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Objective: Limb-girdle muscular dystrophy (LGMD) is usually confused with idiopathic inflammatory myopathy (IIM) in clinical practice. Our study aimed to establish convenient and reliable diagnostic models for distinguishing between LGMD and IIM., Methods: A total of 71 IIM patients, 24 LGMDR2 patients and 22 LGMDR1 patients diagnosed at our neuromuscular center were enrolled. Differences in clinical, laboratory and histopathological characteristics were comprehensively compared. A nomogram and a decision tree were developed to distinguish between LGMD and IIM patients., Results: Compared to patients with LGMD, IIM patients exhibited a significantly older age of onset, a higher prevalence of cervical flexor weakness and a more commonly diffuse MHC-I expression on muscle pathology. The ratio of synchronous serum myoglobin (Mb, ng/ml) to creatine kinase (CK, U/L) before immunotherapy was significantly higher in IIM patients than in LGMD patients. Receiver operating characteristic analysis indicated a high differential diagnostic efficiency of synchronous Mb/CK with a cutoff value of 0.18. A nomogram prediction model and a decision tree were developed based on four independent indicators (age of onset, cervical flexor weakness, synchronous Mb/CK and diffuse MHC-I expression). Five-fold cross-validation and bootstrapping techniques substantiated the discriminate efficacy of the nomograph and decision tree., Conclusion: We developed two practical differential diagnosis models for LGMD and IIM based on the analysis of four accessible indicators, including the age of onset, cervical flexor weakness, the ratio of synchronous Mb/CK values and diffuse MHC-I expression. Further studies with larger samples are needed to refine the predictive efficiency of the differential diagnostic models., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Ethics Committee of Qilu Hospital (Qingdao), Shandong University, China (KYLL-KS-2022054). Written consent for muscle biopsy, laboratory tests and article publication was obtained from all the patients or their parents in the present study. The study was performed in accordance with the Declaration of Helsinki. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: Limb-girdle muscular dystrophies constitute a heterogeneous group of neuromuscular diseases, both clinically and genetically. Limb-girdle muscular dystrophy by alpha-sarcoglycan deficiency or LGMD R3 α-sarcoglycan-related is a subtype of the autosomal recessive sarcoglycanopathies caused by variants in the alpha-sarcoglycan gene (SGCA) at 17q21.33. It appears in childhood by progressive weakness of pelvic and/or scapular girdle muscles and calf hypertrophy, with a wide range of clinical inter- and intra-familial clinical variability., Aims: Our report extends the molecular spectrum of SGCA gene with the identification of variant disease causing and will help for better management of patients and genetic counseling of families., Methods: In our study, seven unrelated families presented a clinical and paraclinical picture consistent with alpha-sarcoglycanopathy. A molecular study using Next-Generation Sequencing (NGS) was carried out on them., Results: Six different homozygous variants of the SGCA gene were identified in the patients analyzed, including four previously reported variants and two novel variants predicted to be deleterious by the prediction tools., Conclusions: Our results expand the spectrum of variants in Moroccan patients with sarcoglycanopathy, specifically LGMDR3, most importantly as this form is not common in the Moroccan population., Competing Interests: Declarations. Ethics approval: This study was approved by the Rabat ethics committee for Biomedical research (Approval Number: CERB-37–23). Consent to participate: Informed consent was obtained from all individual participants (or their parents) included in the study. Competing interests: The authors have no conflicts of interest to declare., (© 2024. The Author(s), under exclusive licence to Royal Academy of Medicine in Ireland.)

Background: Limb-girdle muscular dystrophy (LGMD) is a group of hereditary myopathies. This group of diseases is highly heterogeneous in terms of genetic mode, age at onset, and disease progression; therefore, they are easily misdiagnosed and missed in clinical practice., Case Presentation: We describe a case of adult late-onset LGMD R1/2A in a 56-year-old female patient. The patient experienced elevated creatine kinase levels lasting 5 years, muscle soreness of the limbs lasting 4 years, and exacerbation of limb fatigue lasting 1 month. Early in the course of the disease, the patient experienced severe bradycardia and was later diagnosed with sick sinus syndrome. In addition to cardiac involvement, our patient also had primary hyperparathyroidism during the disease course, which was confirmed pathologically as a parathyroid adenoma. A biopsy of the left biceps showed pathological manifestations of mild myogenic damage. All-exon gene sequencing confirmed the diagnosis of LGMD R1/2A, and she was treated with vitamin E, vitamin B2, and coenzyme Q. Due to atrial fibrillation secondary to sick sinus syndrome, a pacemaker was implanted., Conclusion: The patient in this case study had adult late-onset LGMD R1/2A with cardiac involvement and functional parathyroid adenoma, which is rare and clinically significant. Therefore, early clinical identification, diagnosis, as well as targeted and active treatments can improve the prognosis of such patients., Competing Interests: Declarations. Ethics approval and consent to participate: The study was approved by the local ethics committee, and written informed consent was obtained from all participants. Ethics approval number: (2021) Ethics approval No.(96). Consent for publication: The participant gave written informed consent for their personal or clinical details along with any identifying images to be published in this study. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Calpainopathy is primarily an autosomal recessive inherited myopathy; however, dominantly inherited cases with a pathogenic variant of c.1333G>A have been reported. A 13-year-old Japanese girl presented with toe walking and elevated serum creatine kinase levels. Genetic panel testing revealed compound heterozygosity for c.1333G>A and a novel variant of c.1331C>T in CAPN3, leading to a diagnosis of calpainopathy. A genetic analysis of her parents revealed the possibility that c.1333G>A was de novo. In this patient, the onset age was earlier than that of the reported autosomal dominant cases, suggesting the influence of the novel variant in the contralateral allele.

Limb-girdle muscular dystrophy (LGMD) poses unique challenges for women during pregnancy, necessitating comprehensive care and tailored management strategies. The present narrative review aims to examine the unique challenges and management strategies required for women with LGMD during pregnancy. With over 30 genetic subtypes identified and the potential for additional discoveries through advanced diagnostic techniques, preconception counseling plays a crucial role in informing prospective parents about reproductive risks and available options. Baseline assessments, including cardiac and pulmonary evaluations, are essential to guide antenatal care, alongside genetic testing for precise diagnosis and counseling. Optimizing maternal health through respiratory exercises, cardiac monitoring, and individualized exercise and nutrition plans is paramount to avoid potential complications. During pregnancy, close monitoring of maternal and fetal well-being is important, with collaborative care between obstetricians and specialists. An individualized approach to delivery mode considering factors such as muscle strength, pelvic size, and fetal presentation is crucial. While vaginal delivery has been proven to be possible, the need for an emergency cesarean delivery should always be kept in mind. Regional anesthesia is preferred, with proactive planning for potential respiratory support. Bupivacaine has been shown to be effective with epidural catheters that may be used for prolonged relief with opioids like morphine and fentanyl, while also evaluating the patients' respiratory function. Postpartum considerations include pain management, mobility support, breastfeeding assistance, and emotional support. Early mobilization and tailored physiotherapy regimens may promote optimal recovery, while comprehensive breastfeeding guidance is needed to address challenges related to muscle weakness. Access to mental health resources and support networks is essential to helping individuals cope with the emotional demands of parenthood alongside managing LGMD. By addressing the unique needs of pregnant individuals with LGMD, healthcare providers can optimize maternal and fetal outcomes while supporting individuals in their journey to parenthood., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Limb-girdle muscular dystrophy type 2G/R7 (LGMD2G/R7) is an ultra-rare condition initially identified within the Brazilian population. We aimed to expand clinical and genetic information about this disease, including its worldwide distribution. A multicenter historical cohort study was performed at 13 centers in Brazil in which data from index cases and their affected relatives from consecutive families with LGMD2G/R7 were reviewed from July 2017 to August 2023. Additionally, a systematic literature review was conducted to identify case reports and series of the disease worldwide. Forty-one LGMD2G/R7 cases were described in the Brazilian cohort, being all subjects homozygous for the c.157C>T/(p.Gln53*) variant in TCAP. Survival curves showed that the median disease duration before individuals required walking aids was 21 years. Notably, women exhibited a slower disease progression, requiring walking aids 13 years later than men. LGMD2G/R7 was frequently reported not only in Brazil but also in China and Bulgaria, with 119 cases identified globally, with possible founder effects in the Brazilian, Eastern European, and Asian populations. These findings are pivotal in raising awareness of LGMD2G/R7, understanding its progression, and identifying potential modifiers. This can significantly contribute to the development of future natural history studies and clinical trials for this disease., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Targeted next generation sequence analyses in a cohort of 961 previously described patients with clinically suspected Duchene muscular dystrophy (DMD) revealed that 145/961 (15%) had variants in genes associated with other muscular dystrophies (OMDs)., Methods: NGS was carried out in DMD negative patients after deletion/duplication analysis followed by WES for No variant cases., Results: The majority of patients with OMDs had autosomal recessive diseases that included Limb-Girdle Muscular Dystrophies (LGMDs), Bethlem, Ullrich congenital Myopathies and Emery-Driefuss muscular dystrophy. 3.5% of patients were identified with other disorders like Charcot-Marie Tooth and Nemaline myopathy. A small percentage of patients, 0.6% remain undiagnosed. Of a total of 78 genetic variants identified, 44 were found to be novel. Interestingly, a third of patients with OMDs were found to have LGMD2E/R4, a severe form of LGMD that afflicts young children with clinical symptoms similar to DMD. Almost one third of the unrelated LGMD2E/R4 patients had the same point mutation (c.544A>C) in the SGCB gene, suggestive of a founder effect, described here for the first time in India., Conclusion: This study underscores the need for a complete genetic work up to precisely diagnose patients and to initiate appropriate counseling programs, disease management and prevention strategies., (© 2024 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

