emerin and Contracture

Emery-Dreifuss syndrome is a heterogeneous entity characterized by the following clinical triad: early contracture of the elbows. Achilles tendons and postcervical muscles; slowly progressive muscle wasting and weakness with a humeroperoneal distribution early in the course of disease; and a cardiomyopathy usually presenting as an atrioventricular block ranging from sinus bradycardia to complete heart block. As the heart block is the major problem, insertion of a cardiac pacemaker can be life saving. Recent advances through genetic and immunochemical studies have provided valuable clues to the understanding and the early diagnosis of this disease.

Topics: Cardiomyopathies; Contracture; Diagnosis, Differential; Genes, Recessive; Heart Block; Humans; Membrane Proteins; Muscular Dystrophies; Nuclear Proteins; Sex Chromosome Aberrations; Thymopoietins; X Chromosome

A 42-year-old man with a history of two previous coronary embolisms was referred to our hospital. He had been experiencing muscle weakness since he was around 40 years old. He had muscle atrophy of the scapula, upper arm, and lower extremities, and electromyography revealed myogenic changes in the limb muscles. Histopathological analysis of the muscle biopsy specimen revealed a complete deficiency of emerin protein, and genetic examination revealed a mutation in the emerin (EMD) gene, resulting in a diagnosis of Emery-Dreifuss muscular dystrophy (EDMD). EDMD is a muscular disorder with three symptoms: joint contracture at early onset, muscle weakness and atrophy, and cardiac dysfunction. Although this patient showed no obvious joint contracture, the course and clinical symptoms vary among patients. Therefore, in patients in whom clinical diagnosis is difficult, muscle biopsy and genetic testing should be performed for EDMD in order to prevent sudden death due to this disease.

Topics: Adult; Contracture; Humans; Joints; Male; Membrane Proteins; Muscle Weakness; Muscle, Skeletal; Muscular Atrophy; Muscular Dystrophy, Emery-Dreifuss; Mutation; Nuclear Proteins

Emery-Dreifuss muscular dystrophy is an early-onset, slowly progressive myopathy characterized by the development of multiple contractures, muscle weakness and cardiac dysfunction. We present here the case of a 65-year-old male patient with a 20 year history of slowly progressive camptocormia, bradycardia and shortness of breath. Examination showed severe spine extensor and neck flexor muscle weakness with slight upper limb proximal weakness. Cardiologic assessment revealed slow atrial fibrillation. Whole body MRI demonstrated adipose substitution of the paravertebral, limb girdle and peroneal muscles as well as the tongue. Emerin immunohistochemistry on patient muscle biopsy revealed the absence of nuclear envelope labeling confirmed by Western Blot. Genetic analysis showed a hemizygous duplication of 5 bases in exon 6 of the EMD, emerin, gene on the X chromosome. This is an unusual presentation of X-linked Emery-Dreifuss muscular dystrophy with adult onset, predominant axial muscles involvement and minimal joint contractures. Diagnosis was prompted by the analysis of emerin on muscle biopsy.

Topics: Age of Onset; Aged; Atrial Fibrillation; Back Muscles; Bradycardia; Contracture; Deltoid Muscle; Dyspnea; Hamstring Muscles; Humans; Magnetic Resonance Imaging; Male; Masticatory Muscles; Membrane Proteins; Muscle, Skeletal; Muscular Atrophy, Spinal; Muscular Dystrophy, Emery-Dreifuss; Nuclear Proteins; Severity of Illness Index; Spinal Curvatures

Prelamin A processing impairment is a common feature of a restricted group of rare genetic alterations/disorders associated with a wide range of clinical phenotypes. Changes in histone posttranslational modifications, alterations in non-histone chromatin proteins and chromatin disorganization have been specifically linked to impairment of specific, distinct prelamin A processing steps, but the molecular mechanism involved in these processes is not yet understood . In this study, we show that the accumulation of wild-type prelamin A detected in restrictive dermopathy (RD), as well as the accumulation of mutated forms of prelamin A identified in familial partial lipodystrophy (FPLD) and mandibuloacral dysplasia (MADA), affect the nuclear localization of barrier-to-autointegration factor (BAF), a protein able to link lamin A precursor to chromatin remodeling functions. Our findings, in accordance with previously described results, support the hypothesis of a prelamin A involvement in BAF nuclear recruitment and suggest BAF-prelamin A complex as a protein platform usually activated in prelamin A-accumulating diseases. Finally, we demonstrate the involvement of the inner nuclear membrane protein emerin in the proper localization of BAF-prelamin A complex.

