Nationwide Characterization of MFN2-Related CMT in 176 Japanese Patients: Clinical and Genetic Insights.

IF 3.9 2区 医学 Q1 CLINICAL NEUROLOGY
Masahiro Ando, Yujiro Higuchi, Jun-Hui Yuan, Akiko Yoshimura, Chikashi Yano, Takahiro Hobara, Fumikazu Kojima, Yu Hiramatsu, Satoshi Nozuma, Tomonori Nakamura, Yusuke Sakiyama, Jun Mitsui, Shoji Tsuji, Hiroshi Takashima
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引用次数: 0

Abstract

Background: Mitofusin 2 (MFN2) is a major causative gene for axonal Charcot - Marie - Tooth disease type 2A (CMT2A), with a wide phenotypic spectrum. Comprehensive large - scale genotype - phenotype association studies are essential for understanding disease pathogenesis and improved clinical management.

Methods: We conducted a nationwide retrospective study of 176 Japanese patients with genetically confirmed pathogenic or likely pathogenic MFN2 variants encompassing clinical, electrophysiological, and genetic characterization.

Results: MFN2 was the second most frequent causative gene among 1211 genetically diagnosed inherited peripheral neuropathy cases in Japan. A total of 76 MFN2 variants were identified, including nine novel likely pathogenic variants. Disease onset occurred at a mean age of 11.1 years, with distal motor weakness and tibialis anterior involvement as prominent features. Sensory symptoms were present in ~60% of patients and were more common in cases with longer disease duration. Central and systemic features, including pyramidal signs, optic atrophy, and vocal cord paralysis, were also observed. Electrophysiological studies revealed a predominantly axonal sensorimotor pattern, with relatively preserved upper limb conduction and marked lower limb abnormalities. Importantly, 24 patients (16%) were non-ambulatory, with earlier onset and greater weakness. Domain-based analysis further revealed that variant location may influence age at onset.

Conclusion: This large-scale study highlights the genetic and clinical diversity of MFN2-related CMT in Japan. Our findings confirm a motor-dominant, length-dependent axonal neuropathy with additional sensory and systemic features in some cases. These results emphasize the importance of early diagnosis, genotype-informed care, and long-term follow-up in managing MFN2-related CMT.

176名日本患者中mfn2相关CMT的全国特征:临床和遗传见解
背景:Mitofusin 2 (MFN2)是轴突性Charcot - Marie - Tooth病2A型(CMT2A)的主要致病基因,具有广泛的表型谱。全面、大规模的基因型-表型关联研究对于了解疾病的发病机制和改善临床管理至关重要。方法:我们对176名日本患者进行了一项全国性的回顾性研究,包括临床、电生理和遗传特征,这些患者经遗传学证实具有致病性或可能致病性的MFN2变异。结果:在日本1211例遗传诊断的遗传性周围神经病变病例中,MFN2是第二常见的致病基因。共鉴定出76个MFN2变异,包括9个新的可能致病的变异。发病的平均年龄为11.1岁,以远端运动无力和胫前肌受累为主要特征。约60%的患者存在感觉症状,在病程较长的病例中更为常见。还观察到中枢和全身特征,包括锥体征象、视神经萎缩和声带麻痹。电生理研究显示以轴突为主的感觉运动模式,上肢传导相对保留,下肢明显异常。重要的是,24例患者(16%)是非卧床患者,发病更早,虚弱程度更大。基于区域的分析进一步揭示了变异位置可能影响发病年龄。结论:这项大规模研究突出了日本mfn2相关CMT的遗传和临床多样性。我们的研究结果证实了一种运动主导的、长度依赖的轴索神经病,在一些病例中伴有额外的感觉和全身特征。这些结果强调了早期诊断、基因型知情护理和长期随访在管理mfn2相关CMT中的重要性。
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来源期刊
Annals of Clinical and Translational Neurology
Annals of Clinical and Translational Neurology Medicine-Neurology (clinical)
CiteScore
9.10
自引率
1.90%
发文量
218
审稿时长
8 weeks
期刊介绍: Annals of Clinical and Translational Neurology is a peer-reviewed journal for rapid dissemination of high-quality research related to all areas of neurology. The journal publishes original research and scholarly reviews focused on the mechanisms and treatments of diseases of the nervous system; high-impact topics in neurologic education; and other topics of interest to the clinical neuroscience community.
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