Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1762617 (weakness)
 37,932 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 52-year-old man had a cardiomyopathy for 22 years as had his brother. Both required pacemakers. For the past 12 years, he also suffered from increasing muscle weakness. His muscle fibres contained granulo-filamentous material as previously seen in muscle fibres of a French family with myopathy and cardiomyopathy. It was rich in desmin, alpha-B crystallin, and dystrophin, the connotation, pathogenesis, and common denominator of which, however, remain unexplained.
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PMID:Immunohistologic and electron microscopic abnormalities of desmin and dystrophin in familial cardiomyopathy and myopathy. 774 13

We report the case of a 28 year-old woman with left scapuloperoneal syndrome since the age of 24. The course was slowly progressive and diffuse weakness was observed 4 years later. Serum creatine kinase levels were moderately elevated (x3 normal value) and EMG showed mixed neurogenic and myogenic patterns. Muscle biopsy showed type I predominance and numerous reducing bodies in muscle fibers. Reducing bodies were strongly immunoreactive with antibodies to dystrophin, alpha-sarcoglycan, vimentin and ubiquitin. Desmin immunoreactivity was increased at the periphery of some reducing bodies but alphaB crystallin, alpha actinin, titin and nebulin were negative. Western blot analysis showed an increase in dystrophin, vimentin and desmin expression. Ultrastructurally, reducing bodies were composed of tubulofilamentous material, 17 nm in diameter, and immunoreactive with anti-Dys 2 antibody. Granulofilamentous material, immunoreactive with anti-desmin antibody was observed at the periphery of some reducing bodies. This report further highlights the proteinic composition of reducing bodies and shows that late onset reducing body myopathy may occur.
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PMID:Adult onset reducing body myopathy. 1061 16

Desmin, the main intermediate filament (IF) protein in skeletal and heart muscle cells, is of great importance as a part of the cytoskeleton. The IFs surround and interlink myofibrils, and connect the peripheral myofibrils with the sarcolemma. In myotendinous junctions and neuromuscular junctions of skeletal muscle fibres, desmin is enriched. In the heart, desmin is increased at intercalated discs, the attachment between cardiomyocytes, and it is the main component in Purkinje fibres of the conduction system. Desmin is the first muscle-specific protein to appear during myogenesis. Nevertheless, lack of desmin, as shown from experiments with desmin knockout (K/O) mice, does not influence myogenesis or myofibrillogenesis. However, the desmin knock-out mice postnatally develop a cardiomyopathy and a muscle dystrophy in highly used skeletal muscles. In other skeletal muscles the organization of myofibrils is remarkably unaffected. Thus, the main consequence of the lack of desmin is that the muscle fibres become more susceptible to damage. The loss of membrane integrity leads to a dystrophic process, with degeneration and fibrosis. In the heart cardiac failure develops, whereas in affected skeletal muscles regenerative attempts are seen. In humans, accumulations of desmin have been a hallmark for presumptive desmin myopathies. Recent investigations have shown that some families with such a myopathy have a defect in the gene coding for alphaB-crystallin, whereas others have mutations in the desmin gene. Typical features of these patients are cardiac affections and muscle weakness. Thus, mutations in the desmin gene is pathogenic for a distinct type of muscle disorder.
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PMID:Desmin-related myopathies in mice and man. 1141 47

Colchicine, a microtubule polymerization inhibitor, can very occasionally induce myopathy. We report two cases of colchicine myopathy. Both patients presented with myalgia and proximal muscle weakness. The first patient, an 80-year-old woman, had chronic renal failure related to renal amyloidosis. She had been treated by colchicine for 4 months. The second, a 75-year-old man with normal renal function, suffering from gout, was treated by colchicine for 3 weeks. Muscle biopsies displayed the same alterations, but the degree of severity was different. Conventional histology revealed vacuolar changes characterized by acid phosphatase-positive vacuoles and myofibrillar disarray foci. The lesions were selective for type I fibers. Ultrastructural study demonstrated autophagic vacuoles. Most of the vacuoles expressed dystrophin but not merosin. Several fibers reacted with anti-MHC class I antibody and granular deposits of membrane attack complex were observed on the surface of numerous myofibers. Anti-alphaB-crystallin antibody strongly reacted with vacuolar content. Physiopathologically, microtubules are primordial for vesicle movements and colchicine induces autophagic vacuole accumulation by preventing their fusion with lysosomes. The selective type I involvement is probably due to the higher tubulin amount in type I fibers. AlphaB-crystallin overexpression is related to its microtubule protection properties. Moreover, we suggest that vacuoles randomly floating in sarcoplasm might occasionally meet the plasma membrane and open in the extracellular space, leading to complement activation. Accurate diagnosis of colchicine myopathy is relevant because the treatment is based on colchicine interruption.
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PMID:Colchicine myopathy: a vacuolar myopathy with selective type I muscle fiber involvement. An immunohistochemical and electron microscopic study of two cases. 1181 Jan 74

