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)

DMD and BMD are now understood at the genetic, biochemical, and molecular levels. At the genetic level, both disorders result from mutations of the X-linked gene encoding dystrophin. At the biochemical level, DMD results from the deficiency of a large protein called dystrophin, whereas BMD results when dystrophin is present, though abnormal in either amount or molecular structure. To date, thousands of patients have been analyzed for mutations of the dystrophin gene in peripheral blood DNA or alterations of the dystrophin protein in muscle tissue. The severity of the clinical phenotype of these patients has been compared with their dystrophin gene mutations and corresponding dystrophin protein alterations, revealing an unexpectedly high degree of correlation. Thus, information derived from the molecular analysis (DNA or protein) of a particular patient provides a "molecular diagnosis," which is highly predictive of the clinical course that patient can be expected to follow. Because molecular diagnoses are independent of the patient's age, they provide a prognosis for the large majority of muscular dystrophy patients even before clinical symptoms of their disease become apparent. Such prognostic molecular diagnoses have proven particularly valuable when the patient is an isolated case, with no family history for the disorder. Prenatal genetic diagnosis of DMD or BMD may involve use of Southern blot or PCR techniques to search for a deletion in the DNA of at-risk fetuses or more complicated family linkage studies using intragenic and flanking RFLPs. More recently, assay of dystrophin content in fetal skeletal or cardiac muscle from at-risk abortuses has been accomplished, allowing definitive discrimination of affected and normal fetuses in cases in which deletion analyses and family DNA studies were equivocal. In utero fetal skeletal muscle biopsy for dystrophin protein assay has actually been accomplished in at least one at-risk pregnancy in which family DNA studies were uninformative. Dystrophin was present in skeletal muscle from this 20-week-old male fetus, and the pregnancy continued, resulting in the term birth of a healthy male infant. The future holds exciting opportunities for neonatal screening and treatment of these devastating neuromuscular diseases.
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PMID:Duchenne and Becker muscular dystrophies: genetics, prenatal diagnosis, and future prospects. 228 31

In this report we describe the use of dystrophin analysis both in the diagnosis of Duchenne muscular dystrophy (DMD) in an aborted fetus and in genetic counseling. Our consultand's initial carrier risk, as based on family history and creatine kinase determinations, was calculated as 0.6%. DNA analysis of her family (and fetus) modified this risk to 8.5%. Skeletal muscle of the 23-wk male abortus was found to be histologically indistinguishable from that of age-matched controls. However, immunoblot testing for dystrophin indicated that the fetus had indeed inherited dystrophin deficiency. The carrier risk of the consultand was thus elevated to 100%. Dystrophin assays should be employed whenever the diagnosis of fetal DMD is equivocal (e.g., cases in which a gene deletion cannot be identified). Assay results are crucial for genetic counseling for subsequent pregnancies and for studies of the early pathogenesis of muscular dystrophy.
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PMID:Dystrophin analysis in duchenne muscular dystrophy: use in fetal diagnosis and in genetic counseling. 267

Skeletal muscle from patients with 5 different forms of muscular dystrophy and from 6 fetuses at high risk (95%) for Duchenne muscular dystrophy (DMD) were probed with specific antibodies for the presence of dystrophin and nebulin. Dystrophin was absent in all 5 patients with DMD and 4 of 6 fetuses at high risk for DMD and present in trace amounts in the remaining two. Dystrophin was also undetectable in one borderline DMD/Becker muscular dystrophy (BMD) case and reduced in 2 of 4 cases of BMD. In contrast, dystrophin was present in all 16 biopsies from 4 other types of muscular dystrophy (congenital, limb girdle, Emery-Dreifuss and facioscapulohumeral). Nebulin profiles varied with the type, severity and duration of the dystrophic process. Nebulin was present in 5 of 6 DMD fetal samples but vastly reduced or absent in all samples of clinically manifest DMD.
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PMID:Dystrophin and nebulin in the muscular dystrophies. 306 33

Dystrophin gene deletions account for up to 68% of all Duchenne (DMD) and Becker (BMD) muscular dystrophy mutations. In affected males, these deletions can be detected easily using multiplex PCR tests which monitor for exon presence. In addition, quantitative dosage screening can discriminate female carriers. We previously analyzed multiplex PCR products by gel electrophoresis and quantitation of fluorescently labeled primers with the Gene Scanner in order to test carrier status. These multiplex PCR protocols detect DMD gene deletions adequately, but require up to 18 pairs of fluorochrome-labeled primers. We previously described two alternative fluorescent labeling strategies, each with approximately 1,000-fold greater sensitivity than ethidium bromide staining, which can be used to quantify the products of multiplex PCR. The first method uses the DNA intercalating thiazole orange dye TOTO-1 to stain PCR products after 20 cycles. In the second method, fluorescein-12,2'-dUTP is incorporated into products during PCR as a fluorescent tag for subsequent quantitative dosage studies. Both methods label all multiplexed exons including the 506 bp exon 48 fragment that is difficult to detect and quantify by standard ethidium bromide staining. Using this approach, we determined DMD/BMD carrier status in 24 unrelated families using a fluorescent fragment analyzer. Analysis of fluorochrome-labeled PCR products facilitates quantitative multiplex PCR for gene-dosage analysis.
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PMID:Duchenne/Becker muscular dystrophy carrier detection using quantitative PCR and fluorescence-based strategies. 751 Sep 32

