• Marie Bahout, Gianmarco Severa, Emna Kamoun, Françoise Bouhour, Antoine Pegat, Annick Toutain, Emmeline Lagrange, Fanny Duval, Celine Tard, Elisa De la Cruz, Léonard Féasson, Agnès Jacquin-Piques, Pascale Richard, Corinne Métay, Michele Cavalli, Norma Beatriz Romero, Teresinha Evangelista, Guilhem Sole, Robert Yves Carlier, Pascal Laforêt, Blandine Acket, Anthony Behin, Gorka Fernández-Eulate, Sarah Léonard-Louis, Susana Quijano-Roy, Yann Pereon, Emmanuelle Salort-Campana, Aleksandra Nadaj-Pakleza, Marion Masingue, Edoardo Malfatti, Tanya Stojkovic, and Rocío Nur Villar-Quiles.
• Assistance Publique Hôpitaux de Paris, Département de Neurologie, Hôpital Pitié-Salpêtrière, Paris, France.
• J. Neurol. Neurosurg. Psychiatr. 2024 Oct 24.

BackgroundMyosin heavy chain 7 (MYH7)-related myopathies (MYH7-RMs) are a group of muscle disorders linked to pathogenic variants in the MYH7 gene, encoding the slow/beta-cardiac myosin heavy chain, which is highly expressed in skeletal muscle and heart. The phenotype is heterogeneous including distal, predominantly axial or scapuloperoneal myopathies with variable cardiac involvement.MethodsWe retrospectively analysed the clinical, muscle MRI, genetic and myopathological features of 57 MYH7 patients. Patients received a thorough neurological (n=57, 100%), cardiac (n=51, 89%) and respiratory (n=45, 79%) assessment. Muscle imaging findings and muscle biopsies were reappraised in 19 (33%) and 27 (47%) patients, respectively.ResultsWe identified three phenotypes with varying degrees of overlap: distal myopathy (70%), scapuloperoneal (23%) and axial with peculiar cervical spine rigidity called the 'sphinx' phenotype (7%). 14% of patients had either dilated cardiomyopathy, hypertrophic cardiomyopathy or left ventricular non-compaction cardiomyopathy. 31% of patients had prominent respiratory involvement, including all patients with the 'sphinx' phenotype. Muscle MRI showed involvement of tibialis anterior, followed by quadriceps, and erector spinae in patients with axial phenotype. Cores represented the most common myopathological lesion. We report 26 pathogenic variants of MYH7 gene, 9 of which are novel.ConclusionsMYH7-RMs have a large phenotypic spectrum, including distal, scapuloperoneal or axial weakness, and variable cardiac and respiratory involvement. Tibialis anterior is constantly and precociously affected both clinically and on muscle imaging. Cores represent the most common myopathological lesion. Our detailed description of MYH7-RMs should improve their recognition and management.© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

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