Topics: Acro-Osteolysis; Adult; Animals; Cell Nucleus; Contracture; DNA-Binding Proteins; HEK293 Cells; Humans; Infant, Newborn; Lamin Type A; Lipodystrophy; Lipodystrophy, Familial Partial; Mandible; Membrane Proteins; Mutant Proteins; Nuclear Proteins; Protein Binding; Protein Precursors; Protein Transport; Rats; Skin Abnormalities; Transfection

Topics: Arrhythmias, Cardiac; Atrial Fibrillation; Biopsy; Contracture; Creatine Kinase; Disease Progression; DNA Mutational Analysis; Electromyography; Genetic Diseases, X-Linked; Genetic Markers; Humans; Male; Membrane Proteins; Middle Aged; Muscle Weakness; Muscle, Skeletal; Muscular Dystrophy, Emery-Dreifuss; Myocardium; Nuclear Proteins; Prognosis

Hauptmann-Thannhauser muscular dystrophy is characterized by the clinical triad of early-onset contractures of elbow, Achilles tendons, and cervical spine, slowly progressive humeroperoneal muscle wasting and weakness, and life-threatening cardiac involvement with conduction blocks manifesting in the third decade. Hauptmann-Thannhauser muscular dystrophy is due to mutations in the LMNA gene affecting the nuclear envelope proteins lamin A and C. We present a 16-year-old German boy with typical muscular involvement and contractures and typical course of Hauptmann-Thannhauser muscular dystrophy due to the novel missense mutation R401C. The data of this family suggest a lower penetrance of muscular and especially cardiac symptoms than expected. Autosomal-dominant Hauptmann-Thannhauser muscular dystrophy and X-chromosomal Emery-Dreifuss muscular dystrophy are not clearly distinguishable by phenotypic criteria. Other muscular diseases associated with contractures and congenital or childhood onset are reviewed.

Topics: Adolescent; Biopsy; Cardiomyopathies; Cell Nucleus; Contracture; Humans; Lamin Type A; Male; Membrane Proteins; Muscle Weakness; Muscle, Skeletal; Muscular Atrophy; Muscular Dystrophy, Emery-Dreifuss; Mutation, Missense; Neurologic Examination; Nuclear Proteins; Pedigree; Phenotype; Syndrome; Thymopoietins

To describe the clinical and histopathologic picture of a childhood-onset, severe variant of scapuloperoneal MD with rigidity of the spine.. Rigidity of the spine is a feature of numerous syndromes, including X-linked Emery-Dreifuss MD, Bethlem myopathy, and the rigid spine syndrome. These are, however, relatively static or very slowly progressive neuromuscular disorders, usually associated with preserved ambulation into adult life.. Five unrelated children (three boys and two girls) presented in the first 2 years of life with poor neck control, waddling gait, and frequent falls. Early wasting of the distal leg muscles, biceps, triceps, and neck muscles was noted in all patients, and all had contractures and severe rigidity of the spine. The condition progressed rapidly, and all patients lost ambulation before the age of 8 years. Cardiac function was normal in all.. Creatine kinase was moderately elevated in all, and muscle biopsy specimens showed nonspecific dystrophic changes with normal expression of dystrophin, the sarcoglycans, and laminin alpha2, alpha5, beta1, and gamma1 chains. Emerin expression was normal in two of the boys whose tissue was available for study.. The distribution of weakness, wasting, and contractures of the patients described resembled Emery-Dreifuss MD, but the rapid progression of weakness and contractures and the involvement of both sexes together with normal emerin expression suggest that this form is not X-linked Emery-Dreifuss MD. We suggest that these patients represent a severe MD characterized by early onset distal wasting and severe rigidity of the spine, with probable autosomal recessive inheritance.

Topics: Age of Onset; Biopsy; Child, Preschool; Contracture; Female; Genes, Recessive; Humans; Infant; Male; Membrane Proteins; Muscle Weakness; Muscle, Skeletal; Muscular Dystrophies; Nuclear Proteins; Phenotype; Thymopoietins; X Chromosome