Purpose of Review: In the last 30 years, there have many publications describing the pattern of muscle involvement of different neuromuscular diseases leading to an increase in the information available for diagnosis. A high degree of expertise is needed to remember all the patterns described. Some attempts to use artificial intelligence or analysing muscle MRIs have been developed. We review the main patterns of involvement in limb girdle muscular dystrophies (LGMDs) and summarize the strategies for using artificial intelligence tools in this field., Recent Findings: The most frequent LGMDs have a widely described pattern of muscle involvement; however, for those rarer diseases, there is still not too much information available. patients. Most of the articles still include only pelvic and lower limbs muscles, which provide an incomplete picture of the diseases. AI tools have efficiently demonstrated to predict diagnosis of a limited number of disease with high accuracy., Summary: Muscle MRI continues being a useful tool supporting the diagnosis of patients with LGMD and other neuromuscular diseases. However, the huge variety of patterns described makes their use in clinics a complicated task. Artificial intelligence tools are helping in that regard and there are already some accessible machine learning algorithms that can be used by the global medical community., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Dysferlin-deficient limb girdle muscular dystrophy (LGMD R2), also referred to as dysferlinopathy, can be associated with respiratory muscle weakness as the disease progresses. Clinical practice guidelines recommend biennial lung function assessments in patients with dysferlinopathy to screen for respiratory impairment. However, lack of universal access to spirometry equipment and trained specialists makes regular monitoring challenging. This study investigated the use of the Performance of Upper Limb (PUL) clinical scale entry item as a low-cost screening tool to identify patients with dysferlinopathy at risk of respiratory impairment. Using data from 193 patients from the Jain Foundation's International Clinical Outcomes Study, modelling identified a significant positive relationship between the PUL entry item and forced vital capacity (FVC). Eighty-eight percent of patients with the lowest PUL entry item score of 1 presented with FVC % predicted values of <60 %, suggestive of respiratory impairment. By contrast, only 10 % of the remainder of the cohort (PUL entry item of 2 or more) had an FVC of <60 %. This relationship also held true when accounting for ambulatory status, age, and sex as possible confounding factors. In summary, our results suggest that the PUL entry item could be implemented in clinical practice to screen for respiratory impairment where spirometry is not readily available., Competing Interests: Declaration of competing interest Apart from the grant from the Jain Foundation that financed the study, there are no relevant conflicts of interest that impact on the paper referenced above., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Diagnosis of hereditary myopathy is often challenging owing to overlapping clinical phenotypes and muscle histopathological findings. This retrospective study aimed to identify the phenotypic and genotypic spectra of hereditary myopathies at a tertiary hospital in Riyadh, Saudi Arabia., Methods: We reviewed the medical records of patients with hereditary myopathy who were evaluated between January 2018 and December 2022., Results: Eighty-seven patients (78 families) were included, two-thirds were men with a mean age of 35 (SD 14.2) years. Limb-girdle muscular dystrophy (LGMD) was the most prevalent clinical diagnosis (25 cases; 29%), of whom, a genetic diagnosis was achieved in 15 of 22 patients tested (68%). In genetically confirmed LGMD, the most prevalent disorders were dysferlinopathy (27%) followed by fukutin-related protein (FKRP) - related limb girdle muscular dystrophy (20%), sarcoglycanopathy (20%), lamin A/C related myopathy (13%), and calpain-3 myopathy (13%). In 26 patients with pathogenic/likely pathogenic variants, the genetic testing method was whole exome sequencing (WES) (42%), Next generation sequencing (NGS) (31%), and targeted single gene analysis (27%). The sensitivity of each genetic testing method was as follows: 100% for targeted single-gene analysis, 100% for targeted analysis of D4Z4 repeat array units, 88% for myotonic dystrophy protein kinase (DMPK) repeat expansion analysis, 42% for NGS-neuromuscular panel, and 46% for WES., Conclusion: The prevalent types of hereditary myopathies were consistent with those reported locally and internationally. This study highlights the diagnostic yield of various molecular genetic tests for the diagnosis of hereditary myopathy in an adult cohort and the need for improved access to advanced molecular testing in cases suspected to have facioscapulohumeral muscular dystrophy (FSHD) or mitochondrial myopathies., (© 2024. The Author(s).)

Objective: Limb girdle muscular dystrophies (LGMDs) are a group of genetically heterogeneous autosomal conditions with some degree of phenotypic homogeneity. LGMD is defined as having onset >2 years of age with progressive proximal weakness, elevated serum creatine kinase levels and dystrophic features on muscle biopsy. Advances in massively parallel sequencing have led to a surge in genes linked to LGMD., Methods: The ClinGen Muscular Dystrophies and Myopathies gene curation expert panel (MDM GCEP, formerly Limb Girdle Muscular Dystrophy GCEP) convened to evaluate the strength of evidence supporting gene-disease relationships (GDR) using the ClinGen gene-disease clinical validity framework to evaluate 31 genes implicated in LGMD., Results: The GDR was exclusively LGMD for 17 genes, whereas an additional 14 genes were related to a broader phenotype encompassing congenital weakness. Four genes (CAPN3, COL6A1, COL6A2, and COL6A3) were split into two separate disease entities, based on each displaying both dominant and recessive inheritance patterns, resulting in curation of 35 GDRs. Of these, 30 (86%) were classified as definitive, 4 (11%) as moderate, and 1 (3%) as limited. Two genes, POMGNT1 and DAG1, though definitively related to myopathy, currently have insufficient evidence to support a relationship specifically with LGMD., Interpretation: The expert-reviewed assertions on the clinical validity of genes implicated in LGMDs form an invaluable resource for clinicians and molecular geneticists. We encourage the global neuromuscular community to publish case-level data that help clarify disputed or novel LGMD associations., (© 2024 The Author(s). Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

We report a woman in her 30s with dysferlinopathy whose diagnosis was masked by superimposed hypothyroidism. Laboratory studies revealed Hashimoto's thyroiditis and markedly raised serum creatine kinase (CK of 6255 U/L; reference range 0-170 U/L). Electromyography, nerve conduction studies and MRI of the hip and thigh were consistent with a diagnosis of hypothyroid myopathy, but thyroxine failed to resolve her clinical presentation or normalise the CK level. Immunohistochemical (IHC) staining of right vastus lateralis muscle biopsy revealed the selective absence of dysferlin leading to a diagnosis of limb-girdle muscular dystrophy type IIB. Dysferlinopathy is a challenging diagnosis due to a varied clinical picture and low incidence. Misdiagnosis is common even in uncomplicated presentations, and this case outlines the need for routine inclusion of IHC and a low threshold for genetic testing, in the workup of complex myopathy., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Neuromuscular disorders (NMDs) include a wide range of diseases affecting the peripheral nervous system. The genetic diagnoses are increasingly obtained with using the next generation sequencing (NGS). We applied the custom-design targeted NGS panel including 89 genes, together with genotyping and multiplex ligation-dependent probe amplification (MLPA) to identify a genetic spectrum of NMDs in 52 Polish patients. As a result, the genetic diagnosis was determined by NGS panel in 29 patients so its diagnostic utility is estimated at 55.8%. The most pathogenic variants were found in CLCN1, followed by CAPN3, SCN4A, and SGCA genes. Genotyping of myotonic dystrophy type 1 and 2 (DM1 and DM2) as a secondary approach has been performed. The co-occurrence of CAPN3 and CNBP mutations in one patient as well as DYSF and CNBP mutations in another suggests possibly more complex inheritance as well as expression of a phenotype. In 7 individuals with single nucleotide variant found in NGS testing, the MLPA of the CAPN3 gene was performed detecting the deletion encompassing exons 2-8 in the CAPN3 gene in one patient, confirming recessive limb-girdle muscular dystrophy type 1 (LGMDR1). Thirty patients obtained a genetic diagnosis (57.7%) after using NGS testing, genotyping and MLPA analysis. The study allowed for the identification of 27 known and 4 novel pathogenic/likely pathogenic variants and variants of uncertain significance (VUS) associated with NMDs.In conclusion, the diagnostic approach with diverse molecular techniques enables to broaden the mutational spectrum and maximizes the diagnostic yield. Furthermore, the co-occurrence of DM2 and LGMD has been detected in 2 individuals., (© 2024. The Author(s).)

