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Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe a strategy for molecular diagnosis in the autosomal recessive limb-girdle muscular dystrophies, a highly heterogeneous group of inherited muscle-wasting diseases. Genetic mutation analysis is directed by immunoanalysis of muscle biopsies using antibodies against a panel of muscular dystrophy-associated proteins. Performing the molecular analysis in this way greatly increases the chance that mutations will be found in the first gene examined. The use of this strategy can significantly decrease the time involved in determining the genetic fault in a patient with a clinical diagnosis of recessive limb-girdle muscular dystrophy, as well as having a feedback effect, which is useful in helping clinicians to identify subtle clinical differences between the subtypes of the disease. The use of this approach has so far helped us to identify mutations in ten sarcoglycanopathy (limb-girdle muscular dystrophy 2C-2F) patients, and seven calpainopathy (limb-girdle muscular dystrophy 2A) patients.
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PMID:Strategy for mutation analysis in the autosomal recessive limb-girdle muscular dystrophies. 1116 69

The muscular dystrophies are characterised by progressive muscle weakness and wasting. Pathologically the hallmarks are muscle fibre degeneration and fibrosis. Several recessive forms of muscular dystrophy are caused by defects in proteins localised to the sarcolemma. However, it is now apparent that others are due to defects in a wide range of proteins including those which are either nuclear-related (Emery-Dreifuss type muscular dystrophies, oculopharyngeal muscular dystrophy), enzymatic (limb-girdle muscular dystrophy 2A, myotonic dystrophy) or sarcomeric (limb-girdle muscular dystrophies 1A and 2G). Although the clinical and molecular basis of these disorders is heterogeneous all display myopathic morphological features. These include variation in fibre size, an increase in internal nuclei, and some myofibrillar distortion. Degeneration and fibrosis occur, but usually not to the same extent as in muscular dystrophies associated with sarcolemmal protein defects. This review outlines the genetic basis of these "non-sarcolemmal" forms of dystrophy and discusses current ideas on their pathogenesis.
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PMID:Non-sarcolemmal muscular dystrophies. 1130 95

We describe a child who presented at birth with arthrogryposis. Following a muscle biopsy a diagnosis of congenital muscular dystrophy was made and a skin biopsy 12 years later confirmed the presence of merosin. Her clinical picture was unusual, however, for merosin-positive congenital muscular dystrophy. She had extreme wasting and weakness of her arms and legs. In contrast, she had good neck and trunk control, and no facial or respiratory muscle weakness. We have used magnetic resonance imaging to examine the pattern of muscle involvement in this case. No recognizable muscle could be identified in the limbs. In contrast, the axial muscles were preserved. This striking pattern of virtual absence of muscles in the limbs with sparing of the axial muscle suggests that a gene responsible for the migration and/or proliferation of limb muscle precursor cells may be involved in the disease process. It is recognized that merosin-positive congenital muscular dystrophy is a heterogeneous disease. Magnetic resonance imaging is a useful tool for examining in detail the pattern of muscle involvement and identifying individual phenotypes. Understanding more about which muscles are affected in children with congenital myopathies may provide information on the underlying pathological process and help in the search for candidate proteins and genes.
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PMID:Neonatal arthrogryposis and absent limb muscles: a muscle developmental gene defect? 1140 23

Muscular dystrophy is a nosology for a group of hereditary muscle disorders characterized by progressive wasting and weakness of skeletal muscle, where degeneration of muscle fibers is detected by pathological examination. Since the causative gene of Duchenne muscular dystrophy (DMD), the most severe and abundant form of muscular dystrophy, the DMD gene, and its product dystrophin was isolated by positional cloning by Dr. Kunkel and his colleagues, the studies on molecular pathologies of muscular dystrophy has been extensively developed. The current therapeutic approaches of muscular dystrophy, such as DMD involves pharmacological suppression of the inflammatory and immure responses, which usually provides only modest and temporary beneficial effects. Future approaches depend on cell and gene therapy technology and will require different strategies, none of which are currently ready to enter clinical practice. These approaches involve the efficient, non-antigenic gene transfer for in vivo gene therapy, pharmacological upregulation of the synthesis of utrophin, a related protein that compensates for the loss of dystrophin, and myogenic stem cell transplantation. These approaches could be integrated each other and called as molecular therapy.
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PMID:[Molecular therapy of muscular dystrophy]. 1146 75

