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

Aberrant expression of the dystrophin-associated protein complex is thought to underlie the pathogenesis of Duchenne dystrophy, Becker muscular dystrophy, and severe childhood autosomal recessive muscular dystrophy. Recently, our laboratory identified an agrin receptor from Torpedo electric organ postsynaptic membranes. It is a heteromer of 190- and 50-kDa subunits with similarity to two components of the dystrophin-associated protein complex of alpha- and beta-dystroglycan. We now confirm the relationship between the Torpedo agrin receptor and mammalian dystroglycans and provide further information about the structure of the alpha-dystroglycan-beta-dystroglycan complex. The sequences of three peptides from each Torpedo subunit were 69% identical to mammalian dystroglycans. An antiserum to mammalian beta-dystroglycan recognizes the Torpedo 50-kDa polypeptide. Additionally, like alpha-dystroglycan, the 190-kDa agrin receptor subunit binds laminin. Previous studies have indicated that alpha- and beta-dystroglycan arise by cleavage of a precursor protein. Tryptic peptide mapping of both subunits and amino-terminal sequencing of Torpedo beta-dystroglycan indicate a single cleavage site, corresponding to serine 654 of the mammalian dystroglycan precursor. Gel electrophoresis analysis indicates there is at least one intrachain disulfide bond in beta-dystroglycan. These results provide precise primary structures for alpha- and beta-dystroglycan.
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PMID:The alpha-dystroglycan-beta-dystroglycan complex. Membrane organization and relationship to an agrin receptor. 759 85

A calcium-dependent proteinase (calpain) has been suggested to play an important role in muscle degradation in Duchenne muscular dystrophy (DMD). In immunohistochemical studies, calpain and its endogenous inhibitor (calpastatin) were located exclusively in the cytoplasm in normal human muscles. The intensity of the staining was stronger in type 1 than in type 2 fibers. Quantitative immunohistochemical study showed an increase of calpain in biopsied muscles from the patients with DMD and Becker muscular dystrophy. Abnormal increases in calpain and calpastatin were demonstrated mainly in atrophic fibers, whereas necrotic fibers showed moderate or weak immunoreactions for the enzymes. Opaque fibers and hypertrophic fibers were negative. Not all dystrophin-deficient muscle fibers necessarily showed a strong reaction for calpain. We suggest that calpain may play an important role in muscle fiber degradation, especially in the early stage of muscle degradation in muscular dystrophy.
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PMID:Immunohistochemical study of calpain and its endogenous inhibitor in the skeletal muscle of muscular dystrophy. 761 37

A significant number of major neurogenetic diseases have been defined at the molecular level in recent years, making it possible to determine precisely the genotype for familial Alzheimer's disease, Huntington's disease, Machado-Joseph disease, dominantly inherited ataxia, Charcot-Marie-Tooth disease, myotonic muscular dystrophy, Duchenne-Becker muscular dystrophy, familial amyotrophic lateral sclerosis, and neurofibromatosis. This information has made it possible to identify the abnormal genotype of at-risk persons for these diseases and for at-risk pregnancies for several of them. Precise molecular diagnoses are thus possible using applied molecular markers. Prevention of disease can be achieved using these molecular markers with genetic counseling and appropriate family planning. Significant progress is being made in this regard with Tay-Sachs disease, Huntington's disease, the dominantly inherited ataxias, and the muscular dystrophies. Further, this molecular genotyping will be of indispensible value to families with these diseases when somatic cell gene therapy becomes available. The field of molecular neurogenetics is moving forward rapidly, and advances in gene identification for these diseases will lead in the near future to the means to prevent many of them.
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PMID:The prevention of neurogenetic disease. 771 Mar 70