Two siblings (patients 1 and 2) had adult-onset muscle weakness that was greater distally than proximally, as well as respiratory insufficiency, cardiomyopathy, and cervical spine anomalies. Electromyography studies indicated myopathy and findings consistent with neuropathy in both. In the deltoid muscle of patient 1 and the anterior tibial muscle of patient 2, myriad type 1 fibers harbored large, irregularly polygonal, and mostly central hyaline masses, small vacuoles, and nemaline rods flanking the hyaline masses or congregated under the sarcolemma. The hyaline masses are intensely congophilic; react strongly for desmin, alphaB-crystallin, alpha1-antichymotrypsin, and ubiquitin and variably for gelsolin and dystrophin; and are devoid of alpha-actinin, nebulin, titin, and slow myosin. The presence of ubiquitin, gelsolin, and fragmented filaments, and the absence of nebulin, titin, alpha-actinin, and slow myosin in the hyaline masses, signal nonlysosomal protein degradation. Ultrastructurally, the hyaline masses are composed of intermediate-density amorphous material intermingled with fragmented filaments and irregularly branching, pleomorphic, highly electron-dense material, resembling the hyaline structures of myofibrillar myopathy. We conclude that the pathological process in this syndrome is one that induces destruction of myofibrillar components, resulting in aggregation of the degraded residues in hyaline masses, and causes replication of Z disks, resulting in formation of nemaline rods.
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PMID:Familial cardioneuromyopathy with hyaline masses and nemaline rods: a novel phenotype. 1183 79

The molecular events by which eccentric muscle contractions induce muscle damage and remodelling remain largely unknown. We assessed whether eccentric exercise modulates the expression of proteinases (calpains 1, 2 and 3, proteasome, cathepsin B+L), muscle structural proteins (alpha-sarcoglycan and desmin), and the expression of the heat shock proteins Hsp27 and alphaB-crystallin. Vastus lateralis muscle biopsies from twelve healthy male volunteers were obtained before, immediately after, and 1 and 14 days after a 30 min downhill treadmill running exercise. Eccentric exercise induced muscle damage as evidenced by the analysis of muscle pain and weakness, creatine kinase serum activity, myoglobinaemia and ultrastructural analysis of muscle biopsies. The calpain 3 mRNA level was decreased immediately after exercise whereas calpain 2 mRNA level was increased at day 1. Both mRNA levels returned to control values by day 14. By contrast, cathepsin B+L and proteasome enzyme activities were increased at day 14. The alpha-sarcoglycan protein level was decreased immediately after exercise and at day 1, whereas the desmin level peaked at day 14. alphaB-crystallin and Hsp27 protein levels were increased at days 1 and 14. Our results suggest that the differential expression of calpain 2 and 3 mRNA levels may be important in the process of exercise-induced muscle damage, whereas expression of alpha-sarcoglycan, desmin, alphaB-crystallin and Hsp27 may be essentially involved in the subsequent remodelling of myofibrillar structure. This remodelling response may limit the extent of muscle damage upon a subsequent mechanical stress.
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PMID:Molecular adaptations of neuromuscular disease-associated proteins in response to eccentric exercise in human skeletal muscle. 1218

We here report the second and third mutations in alphaB-crystallin causing myofibrillar myopathy. Two patients had adult-onset muscle weakness. Patient 1 had cervical, limb girdle, and respiratory muscle weakness and died of respiratory failure. Patient 2 had proximal and distal leg muscle weakness. Both had myopathic electromyogram with abnormal electrical irritability and muscle biopsy findings of myofibrillar myopathy and mild denervation. Myofibrillar disintegration begins at the Z-disk and results in abnormal local expression of desmin, alphaB-crystallin, dystrophin, neural cell adhesion molecule (NCAM), and CDC2 kinase. Seven to 8% of nuclei display early apoptotic changes. Both patients carry a truncating mutation in the C-terminal region of alphaB-crystallin (464delCT in Patient 1 and Q151X in Patient 2) which is crucial for the solubilization and chaperone functions of the molecule. cDNA analysis shows the same mutations and no alternatively spliced transcripts. Immunoblots of muscle demonstrate increased expression of wild-type and reduced expression of the mutant protein. Immunoblots under nondenaturing conditions show that the mutant protein forms lower than normal molecular weight multimeric complexes with wild type. We conclude that (1) despite its reduced expression, the mutant protein exerts a dominant negative effect; (2) mutations in alphaB-crystallin are an infrequent cause of myofibrillar myopathy; (3) alphaB-crystallin-related myopathies display phenotypic heterogeneity.
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PMID:Myofibrillar myopathy caused by novel dominant negative alpha B-crystallin mutations. 1468 90

