Fusion of single-nucleated myoblasts is essential for the formation of multinucleated myocytes. Mechanisms that regulate myoblast fusion have been a focus of recent studies.1–4 Transmembrane protein 8 (TMEM8C), also known as myomaker, is a highly conserved muscle-specific transmembrane protein encoded by the MYMK gene. The protein is expressed during early muscle development. Mymk-null mice die soon after birth because of skeletal muscle deficiency. In these mice, skeletal muscle tissue is present but consists of a smaller number of mononucleated cells indicating failure of myoblast cell fusion.1 Myomaker is also expressed during muscle regeneration when it coordinates fusion of satellite cells with residual muscle fibers to regenerate the damaged muscle tissue. In the absence of myomaker, adult mouse muscle tissue is unable to regenerate.5
Acknowledgment
The authors are grateful to the patient reported here for giving them permission to share his data and his photographs. They are also grateful to the Newcastle MRC Centre Biobank for Neuromuscular Diseases. Diagnostic facilities at the John Walton Muscular Dystrophy Research Centre are supported by the Nationally Commissioned Highly Specialised Service (HSS) for Neuromuscular Diseases (NHS England). The authors thank Dr. Tuomo Polvikoski from The Newcastle upon Tyne Hospitals NHS Foundation Trust for his help in interpreting muscle biopsy images. They also thank Dr. Chiara Marini Bettolo and Dr. Michela Guglieri from the MRC Centre for Neuromuscular Diseases for their help with clinical logistics.
Footnotes
Funding information and disclosures are provided at the end of the article. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/NG.
The Article Processing Charge was funded by the Wellcome Trust, UK.
- Received November 30, 2017.
- Accepted in final form February 20, 2018.
- Copyright © 2018 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.
This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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