髓鞘寡突细胞糖蛋白（MOG）抗体相关疾病（MOGAD）是一种自身免疫脱髓鞘障碍疾病，常常在感染或接种疫苗后表现出来。我们报道了两例来自未曾报道的8例青少年髓细胞白血病（JMML）患者的MOGAD病例。我们调查了2012年至2021年间，127例白血病患者中的两例JMML患者。患者1在两岁零一个月时接受JMML治疗，并出现发热和意识障碍。磁共振成像显示左额叶和左枕叶白质中有高强度病变。血清抗-MOG抗体检测呈阳性，而在脑病发作前45天存储的血清检测为阴性。他在接受类固醇治疗和血浆置换后复发MOGAD。患者2在三岁七个月接受JMML治疗后变得冷漠和缄默。磁共振成像显示左额顶叶皮质下有高强度病变。脑病发作时的抗-MOG抗体呈阳性，在发病前57天和发病后47天的存储血清检测均为阴性。我们治疗了8例JMML患者中出现的两例MOGAD病例，而在119例急性淋巴细胞白血病、急性髓系白血病或慢性髓系白血病患者中不存在MOGAD病例。RAS途径异常通过激活自身免疫过程可能导致抗-MOG抗体的形成和MOGAD的发作。JMML患儿也可能患有MOGAD，RAS途径的异常可能对其发病有贡献。 版权所有 © 2023 The Authors。Elsevier Inc.保留所有权利。

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an autoimmune demyelinating disorder that often manifests after infections or vaccinations. We report two patients who developed MOGAD out of eight patients with juvenile myelomonocytic leukemia (JMML) that has never been reported.We investigated two patients with JMML who developed MOGAD among 127 patients with leukemia from 2012 to 2021.Patient 1 was treated for JMML and developed fever and impaired consciousness at two years and one month of age. Magnetic resonance imaging revealed high-intensity lesions in the left frontal and left occipital white matter. The serum anti-MOG antibody test was positive, while the test was negative in the stored serum 45 days before the onset of encephalopathy. He had relapse of MOGAD after steroid therapy and plasmapheresis. Patient 2, who was treated for JMML, became apathetic and mute at three years and seven months of age. Magnetic resonance imaging revealed left frontoparietal subcortical high-intensity lesions. Anti-MOG antibody at the onset of encephalopathy was positive, while it was negative in stored serum 57 days before and 47 days after the onset.We treated two patients who developed MOGAD out of eight patients with JMML and none with MOGAD out of 119 patients with acute lymphocytic leukemia, acute myelocytic leukemia, or chronic myelocytic leukemia. The activated autoimmune process via the RAS pathway abnormality may have led to the formation of the anti-MOG antibody and the onset of MOGAD. MOGAD can occur in children with JMML, and abnormalities of the RAS pathway possibly contribute to its onset.Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.