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)

Dystrophin is the protein whose defect underlies Duchenne Muscular Dystrophy, DMD, a common (1:3500 male births) and fatal condition in which muscle tissue deteriorates leading to death in the second or third decade of life. Dystrophin is coded for by the largest human gene, and one of the most complex. It is translated from at least 7 distinct promoters, with the largest transcripts (which are the ones involved in DMD) containing 79 exons over >2.5 Mbp [K.F. O'Brien, L.M. Kunkel, Dystrophin and muscular dystrophy: past, present, and future, Mol. Genet. Metab. 74 (2001) 75-88, H.M. Sadoulet-Puccio, L.M. Kunkel, Dystrophin and its isoforms, Brain Pathol. 6 (1996) 25-35]. Exacerbating this complexity, it has recently been shown that dystrophin is subject to extensive alternative RNA processing, potentially producing a wide variety dystrophin variants [M. Sironi, R. Cagliani, U. Pozzoli, A. Bardoni, G.P. Comi, R. Giorda, N. Bresolin, The dystrophin gene is alternatively spliced throughout its coding sequence FEBS Lett 517 (2002) 163-166]. The structure of the dystrophin protein is highly modular, with the most common module being a motif termed the spectrin type repeat, or STR, of which there are 24. Each STR is roughly coded for by two exons, and the most common type of multiple exon-skipping events start and end at introns in the middle of STRs [R.G. Roberts, A.J. Coffey, M. Bobrow, D.R. Bentley, Exon structure of the human dystrophin gene Genomics 16 (1993) 536-538, M. Koenig, L.M. Kunkel, Detailed analysis of the repeat domain of dystrophin reveals four potential hinge segments that may confer flexibility, J. Biol. Chem. 265 (1990) 4560-4566]. This would produce fractional STR modules, however, the concept of STRs as proteins domains makes the viability of such fractional motifs questionable. However, certain of these events produce pairs of potentially complementary fractional domain that might reassemble into a hybrid STR motif. We have constructed model fragment corresponding to one such exon-skipping event, and show that the hybrid STR so produced is viable, and furthermore that some of the properties of the protein containing it differ substantially of the native, un-skipped parent.
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PMID:Hybrid spectrin type repeats produced by exon-skipping in dystrophin. 1671 78

There exists much phenotypic heterogeneity in Duchenne muscular dystrophy and its allelic variant, Becker muscular dystrophy. The molecular findings on 53 patients with Duchenne and 15 patients with Becker type muscular dystrophy in KwaZulu Natal, South Africa are reported. Multiplex PCR was performed using primers targeting 18 hot-spot exons throughout the dystrophin gene. Analysis of the multiplex PCR data revealed that 39/68 (57.0%) patients included in the study showed a deletion (33 DMD and 6 BMD patients). Twenty-five patients were Black, 4 were White and 10 were Indian. Using the Chamberlain and Beggs multiplex PCR assays, the region of the genome most frequently affected by a deletion includes exons 47-51. The distal region of the dystrophin gene was most frequently affected by the deletion in both Black and Indian patients. There were too few White patients for conclusions to be drawn concerning the most frequently affected part of the gene. Although the numbers are insufficient to determine whether ethnic differences are present, the Chamberlain and Beggs multiplex PCR assays detect deletions with the same frequency in South African DMD/BMD patients as that reported in the literature.
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PMID:Molecular deletion patterns in Duchenne and Becker muscular dystrophy patients from KwaZulu Natal. 1714 Dec 73

Overexpression of the cytotoxic T cell (CT) GalNAc transferase (Galgt2) in the skeletal muscles of transgenic mdx mice has been reported to inhibit the development of muscular dystrophy. The profound effect of Galgt2 on muscular dystrophy in transgenic mice, where overexpression is begins from embryonic stages, is complicated by its additional effects on muscle growth and neuromuscular structure. Here, we use adeno-associated virus (AAV) to show that overexpression of Galgt2 in skeletal myofibers in the early postnatal period is equally effective in inhibiting muscular dystrophy, but that it does so without altering muscle growth or neuromuscular structure. Unlike embryonic overexpression, postnatal overexpression of Galgt2 did not reproducibly increase the expression of utrophin, synaptic laminins, or dystrophin-associated glycoproteins along infected myofibers. Moreover, Galgt2 overexpression inhibited muscular dystrophy to the same extent in utrophin-deficient mdx muscles as it did in utrophin-expressing mdx muscles. Thus, Galgt2 is a molecular target for therapy in DMD that can be utilized in a manner that separates its clinical benefit from its effects on development, and its clinical benefit is distinct from that achieved by utrophin.
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PMID:Postnatal overexpression of the CT GalNAc transferase inhibits muscular dystrophy in mdx mice without altering muscle growth or neuromuscular development: evidence for a utrophin-independent mechanism. 1730 Sep 37