Limb girdle muscular dystrophy (LGMD) is a debilitating disease and the fourth most common muscular dystrophy. This study describes the development of the LGMD-Health Index (LGMD-HI). Participants were aged >18 years and recruited from three LGMD registries and GRASP-LGMD consortium. The initial instrument, comprised of 16 thematic subscales and 161 items, underwent expert review resulting in item removal as well as confirmatory factor analysis followed by inter-rater reliability and internal consistency of the subscales. Following expert review, one subscale and 59 items were eliminated. Inter-rater reliability was assessed and five items were removed due to Cohen's kappa <0.5. The final subscales had high internal consistencies with an average Cronbach alpha of 0.92. Test re-test reliability of the final instrument was high (intraclass correlation coefficient=0.97). Known groups validity testing showed a statistically significant difference in LGMD-HI scores amongst subjects based on ambulation status (28.7 vs 50.0, p < 0.0001), but not sex, employment status, or genetic subtype. The final instrument is comprised of 15 subscales and 97 items. The LGMD-HI is a disease-specific, patient-reported outcome measure designed in compliance with published FDA guidelines. This instrument is capable of measuring burden of disease with no significant variation based on LGMD subtype., Competing Interests: Declaration of competing interest Chad Heatwole receives royalties for the use of multiple disease specific instruments. He has provided consultation to Biogen Idec, Ionis Pharmaceuticals, aTyr Pharma, AMO Pharma, Acceleron Pharma, Cytokinetics, Expansion Therapeutics, Harmony Biosciences, Regeneron Pharmaceuticals, Astellas Pharmaceuticals, AveXis, Recursion Pharmaceuticals, IRIS Medicine, Inc., Takeda Pharmaceutical Company, Scholar Rock, Avidity Biosciences, Novartis Pharmaceuticals Corporation, SwanBio Therapeutics, Neurocrine Biosciences, Sanofi, Lupin Pharmaceuticals, Vertex, and the Marigold Foundation. He receives grant support from the Department of Defense, Duchenne UK, Parent Project Muscular Dystrophy, Recursion Pharmaceuticals, Swan Bio Therapeutics, the National Institute of Neurological Disorders and Stroke, the Muscular Dystrophy Association, the Friedreich's Ataxia Research Alliance, Cure Spinal Muscular Atrophy, the Amyotrophic Lateral Sclerosis Association, and the Michael J. Foxx Foundation. He is the director of the University of Rochester's Center for Health and Technology. Nicholas Johnson has received grant funding from NINDS (4K23NS091511; R01NS104010), CDC (DD19-002) and the FDA (7R01FD006071-02). He receives royalties from the CCMDHI and the CMTHI. He receives research funds from Dyne, AveXis, CSL Behring, Vertex Pharmaceuticals, Fulcrum Therapeutics, ML Bio, Sarepta, and Acceleron Pharma. He has provided consultation for AveXis, AMO Pharma, Strongbridge BioPharma, Acceleron Pharma, Fulcrum Therapeutics, Dyne, Avidity, Arthex, and Vertex Pharmaceuticals. He receives licensing fees from the University of Rochester for the CCMDHI and CMTHI. He has received stock options from ML Bio., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Limb-girdle muscular dystrophy (LGMD) comprises a heterogeneous group of rare genetic disorders characterised by progressive weakness and atrophy of the muscles, primarily affecting the pelvic and shoulder girdles. A developmentally normal, early adolescent male presented with complaints of difficulty in using all four limbs with a waddling gait, gradually progressive over the last 5 years. No significant family history was noted. We noticed thinning and atrophy of both upper and lower limbs, proximal more than distal, associated with wasting, hypotonia and decreased power in all four limbs. Gower's sign was positive. The winging of the scapula was present. All deep tendon reflexes and superficial reflexes were present with flexor response in both plantars. The sensory system was normal. An initial diagnosis of muscular dystrophy was made and confirmed with clinical exome sequencing, which showed a pathogenic variant indicating a very rare type of autosomal recessive LGMD. This disease was previously named LGMD2C and has now been renamed under LGMDR5., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Dysferlin is a large transmembrane protein involved in critical cellular processes including membrane repair and vesicle fusion. Mutations in the dysferlin gene ( DYSF ) can result in rare forms of muscular dystrophy; Miyoshi myopathy; limb girdle muscular dystrophy type 2B (LGMD2B); and distal myopathy. These conditions are collectively known as dysferlinopathies and are caused by more than 600 mutations that have been identified across the DYSF gene to date. In this review, we discuss the key molecular and clinical features of LGMD2B, the causative gene DYSF , and the associated dysferlin protein structure. We also provide an update on current approaches to LGMD2B diagnosis and advances in drug development, including splice switching antisense oligonucleotides. We give a brief update on clinical trials involving adeno-associated viral gene therapy and the current progress on CRISPR/Cas9 mediated therapy for LGMD2B, and then conclude by discussing the prospects of antisense oligomer-based intervention to treat selected mutations causing dysferlinopathies.

The trafficking protein particle (TRAPP) complex is a multisubunit protein complex that functions as a tethering factor involved in intracellular trafficking. TRAPPC11, a crucial subunit of this complex, is associated with pathogenic variants that cause a spectrum of disease, which can range from a limb girdle muscular dystrophy (LGMD) to developmental disability with muscle disease, movement disorder and global developmental delay (GDD)/intellectual disability (ID), or even a congenital muscular dystrophy (CMD). We reviewed the phenotype of all reported individuals with TRAPPC11-opathies, including an additional Mexican patient with novel compound heterozygous missense variants in TRAPPC11 (c.751 T > C and c.1058C > G), restricted to the Latino population. In these 54 patients muscular dystrophy signs are common (early onset muscle weakness, increased serum creatine kinase levels, and dystrophic changes in muscle biopsy). They present two main phenotypes, one with a slowly progressive LGMD with or without GDD/ID (n = 12), and another with systemic involvement characterized by short stature, GDD/ID, microcephaly, hypotonia, poor speech, seizures, cerebral atrophy, cerebellar abnormalities, movement disorder, scoliosis, liver disease, and cataracts (n = 42). In 6 of them CMD was identified. Obstructive hydrocephaly, retrocerebellar cyst, and talipes equinovarus found in the individual reported here has not been described in TRAPPC11 deficiency. As in previous patients, membrane trafficking assays in our patient showed defective abnormal endoplasmic reticulum-Golgi transport as well as decreased expression of LAMP2, and ICAM-1 glycoproteins. This supports previous statements that TRAPPC11-opathies are in fact a congenital disorder of glycosylation (CDG) with muscular dystrophy., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Limb Girdle Muscular Dystrophy R1 (LGMDR1) is an autosomal recessive neuromuscular disease caused by mutations in the calpain-3 (CAPN3) gene. As clinical and pathological features may overlap with other types of LGMD, therefore definite molecular diagnosis is required to understand the progression of this debilitating disease. This study aims to identify novel variants of CAPN3 gene in LGMDR1 patients., Results: Thirty-four patients with clinical and histopathological features suggestive of LGMD were studied. The muscle biopsy samples were evaluated using Enzyme histochemistry, Immunohistochemistry, followed by Western Blotting and Sanger sequencing. Out of 34 LGMD cases, 13 patients were diagnosed as LGMDR1 by immunoblot analysis, demonstrating reduced or absent calpain-3 protein as compared to controls. Variants of CAPN3 gene were also found and pathogenicity was predicted using in-silico prediction tools. The CAPN3 gene variants found in this study, included, two missense variants [CAPN3: c.1189T > C, CAPN3: c.2338G > C], one insertion-deletion [c.1688delinsTC], one splice site variant [c.2051-1G > T], and one nonsense variant [c.1939G > T; p.Glu647Ter]., Conclusions: We confirmed 6 patients as LGMDR1 (with CAPN3 variants) from our cohort and calpain-3 protein expression was significantly reduced by immunoblot analysis as compared to control. Besides the previously known variants, our study found two novel variants in CAPN3 gene by Sanger sequencing-based approach indicating that genetic variants in LGMDR1 patients may help to understand the etiology of the disease and future prognostication., (© 2024. The Author(s).)

