Expression of dystrophin-associated glycoproteins and utrophin in carriers of Duchenne muscular dystrophy

The expression of dystrophin, the dystrophin-associated proteins and utrophin has been studied immunocytochemically in three young, manifesting carriers of Duchenne muscular dystrophy, aged 3, 5 and 12 yrs, one adult manifesting carrier, aged 60 yrs, and one presumptive carrier with a raised serum creatine kinase, aged 24 yrs, the mother of the 5-yr-old manifesting carrier. The manifesting carriers had variable degrees of weakness; the presumptive carrier had no weakness. Morphological abnormalities were also variable and were most marked in the young manifesting carriers. The three young manifesting carriers and the presumptive carrier had a mosaic pattern of dystrophin-positive and dystrophin-negative fibres. All the dystrophin-associated proteins were reduced in the dystrophin-deficient fibres, giving a similar mosaic pattern to dystrophin. Expression of dystrophin and the dystrophin-associated proteins was normal in the adult manifesting carrier. Utrophin was detected on the sarcolemma of fibres both with and without dystrophin and the dystrophin-associated proteins. Thus, dystrophin and utrophin are co-expressed in several fibres in carriers. The results emphasize the close association between dystrophin and the glycoprotein complex and their role in the pathogenesis of muscle damage. In addition, the presence of utrophin in fibres with greatly reduced glycoproteins suggests that very little of the glycoprotein complex may be required to anchor the amount of utrophin expressed at the sarcolemma in these particular cases.     

Heterogeneity of dystrophin expression in patients with Duchenne and Becker muscular dystrophy

Summary This report documents the results of an integrated biochemical and immunocytochemical investigation into the expression of dystrophin (the protein product of the Duchenne muscular dystrophy gene) in muscle biopsies from 226 patients. It is the first study in which dystrophin has been analysed on blots and on tissue sections in such a large number of patients using the same (monoclonal) antibody. The 140 patients with Xp21 muscular dystrophy who were included in this study represent a continuous spectrum of disease severity and this range was reflected in the heterogeneity of dystrophin expression which was observed with respect to abundance, size and the pattern of tissue localisation. Approximately 40% of biopsies obtained from patients diagnosed as having Duchenne muscular, dystrophy (DMD) contained isolated clearly positive fibres and a further 20% had very weak labelling on a large number of fibres. Biopsies from patients with Becker muscular dystrophy (BMD) showed labelling patterns which varied from weak labelling on the majority of fibres to clear labelling on all fibres. Typically, however, there was inter-and intra-fibre variation in labelling intensity. Approximately 85% of the 52 BMD and 54 DMD patients who had unequivocal labelling on blots demonstrated a protein of abnormal size. The remaining 15% had a protein of normal size but reduced abundance. Overall, the estimated abundance of dystrophin correlated well with clinical assessments of the disease severity expressed in patients: We conclude that dystrophin analysis is an essential and dependable technique for the differential diagnosis of patients with Xp21 muscular dystrophy.Supported by the University of Newcastle-upon-Tyne Research Committee, the Muscular Dystropy Group of Great Britain and the Medical Research Council     

Expression of utrophin (dystrophin-related protein) and dystrophin-associated glycoproteins in muscles from patients with Duchenne muscular dystrophy

We examined whether the dystrophin-associated glycoprotein complex (GPC), which serves to fix dystrophin to cell membranes, is present at the sarcolemma in Duchenne muscular dystrophy (DMD) muscles using an immunohistochemical method. Antibodies against 50DAG (A2) and 43DAG (A3a). the components of GPC, were used for the detection of GPC. We found that, although the amount of GPC was reduced in DMD muscles where ulrophin but not dystrophin was distinctly present, 43DAG (A3a) was fairly heavily and 50DAG (A2) was lightly but distinctly stained on the cell surfaces. It is likely that the capability of utrophin to preserve 50DAG (A2) is less than that of dystrophin, although utrophin has been reported to bind to GPC. We also found that 43DAG (A3a) but not 50DAG (A2) was detected in the peripheral nerves where utrophin was detected. Therefore, it is likely that 43DAG (A3a) is essential for the fixation of utrophin to cell membranes, as in the case of dystrophin. 50DAG (A2) may play other important roles in the pathogenesis of DMD. © 1994 John Wiley & Sons, Inc.     

