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Introduction: Certain types of muscular dystrophy (MD), notably facioscapulohumeral muscular dystrophy (FSHD), exhibit muscle fiber necrosis with regeneration and a nonspecific inflammatory process. Although rare, the coexistence of MDs and autoimmune myositis has been observed. We hypothesized that, in some circumstances, FSHD may predispose individuals to myositis through muscle damage-induced autoantigen overexpression, contributing to an autoimmune response., Methods: We conducted a retrospective analysis of patient data from neuromuscular disease centers in France and Italy between September 2012 and May 2024. Clinical, immunological, and myopathological features of 1750 myositis patients were comprehensively reviewed., Results: Five patients were identified with both FSHD and IIM. Two patients were first diagnosed with FSHD and later developed IIM, while two others initially had IIM followed by an FSHD diagnosis. The fifth patient received simultaneous diagnoses of both conditions. The prevalence of FSHD in the IIM cohort was 1/350, and the prevalence of IIM in the FSHD cohort was 1/40 (p < 0.0001)., Discussion: Our study showed a high prevalence of FSHD and IIM association compared to the general population, with underlying mechanisms that remain unclear. This association might be more frequent than previously reported, indicating a need for increased clinical awareness. Understanding the interplay between FSHD and autoimmune myositis could reveal insights into the immunopathological processes of these diseases and improve diagnostic and therapeutic approaches., Competing Interests: Declaration of competing interest None., (Copyright © 2025 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Monoclonal gammopathy (MG) has been reported in association with numerous neurological disorders but the spectrum of MG-associated myopathies remains poorly described., Objective: To report a newly acquired myopathy associated with MG., Methods: Three adult patients with the same phenotype from two French referral centers were prospectively analyzed. Clinical, electrophysiological, muscle biopsy data, and patients' outcomes under treatment are reported., Results: The patients, aged 37, 46, and 56 years, presented progressive weakness with subacute worsening and stiffness, in the context of severe weight loss. The weakness mainly involved the proximal limbs and axial muscles. Creatine kinase levels were 1400-2900 IU/L and electromyography revealed a myopathic pattern with spontaneous complex repetitive discharges. Muscle biopsies showed vacuoles containing glycogen and autophagic material along with the presence of sarcolemmal complement membrane attack complex deposits. There was no evidence of a genetic glycogen metabolic disorder. IgGκ monoclonal gammopathy was identified in all cases, without signs of lymphoplasmocytic proliferation. All patients improved with a treatment combining corticosteroids, intravenous immunoglobulins, and immunosuppressants, and two patients recovered walking ability., Conclusion and Relevance: We report a new muscle disease defined by a vacuolar myopathy characterized by axial and proximal muscle weakness with prominent stiffness and high frequency discharges on electromyography associated with monoclonal gammopathy, defined under the acronym VAMMGAS., (© 2025 The Author(s). European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Background: Myosin 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., Methods: We 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., Results: We 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., Conclusions: MYH7 -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., Competing Interests: Competing interests: None declared., (© 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.)

Myositis with anti-Ku-autoantibodies is a rare inflammatory myopathy associated with various connective tissue diseases. Histopathological studies have identified inflammatory and necrotizing aspects, but a precise morphological analysis and pathomechanistic disease model are lacking. We therefore aimed to carry out an in-depth morpho-molecular analysis to uncover possible pathomechanisms. Muscle biopsy specimens from 26 patients with anti-Ku-antibodies and unequivocal myositis were analyzed by immunohistochemistry, immunofluorescence, transcriptomics, and proteomics and compared to biopsy specimens of non-disease controls, immune-mediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM). Clinical findings and laboratory parameters were evaluated retrospectively and correlated with morphological and molecular features. Patients were mainly female (92%) with a median age of 56.5 years. Isolated myositis and overlap with systemic sclerosis were reported in 31%, respectively. Isolated myositis presented with higher creatine kinase levels and cardiac involvement (83%), whereas systemic sclerosis-overlap patients often had interstitial lung disease (57%). Histopathology showed a wide spectrum from mild to pronounced myositis with diffuse sarcolemmal MHC-class I (100%) and -II (69%) immunoreactivity, myofiber necrosis (88%), endomysial inflammation (85%), thickened capillaries (84%), and vacuoles (60%). Conspicuous sarcoplasmic protein aggregates were p62, BAG3, myotilin, or immunoproteasomal beta5i-positive. Proteomic and transcriptomic analysis identified prominent up-regulation of autophagy, proteasome, and hnRNP-related cell stress. To conclude, Ku + myositis is morphologically characterized by myofiber necrosis, MHC-class I and II positivity, variable endomysial inflammation, and distinct protein aggregation varying from IBM and IMNM, and it can be placed in the spectrum of scleromyositis and overlap myositis. It features characteristic sarcoplasmic protein aggregation on an acquired basis being functionally associated with altered chaperone, proteasome, and autophagy function indicating that Ku + myositis exhibit aspects of an acquired inflammatory protein-aggregate myopathy., (© 2024. The Author(s).)

