Nesprin proteins: bridging nuclear envelope dynamics to muscular dysfunction.

This review presents a comprehensive exploration of the pivotal role played by the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex, with a particular focus on Nesprin proteins, in cellular mechanics and the pathogenesis of muscular diseases. Distinguishing itself from prior works, the analysis delves deeply into the intricate interplay of the LINC complex, emphasizing its indispensable contribution to maintaining cellular structural integrity, especially in mechanically sensitive tissues such as cardiac and striated muscles. Additionally, the significant association between mutations in Nesprin proteins and the onset of Dilated Cardiomyopathy (DCM) and Emery-Dreifuss Muscular Dystrophy (EDMD) is highlighted, underscoring their pivotal role in disease pathogenesis. Through a comprehensive examination of DCM and EDMD cases, the review elucidates the disruptions in the LINC complex, nuclear morphology alterations, and muscular developmental disorders, thus emphasizing the essential function of an intact LINC complex in preserving muscle physiological functions. Moreover, the review provides novel insights into the implications of Nesprin mutations for cellular dynamics in the pathogenesis of muscular diseases, particularly in maintaining cardiac structural and functional integrity. Furthermore, advanced therapeutic strategies, including rectifying Nesprin gene mutations, controlling Nesprin protein expression, enhancing LINC complex functionality, and augmenting cardiac muscle cell function are proposed. By shedding light on the intricate molecular mechanisms underlying nuclear-cytoskeletal interactions, the review lays the groundwork for future research and therapeutic interventions aimed at addressing genetic muscle disorders.

Desmin and Plectin Recruitment to the Nucleus and Nuclei Orientation Are Lost in Emery-Dreifuss Muscular Dystrophy Myoblasts Subjected to Mechanical Stimulation.

In muscle cells subjected to mechanical stimulation, LINC complex and cytoskeletal proteins are basic to preserve cellular architecture and maintain nuclei orientation and positioning. In this context, the role of lamin A/C remains mostly elusive. This study demonstrates that in human myoblasts subjected to mechanical stretching, lamin A/C recruits desmin and plectin to the nuclear periphery, allowing a proper spatial orientation of the nuclei. Interestingly, in Emery-Dreifuss Muscular Dystrophy (EDMD2) myoblasts exposed to mechanical stretching, the recruitment of desmin and plectin to the nucleus and nuclear orientation were impaired, suggesting that a functional lamin A/C is crucial for the response to mechanical strain. While describing a new mechanism of action headed by lamin A/C, these findings show a structural alteration that could be involved in the onset of the muscle defects observed in muscular laminopathies.

COMPREHENSIVE CARDIOVASCULAR THERAPY IN EMERY-DREIFUSS MUSCULAR DYSTROPHY: A CASE REPORT.

A 25-year-old male with known EDMD was referred for the cardiology consultation due to symptoms of heart failure. Echocardiography showed decrease left ventricular ejection fraction (LVEF) and therapy with ramipril, torsemide and rivaroxaban was initiated. Despite initial improvement, the patient later developed presyncope, bradycardia, irregular heartbeat and worsening of dyspnea. Therefore, implantation of resynchronization pacemaker with the function of implantable cardioverter-defibrillator (CRT-D/P) was performed. Ramipril was substituted by sacubitril/valsartan, and mineralocorticoid receptor antagonist and beta-blocker were initiated. Genetic testing found AD mutation in lamin A/C gene LMNA c.746G>A, p.(Arg249Gln). Upon follow-up, the patient demonstrated resolution of dyspnea and reverse remodeling of the left ventricle with complete restoration of the LVEF.

Enfoque anestésico para trasplante cardiaco en un paciente con distrofia muscular de Emery-Dreyfuss: informe de caso / Heart transplant anesthetic approach in a patient with Emery Dreyfuss muscular dystrophy: A case report

La distrofia muscular de Emery-Dreifuss está asociada a anomalías cardiacas, pudiendo ser el trasplante cardiaco el tratamiento de elección en ciertos casos raros. En este caso, un paciente con distrofia muscular de Emery-Dreifuss desarrolló insuficiencia cardiaca de clase IV de NYHA a los 33 años de edad, y fue sometido a trasplante cardiaco. Se adaptó la anestesia para prevenir el desarrollo de hipertermia maligna y rabdomiólisis. La cirugía fue exitosa, y el paciente progresó de manera excelente con mejora sintomática. En estos casos, es esencial ajustar, no solo el posicionamiento del paciente, sino también la terapia administrada, a fin de reducir la iatrogenia y acelerar la recuperación. (AU)