Detection of deletions within the dystrophin gene in Polish families affected with Duchenne/Becker muscular dystrophy

DNA analysis was performed in 190 cases of Duchenne and Becker muscular dystrophies (DMD/BMD), including 150 cases with DMD and 40 cases with BMD, using Southern blotting and PCR multiplex techniques with application of 25 pairs of primers. Deletions in the overall material were found in 109 cases: 81 (54%) in patients with DMD and 28 (70%) in patients with BMD. All the deletions in DMD were out of frame with the exception of two cases, whereas in BMD all the deletions but two were in frame. Junction fragments were detected in 12 cases of DMD. In five cases duplications were found: four in patients with DMD and one in a patient with BMD.     

假肥大型肌营养不良症40例临床特征与基因诊断

目的对假肥大型肌营养不良症（DMD／BMD）患者总结其临床特征并进行基因诊断,以提高对DMD／BMD疾病的认识及诊断水平。方法对40例DMD／BMD患者临床特征进行总结包括临床表现、血清肌酶、肌电图及肌肉活检等,并应用18对引物多重PCR的方法对其进行Dystrophin基因缺失诊断。结果DMD／BMD为儿童期隐匿起病、缓慢进行性加重,以肌无力和肌萎缩为特点,主要选择性侵犯四肢近端肌、盆带肌、腰带肌等,可有肌肉假性肥大,有些患者可有智能减退和心肌损害;血清肌酶水平异常增高,肌电图示肌源性损害,肌肉活检呈肌病特征。基因诊断27例存在外显子片段缺失,13例未检测到缺失。结论识别DMD／BMD的临床特征有助于提高对其的诊断水平,多重PCR作为一种简便快速的诊断方法可对DMD／BMD患者进行基因诊断。     

Duchenne/Becker muscular dystrophy: A report on clinical,biochemical, and genetic study in Gujarat population,India

Objective:

In India, various groups have studied different regions to find out deletion pattern of dystrophin gene. We have investigated its deletion pattern among Duchenne/Becker muscular dystrophy (D/BMD) patients across Gujarat. Moreover, in this study we also correlate the same with reading frame rule. However, we too consider various clinicopathological features to establish as adjunct indices when deletion detection fails.

Materials and Methods:

In this pilot study, a total of 88 D/BMD patients consulting at our centers in Gujarat, India were included. All patients were reviewed on basis of their clinical characteristics, tested by three primer sets of 10-plex, 9-plex, and 7-plex polymerase chain reaction (PCR) for genetic analysis; whereas, biochemical indices were measured using automated biochemical analyzers.

Results:

The diagnosis of D/BMD was confirmed by multiplex-PCR (M-PCR) in D/BMD patients. A number of 65 (73.86%) out of 88 patients showed deletion in dystrophin gene. The exon 50 (58.46%) was the most frequent deletion found in our study. The mean age of onset of DMD and BMD was 4.09 ± 0.15 and 7.14 ± 0.55 years, respectively. In patients, mean creatine phosphokinase (CPK), lactate dehydrogenase (LDH), and myoglobin levels were elevated significantly (P < 0.05) in comparison to controls. Addition to CPK, LDH and myoglobin are good adjunct when deletion detection failed. These data are further in accordance with world literature when correlated with frame rule.

Conclusion:

The analysis has been carried out for the first time for a total of 88 D/BMD patients particularly from Gujarat, India. More research is essential to elucidate specific mutation pattern in association with management and therapies of proband.     