Various autoantibodies had been detected in patients with dilated cardiomyopathy (DCM). Among them, anti-beta 1 adrenoreceptor antibody (ARAb) had been proven to act as agonist on beta 1 adrenoreceptor and cause DCM. Cardiomyopathy is also serious problem in progressive muscular dystrophy (PMD). Because cardiac dysfunction is quite variable even in siblings sharing identical mutations, it is highly possible that there are some modifier factors. Thus, we measured ARAb in 93 patients with PMD and 11 patients with DCM to clarify immune function for cardiac impairment of PMD. The titer was abnormally elevated in 30.1% of PMD, 72.7% of DCM and 75.0% (9/12) of PMD patients with symptomatic cardiac failure. ARAb was weakly correlated to fractional shortening, brain natriuretic peptide, noradrenalin and severity of premature ventricular contractions (Lown grade). During the study period, four patients developed cardiac failure and ARAb was increased in all these patients. In DMD, although the patients receiving both beta blocker and angiotensin converting enzyme inhibitor showed worst cardiac function, the titers were rather low compared to patients with angiotensin converting enzyme inhibitor alone. Four of five patients initiating beta blocker showed decrease of ARAb. Autoantibodies for myocardium actually exist in PMD in certain ratio as is the case with DCM. It is highly possible that immune system plays some role in cardiac impairment even in PMD. We should pay enough attention to immune system to elucidate the mechanism of cardiac dysfunction and refine strategy of cardiac treatments.
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PMID:[Anti-beta 1 adrenoreceptor antibody is frequently elevated in patients with muscular dystrophy]. 1732 76

We report the generation of mice with an intact and functional copy of the 2.3-megabase human dystrophin gene (hDMD), the largest functional stretch of human DNA thus far integrated into a mouse chromosome. Yeast spheroplasts containing an artificial chromosome with the full-length hDMD gene were fused with mouse embryonic stem cells and were subsequently injected into mouse blastocysts to produce transgenic hDMD mice. Human-specific PCR, Southern blotting, and fluorescent in situ hybridization techniques demonstrated the intactness and stable chromosomal integration of the hDMD gene on mouse chromosome 5. Expression of the transgene was confirmed by RT-PCR and Western blotting. The tissue-specific expression pattern of the different DMD transcripts was maintained. However, the human Dp427p and Dp427m transcripts were expressed at 2-fold higher levels and human Dp427c and Dp260 transcripts were expressed at 2- and 4-fold lower levels than their endogenous counterparts. Ultimate functional proof of the hDMD transgene was obtained by crossing of hDMD mice with dystrophin-deficient mdx mice and dystrophin and utrophin-deficient mdx x Utrn-/- mice. The hDMD transgene rescued the lethal dystrophic phenotype of the mdx x Utrn-/- mice. All signs of muscular dystrophy disappeared in the rescued mice, as demonstrated by histological staining of muscle sections and gene expression profiling experiments. Currently, hDMD mice are extensively used for preclinical testing of sequence-specific therapeutics for the treatment of Duchenne muscular dystrophy. In addition, the hDMD mouse can be used to study the influence of the genomic context on deletion and recombination frequencies, genome stability, and gene expression regulation.
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PMID:Generation and characterization of transgenic mice with the full-length human DMD gene. 1808 4

Adverse reactions to genral anesthesia, which partly resembled malignant hyperthermia (MH), were more frequent in muscular dystrophy than in controls. In the present study, 35 cases so far reported in Duchenne or Becker muscular dystrophy (DMD or BMD) were analyzed and their pathogenesis was discussed. Cardiac involvements were sole manifestations in 7 cases. In other 28 cases, the acute rhabdomyolysis was the most prevailing manifestation. About 60% of myolysis cases were associated with muscle contracture (rigidity) or other hypermetabolic signs such as hypercapnia, hyperthermia and metabolic acidosis. Cases with BMD were more hyperthermic than with DMD. These results suggest Ca ion-induced hypermetabolic reactions are also present in dystrophinopathy, which have been assumed as core syndromes of the classical (gene-defined) MH. However, question whether the abnormal Ca ion is from the extracellular or intracellular stores is still unclear. Circumstancial evidences suggest that the Ca-induced Ca release (CICR) mechanism might also be involved. Endogenous redox modulators such as nitric oxide or reactive oxygen species in the dystrophic muscle might contribute to the perturbed Ca ion homeostasis.
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PMID:[Malignant hyperthermia-like reactions in Duchenne or Becker muscular dystrophy: review and hypothesis]. 1832 2

