Background: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by tumors in multiple endocrine organs, caused by variants in the MEN1 gene. This study analyzed the clinical and genetic features of MEN1 in a Korean cohort, identifying prevalent manifestations and genetic variants, including novel variants. Methods: This multicenter retrospective study reviewed the medical records of 117 MEN1 patients treated at three tertiary centers in Korea between January 2012 and September 2022. Patient demographics, tumor manifestations, outcomes, and MEN1 genetic testing results were collected. Variants were classified using American College of Medical Genetics and Genomics (ACMG) and French Oncogenetics Network of Neuroendocrine Tumors propositions (TENGEN) guidelines. Results: A total of 117 patients were enrolled, including 55 familial cases, with a mean age at diagnosis of 37.4±15.3 years. Primary hyperparathyroidism was identified as the most common presentation (84.6%). The prevalence of gastroenteropancreatic neuroendocrine tumor and pituitary neuroendocrine tumor (PitNET) was 77.8% (n=91) and 56.4% (n=66), respectively. Genetic testing revealed 61 distinct MEN1 variants in 101 patients, with 18 being novel. Four variants were reclassified according to the TENGEN guidelines. Patients with truncating variants (n=72) exhibited a higher prevalence of PitNETs compared to those with non-truncating variants (n=25) (59.7% vs. 36.0%, P=0.040). Conclusion The association between truncating variants and an increased prevalence of PitNETs in MEN1 underscores the importance of genetic characterization in guiding the clinical management of this disease. Our study sheds light on the clinical and genetic characteristics of MEN1 among the Korean population.

Background: We aimed to investigate the characteristics of pediatric ulcerative colitis (UC) at diagnosis in Korea. Methods: This was a multicenter, registry-based, inception cohort study conducted in Korea between 2021 and 2023. Children and adolescents newly diagnosed with UC < 18 years were included. Baseline clinicodemographics, results from laboratory, endoscopic exams, and Paris classification factors were collected, and associations between factors at diagnosis were investigated. Results: A total 205 patients with UC were included. Male-to-female ratio was 1.59:1, and the median age at diagnosis was 14.7 years (interquartile range 11.9–16.2). Disease extent of E1 comprised 12.2% (25/205), E2 24.9% (51/205), E3 11.2% (23/205), and E4 51.7% (106/205) of the patients. S1 comprised 13.7% (28/205) of the patients. The proportion of patients with a disease severity of S1 was significantly higher in patients with E4 compared to the other groups (E1: 0% vs. E2: 2% vs. E3: 0% vs. E4: 24.5%, P < 0.001). Significant differences between disease extent groups were also observed in Pediatric Ulcerative Colitis Activity Index (median 25 vs. 35 vs. 40 vs. 45, respectively, P < 0.001), hemoglobin (median 13.5 vs.13.2 vs. 11.6 vs. 11.4 g/dL, respectively, P < 0.001), platelet count (median 301 vs. 324 vs. 372 vs. 377 × 103 /μL, respectively, P = 0.001), C-reactive protein (median 0.05 vs. 0.10 vs. 0.17 vs. 0.38 mg/dL, respectively, P < 0.001), and Ulcerative Colitis Endoscopic Index of Severity (median 4 vs. 4 vs. 4 vs. 5, respectively, P = 0.006). No significant differences were observed in factors between groups divided according to sex and diagnosis age. Conclusion This study represents the largest multicenter pediatric inflammatory bowel disease cohort in Korea. Disease severity was associated with disease extent in pediatric patients with UC at diagnosis.

