ; Minki KIM ; Jae Woong JEONG ; Sugyeong JO ; Nahee HWANG ; Sungsoon FANG
Yonsei Medical Journal 2025;66(6):354-365
Purpose:
Chronic obstructive pulmonary disease (COPD) is characterized by alveolar destruction and increased inflammation, leading to respiratory symptoms. This study aimed to identify the traits for COPD progression from mild to severe stages. Additionally, we explored the correlation between coronavirus disease-2019 (COVID-19) and COPD to uncover overlapping respiratory patterns.
Materials and Methods:
Bulk RNA sequencing was conducted on data from 43 healthy individuals and 39 COPD patients across one dataset (GSE239897) to distinguish COPD characteristics. Single-cell RNA analysis was then performed on samples from seven mild patients, seven moderate patients, and three severe patients from three datasets (GSE167295, GSE173896, and GSE227691) to analyze disease progression. Finally, single-nuclei RNA analysis was applied to data from seven healthy individuals and 20 COVID-19 patients from one dataset (GSE171524) to compare the two conditions.
Results:
Bulk RNA sequencing revealed enhanced inflammatory pathways in COPD patients, indicating increased inflammation.Single-cell RNA sequencing showed a stronger inflammatory response from mild to moderate COPD with a decrease from moderate to severe stages. COVID-19 displayed similar biological patterns to moderate COPD, suggesting that stage-specific COPD analysis could enhance COVID-19 management.
Conclusion
The analysis found that immune responses increased from mild to moderate stages but declined in severe cases, marked by reduced pulmonary T cell activation. The overlap between moderate COPD and COVID-19 suggests shared therapeutic strategies, warranting further investigation.
4.Dynamics of T Cell-Mediated Immune Signaling Network During Pathogenesis of Chronic Obstructive Pulmonary Disease
Chae Min LEE ; Andrew Sehoon KIM ; Minki KIM ; Jae Woong JEONG ; Sugyeong JO ; Nahee HWANG ; Sungsoon FANG
Yonsei Medical Journal 2025;66(6):354-365
Purpose:
Chronic obstructive pulmonary disease (COPD) is characterized by alveolar destruction and increased inflammation, leading to respiratory symptoms. This study aimed to identify the traits for COPD progression from mild to severe stages. Additionally, we explored the correlation between coronavirus disease-2019 (COVID-19) and COPD to uncover overlapping respiratory patterns.
Materials and Methods:
Bulk RNA sequencing was conducted on data from 43 healthy individuals and 39 COPD patients across one dataset (GSE239897) to distinguish COPD characteristics. Single-cell RNA analysis was then performed on samples from seven mild patients, seven moderate patients, and three severe patients from three datasets (GSE167295, GSE173896, and GSE227691) to analyze disease progression. Finally, single-nuclei RNA analysis was applied to data from seven healthy individuals and 20 COVID-19 patients from one dataset (GSE171524) to compare the two conditions.
Results:
Bulk RNA sequencing revealed enhanced inflammatory pathways in COPD patients, indicating increased inflammation.Single-cell RNA sequencing showed a stronger inflammatory response from mild to moderate COPD with a decrease from moderate to severe stages. COVID-19 displayed similar biological patterns to moderate COPD, suggesting that stage-specific COPD analysis could enhance COVID-19 management.
Conclusion
The analysis found that immune responses increased from mild to moderate stages but declined in severe cases, marked by reduced pulmonary T cell activation. The overlap between moderate COPD and COVID-19 suggests shared therapeutic strategies, warranting further investigation.
5.Dynamics of T Cell-Mediated Immune Signaling Network During Pathogenesis of Chronic Obstructive Pulmonary Disease
Chae Min LEE ; Andrew Sehoon KIM ; Minki KIM ; Jae Woong JEONG ; Sugyeong JO ; Nahee HWANG ; Sungsoon FANG
Yonsei Medical Journal 2025;66(6):354-365
Purpose:
Chronic obstructive pulmonary disease (COPD) is characterized by alveolar destruction and increased inflammation, leading to respiratory symptoms. This study aimed to identify the traits for COPD progression from mild to severe stages. Additionally, we explored the correlation between coronavirus disease-2019 (COVID-19) and COPD to uncover overlapping respiratory patterns.
Materials and Methods:
Bulk RNA sequencing was conducted on data from 43 healthy individuals and 39 COPD patients across one dataset (GSE239897) to distinguish COPD characteristics. Single-cell RNA analysis was then performed on samples from seven mild patients, seven moderate patients, and three severe patients from three datasets (GSE167295, GSE173896, and GSE227691) to analyze disease progression. Finally, single-nuclei RNA analysis was applied to data from seven healthy individuals and 20 COVID-19 patients from one dataset (GSE171524) to compare the two conditions.
Results:
Bulk RNA sequencing revealed enhanced inflammatory pathways in COPD patients, indicating increased inflammation.Single-cell RNA sequencing showed a stronger inflammatory response from mild to moderate COPD with a decrease from moderate to severe stages. COVID-19 displayed similar biological patterns to moderate COPD, suggesting that stage-specific COPD analysis could enhance COVID-19 management.
Conclusion
The analysis found that immune responses increased from mild to moderate stages but declined in severe cases, marked by reduced pulmonary T cell activation. The overlap between moderate COPD and COVID-19 suggests shared therapeutic strategies, warranting further investigation.