Background and Purpose: Biallelic variants in SORD have been reported as one of the main recessive causes for hereditary peripheral neuropathies such as Charcot-Marie-Tooth disease type 2 (CMT2) and distal hereditary motor neuropathy (dHMN) resulting in lower limb (LL) weakness and muscular atrophy. In this study, phenotype and genotype landscapes of SORD-related peripheral neuropathies were described in a French and Swiss cohort. Serum sorbitol dosages were used to classify SORD variants., Methods: Patients followed at neuromuscular reference centres in France and Switzerland were ascertained. Sanger sequencing and next generation sequencing were performed to sequence SORD, and mass spectrometry was used to measure patients' serum sorbitol., Results: Thirty patients had SORD peripheral neuropathy associating LL weakness with muscular atrophy, foot deformities (87%), and sometimes proximal LL weakness (20%) or distal upper limb weakness (50%). Eighteen had dHMN, nine had CMT2, and three had intermediate CMT. Most of them had a mild or moderate disease severity. Sixteen carried a homozygous c.757delG (p.Ala253Glnfs*27) variant, and 11 carried compound heterozygous variants, among which four variants were not yet reported: c.403C > G, c.379G > A, c.68&#95;100 + 1dup, and c.850dup. Two unrelated patients with different origins carried a homozygous c.458C > A variant, and one patient carried a new homozygous c.786 + 5G > A variant. Mean serum sorbitol levels were 17.01 mg/L ± 8.9 SD for patients carrying SORD variants., Conclusions: This SORD-inherited peripheral neuropathy cohort of 30 patients showed homogeneous clinical presentation and systematically elevated sorbitol levels (22-fold) compared to controls, with both diagnostic and potential therapeutic implications., (© 2023 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Scleroderma associated myopathy (SScAM) is a common but heterogeneous musculoskeletal manifestation of systemic sclerosis (SSc) for which there is still no clear definition. Still, SScAM is associated with disability, poor quality of life and mortality. This review discusses the most updated literature of SScAM including clinical and antibody associations, recent updates on histopathological findings, prognosis and treatment., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Neuropathies in Myoclonic Epilepsy with Ragged Red Fibers (MERRF) syndrome are frequent but ganglionopathies have never been reported. We retrospectively identified 24 patients with MERRF mutations in the neuromuscular center Nord/Est/Ile de France (Pitié-Salpêtrière, Paris, France). Seventeen nerve conduction studies (NCS) were available. Five patients had MERRF syndrome and ganglionopathy, a pure sensory neuropathy. All of them displayed ataxia and mild clinical sensory abnormalities. Ganglionopathies have been reported in mitochondrial diseases but never in MERRF syndrome. We suggest that patients presenting with ganglionopathy, especially if associated with myopathy, lipomatosis or epilepsy, should be screened for MERRF mutations.

Currently only 25-30% of patients with axonal forms of Charcot-Marie-Tooth disease (CMT) receive a genetic diagnosis. We aimed to identify the causative gene of CMT type 2 in 8 non-related French families with a distinct clinical phenotype. We collected clinical, electrophysiological, and laboratory findings and performed genetic analyses in four different French laboratories. Seventy-two patients with autosomal dominant inheritance were identified. The disease usually started in the fourth decade and the clinical picture was dominated by sensory ataxia (80%), neuropathic pain (38%), and length-dependent sensory loss to all modalities. Electrophysiological studies showed a primarily axonal neuropathy, with possible isolated sensory involvement in milder phenotypes. Disease severity varied greatly but the clinical course was generally mild. We identified 2 novel variants in LRSAM1 gene: a deletion of 4 amino acids, p.(Gln698&#95;Gln701del), was found in 7 families and a duplication of a neighboring region of 10 amino acids, p.(Pro702&#95;Gln711dup), in the remaining family. A common haplotype of ~450 kb suggesting a founder effect was noted around LRSAM1 in 4 families carrying the first variant. LRSAM1 gene encodes for an E3 ubiquitin ligase important for neural functioning. Our results confirm the localization of variants in its catalytic C-terminal RING domain and broaden the phenotypic spectrum of LRSAM1-related neuropathies, including painful and predominantly sensory ataxic forms.