Background: The Limb Girdle Muscular Dystrophies (LGMDs) are characterized by progressive weakness of the shoulder and hip girdle muscles as a result of over 30 different genetic mutations. This study is designed to develop clinical outcome assessments across the group of disorders., Methods/design: The primary goal of this study is to evaluate the utility of a set of outcome measures on a wide range of LGMD phenotypes and ability levels to determine if it would be possible to use similar outcomes between individuals with different phenotypes. We will perform a multi-center, 12-month study of 188 LGMD patients within the established Genetic Resolution and Assessments Solving Phenotypes in LGMD (GRASP-LGMD) Research Consortium, which is comprised of 11 sites in the United States and 2 sites in Europe. Enrolled patients will be clinically affected and have mutations in CAPN3 (LGMDR1), ANO5 (LGMDR12), DYSF (LGMDR2), DNAJB6 (LGMDD1), SGCA (LGMDR3), SGCB (LGMDR4), SGCD (LGMDR6), or SGCG (LGMDR5, or FKRP-related (LGMDR9)., Discussion: To the best of our knowledge, this will be the largest consortium organized to prospectively validate clinical outcome assessments (COAs) in LGMD at its completion. These assessments will help clinical trial readiness by identifying reliable, valid, and responsive outcome measures as well as providing data driven clinical trial decision making for future clinical trials on therapeutic agents for LGMD. The results of this study will permit more efficient clinical trial design. All relevant data will be made available for investigators or companies involved in LGMD therapeutic development upon conclusion of this study as applicable., Trial Registration: Clinicaltrials.gov NCT03981289; Date of registration: 6/10/2019., (© 2024. The Author(s).)

The Quality of Life (QOL) is influenced by several disease-related factors, support, resources, expectations, and aspirations, within the disease-related concepts. The Individualized Neuromuscular Quality of Life (INQoL) is a validated muscle disease-specific measure of the QoL developed from the experiences of patients with muscle disease and can be used for people or large cohorts. This review of QoL in transportinopathy cases reports adjustments in an autosomal dominant (AD) LGMD, and a comparison is made with autosomal recessive (AR) LGMD evaluated by INQoL. The locus for this form of LGMD with AD inheritance was found on chromosome 7, and then identification of the gene and its encoded protein (transportin-3) was obtained in 2013. A large three-generation family with several branches in Spain and Italy was previously reported and described in detail. Some patients had an early onset weakness, but others had an adult onset of the disease, as late as 58 years. The severity of the appearance of the phenotype is correlated with QoL and progresses with age. Assessing the impact on their QoL is particularly relevant to know whether the treatment is reducing their suffering., Competing Interests: The author declares no conflict of interest., (©2024 Gaetano Conte Academy - Mediterranean Society of Myology, Naples, Italy.)

Objective: To identify novel biomarkers as an alternative diagnostic tool for limb girdle muscular dystrophy (LGMD)., Background: LGMD encompasses a group of muscular dystrophies characterized by proximal muscles weakness, elevated CK levels and dystrophic findings on muscle biopsy. Heterozygous CAPN3 mutations are associated with autosomal dominant LGMD-4, while biallelic mutations can cause autosomal recessive LGMD-1. Diagnosis is currently often based on invasive methods requiring muscle biopsy or blood tests. In most cases Western blotting (WB) analysis from muscle biopsy is essential for a diagnosis, as muscle samples are currently the only known tissues to express the full-length CAPN3 isoform., Methods: We analyzed CAPN3 in a cohort including 60 LGMD patients. Selected patients underwent a complete neurological examination, electromyography, muscle biopsy, and skin biopsies for primary fibroblasts isolation. The amount of CAPN3 was evaluated by WB analysis in muscle and skin tissues. The total RNA isolated from muscle, fibroblast and urine was processed, and cDNA was used for qualitative analysis. The expression of CAPN3 was investigated by qRT-PCR. The CAPN3 3D structure has been visualized and analyzed using PyMOL., Results: Among our patients, seven different CAPN3 mutations were detected, of which two were novel. After sequencing CAPN3 transcripts from fibroblast and urine, we detected different CAPN3 isoforms surprisingly including the full-length transcript. We found comparable protein levels from fibroblasts and muscle tissue; in particular, patients harboring a novel CAPN3 mutation showed a 30% reduction in protein compared to controls from both tissues., Conclusions: Our findings showed for the first time the presence of the CAPN3 full-length transcript in urine and skin samples. Moreover, we demonstrated surprisingly comparable CAPN3 protein levels between muscle and skin samples, thus allowing us to hypothesize the use of skin biopsy and probably of urine samples as an alternative less invasive method to assess the amount of CAPN3 when molecular diagnosis turns out to be inconclusive.

Purpose: To report bilateral retinal vascular occlusive disease in limb-girdle muscular dystrophy (LGMD)., Methods: Case report., Results: A 34-year-old Asian woman was referred for evaluation and management of central retinal vein occlusion. Ultra-wide-field fluorescein angiography showed resolving initial peripheral retinal vein occlusion in one eye and peripheral venular segmental staining in the fellow asymmetric eye. Genetic testing established the diagnosis of LGMD., Conclusion: Similar to other forms of muscular dystrophy, LGMD is caused by genetic abnormalities in sarcolemma proteins, a key structural component that connects the intracellular cytoskeleton of a myofiber to the extracellular matrix. Like other muscular dystrophies, LGMD may be associated with retinal vascular abnormalities noted. In this case, retinal vascular smooth muscle dysfunction was seen in LGMD, analogous to reported vascular abnormalities in other muscular dystrophies such as facioscapulohumeral dystrophy and Duchenne muscular dystrophy., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Opthalmic Communications Society, Inc.)

Fukutin-related protein (FKRP) mutations cause a broad spectrum of muscular dystrophies, from a relatively mild limb-girdle muscular dystrophy type 9 (LGMDR9) to severe congenital muscular dystrophy (CMD). This study aims to report two siblings belonging to a non-consanguineous Tunisian family harboring a novel compound heterozygous FKRP variant and presenting a mild LGDMR9 phenotype. For mutation screening, massive parallel sequencing was performed, followed by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) to validate the existence of the discovered variants. The absence of alpha-dystroglycan was determined by immunohistochemistry. Brain and thigh magnetic resonance imaging (MRI) were performed to detect thigh and brain abnormalities. The two siblings had a late age at onset and clinical examination showed that the pelvic girdles had a predominantly proximal and symmetrical distribution of weakness without cardiac or respiratory involvement. They both had a modified Gardner-Medwin Walton Scale mGMWS grade of 4 and a modified Rankin Scale (mRS) score of 1. The DNA sequencing revealed a novel deletion of exons 2 and 3 in one allele and a missense mutation c.1364C > A, which has been reported to be responsible for congenital muscular dystrophy and mental retardation on the second allele. The simultaneous presence of the two variations in the two cases suggests that the variants segregate with the pathophysiology., Competing Interests: The authors declare that they have no conflicts of interest., (©2023 Gaetano Conte Academy - Mediterranean Society of Myology, Naples, Italy.)

Limb girdle muscular dystrophies (LGMDs) are a group of genetically inherited neuromuscular diseases with a very variable clinical presentation and overlapping traits. Over the last few years there has been an increasing interest in the use of non-invasive circulating biomarkers to monitor disease progression and to evaluate the efficacy of therapeutic approaches. Our aim was to identify the miRNA signature with potential value for LGMD patient screening and stratification. Using miRCURY LNA miRNA qPCR Serum/Plasma Panel, we analyzed 179 miRNAs from 16 patients, divided in four pools based on their genetic diagnosis, and from healthy controls. The miRNAs analysis showed a total of 107 dysregulated miRNAs in LGMD patients when compared to the healthy controls. After filtering via skeletal tissue expression and gene/pathways target analysis, the number of dysregulated miRNAs drastically reduced. Six selected miRNAs-let-7f-5p (in LGMDR1), miR-20a-5p (in LGMDR2), miR-130b-5p, miR-378a-5p (both in LGMDR3), miR-376c-3p and miR-382-5p (both in LGMDR4)-whose expression was significantly lower compared to controls in the different LGMD pools, were further investigated. The bioinformatic analysis of the target genes in each selected miRNA revealed ECM-receptor interaction and TGF-beta signaling as the most involved pathways. The correlation analysis showed a good correlation of let-7f-5p with fibrosis and with the cross sectional area of type I and type II fibers, while miR-130b-5p showed a good correlation with the age of onset of the disease. The receiver operating characteristic curves showed how single miRNAs were able to discriminate a specific group of LGMD patients and how the combination of six miRNAs was able to discriminate LGMD patients from controls.