Emery-Dreifuss muscular dystrophy is associated with cardiac abnormalities and rarely heart transplantation may be the treatment of choice. In this case, a male patient with Emery- Dreifuss muscular dystrophy developed NYHA class IV heart failure at 33 years of age and was submitted to heart transplantation. Anesthesia was adapted to prevent the development of malignant hyperthermia and rhabdomyolysis. The surgery was a success and the patient's progress was extremely positive with symptomatic improvement. In these patients, is critical to adjust not only his positioning but also the therapy administered in order to reduce iatrogeny and promote a faster recovery. (AU)

Several challenges associated with the anesthetic management of Emery-Dreifuss muscular dystrophy patients: case report

Abstract Emery-Dreifuss Muscular Dystrophy is a very rare type of muscular dystrophy, associated with contractures, atrophy, and muscle weakness, besides cardiomyopathy with severe arrhythmias. Published studies focusing on this disorder are scarce. We describe the anesthetic management of a male patient with Emery-Dreifuss Muscular Dystrophy, to be submitted to umbilical and inguinal hernioplasty and hydrocele repair under epidural anesthesia. The anesthesia approach enabled us to circumvent the patient's susceptibility to malignant hyperthermia and his potentially difficult airway, in addition to maintaining hemodynamic stability. The day after surgery the patient resumed walking, and two days later he was discharged from the hospital.

Distrofia muscular de Emery-Dreifuss tipo 2: nueva mutación de novo en el gen la lamina A/C / Emery-Dreifuss muscular dystrophy type 2: New de novo mutation in the lamin A/C gene

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Manifestaciones cardiacas de las enfermedades neuromusculares / Cardiac manifestations of neuromuscular disease

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Muscle Magnetic Resonance Imaging in Patients with Various Clinical Subtypes of -Related Muscular Dystrophy / 中华医学杂志(英文版)

<p><b>Background</b>LMNA-related muscular dystrophy can manifest in a wide variety of disorders, including Emery-Dreifuss muscular dystrophy (EDMD), limb-girdle muscular dystrophy (LGMD), and LMNA-associated congenital muscular dystrophy (L-CMD). Muscle magnetic resonance imaging (MRI) has become a useful tool in the diagnostic workup of patients with muscle dystrophies. This study aimed to investigate whether there is a consistent pattern of MRI changes in patients with LMNA mutations in various muscle subtypes.</p><p><b>Methods</b>Twenty-two patients with LMNA-related muscular dystrophies were enrolled in this study. MRI of the thigh and/or calf muscles was performed in them. The muscle MRI features of the three subtypes were compared by the Mann-Whitney U-test. The relationship between the clinical and MRI findings was also investigated by Spearman's rank analyses.</p><p><b>Results</b>The present study included five EDMD, nine LGMD, and eight L-CMD patients. The thigh muscle MRI revealed that the fatty infiltration of the adductor magnus, semimembranosus, long and short heads of the biceps femoris, and vasti muscles, with relative sparing of the rectus femoris, was the predominant change observed in the EDMD, LGMD, and advanced-stage L-CMD phenotypes, although the involvement of the vasti muscles was not prominent in the early stage of L-CMD. At the level of the calf, six patients (one EDMD, four LGMD, and one L-CMD) also showed a similar pattern, in which the soleus and the medial and lateral gastrocnemius muscles were most frequently observed to have fatty infiltration. The fatty infiltration severity demonstrated higher scores associated with disease progression, with a corresponding rate of 1.483 + 0.075 × disease duration (X) (r = 0.444, P = 0.026). It was noteworthy that in six L-CMD patients with massive inflammatory cell infiltration in muscle pathology, no remarkable edema-like signals were observed in muscle MRI.</p><p><b>Conclusions</b>EDMD, LGMD and advanced-staged L-CMD subtypes showed similar pattern of muscle MRI changes, while early-staged L-CMD showed somewhat different changes. Muscle MRI of L-CMD with a muscular dystrophy pattern in MRI provided important clues for differentiating it from childhood inflammatory myopathy. The fatty infiltration score could be used as a reliable biomarker for outcome measure of disease progression.</p>

Early-Onset LMNA-Associated Muscular Dystrophy with Later Involvement of Contracture

