Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The limb-girdle muscular dystrophies are a diverse group of muscle-wasting disorders characteristically affecting the large muscles of the pelvic and shoulder girdles. Molecular genetic analyses have demonstrated causative mutations in the genes encoding a disparate collection of proteins involved in all aspects of muscle cell biology. Muscular dystrophy includes a spectrum of disorders caused by loss of the linkage between the extracellular matrix and the actin cytoskeleton. Within this are the forms of limb-girdle muscular dystrophy caused by deficiencies of the sarcoglycan complex and by aberrant glycosylation of alpha-dystroglycan caused by mutations in the fukutin-related protein gene. However, other forms of this disease have distinct pathophysiological mechanisms. For example, deficiency of dysferlin disrupts sarcolemmal membrane repair, whilst loss of calpain-3 may exert its pathological influence either by perturbation of the IkappaBalpha/NF-kappaB pathway, or through calpain-dependent cytoskeletal remodelling. Caveolin-3 is implicated in numerous cell-signalling pathways and involved in the biogenesis of the T-tubule system. Alterations in the nuclear lamina caused by mutations in laminA/C, sarcomeric changes in titin, telethonin or myotilin at the Z-disc, and subtle changes in the extracellular matrix proteins laminin-alpha2 or collagen VI can all lead to a limb-girdle muscular dystrophy phenotype, although the specific pathological mechanisms remain obscure. Differential diagnosis of these disorders requires the careful application of a broad range of disciplines: clinical assessment, immunohistochemistry and immunoblotting using a panel of antibodies and extensive molecular genetic analyses.
 ...
PMID:Limb-girdle muscular dystrophies--from genetics to molecular pathology. 1504 7

Muscular dystrophy covers a group of genetically determined disorders that cause progressive weakness and wasting of the skeletal muscles. Dysferlin was identified as a gene mutated in limb-girdle muscular dystrophy (type 2B) and Miyoshi myopathy. The discovery of dysferlin revealed a new family of proteins, known as the ferlin family, which includes four different genes. Recent work suggests the function of dysferlin in membrane repair and demonstrates that defective membrane repair is a novel mechanism of muscle degeneration. These findings reveal the importance of a basic cellular function in skeletal muscle and a new class of muscular dystrophy where the defect lies in the maintenance, not the structure, of the plasma membrane. Here, we discuss the current knowledge of dysferlin function in the repair of the plasma membrane of the skeletal muscle cells.
 ...
PMID:Dysferlin and the plasma membrane repair in muscular dystrophy. 1506 38

The introduction of molecular genetics in medicine, specifically in the field of neuromuscular pathology, has created a drastic change in the diagnostic approach used for neuromuscular disorders. Diagnosis of muscle biopsy is based on important aspects such as morphology and histochemistry, but nowadays immunohistochemistry and Western blot analysis of certain proteins is of utmost importance for a correct diagnosis in a large number of neuromuscular disorders and is crucial to direct the genetic study, which is also necessary. To date, more than 30 muscular dystrophy types have been genetically characterized, and the protein product is known in most of them as well as its structural location in the muscle fiber and its relation with other muscle proteins and the extracellular matrix. With the diagnostic specificity conferred by the absence of expression by a specific protein or a mutation of a specific gene, we have learned that similar clinical phenotype may occur in different diseases, such as Duchenne muscular dystrophy and gamma-sarcoglycanopathy, but also that mutations in the same gene may cause different clinical phenotypes, as occurs in Miyoshi distal myopathy and limb girdle muscular dystrophy 2B, both caused by mutations in the dysferlin gene. Herein we describe the recommendable diagnostic methodology and strategy to be employed in the study of the large group of the <<limb girdle muscular dystrophies >>, especially focused on the autosomal recessive dystrophies, taking the study of dystrophinopathies as an example.
 ...
PMID:[Myopathology. New concept. New laboratory]. 1513 36