Neuromuscular diseases (NMDs) affect ∼15 million people globally. In high income settings DNA-based diagnosis has transformed care pathways and led to gene-specific therapies. However, most affected families are in low-to-middle income countries (LMICs) with limited access to DNA-based diagnosis. Most (86%) published genetic data is derived from European ancestry. This marked genetic data inequality hampers understanding of genetic diversity and hinders accurate genetic diagnosis in all income settings. We developed a cloud-based transcontinental partnership to build diverse, deeply-phenotyped and genetically characterized cohorts to improve genetic architecture knowledge, and potentially advance diagnosis and clinical management. We connected 18 centres in Brazil, India, South Africa, Turkey, Zambia, Netherlands and the UK. We co-developed a cloud-based data solution and trained 17 international neurology fellows in clinical genomic data interpretation. Single gene and whole exome data were analysed via a bespoke bioinformatics pipeline and reviewed alongside clinical and phenotypic data in global webinars to inform genetic outcome decisions. We recruited 6001 participants in the first 43 months. Initial genetic analyses 'solved' or 'possibly solved' ∼56% probands overall. In-depth genetic data review of the four commonest clinical categories (limb girdle muscular dystrophy, inherited peripheral neuropathies, congenital myopathy/muscular dystrophies and Duchenne/Becker muscular dystrophy) delivered a ∼59% 'solved' and ∼13% 'possibly solved' outcome. Almost 29% of disease causing variants were novel, increasing diverse pathogenic variant knowledge. Unsolved participants represent a new discovery cohort. The dataset provides a large resource from under-represented populations for genetic and translational research. In conclusion, we established a remote transcontinental partnership to assess genetic architecture of NMDs across diverse populations. It supported DNA-based diagnosis, potentially enabling genetic counselling, care pathways and eligibility for gene-specific trials. Similar virtual partnerships could be adopted by other areas of global genomic neurological practice to reduce genetic data inequality and benefit patients globally., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Background: Limb-girdle muscular dystrophies (LGMDs) are a group of heterogeneous inherited diseases predominantly characterized by limb-girdle muscle weakness and dystrophic changes on histological analysis. The frequency of LGMD subtypes varies among regions in China and ethnic populations worldwide. Here, we analyzed the prevalence of LGMD subtypes, their corresponding clinical manifestations, and molecular data in a cohort of LGMD patients in Southeast China., Methods: A total of 81 consecutive patients with clinically suspected LGMDs from 62 unrelated families across Southeast China were recruited for targeted next-generation sequencing and whole-exome sequencing from July 2017 to February 2020., Results: Among 50 patients (41 families) with LGMDs, the most common subtypes were LGMD-R2/LGMD2B (36.6%) and LGMD-R1/LGMD2A (29.3%). Dystroglycanopathies (including LGMD-R9/LGMD2I, LGMD-R11/LGMD2K, LGMD-R14/LGMD2N and LGMD-R20/LGMD2U) were the most common childhood-onset subtypes and were found in 12.2% of the families. A total of 14.6% of the families had the LGMD-R7/LGMD2G subtype, and the mutation c.26&#95;33dupAGGTGTCG in TCAP was the most frequent (83.3%). The only patient with the rare subtype LGMD-R18/LGMD2S had TRAPPC11 mutations; had a later onset than those previously reported, and presented with proximal‒distal muscle weakness, walking aid dependency, fatty liver disease and diabetes at 33 years of age. A total of 22.0% of the patients had cardiac abnormalities, and one patient with LMNA-related muscular dystrophy/LGMD1B experienced sudden cardiac death at 37 years of age. A total of 15.4% of the patients had restrictive respiratory insufficiency. Muscle imaging in patients with LGMD-R1/LGMD2A and LGMD-R2/LGMD2B showed subtle differences, including more severe fatty infiltration of the posterior thigh muscles in those with LGMD-R1/LGMD2A and edema in the lower leg muscles in those with LGMD-R2/LGMD2B., Conclusion: We determined the prevalence of different LGMD subtypes in Southeast China, described the detailed clinical manifestations and distinct muscle MRI patterns of these LGMD subtypes and reported the frequent mutations and the cardiorespiratory involvement frequency in our cohort, all of which might facilitate the differential diagnosis of LGMDs, allowing more timely treatment and guiding future clinical trials., (© 2023. The Author(s).)

Introduction/aims: In our experience, patients with late-onset facioscapulohumeral muscular dystrophy type 1 (FSHD1) are frequently misdiagnosed, some for many years. The aim of this report is to document this clinical experience including the presenting symptoms and misdiagnoses and to discuss the challenges in diagnosing patients with late-onset FSHD1., Methods: We performed a retrospective medical record review and recorded clinical data on patients with a genetically confirmed diagnosis of FSHD1, who began to have symptoms at 50 years of age or older, and either had no family history of FSHD1 or had a history of an undiagnosed weakness in a family member., Results: Thirteen patients, 7 men and 6 women, met the study inclusion criteria. Age of onset ranged from 52 to 74 (mean, 59.8) years, age of diagnosis ranged from 54 to 80 (mean, 66.5) years, and duration of symptoms from onset to diagnosis was 1 to 15 (mean, 6.7) years. Prior diagnoses included lumbosacral polyradiculopathy in five (38%); statin-related myopathy in two (15%); and one each of polymyositis, inclusion-body myositis, distal myopathy, limb-girdle muscular dystrophy, unspecific myopathy, and unspecified scapular winging. For eight patients (62%), family history was suspected in deceased members or if by confirmed DNA test postdiagnosis., Discussion: The diagnosis of late-onset FSHD1 is often delayed by many years with patients frequently receiving misdiagnoses. FSHD1 may not be considered in the differential diagnosis of late-onset weakness due to its rarity and because its clinical features are subtler, nonspecific, and mimic other neuromuscular disorders., (© 2023 Wiley Periodicals LLC.)

Objective: Clinical and genetic heterogeneities make diagnosis of limb-girdle muscular dystrophy (LGMD) and other overlapping disorders of muscle weakness complicated and expensive. We aimed to develop a comprehensive next generation sequence-based multi-gene panel ("The Lantern Focused Neuromuscular Panel") to detect both sequence variants and copy number variants in one assay., Methods: Patients with clinical diagnosis of LGMD or other overlapping muscular dystrophies in the United States were tested by PerkinElmer Genomics in 2018-2021 via "The Lantern Project," a sponsored diagnostic testing program. Sixty-six genes related to LGMD subtypes- and other myopathies were investigated. Main outcomes were diagnostic yield, gene-variant spectrum, and LGMD subtypes' prevalence., Results: Molecular diagnosis was established in 19.6% (1266) of 6473 cases. Major genes contributing to LGMD were identified including CAPN3 (5.4%, 68), DYSF (4.0%, 51), GAA (3.7%, 47), ANO5 (3.6%, 45), and FKRP (2.7%, 34). Genes of other overlapping MD subtypes identified included PABPN1 (10.5%, 133), VCP (2.2%, 28), MYOT (1.2% 15), LDB3 (1.0%, 13), COL6A1 (1.5%, 19), FLNC (1.1%, 14), and DNAJB6 (0.8%, 10). Different sizes of copy number variants including single exon, multi-exon, and whole genes were identified in 7.5% (95) cases in genes including DMD, EMD, CAPN3, ANO5, SGCG, COL6A2, DOK7, and LAMA2., Interpretation: "The Lantern Focused Neuromuscular Panel" enables identification of LGMD subtypes and other myopathies with overlapping clinical features. Prevalence of some MD subtypes was higher than previously reported. Widespread deployment of this comprehensive NGS panel has the potential to ensure early, accurate diagnosis as well as re-define MD epidemiology., (© 2023 Revvity, Inc. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Anoctamin-5 related muscle disease is caused by biallelic pathogenic variants in the anoctamin-5 gene (ANO5) and shows variable clinical phenotypes: limb-girdle muscular dystrophy type 12 (LGMD-R12), distal muscular dystrophy type 3 (MMD3), pseudometabolic myopathy or asymptomatic hyperCKaemia. In this retrospective, observational, multicentre study we gathered a large European cohort of patients with ANO5-related muscle disease to study the clinical and genetic spectrum and genotype-phenotype correlations. We included 234 patients from 212 different families, contributed by 15 centres from 11 European countries. The largest subgroup was LGMD-R12 (52.6%), followed by pseudometabolic myopathy (20.5%), asymptomatic hyperCKaemia (13.7%) and MMD3 (13.2%). In all subgroups, there was a male predominance, except for pseudometabolic myopathy. Median age at symptom onset of all patients was 33 years (range 23-45 years). The most frequent symptoms at onset were myalgia (35.3%) and exercise intolerance (34.1%), while at last clinical evaluation most frequent symptoms and signs were proximal lower limb weakness (56.9%) and atrophy (38.1%), myalgia (45.1%) and atrophy of the medial gastrocnemius muscle (38.4%). Most patients remained ambulatory (79.4%). At last evaluation, 45.9% of patients with LGMD-R12 additionally had distal weakness in the lower limbs and 48.4% of patients with MMD3 also showed proximal lower limb weakness. Age at symptom onset did not differ significantly between males and females. However, males had a higher risk of using walking aids earlier (P = 0.035). No significant association was identified between sportive versus non-sportive lifestyle before symptom onset and age at symptom onset nor any of the motor outcomes. Cardiac and respiratory involvement that would require treatment occurred very rarely. Ninety-nine different pathogenic variants were identified in ANO5 of which 25 were novel. The most frequent variants were c.191dupA (p.Asn64Lysfs*15) (57.7%) and c.2272C>T (p.Arg758Cys) (11.1%). Patients with two loss-of function variants used walking aids at a significantly earlier age (P = 0.037). Patients homozygous for the c.2272C>T variant showed a later use of walking aids compared to patients with other variants (P = 0.043). We conclude that there was no correlation of the clinical phenotype with the specific genetic variants, and that LGMD-R12 and MMD3 predominantly affect males who have a significantly worse motor outcome. Our study provides useful information for clinical follow up of the patients and for the design of clinical trials with novel therapeutic agents., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Limb-girdle muscular dystrophy (LGMD), a rare group of non-congenital inherited muscle diseases, is characterized by a progressive reduction in muscle tone and force of the proximal limbs. The clinical manifestations and genetic patterns of LGMD are heterogeneous. This study reported on a 10-year-old male patient with LGMD type 2U who experienced muscle weakness in the lower limbs after exercise. Upon admission, the patient's creatine kinase levels were significantly elevated, and hydration and alkalinization therapy were ineffective. Using high-throughput sequencing, muscular dystrophy-related genes were tested in the patient, his parents, and his sister. The patient was found to have a heterozygous deletion of exon 9 of the ISPD gene and a heterozygous missense mutation c.1231C>T (p.Leu411Phe). The patient's father carried the heterozygous missense mutation c.1231C>T (p.Leu411Phe) of the ISPD gene, while his mother and sister carried a heterozygous deletion of exon 9 of the ISPD gene. These mutations have not been reported in existing databases or literature. Conservation and protein structure prediction analyses of the mutation sites indicated that they are highly conserved and located in the C-terminal domain of the ISPD protein, which may affect protein function. Based on the above results and relevant clinical data, the patient was definitively diagnosed with LGMD type 2U. This study enriched the spectrum of ISPD gene mutations by summarizing the patient's clinical characteristics and analyzing new ISPD gene variations. This can aid in the early diagnosis and genetic counseling of the disease.