6.Dynamics of T Cell-Mediated Immune Signaling Network During Pathogenesis of Chronic Obstructive Pulmonary Disease
Chae Min LEE ; Andrew Sehoon KIM ; Minki KIM ; Jae Woong JEONG ; Sugyeong JO ; Nahee HWANG ; Sungsoon FANG
Yonsei Medical Journal 2025;66(6):354-365
Purpose:
Chronic obstructive pulmonary disease (COPD) is characterized by alveolar destruction and increased inflammation, leading to respiratory symptoms. This study aimed to identify the traits for COPD progression from mild to severe stages. Additionally, we explored the correlation between coronavirus disease-2019 (COVID-19) and COPD to uncover overlapping respiratory patterns.
Materials and Methods:
Bulk RNA sequencing was conducted on data from 43 healthy individuals and 39 COPD patients across one dataset (GSE239897) to distinguish COPD characteristics. Single-cell RNA analysis was then performed on samples from seven mild patients, seven moderate patients, and three severe patients from three datasets (GSE167295, GSE173896, and GSE227691) to analyze disease progression. Finally, single-nuclei RNA analysis was applied to data from seven healthy individuals and 20 COVID-19 patients from one dataset (GSE171524) to compare the two conditions.
Results:
Bulk RNA sequencing revealed enhanced inflammatory pathways in COPD patients, indicating increased inflammation.Single-cell RNA sequencing showed a stronger inflammatory response from mild to moderate COPD with a decrease from moderate to severe stages. COVID-19 displayed similar biological patterns to moderate COPD, suggesting that stage-specific COPD analysis could enhance COVID-19 management.
Conclusion
The analysis found that immune responses increased from mild to moderate stages but declined in severe cases, marked by reduced pulmonary T cell activation. The overlap between moderate COPD and COVID-19 suggests shared therapeutic strategies, warranting further investigation.
7.DGAT2 Plays a Crucial Role to Control ESRRAPROX1 Transcriptional Network to Maintain Hepatic Mitochondrial Sustainability
Yoseob LEE ; Yeseong HWANG ; Minki KIM ; Hyeonuk JEON ; Seyeon JOO ; Sungsoon FANG ; Jae-Woo KIM
Diabetes & Metabolism Journal 2024;48(5):901-914
Background:
Diacylglycerol O-acyltransferase 2 (DGAT2) synthesizes triacylglycerol (TG) from diacylglycerol; therefore, DGAT2 is considered as a therapeutic target for steatosis. However, the consequence of inhibiting DGAT2 is not fully investigated due to side effects including lethality and lipotoxicity. In this article, we observed the role of DGAT2 in hepatocarcinoma.
Methods:
The role of DGAT2 is analyzed via loss-of-function assay. DGAT2 knockdown (KD) and inhibitor treatment on HepG2 cell line was analyzed. Cumulative analysis of cell metabolism with bioinformatic data were assessed, and further compared with different cohorts of liver cancer patients and non-alcoholic fatty liver disease (NAFLD) patients to elucidate how DGAT2 is regulating cancer metabolism.
Results:
Mitochondrial function is suppressed in DGAT2 KD HepG2 cell along with the decreased lipid droplets. In the aspect of the cancer, DGAT2 KD upregulates cell proliferation. Analyzing transcriptome of NAFLD and hepatocellular carcinoma (HCC) patients highlights negatively correlating expression patterns of 73 lipid-associated genes including DGAT2. Cancer patients with the lower DGAT2 expression face lower survival rate. DGAT2 KD cell and patients’ transcriptome show downregulation in estrogen- related receptor alpha (ESRRA) via integrated system for motif activity response analysis (ISMARA), with increased dimerization with corepressor prospero homeobox 1 (PROX1).
Conclusion
DGAT2 sustains the stability of mitochondria in hepatoma via suppressing ESRRA-PROX1 transcriptional network and hinders HCC from shifting towards glycolytic metabolism, which lowers cell proliferation.
8.Epidemiology of Inherited Retinal Diseases in Korea: A National Health Information Database Analysis (2011-2020)
Hee Jee YUN ; Sungsoon HWANG ; Sang Jin KIM
Journal of the Korean Ophthalmological Society 2024;65(9):605-613
Purpose:
We evaluated the incidence and prevalence of inherited retinal diseases (IRDs) in Korea using a national database.
Methods:
This retrospective study used the National Health Information Database to enroll patients with IRDs (registration code V209) between January 2011 and December 2020. Incidence and prevalence of IRDs were analyzed and stratified by age, sex, geographic location, and socioeconomic status.
Results:
During the study period, 10,228 patients were diagnosed with IRD, yielding an annual incidence rate of 1.60–2.35 per 100,000 individuals. In 2020, the prevalence of IRD reached 27.1 cases per 100,000 individuals. Initial diagnoses were primarily concentrated in Seoul (44.4%), metropolitan areas (29.4%), and Gyeonggi province (12.1%). Notably, less than 50% of patients received their initial diagnosis in their home region, except for residents of Seoul (94.0%), metropolitan areas (76.8%), and Jeju Island (70.8%). The incidence of IRDs was higher among the top 25% income bracket, compared to other income levels.
Conclusions
Our study provides the first nationwide, population-based estimates of IRD incidence and prevalence in Korea. Our findings reveal significant regional and socioeconomic disparities in IRD healthcare access, emphasizing the need for targeted interventions.

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