Dystrophin is a protein product of the gene responsible for Duchenne muscular dystrophy (DMD), and is a long slender protein localized at the protoplasmic surface of sarcolemma. Dystrophin binds with actin filaments at its amino-terminal region, and with dystrophin-associated proteins (DAPs) at its carboxyl-terminal region. DAPs are composed of a glycoprotein complex and a syntrophin complex, a complex of proteins binding with dystrophin and located intracellularly. Glycoprotein complex is composed of dystroglycan complex and sarcoglycan complex, both of which are membrane-integrated. Dystrophin binds with dystroglycan complex which transverse through sarcolemma and then binds with laminin in the basal lamina, forming a long axis between action threads and the extracellular matrix. Sarcoglycan complex does not directly bind with dystrophin but binds with dystroglycan complex. Disruption of the axis results in dystrophic changes in one kind of congenital muscular dystrophy (CMD). Loss of the sarcoglycan complex gives rise to childhood severe autosomal recessive muscular dystrophy (SCARMD) which is clinically very similar to DMD. In DMD, the sarcoglycan complex is mostly lost, and the axis is for the most part defective. Therefore, it is likely that the causes of DMD and SCARMD may be similar and may be modified by the mechanism which gives rise to CMD.
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PMID:[Dystrophin, dystrophin-associated protein and dystrophinopathy]. 758 23

A patient with non-Fukuyama type merosin-positive congenital muscular dystrophy (nonFCMD) who had severe muscle weakness leading to early death was reported. He was the first product of epileptic mother who had been placed on phenobarbital and phenytoin. The patient had severe respiratory failure and muscle weakness at the neonatal period, and died at 4 months of age. Multiple joint contractures were also noted at birth. Serum creatine kinase was within normal limits (123 IU/l). Electromyography showed a myogenic pattern. Brain computed tomographic (CT) scan and magnetic resonance imaging (MRI) were normal without white matter lucency or pachygyria. Muscle biopsy revealed dystrophic changes and type 2C fiber predominance. Dystrophin, dystrophin-associated glycoproteins and merosin were all positively demonstrated. Although patients with merosin-positive nonFCMD have relatively mild clinical course, our patient had severe muscle weakness with fatal outcome. Defect in muscle fiber maturation and differentiation, such as an increase of undifferentiated type 2C fibers, may be a major factor to influence muscle symptoms in non FCMD.
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PMID:[Non-Fukuyama type merosin-positive congenital muscular dystrophy with delayed muscle fiber type differentiation: a case report]. 761 93

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

Dystrophin is a 427-kDa protein localized adjacent to the sarcolemma in skeletal muscle. Its physiological role remains uncertain, although its absence is known to cause muscular dystrophy. In this study, the function of dystrophin was investigated using the dystrophin-deficient mdx mouse. Control and mdx animals at 2, 5, and 13 wk of age (n = 8-11/age) were compared to evaluate in situ gastrocnemius-plantaris-soleus muscle contractile, endurance, and excitability properties at nondegenerated, degenerated, and regenerated stages, respectively. Twitch and tetanic tensions expressed per gram of muscle mass were lower in mdx muscle only at 5 wk. Fatigue produced during successive contractions at 2, 10, and 20 Hz did not differ between the two groups at 2 and 5 wk but was lower in mdx muscle at 13 wk. This was not attributed to differences in mitochondria, since cytochrome-c oxidase activity was similar in mdx and control muscle. Contractile properties of control and mdx muscle became faster with age, and at 13 wk the time to peak twitch tension was shorter in mdx muscle relative to control, whereas the half-relaxation times did not differ. Mass action potential area (M wave), an index of muscle excitability, was not significantly different between mdx and control muscle at 2 or 5 wk but was greater in mdx muscle at 13 wk. Thus, in this weight-bearing muscle group, the lack of dystrophin has only a moderate impact in modifying muscle function relative to contractile properties, fatigability, or excitability.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Performance and excitability of mdx mouse muscle at 2, 5, and 13 wk of age. 777 42

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.
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PMID:Human adhalin is alternatively spliced and the gene is located on chromosome 17q21. 793 74

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.
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PMID:Prevalent cardiac involvement in dystrophin Becker type mutation. 798 95


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