Statins are a mainstay intervention for cardiovascular disease prevention, yet their use can cause rare severe myopathy. HMG-CoA reductase, an essential enzyme in the mevalonate pathway, is the target of statins. We identified nine individuals from five unrelated families with unexplained limb-girdle like muscular dystrophy and bi-allelic variants in HMGCR via clinical and research exome sequencing. The clinical features resembled other genetic causes of muscular dystrophy with incidental high CPK levels (>1,000 U/L), proximal muscle weakness, variable age of onset, and progression leading to impaired ambulation. Muscle biopsies in most affected individuals showed non-specific dystrophic changes with non-diagnostic immunohistochemistry. Molecular modeling analyses revealed variants to be destabilizing and affecting protein oligomerization. Protein activity studies using three variants (p.Asp623Asn, p.Tyr792Cys, and p.Arg443Gln) identified in affected individuals confirmed decreased enzymatic activity and reduced protein stability. In summary, we showed that individuals with bi-allelic amorphic (i.e., null and/or hypomorphic) variants in HMGCR display phenotypes that resemble non-genetic causes of myopathy involving this reductase. This study expands our knowledge regarding the mechanisms leading to muscular dystrophy through dysregulation of the mevalonate pathway, autoimmune myopathy, and statin-induced myopathy., Competing Interests: Declaration of interests The Department of Molecular and Human Genetics at Baylor College of Medicine receives revenue from clinical genetic testing from Baylor Genetics Laboratories. J.R.L. has stock ownership in 23andMe, is a paid consultant for Regeneron Pharmaceuticals, and is a co-inventor on multiple United States and European patents related to molecular diagnostics for inherited neuropathies, eye diseases, genomic disorders, and bacterial genomic fingerprinting., (Copyright © 2023. Published by Elsevier Inc.)

Background: Limb-girdle muscular dystrophy R8 (LGMD R8) is a rare autosomal recessive muscle disease caused by TRIM32 gene biallelic defects. The genotype-phenotype correlation of this disease has been reported poorly. Here, we report a Chinese family with two female LGMD R8 patients., Methods: We performed whole-genome sequencing (WGS) and Sanger sequencing on the proband. Meanwhile, the function of mutant TRIM32 protein was analyzed by bioinformatics and experimental analysis. In addition, a summary of the reported TRIM32 deletions and point mutations and an investigation of genotype-phenotype correlation were performed through a combined analysis of the two patients and other cases reported in previous literature., Results: The two patients displayed typical symptoms of LGMD R8, which worsened during pregnancy. Genetic analysis by whole-genome sequencing (WGS) and Sanger sequencing showed that the patients were compound heterozygotes of a novel deletion (chr9.hg19:g.119431290&#95;119474250del) and a novel missense mutation (TRIM32:c.1700A > G, p.H567R). The deletion encompassed 43 kb and resulted in the removal of the entire TRIM32 gene. The missense mutation altered the structure and further affected function by interfering with the self-association of the TRIM32 protein. Females with LGMD R8 showed less severe symptoms than males, and patients carrying two mutations in NHL repeats of the TRIM32 protein had earlier disease onset and more severe symptoms than other patients., Conclusions: This research extended the spectrum of TRIM32 mutations and firstly provided useful data on the genotype-phenotype correlation, which is valuable for the accurate diagnosis and genetic counseling of LGMD R8., (© 2023. The Author(s).)

Introduction: Limb girdle muscular dystrophies (LGMDs) are a group of rare and heterogeneous disorders involving progressive wasting of shoulder and pelvic girdle musculature. This study aimed to generate qualitative evidence on patient and caregiver experiences with symptoms and impacts of LGMD on overall function and daily life for sarcoglycanopathy subtypes 2C/R5, 2D/R3, and 2E/R4., Methods: Twenty-three individuals with LGMD with (n = 5) or without (n = 18) a caregiver participated in 60-minute semi-structured video interviews. Interview transcripts were analyzed using thematic analysis. Differences in patient experience by ambulation status and LGMD subtype were examined., Results: Participants were ambulatory (n = 14) and non-ambulatory (n = 9), representing three subtypes: 2C/R5 (n = 4), 2D/R3 (n = 12), and 2E/R4 (n = 7), with mean age of 34.8 years (SD = 16.08). 56.5% identified as female. Conceptual saturation was achieved within 18/23 interviews. Ambulatory participants identified difficulty with complex physical activities, e.g., running (n = 11, 78.6%), physical strength (n = 14, 100%), and difficulty with transfers, e.g., difficulty getting off the floor (n = 10, 71.4%). All non-ambulatory participants discussed problems with activities of daily living (ADLs) and transfers, e.g., getting in/out of bed and upper extremity function, particularly reaching (n = 8, 88.9%) and fine motor skills (n = 6, 66.7%). Fatigue and pain were reported by the majority of participants (n = 16, 69.6% and n = 19, 82.6%, respectively). A conceptual disease model was developed illustrating symptoms and impacts and their relationships to disease stage, capturing the patient experience across LGMD disease trajectory., Conclusions: This study contributes to the limited evidence describing the patient experience of living with LGMD. The conceptual model can inform patient-centered assessment in future LGMD clinical trials., (© 2023. The Author(s).)

Muscular dystrophies are a heterogeneous group of neuromuscular disorders with a wide range of the clinical and genetic spectrum. Whole-exome sequencing (WES) has been on the rise to become the usual method of choice for molecular diagnosis in patients presenting with muscular dystrophy or congenital or metabolic myopathy phenotype. Here, we used a panel with 47 genes including not only muscular dystrophy but also myopathy-associated genes that had been used as a first-tier approach. A total of 146 patients who were referred to our clinic with the prediagnosis of muscular dystrophy and/or myopathy were included in the study. Dystrophin gene deletion/duplication was ruled out on the patients with a preliminary diagnosis of Duchenne muscular dystrophy. In this study, the molecular etiology of 67 patients was proved with the gene panel with a diagnostic yield of 46%. Causal variants were identified in 23 genes including CAPN3(11), DYSF(9), DMD(8), SGCA(5), TTN(4), LAMA2(3), LMNA(3), SGCB(3), COL6A1(3), DES (2), CAV3(2), FKRP(2), FKTN(2), ANO5, COL6A2, CLCN1, GNE, POMGNT1, POMGNT2, POMT2, SYNE1, TCAP, and FLNC with 16 novel variants. There were 27 patients with uncertain molecular results including the ones who had a variant of uncertain significance, who had only one heterozygous variant for an autosomal recessive disease, and the ones who had two variants in different genes. Molecular diagnosis in muscular dystrophy is essential to plan clinical management and choosing treatment options. Also, the results will affect the reproduction options. Targeted next-generation sequencing is a cost-effective method that reduces the WES requirements with a significant diagnostic rate., (© 2022 John Wiley & Sons Ltd/University College London.)

