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 C-terminal domain of dystrophin is alternatively spliced to produce a variety of tissue and developmental stage-specific isoforms. Recent studies suggest that the C-terminal domain binds to the dystrophin-associated glycoprotein complex (DGC) in muscle, but little is known about the functional significance of the alternative splicing or what role individual isoforms may play in specific tissues. The major dystrophin transcript in brain lacks exons 71-74, and encodes an isoform not observed in skeletal muscle. To explore the capacity of this truncated isoform to function in muscle, we have generated transgenic mice expressing a murine dystrophin mini-gene missing exons 71-74. Uniform expression of this construct on a mutant mdx mouse background results in normal muscle morphology and physiology, and prevents the development of muscular dystrophy. These mice also display normal expression and localization of the DGC, suggesting that the alternatively spliced exons are not required for dystrophin function in skeletal muscle. An additional line of mice was analyzed that had a mosaic pattern of expression. These mice display a markedly milder phenotype than mdx mice, despite the expression of dystrophin in only half the muscle fibers. These results indicate that viral delivery of dystrophin to a simple majority of fibers in a muscle group would greatly reduce the dystrophic pathology associated with Duchenne muscular dystrophy.
 ...
PMID:Prevention of dystrophic pathology in mdx mice by a truncated dystrophin isoform. 784 95

We recently reported that the dystrophin-associated glycoprotein (DAG) complex is biochemically divided into two subcomplexes: one is the dystroglycan complex comprised of 156DAG and 43DAG and the other is the sarcoglycan complex comprised of 50DAG, A3b, and 35DAG. A3b is a novel dystrophin-associated glycoprotein with an approximate molecular mass of 43 kd but is distinct from 43DAG. In the present study, we examined the striated muscles of the dystrophic hamster with anti-A3b antibody in addition to anti-50DAG, anti-43DAG, anti-35DAG, anti-dystrophin, and anti-laminin antibodies by both immunohistochemistry and immunoblot analysis and found that 50DAG, A3b, and 35DAG are selectively lost. This selective defect of the sarcoglycan complex in dystrophic hamster muscles may give rise to dystrophic changes in striated muscles. Thus, the differentiation of the dystrophin-associated glycoprotein complex into the dystroglycan and sarcoglycan complexes is important not only from a biochemical standpoint but also in understanding the cause of muscular dystrophy in the hamster. Our findings further show that the dystrophic hamster may serve as an animal model for a human disease, severe childhood autosomal recessive muscular dystrophy, which has recently been shown to result from a selective defect in the sarcoglycan complex.
 ...
PMID:Sarcoglycan complex is selectively lost in dystrophic hamster muscle. 785 62

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.
 ...
PMID:A molecular survey of Israeli Duchenne and Becker muscular dystrophy patients. 785 72

The 50-kd dystrophin-associated glycoprotein (50DAG or adhalin) in the skeletal muscle has been shown to be deficient in patients with severe childhood autosomal recessive muscular dystrophy prevalent in North Africa. To elucidate the frequency of patients having the 50DAG deficiency in a muscular dystrophy population in Japan, we immunocytochemically examined 50DAG, 43DAG, dystrophin, and utrophin. A total of 243 patients with muscular dystrophy, among 1,035 diagnostic muscle biopsies during the past 2.5 years, were analyzed. We identified five unrelated patients (three females and two males who have no family history) with 50DAG deficiency in the sarcolemma. Thus, 2.1% (5/243) of our muscular dystrophy patient population had 50DAG deficiency.
 ...
PMID:The frequency of patients with 50-kd dystrophin-associated glycoprotein (50DAG or adhalin) deficiency in a muscular dystrophy patient population in Japan: immunocytochemical analysis of 50DAG, 43DAG, dystrophin, and utrophin. 864 3

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.
 ...
PMID:Amino-terminal deletion of 53% of dystrophin results in an intermediate Duchenne-Becker muscular dystrophy phenotype. 793 90