BACKGROUND AND PURPOSE: The early diagnosis of LMNA-associated muscular dystrophy is important for preventing sudden arrest related to cardiac conduction block. However, diagnosing early-onset Emery-Dreifuss muscular dystrophy (EDMD) with later involvement of contracture and limb-girdle muscular dystrophy type 1B is often delayed due to heterogeneous clinical presentations. We aimed to determine the clinical features that contribute to a delayed diagnosis. METHODS: We reviewed four patients who were recently diagnosed with LMNA-associated muscular dystrophy by targeted exome sequencing and who were initially diagnosed with nonspecific or other types of muscular dystrophy. RESULTS: Certain clinical features such as delayed contracture involvement and calf hypertrophy were found to contribute to a delayed diagnosis. Muscle biopsies were not informative for the diagnosis in these patients. CONCLUSIONS: Genetic testing of single or multiple genes is useful for confirming a diagnosis of LMNA-associated muscular dystrophy. Even EDMD patients could experience the later involvement of contracture, so clinicians should consider early genetic testing for patients with undiagnosed muscular dystrophy or laminopathy.

Alteraciones del ritmo cardiaco como inicio de la distrofia muscular de Emery-Dreifuss / Rythm disturbances as Emery-Dreifuss muscular dystrophy onset

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Application of targeted capture technology and next generation sequencing in molecular diagnosis of inherited myopathy / 中华儿科杂志

<p><b>OBJECTIVE</b>To elucidate the usefulness of next generation sequencing for diagnosis of inherited myopathy, and to analyze the relevance between clinical phenotype and genotype in inherited myopathy.</p><p><b>METHOD</b>Related genes were selected for SureSelect target enrichment system kit (Panel Version 1 and Panel Version 2). A total of 134 patients who were diagnosed as inherited myopathy clinically underwent next generation sequencing in Department of Pediatrics, Peking University First Hospital from January 2013 to June 2014. Clinical information and gene detection result of the patients were collected and analyzed.</p><p><b>RESULT</b>Seventy-seven of 134 patients (89 males and 45 females, visiting ages from 6-month-old to 26-year-old, average visiting age was 6 years and 1 month) underwent next generation sequencing by Panel Version 1 in 2013, and 57 patients underwent next generation sequencing by Panel Version 2 in 2014. The gene detection revealed that 74 patients had pathogenic gene mutations, and the positive rate of genetic diagnosis was 55.22%. One patient was diagnosed as metabolic myopathy. Five patients were diagnosed as congenital myopathy; 68 were diagnosed as muscular dystrophy, including 22 with congenital muscular dystrophy 1A (MDC1A), 11 with Ullrich congenital muscular dystrophy (UCMD), 6 with Bethlem myopathy (BM), 12 with Duchenne muscular dystrophy (DMD) caused by point mutations in DMD gene, 5 with LMNA-related congenital muscular dystrophy (L-CMD), 1 with Emery-Dreifuss muscular dystrophy (EDMD), 7 with alpha-dystroglycanopathy (α-DG) patients, and 4 with limb-girdle muscular dystrophy (LGMD) patients.</p><p><b>CONCLUSION</b>Next generation sequencing plays an important role in diagnosis of inherited myopathy. Clinical and biological information analysis was essential for screening pathogenic gene of inherited myopathy.</p>

Utilidad de la resonancia magnética muscular en el diagnóstico diferencial de las distrofias musculares / The value of muscular magnetic resonance imaging in the differential diagnosis of muscular dystrophies

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Laminopatías. Enfermedades de la lámina nuclear / Laminopathies. Nuclear lamina diseases

Laminopathies are a group of diseases that share wrong codification of lamins, building proteins of the nuclear lamina. Different tissues are affected in those disorders: striated muscle, adipose tissue, central or peripheral nervous system and aging process. Emery-Dreifuss muscular dystrophy and Hutchinson-Gildford Progery Syndrome are two examples of laminopathies.Other diseases, due to mutations in different genes, impair lamins function by a direct or an indirect way and they are frequently considered together.The last decade has seen an increasing interest and scientific advances on laminopathies that will allow us to answer key questions regarding metabolism, insulin resistance, sudden death and aging. Laminopathies are reviewed in this article from a molecular, pathogenic and clinical point of view (AU)