Limb girdle muscular dystrophy type 2B and Miyoshi myopathy are clinically distinct forms of muscular dystrophy that arise from defects in the dysferlin gene. Here, we report two novel lines of dysferlin-deficient mice obtained by (a) gene targeting and (b) identification of an inbred strain, A/J, bearing a retrotransposon insertion in the dysferlin gene. The mutations in these mice were located at the 3' and 5' ends of the dysferlin gene. Both lines of mice lacked dysferlin and developed a progressive muscular dystrophy with histopathological and ultrastructural features that closely resemble the human disease. Vital staining with Evans blue dye revealed loss of sarcolemmal integrity in both lines of mice, similar to that seen in mdx and caveolin-3 deficient mice. However, in contrast to the latter group of animals, the dysferlin-deficient mice have an intact dystrophin glycoprotein complex and normal levels of caveolin-3. Our findings indicate that muscle membrane disruption and myofiber degeneration in dysferlinopathy were directly mediated by the loss of dysferlin via a new pathogenic mechanism in muscular dystrophies. We also show that the mutation in the A/J mice arose between the late 1970s and the early 1980s, and had become fixed in the production breeding stocks. Therefore, all studies involving the A/J mice or mice derived from A/J, including recombinant inbred, recombinant congenic and chromosome substitution strains, should take into account the dysferlin defect in these strains. These new dysferlin-deficient mice should be useful for elucidating the pathogenic pathway in dysferlinopathy and for developing therapeutic strategies.
 ...
PMID:Disruption of muscle membrane and phenotype divergence in two novel mouse models of dysferlin deficiency. 1525 15

A 57-year-old woman first noticed difficulty in walking at the age of 34 years, and since then muscle wasting and weakness in the lower limbs and proximal portion of the upper limbs had progressed slowly. Serum CK was elevated. Immunohistochemical study of the biceps brachii muscle showed deficiency of dysferlin in sarcolemma, and the dysferlin gene analysis disclosed 3370 G-->T missense mutation. These findings led us to diagnose her as LGMD2B. Moreover echocardiogram revealed ventricular enlargement and diffuse hypokinesia suggesting secondary cardiomyopathy atributable to muscular dystrophy. Careful cardiac monitoring should be carried out in dysferlinopathy patients.
 ...
PMID:[A patient with limb girdle muscular dystrophy type 2B (LGMD2B) manifesting cardiomyopathy]. 1529 63

Calpain3 (CAPN3, p94) is a muscle-specific nonlysosomal cysteine proteinase. Loss of proteolytic function or change of other properties of this enzyme (such as stability or ability to interact with other muscular proteins) is manifested as limb girdle muscular dystrophy type 2A (LGMD2A, calpainopathy). These pathological changes in properties of calpain3 are caused by mutations in the calpain3 gene. The fact that the human gene for calpain3 is quite long led us to analyse its coding sequence by reverse transcription-PCR followed by sequence analysis. This study reports nine mutations that we found by analysing mRNA of seven unrelated LGMD patients in the Czech Republic. Three of these mutations were novel, not described on the Leiden muscular dystrophy pages so far. Further, we observed a reduction of dysferlin in muscle membrane in five of our seven LGMD2A patients by immunohistochemical analysis of muscle sections.
 ...
PMID:Mutations in Czech LGMD2A patients revealed by analysis of calpain3 mRNA and their phenotypic outcome. 1535 23

Mutations in the dysferlin gene (DYSF) on chromosome 2p13 cause distinct phenotypes of muscular dystrophy: limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy (MM), and distal anterior compartment myopathy, which are known by the term 'dysferlinopathy'. We performed mutation analyses of DYSF in 14 Italian patients from 10 unrelated families with a deficiency of dysferlin protein below 20% of the value in normal controls by immunoblotting analysis. We identified 11 different mutations, including eight missense and three deletion mutations. Nine of them were novel mutations. We also identified a unique 6-bp insertion polymorphism within the coding region of DYSF in 15% of Italian population, which was not observed in East Asian populations. The correlation between clinical phenotype and the gene mutations was unclear, which suggested the role of additional genetic and epigenetic factors in modifying clinical symptoms.
 ...
PMID:Dysferlin mutation analysis in a group of Italian patients with limb-girdle muscular dystrophy and Miyoshi myopathy. 1546 49

Limb girdle muscular dystrophy type 2B form (LGMD-2B) and Miyoshi myopathy (MM) are both caused by mutations in the dysferlin (dysf) gene. In this study, we used dysferlin-deficient sjl mice as a mouse model to study cell therapy for LGMD-2B and MM. A single-blind study evaluated the therapeutic potential of human umbilical cord blood (HUCB) as a source of myogenic progenitor stem cells. Three groups of donor cells were used: unfractionated mononuclear HUCB cells, HUCB subfractionated to enrich for cells that were negative for lineage surface markers (LIN(-)) and substantially enriched for the CD34 surface marker (CD34(+)), and irradiated control spleen cells. We administrated 1 x 10(6) donor cells to each animal intravenously and euthanized them at different time points (1-12 weeks) after transplantation. All animals were immunosuppressed (FK506 and leflunomide) from the day before the injection until the time of euthanasia. Immunohistochemical analyses documented that a small number of human cells from the whole HUCB and LIN(-)CD34(+/-)-enriched HUCB subgroups engraft in the recipient muscle to express both dysferlin and human-specific dystrophin at 12 weeks after transplantation. We conclude that myogenic progenitor cells are present in the HUCB, that they can disseminate into muscle after intravenous administration, and that they are capable of myogenic differentiation in host muscle.
 ...
PMID:Human umbilical cord blood cells differentiate into muscle in sjl muscular dystrophy mice. 1553 89