Background: We aimed to investigate the characteristics of pediatric ulcerative colitis (UC) at diagnosis in Korea. Methods: This was a multicenter, registry-based, inception cohort study conducted in Korea between 2021 and 2023. Children and adolescents newly diagnosed with UC < 18 years were included. Baseline clinicodemographics, results from laboratory, endoscopic exams, and Paris classification factors were collected, and associations between factors at diagnosis were investigated. Results: A total 205 patients with UC were included. Male-to-female ratio was 1.59:1, and the median age at diagnosis was 14.7 years (interquartile range 11.9–16.2). Disease extent of E1 comprised 12.2% (25/205), E2 24.9% (51/205), E3 11.2% (23/205), and E4 51.7% (106/205) of the patients. S1 comprised 13.7% (28/205) of the patients. The proportion of patients with a disease severity of S1 was significantly higher in patients with E4 compared to the other groups (E1: 0% vs. E2: 2% vs. E3: 0% vs. E4: 24.5%, P < 0.001). Significant differences between disease extent groups were also observed in Pediatric Ulcerative Colitis Activity Index (median 25 vs. 35 vs. 40 vs. 45, respectively, P < 0.001), hemoglobin (median 13.5 vs.13.2 vs. 11.6 vs. 11.4 g/dL, respectively, P < 0.001), platelet count (median 301 vs. 324 vs. 372 vs. 377 × 103 /μL, respectively, P = 0.001), C-reactive protein (median 0.05 vs. 0.10 vs. 0.17 vs. 0.38 mg/dL, respectively, P < 0.001), and Ulcerative Colitis Endoscopic Index of Severity (median 4 vs. 4 vs. 4 vs. 5, respectively, P = 0.006). No significant differences were observed in factors between groups divided according to sex and diagnosis age. Conclusion This study represents the largest multicenter pediatric inflammatory bowel disease cohort in Korea. Disease severity was associated with disease extent in pediatric patients with UC at diagnosis.

Background: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by tumors in multiple endocrine organs, caused by variants in the MEN1 gene. This study analyzed the clinical and genetic features of MEN1 in a Korean cohort, identifying prevalent manifestations and genetic variants, including novel variants. Methods: This multicenter retrospective study reviewed the medical records of 117 MEN1 patients treated at three tertiary centers in Korea between January 2012 and September 2022. Patient demographics, tumor manifestations, outcomes, and MEN1 genetic testing results were collected. Variants were classified using American College of Medical Genetics and Genomics (ACMG) and French Oncogenetics Network of Neuroendocrine Tumors propositions (TENGEN) guidelines. Results: A total of 117 patients were enrolled, including 55 familial cases, with a mean age at diagnosis of 37.4±15.3 years. Primary hyperparathyroidism was identified as the most common presentation (84.6%). The prevalence of gastroenteropancreatic neuroendocrine tumor and pituitary neuroendocrine tumor (PitNET) was 77.8% (n=91) and 56.4% (n=66), respectively. Genetic testing revealed 61 distinct MEN1 variants in 101 patients, with 18 being novel. Four variants were reclassified according to the TENGEN guidelines. Patients with truncating variants (n=72) exhibited a higher prevalence of PitNETs compared to those with non-truncating variants (n=25) (59.7% vs. 36.0%, P=0.040). Conclusion The association between truncating variants and an increased prevalence of PitNETs in MEN1 underscores the importance of genetic characterization in guiding the clinical management of this disease. Our study sheds light on the clinical and genetic characteristics of MEN1 among the Korean population.

Background: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by tumors in multiple endocrine organs, caused by variants in the MEN1 gene. This study analyzed the clinical and genetic features of MEN1 in a Korean cohort, identifying prevalent manifestations and genetic variants, including novel variants. Methods: This multicenter retrospective study reviewed the medical records of 117 MEN1 patients treated at three tertiary centers in Korea between January 2012 and September 2022. Patient demographics, tumor manifestations, outcomes, and MEN1 genetic testing results were collected. Variants were classified using American College of Medical Genetics and Genomics (ACMG) and French Oncogenetics Network of Neuroendocrine Tumors propositions (TENGEN) guidelines. Results: A total of 117 patients were enrolled, including 55 familial cases, with a mean age at diagnosis of 37.4±15.3 years. Primary hyperparathyroidism was identified as the most common presentation (84.6%). The prevalence of gastroenteropancreatic neuroendocrine tumor and pituitary neuroendocrine tumor (PitNET) was 77.8% (n=91) and 56.4% (n=66), respectively. Genetic testing revealed 61 distinct MEN1 variants in 101 patients, with 18 being novel. Four variants were reclassified according to the TENGEN guidelines. Patients with truncating variants (n=72) exhibited a higher prevalence of PitNETs compared to those with non-truncating variants (n=25) (59.7% vs. 36.0%, P=0.040). Conclusion The association between truncating variants and an increased prevalence of PitNETs in MEN1 underscores the importance of genetic characterization in guiding the clinical management of this disease. Our study sheds light on the clinical and genetic characteristics of MEN1 among the Korean population.