Las laminopatías son un conjunto de enfermedades raras que comparten formas erróneas de codificación genética de las láminas, proteínas constitutivas de la lámina nuclear. Son trastornos que afectan a diferentes tejidos y funciones como el tejido muscular estriado, el tejido adiposo, el tejido óseo, el sistema nervioso o el envejecimiento precoz. La distrofia muscular de Emery-Dreifuss o el síndrome Hutchinson-Gildford Progeria son ejemplos de laminopatías. Conjuntamente con ellas suelen estudiarse otros trastornos que provocan de forma directa o indirecta alteración de la función de las láminas. El creciente interés y estudio que las laminopatías han suscitado desde hace una década podrían permitir encontrar respuestas a preguntas clave en relación con el metabolismo, la resistencia a la insulina, la muerte súbita o el envejecimiento. En este trabajo se revisan las laminopatías desde un punto de vista molecular, patogénico y clínico (AU)

Mutation analysis of a Chinese family with autosomal dominant Emery-Dreifuss muscular dystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the clinical, pathological and genetic characteristics in a family with autosomal dominant Emery-Dreifuss muscular dystrophy (AD-EDMD).</p><p><b>METHODS</b>Clinical data and skeletal muscle specimens were collected from two patients (the proband and her daughter) for pathological analysis. DNA samples of the proband and her family members (7 persons from 3 generations) were obtained for PCR amplification and direct DNA sequencing of the lamin A/C (LMNA) gene. Haplotype analysis was performed after the identification of mutation.</p><p><b>RESULTS</b>The proband had typical clinical manifestation of EDMD: joint contracture, progressive muscle weakness and atrophy and cardiac conduction dysfunction. Muscular pathology revealed myopathic changes combined with slight neuropathic changes. A heterozygous missense mutation 1583 (C to G)(T528R) was identified in exon 9 of the LMNA gene in the two patients, but not in other family members. Haplotype analysis indicated that the proband and her daughter shared the same causative haplotype.</p><p><b>CONCLUSION</b>This is the first report of the phenotype and genotype of AD-EDMD in Chinese.</p>

Enfermedad de Emery-Dreifuss / Emery-Dreifuss disease

La enfermedad de Emery-Dreifuss (EMD) es una distrofia neuromuscular ligada al cromosoma X, causada por un defecto en el gen STA del Xq28 que codifica la proteína nuclear llamada emerina. Se presenta, normalmente, en la adolescencia y se caracteriza por debilidad escapuloperoneal y rigidez articular de codos, tobillos, columna cervical y lumbar. Asimismo, puede presentar afectación cardíaca. Se presentan dos hermanos, de 12 y 9 años, que llegaron al servicio de Rehabilitación aquejando debilidad escapuloperoneal y flexión irreductible de codos. Las pruebas complementarias muestran una elevación de la CPK y LDH en la analítica de sangre, y un patrón de afectación miopático en el electromiograma (EMG). Ambos pacientes presentan la misma enfermedad neuromuscular, la EMD

Emery-Dreifuss muscular dystrophy is an X-linked neuromuscular disorder caused by defects in the STA gene on Xq28, which codes for a nuclear protein named emerin. This disease usually shows up during early adolescence and is characterized by scapulo-peroneal muscle weakness and wasting. The patients also display contractures of elbows, the tendo-Achilles and paraspinal muscles, which cause spine rigidity. Additionally, the patients can also present cardíac affectation. We present the case of two brothers, 12 and 9 years old. They arrived to the Rehabilitation Department with elbows in flexion and proximal weakness. The complementary tests show an increase in serum creatine kinase or LDH and EMG shows myophatic affectation. We conclude that both brothers present the same disease, the Emery-Dreifuss muscular dystrophy

Distrofia muscular de Emery-Dreifuss: relato de caso / Emery-Dreifuss muscular dystrophy: case report

A distrofia muscular de Emery-Dreifuss é uma forma de distrofia muscular freqüentemente associada a contraturas articulares e defeitos de condução cardíaca, que pode ser causada pela deficiência da proteína emerina na membrana nuclear interna das fibras musculares. Descrevemos o caso de um homem de 19 anos com diminuição de força muscular, hipotrofia nas cinturas escapular e pélvica, disfagia, contraturas articulares em cotovelos e tornozelos, apresentando história familiar compatível com herança ligada ao cromossomo X. A investigação mostrou creatinaquinase sérica elevada, eletrocardiograma com bloqueio atrioventricular de primeiro grau e bloqueio de ramo direito, eletroneuromiografia normal, biópsia muscular com alterações miopáticas e a análise por imuno-histoquímica mostrou deficiência de emerina. São discutidas as manifestações clínicas e genéticas, alterações laboratoriais e eletroneuromiográficas, bem como, a importância do estudo do padrão de herança no aconselhamento genético destas famílias.