Dystrophin is normally localized in smooth muscle fibers of various organs in experimental animals, and it has been shown to be defective in the smooth muscle fibers of the mdx mouse, including the myoepithelial cell layer of the sweat glands. We investigated dystrophin localization, using three antisera raised against different domains of skeletal muscle type of dystrophin, in the smooth muscle structures of the skin, using immunohistochemical methods with monoclonal antibodies against dystrophin, in 24 patients with various neuromuscular diseases, and in a normal control. Skin biopsy showed a strong dystrophin reaction in the arrector pili muscles and in the myoepithelial cells of the sweat glands of patients with congenital muscular dystrophy, polymyositis, distal myopathy, putative Duchenne muscular dystrophy carriers, myoglobinuria, neurogenic atrophy and in a normal control. A faint positive dystrophin reaction was seen in four patients with Becker muscular dystrophy, whereas it was absent in 3 patients with Duchenne muscular dystrophy. As our data suggest that immunohistochemical dystrophin expression in smooth muscle structures of the skin is similar to that observed in striated muscle, skin biopsy may represent an alternative way to ascertain dystrophin deficiency.
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PMID:Dystrophin expression in skin biopsy immunohistochemical. Localisation of striated muscle type dystrophin. 775 41

1. Attachment to extracellular matrix is thought to be particularly important for striated muscle cells, since skeletal and heart muscle have to withstand considerably strong forces. 2. We have recently shown that a defect in a protein of the muscle basement membrane, M-laminin, is correlated with muscular dystrophy in human and mouse. The disease associated with defects in M-laminin is thus analogous to that caused by defects in the cytoskeletal protein, dystrophin, the Duchenne/Becker muscular dystrophy. 3. One may propose the hypothesis that a pathway of interacting proteins is required to connect the cytoskeleton of the muscle fiber to the extracellular matrix, and that a defect in any protein in this chain would result in severe impairment of muscle cell attachment with resulting muscle damage upon use of the muscle. The existence of such chains of proteins may be expected from known mutations in muscle proteins in Drosophila and Caenorhabditis elegans. Some of these mutations cause phenotypes resembling muscular dystrophy in mammals. 4. It will be important to identify all the proteins that are participants in muscle cell attachment, including receptors for M-laminin and proteins associated with these receptors.
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PMID:Cell adhesion in muscle. 778 6

The intramembranous particle (IMP), orthogonal array (OA) and orthogonal array subunit particle (OASP) densities in skeletal muscle plasma membranes from eight patients with Becker's muscular dystrophy (BMD) were analysed by the freeze-fracture technique. The results showed almost normal IMP density with the significant decrease of OA and OASP densities in BMD. The group mean densities +/- SE of IMPs on the protoplasmic faces with and without OASPs, and on extracellular faces/microns 2 were 2137 +/- 207, 1839 +/- 68 and 895 +/- 108, respectively in controls; whereas those of BMD were 1989 +/- 259, 1837 +/- 203 and 900 +/- 239, respectively (P > 0.1 by two-tailed t-test). The group median density of OAs and their pits/microns 2 was 4.89 with mid-ranges (25-75% values of the counts) of 2.66-10.18 in controls; whereas that in BMD was 2.15 with mid-ranges of 1.14-4.31 (P < 0.01 by Wilcoxon rank-sum test). The group mean density +/- SE of OASPs in controls was 15.99 +/- 1.83; whereas that in BMD was 13.47 +/- 1.07 (P < 0.01 by two-tailed t-test). However, the diminution of OA and OASP densities in BMD muscle plasma membranes was not as severe as in Duchenne's muscular dystrophy. There was a relationship between OA density and clinical severity in BMD patients; the decrease of OA density in a severe BMD patient was more marked than that in mildly affected BMD patients. Therefore, it seems that marked depletion of OA density may lead to the severe disability in muscular dystrophies.
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PMID:Freeze-fracture analysis of muscle plasma membrane in Becker's muscular dystrophy. 784 34