Background: We aimed to investigate the characteristics of pediatric ulcerative colitis (UC) at diagnosis in Korea. Methods: This was a multicenter, registry-based, inception cohort study conducted in Korea between 2021 and 2023. Children and adolescents newly diagnosed with UC < 18 years were included. Baseline clinicodemographics, results from laboratory, endoscopic exams, and Paris classification factors were collected, and associations between factors at diagnosis were investigated. Results: A total 205 patients with UC were included. Male-to-female ratio was 1.59:1, and the median age at diagnosis was 14.7 years (interquartile range 11.9–16.2). Disease extent of E1 comprised 12.2% (25/205), E2 24.9% (51/205), E3 11.2% (23/205), and E4 51.7% (106/205) of the patients. S1 comprised 13.7% (28/205) of the patients. The proportion of patients with a disease severity of S1 was significantly higher in patients with E4 compared to the other groups (E1: 0% vs. E2: 2% vs. E3: 0% vs. E4: 24.5%, P < 0.001). Significant differences between disease extent groups were also observed in Pediatric Ulcerative Colitis Activity Index (median 25 vs. 35 vs. 40 vs. 45, respectively, P < 0.001), hemoglobin (median 13.5 vs.13.2 vs. 11.6 vs. 11.4 g/dL, respectively, P < 0.001), platelet count (median 301 vs. 324 vs. 372 vs. 377 × 103 /μL, respectively, P = 0.001), C-reactive protein (median 0.05 vs. 0.10 vs. 0.17 vs. 0.38 mg/dL, respectively, P < 0.001), and Ulcerative Colitis Endoscopic Index of Severity (median 4 vs. 4 vs. 4 vs. 5, respectively, P = 0.006). No significant differences were observed in factors between groups divided according to sex and diagnosis age. Conclusion This study represents the largest multicenter pediatric inflammatory bowel disease cohort in Korea. Disease severity was associated with disease extent in pediatric patients with UC at diagnosis.

Background: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by tumors in multiple endocrine organs, caused by variants in the MEN1 gene. This study analyzed the clinical and genetic features of MEN1 in a Korean cohort, identifying prevalent manifestations and genetic variants, including novel variants. Methods: This multicenter retrospective study reviewed the medical records of 117 MEN1 patients treated at three tertiary centers in Korea between January 2012 and September 2022. Patient demographics, tumor manifestations, outcomes, and MEN1 genetic testing results were collected. Variants were classified using American College of Medical Genetics and Genomics (ACMG) and French Oncogenetics Network of Neuroendocrine Tumors propositions (TENGEN) guidelines. Results: A total of 117 patients were enrolled, including 55 familial cases, with a mean age at diagnosis of 37.4±15.3 years. Primary hyperparathyroidism was identified as the most common presentation (84.6%). The prevalence of gastroenteropancreatic neuroendocrine tumor and pituitary neuroendocrine tumor (PitNET) was 77.8% (n=91) and 56.4% (n=66), respectively. Genetic testing revealed 61 distinct MEN1 variants in 101 patients, with 18 being novel. Four variants were reclassified according to the TENGEN guidelines. Patients with truncating variants (n=72) exhibited a higher prevalence of PitNETs compared to those with non-truncating variants (n=25) (59.7% vs. 36.0%, P=0.040). Conclusion The association between truncating variants and an increased prevalence of PitNETs in MEN1 underscores the importance of genetic characterization in guiding the clinical management of this disease. Our study sheds light on the clinical and genetic characteristics of MEN1 among the Korean population.