Classical merosin (2 laminin)-positive congenital muscular dystrophy is a heterogeneous subgroup of disorders; a few cases characterized by severe mental retardation, brain involvement and no ocular abnormalities were called Fukuyama-like congenital muscular dystrophy. We report a family of healthy non-consanguineous parents, with four affected siblings, of which one died at the age of 7 months due to an intercurrent illness, who presented congenital hypotonia, severe mental retardation, microcephaly, delayed psychomotor development, generalized muscular wasting and weakness with mild facial involvement, calf pseudohypertrophy, joint contractures and areflexia. Muscle biopsy disclosed severe muscular dystrophy. Immunostaining for laminin 2 80 kDa and clone Mer3/22B2 monoclonal antibodies, 1 and 1 chain was preserved. Magnetic resonance imaging findings were consistent with pontocerebellar hypoplasia, bilateral opercular abnormalities and focal cortical dysplasia as well as minute periventricular white matter changes. Clusters of small T2-weighted focal hyperintensities in both cerebellar hemispheres consistent with cysts were observed in two of the three siblings studied with magnetic resonance imaging. Ophthalmologic and cardiologic examination was normal. Haplotype analysis using microsatellite markers excluded the Fukuyama congenital muscular dystrophy, LAMA2 and muscle-eye-brain disease loci. Thus, a wider spectrum of phenotypes, gene defects and protein deficiencies might be involved in congenital muscular dystrophy with brain abnormalities.
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PMID:Merosin-positive congenital muscular dystrophy with mental retardation, microcephaly and central nervous system abnormalities unlinked to the Fukuyama muscular dystrophy and muscular-eye-brain loci: report of three siblings. 1152 87

Here, we describe a novel spontaneous autosomal recessive mutation in the mouse that is characterized by skeletal and cardiac muscle degeneration. We have named this mutant degenerating muscle (dmu). At birth, mutant mice are indistinguishable from their normal littermates. Thereafter, the disease progresses rapidly and a phenotype is first observed at approximately 11 days after birth; the dmu mice are weak and have great difficulty in moving. The principal cause of the lack of mobility is muscle atrophy and wasting in the hindquarters. Affected mice die at or around the time of weaning of unknown causes. Histopathological observations and ultrastructural analysis revealed muscle degeneration in both skeletal and cardiac muscle, but no abnormalities in sciatic nerves. Using linkage analysis, we have mapped the dmu locus to the distal portion of mouse chromosome 15 in a region syntenic to human chromosome 12q13. Interestingly, scapuloperoneal muscular dystrophy (SPMD) in humans has been linked to this region. SPMD patients with associated cardiomyopathy have also been described in the past. Initial analysis of candidate genes on mouse chromosome 15 reveal that although intact transcripts for Scn8a, the gene encoding the sodium channel 8a subunit, are present in dmu mice, their levels are dramatically reduced. Furthermore, genetic complementation crosses between dmu and med (mutation in Scn8a) mice revealed that they are allelic. Our results suggest that at least a portion of the dmu phenotype is caused by a down-regulation of Scn8a, making dmu a new allele of Scn8a.
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PMID:Pathological and genetic analysis of the degenerating muscle (dmu) mouse: a new allele of Scn8a. 1153 91

Congenital muscular dystrophy is a heterogeneous and severe, progressive muscle-wasting disease that frequently leads to death in early childhood. Most cases of congenital muscular dystrophy are caused by mutations in LAMA2, the gene encoding the alpha2 chain of the main laminin isoforms expressed by muscle fibres. Muscle fibre deterioration in this disease is thought to be caused by the failure to form the primary laminin scaffold, which is necessary for basement membrane structure, and the missing interaction between muscle basement membrane and the dystrophin-glycoprotein complex (DGC) or the integrins. With the aim to restore muscle function in a mouse model for this disease, we have designed a minigene of agrin, a protein known for its role in the formation of the neuromuscular junction. Here we show that this mini-agrin-which binds to basement membrane and to alpha-dystroglycan, a member of the DGC-amends muscle pathology by a mechanism that includes agrin-mediated stabilization of alpha-dystroglycan and the laminin alpha5 chain. Our data provides in vivo evidence that a non-homologous protein in combination with rational protein design can be used to devise therapeutic tools that may restore muscle function in human muscular dystrophies.
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PMID:An agrin minigene rescues dystrophic symptoms in a mouse model for congenital muscular dystrophy. 1156 31