Duchenne (DMD) and Becker (BMD) muscular dystrophy are allelic X-linked recessive diseases caused by a mutation in the dystrophin gene located on the short arm of chromosome X (Xp21). The dystrophin gene is the largest gene known in humans, extending over 2300 kb and containing more than 70 exons coding for a 420 KD protein comprising 3685 amino acids. The gene is highly unstable, with a high percentage of deletions and rearrangements. A third of dystrophin mutations are new mutations. The frequency of DMD is 1:3500 liveborn males, and that of BMD 1:10000. These dystrophies are severe, progressive, and lethal. BMD/DMD patients and 2/3 of female carriers have high levels of creatine phosphokinase (CK). During the past 5 years, 169 families with patients affected by progressive muscular dystrophy were examined and counselled. We were able to exclude the diagnosis of DMD/BMD in 49 families on the basis of clinical symptoms and signs, normal dystrophin on biopsy (11 families) and/or the absence of linkage to chromosome X by analysis of RFLP derived haplotypes. Molecular analysis was performed on 111 DMD/BMD families (five BMD and 106 DMD) with 81 available probands. This study resulted in the establishment in Israel of an integrated diagnostic protocol for DMD/BMD, employing genetic, biochemical and molecular techniques. Molecular analysis provided most of the families with new and essential information.
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PMID:A molecular survey of Israeli Duchenne and Becker muscular dystrophy patients. 785 72

We report a Japanese boy with muscular dystrophy whose clinical symptoms were intermediate between those usually considered typical of Duchenne and Becker muscular dystrophies. The patient had a large inframe deletion extending from exons 3 to 41 of the dystrophin gene, which would be expected to cause the production of a dystrophin protein composing only 53% of the normal polypeptide chain. Such an inframe deletion would be expected to cause Becker muscular dystrophy. We did not obtain evidence for alternative splicing or for RNA editing. Immunocytochemical analysis of skeletal muscle showed that a dystrophin-related polypeptide was detectable with antibody directed against the carboxyl-terminal part of the polypeptide but not with antibodies directed against the amino-terminal part, although labeling by antibody against the carboxyl-terminal was faint and patchy. The severity of the disease in this case may be due to the lack of the amino-terminal, actin-binding domain of dystrophin.
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PMID:Amino-terminal deletion of 53% of dystrophin results in an intermediate Duchenne-Becker muscular dystrophy phenotype. 793 90

The muscular dystrophies are a group of inherited disorders that are clinically and genetically distinct. Genetic counselling is an essential part of the management of these patients. Molecular genetic techniques, in particular positional cloning but also now candidate gene analysis, have allowed the beginning of an understanding of the molecular pathology of these conditions. This is most advanced in Duchenne and Becker muscular dystrophy, where the gene and protein responsible have been fully defined, and analyses of the gene and protein can offer specific diagnostic and prognostic information, as well as more precise carrier counselling. Gene localizations are known for Emery-Dreifuss muscular dystrophy, facioscapulohumeral muscular dystrophy, three forms of 'limb-girdle' muscular dystrophy, severe childhood autosomal recessive muscular dystrophy and Fukuyama muscular dystrophy. Closely linked markers for Emery-Dreifuss and facioscapulohumeral muscular dystrophy can be helpful in the investigation of large families with these conditions. Abnormalities of two different proteins associated with dystrophin in the muscle fibre have been shown in severe childhood autosomal recessive muscular dystrophy and Fukuyama muscular dystrophy. The application of the techniques of molecular genetics to the muscular dystrophies has had an enormous impact, from enhancing understanding of the theoretical background of these diseases, to direct implications in their clinical management. These advances are likely to continue.
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PMID:The muscular dystrophies. 795 55

We report a series of 46 patients (32 women and 14 men) with limb-girdle syndrome. After reappraisal, another diagnosis was made in 10 of them. Becker's muscular dystrophy was the most frequent cause among men (near 50 p. 100). A Duchenne muscular dystrophy manifesting carrier was discovered among 13 reevaluated women. Among the 36 cases (29 women and 7 men) without any defined etiology, 29 were without any other known familial history. Fifteen of these women had similar clinical findings: incipient weakness in the pelvic girdle and onset of symptoms most often in the forties. In these cases serum creatine kinase activity was normal or slightly elevated, and muscle biopsy showed non-specific patterns. "Late onset muscular dystrophy in females" should be reevaluated.
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PMID:[Limb-girdle syndrome. A study of 46 cases]. 799 39


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