The term myofibrillar myopathy (MFM) was proposed in 1996 as a non-committal term for a pathological pattern of myofibrillar dissolution associated with accumulation of myofibrillar degradation products and ectopic expression of multiple proteins that include desmin, alphaB-crystallin (alphaBC), dystrophin and congophilic amyloid material. Subsequent studies revealed dominant mutations in desmin and alphaBC in some MFM patients, and clinical differences between kinships. We here review the clinical, structural and genetic features of 63 unrelated patients diagnosed as having MFM at the Mayo Clinic between 1977 and 2003. The age of onset was 54 +/- 16 years (mean +/- SD). Weakness was both proximal and distal in 77% and proximal only in 13%. Cardiomyopathy was diagnosed in 16%. Electro myography revealed a myopathic pattern associated with abnormal electrical irritability; 13 patients had abnormal nerve conduction studies but four of these had long-standing diabetes. The abnormal muscle fibres are best identified in trichrome-stained sections as harbouring amorphous, granular or pleomorphic hyaline structures, and vacuoles containing membranous material. The hyaline structures are strongly congophilic. Semiquantitative analysis in each case indicates that among the abnormal fibres, an average of 90, 75, 75, 70 and 70% abnormally express myotilin, desmin, alphaBC, dystrophin and beta-amyloid precursor protein, respectively. Therefore, immunostains for these proteins, and especially for myotilin, are useful adjuncts in the diagnosis of MFM. Electron microscopy shows progressive myofibrillar degeneration commencing at the Z-disk, accumulation of degraded filamentous material and entrapment of dislocated membranous organelles in autophagic vacuoles. In all patients, we searched for mutations in desmin and alphaBC, as well as in telethonin, a Z-disk-associated protein, or in syncoilin, which together with plectin links desmin to the Z-disk. Two of the 63 patients carry truncation mutations in the C-terminal domain of alphaBC, four carry missense mutations in the head or tail region of desmin, and none carries a mutation in syncoilin or telethonin. Thus, MFM is morphologically distinct but genetically heterogeneous. Further advances in defining the molecular causes of MFM will probably come from linkage studies of informative kinships or from systematic search for mutations in proteins participating in the intricate network supporting the Z-disk.
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PMID:Myofibrillar myopathy: clinical, morphological and genetic studies in 63 patients. 1471 82

Desmin myopathy is a recently identified disease associated with mutations in desmin or alphaB-crystallin. Typically, the illness presents with lower limb muscle weakness slowly spreading to involve truncal, neck-flexor, facial, bulbar and respiratory muscles. Skeletal myopathy is often combined with cardiomyopathy manifested by conduction blocks and arrhythmias resulting in premature sudden death. Sections of the affected skeletal and cardiac muscles show abnormal fibre areas containing amorphous eosinophilic deposits seen as granular or granulofilamentous material on electron microscopic examination. Immuno-staining for desmin is positive in each region containing abnormal structures. The inheritance pattern in familial desmin myopathy is autosomal dominant or autosomal recessive, but many cases have no family history. At least some, and probably most, non-familial desmin myopathy cases are associated with de novo desmin mutations. Age of disease onset and rate of progression may vary depending on the type of inheritance and location of the causative mutation. Multiple mutations have been identified in the desmin gene: point substitutions, insertion, small in-frame deletions and a larger exon-skipping deletion. The majority of these mutations are located in conserved alpha-helical segments of desmin. Many of the missense mutations result in changing the original amino acid into proline, which is known as a helix breaker. Studies of transfected cell cultures indicate that mutant desmin is assembly-incompetent and able to disrupt a pre-existing filamentous network in dominant-negative fashion. Disease-associated desmin mutations in humans or transgenic mice cause accumulation of chimeric intracellular aggregates containing desmin and other cytoskeletal proteins. alphaB-crystallin serves in the muscle as a chaperone preventing desmin aggregation under various forms of stress. If mutated, alphaB-crystallin may cause a myopathy similar to those resulting from desmin mutations. Routine genetic testing of patients for mutations in desmin and alphaB- crystallin genes is now available and necessary for establishing an accurate diagnosis and providing appropriate genetic counselling. Better understanding of disease pathogenesis would stimulate research focused on developing specific treatments for these conditions.
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PMID:Desmin myopathy. 1472 27

Ten Spanish patients from six unrelated families diagnosed with desmin-related myopathy (DRM) were studied. The pattern of DRM inheritance was autosomal dominant in three families, autosomal recessive in one, and there was no family history in two cases. The disease onset was in early adulthood. Cardiac myopathy was the initial presentation in two patients, respiratory insufficiency in one, and lower limb weakness in all others. Cardiac involvement was observed in four patients. Lens opacities were found in four. CK level was normal or slightly elevated, and electrophysiological examination was consistent with myopathy. Muscle biopsies identified intracytoplasmic desmin-immunoreactive inclusions. In addition to desmin, synemin, actin, gelsolin, ubiquitin, alphaB-crystallin and amyloid betaA4 were also present in the deposits. Ultrastructural examination revealed areas of myofibrillary disruption, abnormal electron-dense structures and accumulations of granulofilamentous material. A missense R406W mutation and a novel single amino acid deletion in the desmin gene were identified in two patients; the other patients did not show mutations in desmin, synemin, syncoilin or alphaB-crystallin genes. Analysis of 10 Spanish DRM cases illustrates a wide clinical, myopathological and genetic spectrum of DRM, reinforcing the need for further exploration of genetic causes for this group of disorders.
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PMID:Desmin-related myopathy: clinical, electrophysiological, radiological, neuropathological and genetic studies. 1505 Apr 48


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