The X-linked muscle-wasting disease Duchenne muscular dystrophy is caused by mutations in the gene encoding dystrophin. There is currently no effective treatment for the disease; however, the complex molecular pathology of this disorder is now being unravelled. Dystrophin is located at the muscle sarcolemma in a membrane-spanning protein complex that connects the cytoskeleton to the basal lamina. Mutations in many components of the dystrophin protein complex cause other forms of autosomally inherited muscular dystrophy, indicating the importance of this complex in normal muscle function. Although the precise function of dystrophin is unknown, the lack of protein causes membrane destabilization and the activation of multiple pathophysiological processes, many of which converge on alterations in intracellular calcium handling. Dystrophin is also the prototype of a family of dystrophin-related proteins, many of which are found in muscle. This family includes utrophin and alpha-dystrobrevin, which are involved in the maintenance of the neuromuscular junction architecture and in muscle homeostasis. New insights into the pathophysiology of dystrophic muscle, the identification of compensating proteins, and the discovery of new binding partners are paving the way for novel therapeutic strategies to treat this fatal muscle disease. This review discusses the role of the dystrophin complex and protein family in muscle and describes the physiological processes that are affected in Duchenne muscular dystrophy.
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PMID:Function and genetics of dystrophin and dystrophin-related proteins in muscle. 1191 91

There are a number of cardiomyopathies secondary to a more widespread striated muscle involvement. While in some conditions the heart is affected as part of a severe myopathy (such as the dilated cardiomyopathy found in Duchenne and Becker muscular dystrophies), there are examples in which the skeletal muscle involvement is subtle. From a classification point of view, some of these cardiomyopathies are secondary to muscular dystrophies, or to metabolic disorders, or to other myopathies. From a practical diagnostic point of view, metabolic conditions predominate in infancy, whereas the dystrophic forms are more frequently found from the third decade onwards. Useful clinical clues to suggest a skeletal muscle involvement are muscle hypertrophy or wasting and contractures, in addition to weakness. Serum creatine kinase should always be studied when suspecting a form secondary to a muscular dystrophy, although a normal serum creatine kinase does not exclude a muscular dystrophy. Electromyography and muscle imaging are additional useful investigations in these patients. This article is focused on practical clinical suggestions on when to suspect and how to investigate patients with a cardiomyopathy secondary to neuromuscular disorders.
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PMID:[Dilated cardiomyopathy: role of clinical and instrumental evaluation of the neuromuscular system]. 1202 83

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant form of muscular dystrophy characterized by progressive weakness and wasting of the facial, shoulder-girdle and upper arm muscles. The gene locus for FSHD is mapped to the subtelomeric region of chromosome 4q35, in which smaller EcoRI fragments (10 to 33 kb) are detected in most families by Southern blot analysis. The purpose of this study is to clarify the frequency and clinical/genetical features of early-onset FSHD in Japanese patients with 4q35-FSHD. In a series of 231 patients from 145 families with 4q35-FSHD, there were 31 patients (13.4%; male: female = 12:19) of 29 families (20%) with early-onset FSHD, 16 of whom were sporadic. Genetic analysis revealed that they had significantly smaller sized EcoRI fragments (range, 10 to 23 kb; mean 14.1 kb) than the other patients (range, 12 to 33 kb; mean 19.6 kb) (p < 0.001, U-test). All patients with the smallest EcoRI fragments (10 to 11 kb) were sporadic cases with early onset. Mental retardation (10/11) and epilepsy (4/11) was often observed in them, but not in the other patients. In early-onset FSHD, tongue muscle involvement (8/31) and swallowing disturbance (2/31), which has been regarded as exclusion criteria of FSHD, were also present. The onset of gait disturbance was significantly earlier (mean age = 11.9) in early-onset FSHD compared to the other group (mean age = 28.7). All patients with early-onset FSHD showed gait disturbance before 28 years of age. In conclusion, Japanese early-onset FSHD patients tend to have large gene deletions on chromosome 4q35, and show severe and variable phenotypes.
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PMID:[Clinical and genetical features of Japanese early-onset facioscapulohumeral muscular dystrophy]. 1213 83


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