The fantastic advances in fundamental research into muscular dystrophy over the past few years have led to the discovery of a cytoskeleton protein called dystrophin and a group of associated and analogous molecules. The understanding of their molecular structure and the modes of genetic and functional regulation have forced us to take a new look at our concept of the pathogenesis of muscular dystrophy. Today, the group of diseases called X-linked hereditary muscular dystrophies must now be conceived in light of a deficiency in dystrophin. The exact physiopathology of the process involved is not yet fully understood but most undoubtedly, although the lack of dystrophin can trigger the disease, the deficiency cannot in itself impede muscle contraction. As a result of these discoveries, diagnostic methods have changed drastically, genetic counselling has become more precise, and most importantly, new treatment rationales can call upon pharmacological processes capable of stopping disease progression. Genetic therapy is another approach. The aim is to provide the deficient cells with the capacity of synthesizing normal dystrophin or an analogous molecule, thus halting the cascade of events leading to necrosis. The transfer of the technical means which have made these fundamental advances in basic research possible to successful clinical applications in the treatment of muscular dystrophy will be another of the lessons to be learned from dystrophin.
 ...
PMID:[Lessons of dystrophin]. 793 19

Mutations in the dystrophin gene cause the X chromosome-linked, recessive Duchenne and Becker muscular dystrophies. Dystrophin, a large cytoskeletal protein, copurifies with a complex of dystrophin-associated proteins which serve to anchor dystrophin to the sarcolemma. One of these associated proteins, adhalin, has been implicated as a candidate for severe childhood autosomal recessive muscular dystrophy (SCARMD) due to absence of anti-adhalin staining in muscle biopsy samples taken from SCARMD patients. Furthermore, the Duchenne-like dystrophic phenotype seen in the SCARMD families was shown to be tightly linked to chromosome 13 markers. To determine the genetic mutation responsible for autosomal dystrophy, we characterized the human adhalin gene. Contrary to our expectation, human adhalin was mapped to chromosome 17q21, excluding adhalin as the gene causing chromosome 13-associated SCARMD. Additionally, a splice form of adhalin message was found that predicts a 35-kDa nontransmembrane adhalin. The expression of both adhalin splice forms is exclusively restricted to striated muscle, unlike other components of the dystrophin-glycoprotein complex.
 ...
PMID:Human adhalin is alternatively spliced and the gene is located on chromosome 17q21. 793 74

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.
 ...
PMID:The muscular dystrophies. 795 55

Myocardial involvement is frequently present in Xp21-linked muscular dystrophy, due to a lack of dystrophin in cardiac fibres. We describe a 41-yr-old man affected by dilated cardiomyopathy with sporadic episodes of myoglobinuria induced by effort and increased levels of serum creatine kinase. Very mild signs of skeletal myopathy were clinically evident. His mother was affected by an indefinite cardiopathy and suddenly died when she was 36 yr old. Muscle biopsy of the patient showed a dystrophic process. Dystrophin analysis together with a genetic DMD locus study led us to diagnose Becker type muscular dystrophy, with truncated dystrophin and a gene deletion extending from exon 45 to 48. Prevalent cardiac involvement in a Becker type mutation of the dystrophin gene further confirms clinical variability of dystrophinopathies.
 ...
PMID:Prevalent cardiac involvement in dystrophin Becker type mutation. 798 95

We report a 3 1/2-year-old boy with congenital hypotonia, calf pseudohypertrophy, markedly delayed motor milestones and joint contractures. He was initially diagnosed to have congenital muscular dystrophy on the basis of the age of onset, a myopathic EMG, an elevated creatine kinase and a dystrophic muscle biopsy. Subsequently, dystrophin immunocytochemistry and immunoblot analysis showed complete absence of dystrophin. We suggest that male cases of CMD should undergo dystrophin analysis, if there is calf hypertrophy and markedly elevated CK (> 2000 U/l).
 ...
PMID:Dystrophinopathy presenting as congenital muscular dystrophy. 798 96


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