Respiratory Dysfunction in Becker Muscular Dystrophy Patients: A Case Series and Autopsy Report

Article type: Research Article

Authors: Mori-Yoshimura, Madoka^{a; *} | Oya, Yasushi^a | Komaki, Hirohumi^b | Segawa, Kazuhiko^c | Minami, Narihiro^{d; e; f} | Saito, Yuko^d | Nishino, Ichizo^{e; f} | Takahashi, Yuji^a

Affiliations: [a] Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Ogawahigashi, Kodaira, Tokyo, Japan | [b] Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Ogawahigashi, Kodaira, Tokyo, Japan | [c] Department of Cardiology, National Center Hospital, National Center of Neurology and Psychiatry, Ogawahigashi, Kodaira, Tokyo, Japan | [d] Department of Laboratory Medicine, National Center Hospital, National Center of Neurology and Psychiatry, Ogawahigashi, Kodaira, Tokyo, Japan | [e] Medical Genome Center, National Center of Neurology and Psychiatry, Ogawahigashi, Kodaira, Tokyo, Japan | [f] Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Ogawahigashi, Kodaira, Tokyo, Japan

Correspondence: [*] Correspondence to: Madoka Mori-Yoshimura, Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8551, Japan. Tel.: +81 341 2711; Fax: +81 342 1852, E-mail: [email protected].

Abstract: Background:Few studies have examined respiratory dysfunction in patients with Becker muscular dystrophy (BMD). Objective:This study aimed to examine the characteristics of respiratory dysfunction in patients with BMD. Methods:The present retrospective study assessed respiratory parameters of adult BMD patients using medical records and compared these parameters with various patient characteristics to identify correlations. BMD patients aged 17 years and older who had been diagnosed genetically and/or pathologically were included in the analysis. Results:Of the source population of 133 patients, respiratory function was assessed in 85. Two of these patients had no symptoms, and eight had died. Mean % forced vital capacity (% FVC) was 94.2+/–21.7% (median, 96.1%; range, 5.1–134.1%). In 16 (19%) of the 85 patients, % FVC was <80%. Of these, seven were non-ambulant. Age, ambulation, and cardiac function did not significantly differ between patients with or without respiratory dysfunction, whereas age at onset was significantly lower in patients with respiratory dysfunction (7.7+/–4.7 years vs. 14.4+/–11.9 years; p = 0.001). One non-ambulant patient was a continuous NPPV user, and one patient had been recommended NPPV use but refused. Autopsy of one patient revealed that the diaphragm and intercostal muscles were less affected than proximal skeletal muscles. Conclusion:BMD patients are at risk of developing respiratory dysfunction due to dystrophic changes in respiratory muscles. Respiratory function should be carefully and periodically monitored in these patients.

Keywords: Becker muscular dystrophy (BMD), dystrophinopathy, respiratory dysfunction, cardiac function, genotype-phenotype correlation

DOI: 10.3233/JND-190438

Journal: Journal of Neuromuscular Diseases, vol. 7, no. 4, pp. 425-431, 2020