The purpose of this study was to examine the prevalence and characteristics of pain in children with Duchenne (DMD) or Becker (BMD) muscular dystrophy, including the nature of disagreements concerning pain symptoms among children, parents, and physicians, and limitations in daily activities. Male children (age 8-18 y, n=53) and parents (n=53) completed questionnaires assessing pain intensity (visual analogue scale), pain frequency (Likert scale [LS]), pain duration (LS), emotional distress due to pain (LS), and pain location (body outline markings). The Child Activity Limitations Interview was also completed by both raters to assess daily activities that are limited by recurrent pain. Physicians completed a form indicating medical history and pain symptoms. The majority of children with DMD (mean age 13 y 11 mo [SD 3.38]; range 8-18 y) or BMD (mean 14 y 10 mo [SD 1.48]; range 12-17 y) were non-ambulatory (79 and 50% respectively) and experienced pain according to self (54-80%) and parent reports (70-90%). Pain typically occurred at least once per week and was of mild to moderate intensity. Most children experienced pain for less than a few hours and little to moderate levels of emotional distress due to pain. Pain occurred in the lower back, spine, and legs, and was described as 'aching'. Children and parents indicated significantly more intense pain than the physician. Actual agreement between parent and child report on pain symptoms was poor to fair. Pain is a common occurrence in children with DMD or BMD, yet may be under-recognized. Pain assessment needs to be a standard part of care and may identify difficulties faced by these children to be targeted by interventions.
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PMID:Pain and activity limitations in children with Duchenne or Becker muscular dystrophy. 1861 Dec 7

A case of a 35-year old female with a history of proximal weakness in lower limbs and bulkiness of both calves manifesting before ten years of age was reported. Clinical findings were suggestive of muscular dystrophy. Genetic analysis using polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) and direct sequencing revealed several point mutations, which account for dystrophin dysfunction and DMD type pathogenesis.
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PMID:A case of manifesting carrier with DMD phenotype. 2036 12

Duchenne (DMD) and golden retriever (GRMD) muscular dystrophy are caused by genetic mutations in the dystrophin gene and afflict striated muscles. We investigated systemic gene delivery in 4-day-old GRMD dogs given a single intravenous injection of an AAV9 vector (1.5 x 10(14) vector genomes/kg) carrying a human codon-optimized human mini-dystrophin gene under control of the cytomegalovirus (CMV) promoter. One of the three treated dogs was euthanized 9 days later due to pre-existing conditions. Scattered mini-dystrophin-positive myofibers were seen by immunofluorescent (IF) staining in numerous muscles. At the end of the 16-week study, the other two dogs showed generalized muscle expression of mini-dystrophin in ~15% to nearly 100% of myofibers. Western blot and vector DNA quantitative PCR results agreed with the IF data. Delayed growth and pelvic limb muscle atrophy and contractures were seen several weeks after vector delivery. T-2 weighted magnetic resonance imaging (MRI) at 8 weeks showed increased signal intensity compatible with inflammation in several pelvic limb muscles. This marked early inflammatory response raised concerns regarding methodology. Use of the ubiquitous CMV promoter, extra-high vector dose, and marked expression of a human protein in canine muscles may have contributed to the pathologic changes seen in the pelvic limbs.
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PMID:Widespread muscle expression of an AAV9 human mini-dystrophin vector after intravenous injection in neonatal dystrophin-deficient dogs. 2051 98

The extraocular muscles (EOM) are spared from pathology in aging and many forms of muscular dystrophy. Despite many studies, this sparing remains an enigma. The EOM have a distinct embryonic lineage compared to somite-derived muscles, and we have shown that they continuously remodel throughout life, maintaining a population of activated satellite cells even in aging. These data suggested the hypothesis that there is a population of myogenic precursor cells (mpcs) in EOM that is different from those in limb, with either elevated numbers of stem cells and/or mpcs with superior proliferative capacity compared to mpcs in limb. Using flow cytometry, EOM and limb muscle mononuclear cells were compared, and a number of differences were seen. Using two different cell isolation methods, EOM have significantly more mpcs per mg muscle than limb skeletal muscle. One specific subpopulation significantly increased in EOM compared to limb was positive for CD34 and negative for Sca-1, M-cadherin, CD31, and CD45. We named these the EOMCD34 cells. Similar percentages of EOMCD34 cells were present in both newborn EOM and limb muscle. They were retained in aged EOM, whereas the population decreased significantly in adult limb muscle and were extremely scarce in aged limb muscle. Most importantly, the percentage of EOMCD34 cells was elevated in the EOM from both the mdx and the mdx/utrophin(-/-) (DKO) mouse models of DMD and extremely scarce in the limb muscles of these mice. In vitro, the EOMCD34 cells had myogenic potential, forming myotubes in differentiation media. After determining a media better able to induce proliferation in these cells, a fusion index was calculated. The cells isolated from EOM had a 40% higher fusion index compared to the same cells isolated from limb muscle. The EOMCD34 cells were resistant to both oxidative stress and mechanical injury. These data support our hypothesis that the EOM may be spared in aging and in muscular dystrophies due to a subpopulation of mpcs, the EOMCD34 cells, that are retained in significantly higher percentages in normal, mdx and DKO mice EOM, appear to be resistant to elevated levels of oxidative stress and toxins, and actively proliferate throughout life. Current studies are focused on further defining the EOMCD34 cell subtype molecularly, with the hopes that this may shed light on a cell type with potential therapeutic use in patients with sarcopenia, cachexia, or muscular dystrophy.
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PMID:Sparing of extraocular muscle in aging and muscular dystrophies: a myogenic precursor cell hypothesis. 2127


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