Valosin-containing protein (VCP)-associated multisystem proteinopathy (MSP) is a rare genetic disorder with abnormalities in the autophagy pathway leading to various combinations of myopathy, bone diseases, and neurodegeneration. Ninety percent of patients with VCP-associated MSP have myopathy, but there is no consensus-based guideline. The goal of this working group was to develop a best practice set of provisional recommendations for VCP myopathy which can be easily implemented across the globe. As an initiative by Cure VCP Disease Inc., a patient advocacy organization, an online survey was initially conducted to identify the practice gaps in VCP myopathy. All prior published literature on VCP myopathy was reviewed to better understand the different aspects of management of VCP myopathy, and several working group sessions were conducted involving international experts to develop this provisional recommendation. VCP myopathy has a heterogeneous clinical phenotype and should be considered in patients with limb-girdle muscular dystrophy phenotype, or any myopathy with an autosomal dominant pattern of inheritance. Genetic testing is the only definitive way to diagnose VCP myopathy, and single-variant testing in the case of a known familial VCP variant, or multi-gene panel sequencing in undifferentiated cases can be considered. Muscle biopsy is important in cases of diagnostic uncertainty or lack of a definitive pathogenic genetic variant since rimmed vacuoles (present in ~40% cases) are considered a hallmark of VCP myopathy. Electrodiagnostic studies and magnetic resonance imaging can also help rule out disease mimics. Standardized management of VCP myopathy will optimize patient care and help future research initiatives., (© 2023 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

We aimed to investigate the epidemiology and natural history of FKRP-related limb-girdle muscular dystrophy R9 (LGMDR9) in Norway. We identified 153 genetically confirmed subjects making the overall prevalence 2.84/100,000, the highest reported figure worldwide. Of the 153 subjects, 134 (88 %) were homozygous for FKRP c.826C>A giving a carrier frequency for this variant of 1/101 in Norway. Clinical questionnaires and patient notes from 101 subjects, including 88 c.826C>A homozygotes, were reviewed, and 43/101 subjects examined clinically. Age of onset in c.826C>A homozygotes demonstrated a bimodal distribution. Female subjects showed an increased cumulative probability of wheelchair dependency and need for ventilatory support. Across the cohort, the need for ventilatory support preceded wheelchair dependency in one third of the cases, usually due to sleep apnea. In c.826C>A homozygotes, occurrence of cardiomyopathy correlated positively with male gender but not with age or disease stage. This study highlights novel gender differences in both loss of ambulation, need for ventilatory support and the development of cardiomyopathy. Our results confirm the need for vigilance in order to detect respiratory insufficiency and cardiac involvement, but indicate that these events affect males and females differently., Competing Interests: Declaration of Competing Interest None, (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

The precise detection and interpretation of pathogenic DYSF variants are sometimes challenging, largely due to rare deep-intronic splice-altering variants. Here, we report on the genetic diagnosis of a male patient with dysferlinopathy. He remained genetically unsolved after routine exonic detection approaches that only detected a novel heterozygous frameshift variant (c.407dup, p.Thr137Tyrfs*11) in DYSF exon 5. Via muscle-derived DYSF mRNA studies, we identified a novel deep-intronic DYSF variant in the other allele (c.1397 + 649C > T), which causing in-frame alterations in DYSF mRNA and protein structure and confirmed his genetic diagnosis of dysferlinopathy. Our study emphasizes the potential role of undetected deep-intronic splice-altering variants in monogenic diseases., (© 2022 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Background: Dystroglycanopathies are a heterogeneous group of membrane-related muscular dystrophies. The dystroglycanopathy phenotype includes a spectrum of severity ranging from severe congenital muscular dystrophy to adult-onset limb-girdle muscular dystrophy (LGMD). LGMDR9 is a dystroglycanopathy caused by mutations in the FKRP gene. Previous studies have characterized electroretinogram findings of dystroglycanopathy mouse models but have not been reported in humans., Purpose: This study set out to characterize the electroretinogram in eight participants with LGMDR9., Methods: Eight participants were recruited from an ongoing dystroglycanopathy natural history study at the University of Iowa (NCT00313677). Inclusion criteria for the current study were children and adults > 6 years old with confirmed LGMDR9. Age similar controls were identified from our electrophysiology service normative control database. Full-field electroretinograms were recorded using ISCEV standards. Six of the eight participants underwent light-adapted ON/OFF testing., Results: The electronegative electroretinogram was not seen in any participants with LGMDR9. An unusual sawtooth pattern in the 30 Hz flicker with faster rise than descent was noted in all 8 participants. Our cases showed a decreased b-wave amplitude in light-adapted ON responses (p = 0.011) and decreased d-wave amplitude in light-adapted OFF responses (p = 0.015). Decreased b-wave amplitude in light-adapted 3.0 testing (p = 0.015) and decreased flicker ERG amplitudes were also detected (p = 0.0018). Additionally, compared to controls, participants with LGMDR9 had decreased a-wave amplitudes on dark-adapted 10 testing (p = 0.026)., Conclusions: Abnormal ON/OFF bipolar cell responses and sawtooth 30 Hz flicker waveforms on full-field electroretinogram may be specific for LGMDR9. If confirmed in a larger population and if related to disease stage, these tests are potential biomarkers which could be useful as endpoints in clinical treatment trials., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Limb-girdle muscular dystrophy (LGMD) is a genetic muscle disorder causing weakness and wasting of the proximal limb musculature. When ambulation is lost, the attention must be shifted to the upper limb muscles' function. We studied the upper limb muscle strength and the corresponding function in 15 LGMDR1/LGMD2A and 13 LGMDR2/LGMD2B, through the Performance of Upper Limb scale and the MRC score of upper limbs. The proximal item K and the distal items N and R were lower in LGMD2B/R2. The mean MRC score of all the muscles involved linearly correlated (r2 = 0.922) for item K in LGMD2B/R2. The functional worsening paralleled the muscles weakness in LGMD2B/R2. By contrast, at proximal level the function of LGMD2A/R1 was preserved despite muscle weakness was present, presumably due to compensatory strategies. Sometimes the combination of parameters might be more informative than considering them separately. PUL scale and MRC might be interesting outcome measures in non-ambulant patients., (©2022 Gaetano Conte Academy - Mediterranean Society of Myology, Naples, Italy.)

Background: Water T2 (T2 H2O ) mapping is increasingly being used in muscular dystrophies to assess active muscle damage. It has been suggested as a surrogate outcome measure for clinical trials. Here, we investigated the prognostic utility of T2 H2O to identify changes in muscle function over time in limb girdle muscular dystrophies., Methods: Patients with genetically confirmed dysferlinopathy were assessed as part of the Jain Foundation Clinical Outcomes Study in dysferlinopathy. The cohort included 18 patients from two sites, both equipped with 3-tesla magnetic resonance imaging (MRI) systems from the same vendor. T2 H2O value was defined as higher or lower than the median in each muscle bilaterally. The degree of deterioration on four functional tests over 3 years was assessed in a linear model against covariates of high or low T2 H2O at baseline, age, disease duration, and baseline function., Results: A higher T2 H2O at baseline significantly correlated with a greater decline on functional tests in 21 out of 35 muscles and was never associated with slower decline. Higher baseline T2 H2O in adductor magnus, vastus intermedius, vastus lateralis, and vastus medialis were the most sensitive, being associated bilaterally with greater decline in multiple timed tests. Patients with a higher than median baseline T2 H2O (>40.6 ms) in the right vastus medialis deteriorated 11 points more on the North Star Ambulatory Assessment for Dysferlinopathy and lost an additional 86 m on the 6-min walk than those with a lower T2 H2O (<40.6 ms). Optimum sensitivity and specificity thresholds for predicting decline were 39.0 ms in adductor magnus and vastus intermedius, 40.0 ms in vastus medialis, and 40.5 ms in vastus lateralis from different sites equipped with different MRI systems., Conclusions: In dysferlinopathy, T2 H2O did not correlate with current functional ability. However, T2 H2O at baseline was higher in patients who worsened more rapidly on functional tests. This suggests that inter-patient differences in functional decline over time may be, in part, explained by different severities of the active muscle damage, assessed by T2 H2O measure at baseline. Significant challenges remain in standardizing T2 H2O values across sites to allow determining globally applicable thresholds. The results from the present work are encouraging and suggest that T2 H2O could be used to improve prognostication, patient selection, and disease modelling for clinical trials., (© 2022 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of Society on Sarcopenia, Cachexia and Wasting Disorders.)