Sixteen different forms of limb-girdle muscular dystrophies (LGMDs) have emerged from recent molecular genetic studies, six forms with a dominant trait and ten forms with a recessive trait. Among 1,420 Japanese patients with muscular dystrophy analyzed at NCNP, LGMD is the secondly largest category (19%) following dystrophinopathy (56%). Within LGMDs, the occurrence of LGMD2A (calpainopathy), LGMD2B (dysferlinopathy), and LGMD2C-F (sarcoglycanopathy) is 26%, 18%, and 6.6%, respectively, however, causative genes have not been specified in about 50% of the LGMD patients. LGMD2A patients show atrophy prominent in shoulder and pelvic girdle muscles without calf muscle hypertrophy, and abundant lobulated fibers in muscle biopsy. Four major mutations unique to the Japanese population, have been identified. Pathogenesis attributes to a loss of proteolytic activity of mutant calpain-3. Dysferlin, the defective protein in LGMD2B, is a ferlin family molecule possessing six C2 domains probably mediating the resealing mechanism of the damaged sarcolemma. Mutations in the dysferlin gene result in Miyoshi distal myopathy and distal anterior compartment myopathy other than LGMD2B. Among four sarcoglyconopathies, LGMD2D is the most common form, whereas LGMD2F has not yet been reported. In sarcoglycan-deficient skeletal muscle, matrix metalloproteinases may be involved in the beta-dystroglycan processing which underlies the pathogenesis of sarcoglycanopathy.
 ...
PMID:[Limb-girdle muscular dystrophy; update]. 1565 52

Biglycan and decorin are small extracellular proteoglycans that interact with cytokines, whose activity they may modulate, and with matrix proteins, particularly collagens. To better understand their role in muscle fibrosis, we investigated expression of decorin and biglycan transcripts and protein in muscle of several forms of muscular dystrophy, and also expression of perlecan, an extracellular proteoglycan unrelated to collagen deposition. In Duchenne muscular dystrophy (DMD) and LAMA2-mutated congenital muscular dystrophy (MDC1A) we also quantitated transcript levels of the profibrotic cytokine TGF-beta1. We examined muscle biopsies from nine DMD patients, aged 2-8 years; 14 BMD (Becker muscular dystrophy) patients (nine aged 1-5 years; five aged 30-37 years); four MDC1A patients (aged 2-7 years); six dysferlin-deficient patients (aged 19-53 years) with mutation ascertained in two, and normal expression of proteins related to limb girdle muscular dystrophies in the others; 10 sarcoglycan-deficient patients: seven with alpha-sarcoglycan mutation, two with beta-sarcoglycan mutation and one with gamma-sarcoglycan mutation (five aged 8-15 years; five aged 26-43 years); and nine children (aged 1-6 years) and 12 adults (aged 16-61 years) suspected of neuromuscular disease, but who had normal muscle on biopsy. Biglycan mRNA levels varied in DMD and MDC1A depending on the quantitation method, but were upregulated in BMD, sarcoglycanopathies and dysferlinopathy. Decorin mRNA was significantly downregulated in DMD and MDC1A, whereas TGF-beta1 was significantly upregulated. Decorin mRNA was normal in paediatric BMD, but upregulated in adult BMD, sarcoglycanopathies and dysferlinopathy. Perlecan transcript levels were similar to those of age-matched controls in all disease groups. By immunohistochemistry, decorin and biglycan were mainly localized in muscle connective tissue; their presence increased in relation to increased fibrosis in all dystrophic muscle. By visual inspection, decorin bands on immunoblot did not differ from those of age-matched controls in all patient groups. However, when the intensity of the bands was quantitated against vimentin and normalized against sarcomeric actin, in DMD and MDC1A the ratio of band intensities was significantly lower than in age-matched controls. Variations in the transcript and protein levels of these proteoglycans in different muscular dystrophies probably reflect the variable disruption of extracellular matrix organization that occurs in these diseases. The significantly lowered decorin levels in DMD and MDC1A may be related to the increased TGF-beta1 levels, suggesting a therapeutic role of decorin in these severe dystrophies.
 ...
PMID:Decorin and biglycan expression is differentially altered in several muscular dystrophies. 1618 58


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>