La saga de las laminopatías / The laminopahy saga

Objetivo. Caracterizar clínicamente la distrofia muscular de Emery-Dreifuss, diferenciar las formas de herencia ligadas al cromosoma X de las formas de herencia autosómica dominante desde el punto de vista genético, y describir la heterogeneidad fenotípica en mutaciones del mismo gen LMNA. Desarrollo. Se describe la identificación de las mutaciones en el gen de la lamina A/C, gen LMNA, gracias a las redes de trabajo colaborativo entre diferentes países. Las mutaciones en este gen son responsables de la enfermedad de Emery-Dreifuss autosómica dominante, además de otras enfermedades fenotípicamente muy diferentes, como la distrofia muscular de cinturas asociada a defectos de conducción cardíaca (LGMD1B), la miocardiopatía dilatada con defectos de conducción (DCM-CD), la lipodistrofia familiar parcial de tipo Dunningan (FPLD) y, finalmente, una forma autosómica recesiva de neuropatía axonal o enfermedad de Charcot-Marie-Tooth tipo 2 (AR-CMT). Conclusiones. Las laminas son filamentos intermedios que forman parte de la cubierta interna nuclear de cualquier célula, y las mutaciones en el gen de las laminas A/C pueden producir cuadros clínicos tan diferentes como una distrofia muscular similar a la conocida enfermedad de Emery-Dreifuss ligada al cromosoma X y una forma de neuropatía tipo Charcot-Marie-Tooth. Actualmente, se trabaja sobre un modelo experimental animal para profundizar en los mecanismos fisiopatológicos que intervienen en la producción de estas enfermedades, específicas de tejido aunque se deben a mutaciones en un gen que codifica proteínas que se expresan de forma ubicua (AU)

Aims. Our aim was to clinically characterise Emery-Dreifuss muscular dystrophy, to differentiate the X-linked forms of inheritance from the forms involving autosomal dominant inheritance, from a genetic point of view, and to describe the phenotypical heterogeneity of mutations in the LMNA gene itself. Development. We describe the identification of the mutations in the lamina A/C gene, the LMNA gene, which was made possible thanks to the networks allowing workers in different countries to collaborate. Mutations in this gene are responsible for autosomal dominant Emery-Dreifuss disease, as well as other diseases that are phenotypically very distinct, such as limb girdle muscular dystrophy associated with cardiac conduction defects (LGMD1B), dilated myocardiopathy with conduction defects (DCM-CD), Dunnigan-type familial partial lipodystrophy (FPLD) and, finally, an autosomal recessive form of axonal neuropathy or Charcot-Marie-Tooth disease type 2 (AR-CMT). Conclusions. Laminas are intermediate filaments that constitute the inner nuclear membrane of any cell and the mutations in the lamina A/C gene can give rise to such distinct clinical patterns as a kind of muscular dystrophy that is similar to the well-known X-linked EmeryDreifuss disease or a form of Charcot-Marie-Tooth-type neuropathy. Work is currently being conducted on an experimental animal model capable of providing us with a better understanding of the physiopathological mechanisms involved in the production of these tissue-specific diseases, although they are due to mutations in a gene that codifies for proteins that are expressed all over (AU)

A Case of Emery-Dreifuss Muscular Dystrophy by Emerin Gene Mutation

Emery-Dreifuss muscular dystrophy (EDMD) is a degenerative myopathy characterized by mild, slowly progressing weakness, muscle atrophy, and early contracture of the neck, ankle and elbow. Heart involvement becomes apparent during the teenage years and is characterized by cardiac conduction defects and the infiltration of the myocardium by fibrous and adipose tissues. Heart block can eventually lead to sudden death, and therefore, early treatment with a cardiac pacemaker may improve symptoms and be lifesaving in patients with heart block. We describe our experience of pacemaker implantation in a 14-year old boy with X-linked recessive EDMD and emerin gene mutation. His electrocardiogram findings showed junctional escape beats, and his clinical features, i.e., ECG, nerve conduction test, electromyography and muscle biopsy findings were compatible with EDMD. He was implanted with a VVI type permanent pacemaker following an electrophysiologic study.