Purpose of Review: The limb-girdle muscular dystrophies (LGMDs) are a group of inherited muscle disorders with a common feature of limb-girdle pattern of weakness, caused by over 29 individual genes. This article describes the classification scheme, common subtypes, and the management of individuals with LGMD., Recent Findings: Advances in genetic testing and next-generation sequencing panels containing all of the LGMD genes have led to earlier genetic confirmation, but also to more individuals with variants of uncertain significance. The LGMDs include disorders with autosomal recessive inheritance, which are often due to loss-of-function mutations in muscle structural or repair proteins and typically have younger ages of onset and more rapidly progressive presentations, and those with autosomal dominant inheritance, which can have older ages of presentation and chronic progressive disease courses. All cause progressive disability and potential loss of ability to walk or maintain a job due to progressive muscle wasting. Certain mutations are associated with cardiac or respiratory involvement. No disease-altering therapies have been approved by the US Food and Drug Administration (FDA) for LGMDs and standard treatment uses a multidisciplinary clinic model, but recessive LGMDs are potentially amenable to systemic gene replacement therapies, which are already being tested in clinical trials for sarcoglycan and FKRP mutations. The dominant LGMDs may be amenable to RNA-based therapeutic approaches., Summary: International efforts are underway to better characterize LGMDs, help resolve variants of uncertain significance, provide consistent and improved standards of care, and prepare for future clinical trials., (Copyright © 2022 American Academy of Neurology.)

Purpose: The aim was to investigate the prevalence, characteristics, predictors, and consequences of chronic pain in a national cohort of patients with limb-girdle muscular dystrophy (LGMD)., Materials and Methods: Questionnaires were sent to all Danish LGMD patients (≥18 years of age) registered with the National Rehabilitation Center for Neuromuscular Diseases., Results: Of 209 patients, 121 responded. 44.7% of the patients experienced persistent (daily or constant) chronic pain lasting more than 3 months. 21.0% of patients experienced chronic pain that was not daily. Most pain patients experienced three or more pain problems, primarily in the lower back, neck, shoulders, hips, and legs. Symptoms suggestive of neuropathic pain were sometimes present. Patients with persistent chronic pain reported moderate pain interference with daily activities, greater psychological distress, and lower quality of life compared to patients without pain but did not differ regarding physical functioning. Sex, age, LGMD duration, LGMD type, mechanical ventilation use, mobility, arm function, or performance on activities of daily living did not predict chronic pain., Conclusion: Chronic pain is common in patients with LGMD. Chronic pain should be considered an important component of LGMD and addressed in the clinic and rehabilitation setting from a biopsychosocial perspective.Implication for rehabilitationChronic pain is highly prevalent in patients with limb-girdle muscular dystrophy.Health professionals need to systematically ask patients about pain and the influence of pain on everyday life irrespective of LGMD-duration and extent of muscle wastage.Chronic pain and psychological distress need to be addressed in the clinic and rehabilitation setting as an additional disabling component of LGMD and this should be done within a biopsychosocial framework.

Limb-Girdle muscular dystrophy (LGMD) is a group of muscle disorders with highly heterogeneous genetic patterns and clinical phenotypes, and this group includes multiple subtypes. Different LGMD subtypes have similar phenotypes and clinical overlaps, these subtypes are difficult to distinguish by clinical symptoms alone and can only be accurately diagnosed by analysis in combination with definitive genetic test results. Here, we report a female presenting features of LGMD. After analysis of whole-exome sequencing data, a novel homozygous POPDC3 variant c.486-1G>A (rs113419658) located in the acceptor splice site of intron 2 was identified in the proband. The variant effect on splicing were analyzed by genetic analysis based on cDNA synthesized by the patient's RNA. cDNA analysis indicated that the novel homozygous POPDC3 splice variant disrupted original acceptor splice site, which can cause a frameshift in the mRNA of the POPDC3 gene, thereby producing a truncated POPDC3 protein and ultimately affecting its normal function. POPDC3 variant was recently associated with recessive limb-girdle muscular dystrophy type 26 (LGMDR26). Based on the above results, we hypothesize that this variant is probably a pathogenic variant, and expand the gene variant spectrum of POPDC3., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

New techniques in molecular genetic diagnostics now allow for accurate diagnosis in a large proportion of patients with muscular diseases. Nevertheless, many patients remain unsolved, although the clinical history and/or the muscle biopsy give a clear indication of the involved genes. In many cases, there is a strong suspicion that the cause must lie in unexplored gene areas, such as deep-intronic or other non-coding regions. In order to find these changes, next-generation sequencing (NGS) methods are constantly evolving, making it possible to sequence entire genomes to reveal these previously uninvestigated regions. Here, we present a young woman who was strongly suspected of having a so far genetically unsolved sarcoglycanopathy based on her clinical history and muscle biopsy. Using short read whole genome sequencing (WGS), a homozygous inversion on chromosome 13 involving SGCG and LINC00621 was detected. The breakpoint in intron 2 of SGCG led to the absence of γ-sarcoglycan, resulting in the manifestation of autosomal recessive limb-girdle muscular dystrophy 5 (LGMDR5) in the young woman.

Anoctaminopathies are a group of autosomal recessive skeletal muscle disorders with various clinical phenotypes, caused by anoctamin 5 (ANO5) gene mutations and the abnormal expression of ANO5 protein. Patients with recessive mutations in ANO5 present with variable symptoms ranging from asymptomatic hyperCKemia and exercise-induced myalgia to proximal and/or distal muscle weakness. Here, we describe the clinical, pathological, and molecular findings of two unrelated patients with ANO5-related muscular dystrophy (MD). Ninety-six histologically identified MD cases were subjected to next-generation sequencing using a customized panel of 54 genes (IIlumina Design Studio). Two patients were diagnosed with ANO5-related MD. One patient had a pathogenic homozygous mutation of c.1406G>A in exon 14, while the other patient had a novel heterozygous mutation of c.2141C>G in exon 19 of ANO5 gene. Both showed two different phenotypes (limb girdle MD and Miyoshi myopathy) and histomorphological patterns. Muscle biopsy of one patient in addition showed amyloid deposit in the walls of interstitial blood vessels. ANO5-related MD is a heterogeneous disease with different clinical phenotypes as well as genotypes. All muscle biopsies with unclassified muscular dystrophies should be subjected to Congo red stain. The results of this study suggest that screening for ANO5 gene should represent an early step in the diagnostic work-up of the patients with undiagnosed MD and persistent asymptomatic hyperCKemia, even when muscle biopsy histomorphology is normal., Competing Interests: None

Mutations in the DYSF gene, encoding dysferlin, are responsible for Limb Girdle Muscular Dystrophy type R2/2B (LGMDR2/2B), Miyoshi myopathy (MM), and Distal Myopathy with Anterior Tibialis onset (MDAT). The size of the gene and the reported inter and intra familial phenotypic variability make early diagnosis difficult. Genetic analysis was conducted using Next Gene Sequencing (NGS), with a panel of 40 Muscular Dystrophies associated genes we designed. In the present study, we report a new missense variant c.5033G>A, p.Cys1678Tyr (NM&#95;003494) in the exon 45 of DYSF gene related to Limb Girdle Muscular Dystrophy type R2/2B in a 57-year-old patient affected with LGMD from a consanguineous family of south Italy. Both healthy parents carried this variant in heterozygosity. Genetic analysis extended to two moderately affected sisters of the proband, showed the presence of the variant c.5033G>A in both in homozygosity. These data indicate a probable pathological role of the variant c.5033G>A never reported before in the onset of LGMDR2/2B, pointing at the NGS as powerful tool for identifying LGMD subtypes. Moreover, the collection and the networking of genetic data will increase power of genetic-molecular investigation, the management of at-risk individuals, the development of new therapeutic targets and a personalized medicine.

Introduction/aims: Dysferlinopathy demonstrates heterogeneity in muscle weakness between patients, which can progress at different rates over time. Changing muscle strength due to disease progression or from an investigational product is associated with changing functional ability. The purpose of this study was to compare three methods of strength testing used in the Clinical Outcome Study (COS) for dysferlinopathy to understand which method and which muscle groups were most sensitive to change over time., Methods: Patients were evaluated at each study visit using functional scales, manual muscle testing, and handheld dynamometry (HHD) at all 15 sites. A fixed-frame system (Fixed) was used at a subset of seven sites. Screening and baseline visits were evaluated for reliability. Data over a 1-year period were analyzed to determine sensitivity to change among strength modalities and individual muscle groups., Results: HHD and Fixed captured significant change across 1 year in summed muscle strength score of four muscle groups (P < .01). Strength summed scores were significantly correlated with functional scales (rho = 0.68-0.92, P < .001). Individual muscle groups, however, showed high levels of variability between visits., Discussion: Although both HHD and Fixed demonstrate change over 12 months, HHD is a less expensive option that provides data on a continuous scale and may be easier to implement. Due to variability in strength measures, researchers should carefully consider use of strength testing as an outcome and may wish to select functional measures with less variability as clinical trial endpoints., (© 2022 Wiley Periodicals LLC.)