Background: We aimed to investigate the characteristics of pediatric ulcerative colitis (UC) at diagnosis in Korea. Methods: This was a multicenter, registry-based, inception cohort study conducted in Korea between 2021 and 2023. Children and adolescents newly diagnosed with UC < 18 years were included. Baseline clinicodemographics, results from laboratory, endoscopic exams, and Paris classification factors were collected, and associations between factors at diagnosis were investigated. Results: A total 205 patients with UC were included. Male-to-female ratio was 1.59:1, and the median age at diagnosis was 14.7 years (interquartile range 11.9–16.2). Disease extent of E1 comprised 12.2% (25/205), E2 24.9% (51/205), E3 11.2% (23/205), and E4 51.7% (106/205) of the patients. S1 comprised 13.7% (28/205) of the patients. The proportion of patients with a disease severity of S1 was significantly higher in patients with E4 compared to the other groups (E1: 0% vs. E2: 2% vs. E3: 0% vs. E4: 24.5%, P < 0.001). Significant differences between disease extent groups were also observed in Pediatric Ulcerative Colitis Activity Index (median 25 vs. 35 vs. 40 vs. 45, respectively, P < 0.001), hemoglobin (median 13.5 vs.13.2 vs. 11.6 vs. 11.4 g/dL, respectively, P < 0.001), platelet count (median 301 vs. 324 vs. 372 vs. 377 × 103 /μL, respectively, P = 0.001), C-reactive protein (median 0.05 vs. 0.10 vs. 0.17 vs. 0.38 mg/dL, respectively, P < 0.001), and Ulcerative Colitis Endoscopic Index of Severity (median 4 vs. 4 vs. 4 vs. 5, respectively, P = 0.006). No significant differences were observed in factors between groups divided according to sex and diagnosis age. Conclusion This study represents the largest multicenter pediatric inflammatory bowel disease cohort in Korea. Disease severity was associated with disease extent in pediatric patients with UC at diagnosis.

Autoimmune hepatitis (AIH) is a chronic, autoimmune disease of the liver that occurs when the body’s immune system attacks liver cells, causing the liver to be inflamed. AIH is one of the manifestations of a coronavirus disease 2019 (COVID-19), as well as an adverse event occurring after vaccination against severe acute respiratory syndrome coronavirus 2 (SARSCoV-2). Few cases of AIH have been described after vaccination with two messenger RNA (mRNA)-based vaccines—BTN162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna)—against SARS-CoV-2. Herein, we report a case of AIH occurring after Pfizer-BioNTech COVID-19 vaccine. A 27-year-old female presented with jaundice and hepatomegaly, appearing 14 days after receiving the second dose of Pfizer-BioNTech vaccine. Her laboratory results showed abnormal liver function with high total immunoglobulin G level. She was diagnosed with AIH with histologic finding and successfully treated with oral prednisolone. We report an AIH case after COVID-19 vaccination in Korea.

Background: Liver biopsy is the essential method to diagnose non-alcoholic steatohepatitis (NASH), but histological features of NASH are too subjective to achieve reproducible diagnoses in early stages of disease. We aimed to identify the key histological features of NASH and devise a scoring model for diagnosis. Methods: Thirteen pathologists blindly assessed 12 histological factors and final histological diagnoses (‘not-NASH,’ ‘borderline,’ and ‘NASH’) of 31 liver biopsies that were diagnosed as non-alcoholic fatty liver disease (NAFLD) or NASH before and after consensus. The main histological parameters to diagnose NASH were selected based on histological diagnoses and the diagnostic accuracy and agreement of 12 scoring models were compared for final diagnosis and the NAFLD Activity Score (NAS) system. Results: Inter-observer agreement of final diagnosis was fair (κ = 0.25) before consensus and slightly improved after consensus (κ = 0.33). Steatosis at more than 5% was the essential parameter for diagnosis. Major diagnostic factors for diagnosis were fibrosis except 1C grade and presence of ballooned cells. Minor diagnostic factors were lobular inflammation ( ≥ 2 foci/ × 200 field), microgranuloma, and glycogenated nuclei. All 12 models showed higher inter-observer agreement rates than NAS and post-consensus diagnosis (κ = 0.52–0.69 vs. 0.33). Considering the reproducibility of factors and practicability of the model, summation of the scores of major (× 2) and minor factors may be used for the practical diagnosis of NASH. Conclusions A scoring system for the diagnosis of NAFLD would be helpful as guidelines for pathologists and clinicians by improving the reproducibility of histological diagnosis of NAFLD.