Expression of utrophin (dystrophin–related protein) during regeneration and maturation of skeletal muscle in canine X–linked muscular dystrophy

The regulation of utrophin, the autosomal homologue of dystrophin, has been studied in the canine X–linked model of Duchenne muscular dystrophy. Dystrophic muscle has been shown to exhibit abnormal sarcolemmal expression of utrophin, in addition to the normal expression at the neuromuscular junction, in peripheral nerves, vascular tissues and regenerating fibres. To establish whether this abnormal presence of utrophin in dystrophic muscle is a consequence of continued expression following regeneration, or is attributable to a disease related up–regulation, the expression of utrophin was compared immunocytochemically with that of dystrophin, β–spectrin and neonatal myosin in regenerating normal and dystrophic canine muscle, following necrosis induced by the injection of venom from the snake Notechis scutatis. In normal regenerating muscle, sarcolemmal utrophin and dystrophin were detected concomitantly from 2–3 d post–injection, prior to the expression of β–spectrin. Down–regulation of utrophin was apparent in some fibres from 7 d, and it was no longer present on the extra–junctional sarcolemma by 14 d. Neonatal myosin was still present in all fibres at this stage, but dystrophin and β–spectrin had been fully restored. In dystrophic regenerating muscle, downregulation of utrophin occurred from 7 d, although it persisted on some fibres until 28 d, longer than in normal muscle. At 42 d, however, utrophin in dystrophic muscle was only detected in a population of small fibres thought to represent a second cycle of regeneration, with no immunolabelling of mature fibres. The results show that most utrophin is down–regulated in regenerating dystrophic fibres, prior to neonatal myosin, thus abnormal sarcolemmal expression of utrophin in dystrophic muscle is unlikely to be a continuation of the maturational process. Persistence of both utrophin and neonatal myosin, however, suggest a delay in the maturation of dystrophic muscle. In addition, a second cycle of degeneration and regeneration in dystrophic muscle does not occur whilst utrophin is still present, suggesting it may have a protective role against fibre damage and necrosis.     

肌营养不良蛋白在假肥大肌营养不良症肌组织中的表达研究

目的检测假肥大肌营养不良症肌组织中肌营养不良蛋白（ｄｙｓｔｒｏｐｈｉｎ）的表达。方法用针对ｄｙｓｔｒｏｐｈｉｎ棒状区第１５～１８重复区域的多克隆抗血清Ａｎｔｉ５～７，对２２例Ｄｕｃｈｅｎｎｅ型（ＤＭＤ）和４例Ｂｅｃｋｅｒ型肌营养不良症（ＢＭＤ）患者及１１例无神经肌肉疾病的急诊外伤患者（作为对照）的肌组织进行免疫组化分析。结果在对照组肌细胞中ｄｙｓｔｒｏｐｈｉｎ存在着可达检测水平的表达，并特异地定位于肌细胞膜上。１９例ＤＭＤ没有可达检测水平的ｄｙｓｔｒｏｐｈｉｎ表达，３例ＤＭＤ存在着ｄｙｓｔｒｏｐｈｉｎ表达。４例ＢＭＤ肌细胞膜上则呈现出斑片状、不连续ｄｙｓｔｒｏｐｈｉｎ弱阳性表达。结论ｄｙｓ－ｔｒｏｐｈｉｎ的缺乏是造成ＤＭＤ／ＢＭＤ表型的基本生化因素，此方法为临床上对ＤＭＤ／ＢＭＤ患者作出确诊提供了直接的特异生化测试指标。     

Cardiac involvement in Fukuyama muscular dystrophy is less severe than in Duchenne muscular dystrophy

Background

One of the main complications in patients with muscular dystrophies is cardiac dysfunction. The literature on cardiac involvement in patients with Fukuyama congenital muscular dystrophy (FCMD) is limited.

Long-term electrical stimulation of muscles in children with Duchenne and Becker muscular dystrophy.

Nine children suffering from progressive muscular dystrophy (7 Duchenne and 2 Becker) were included in a program of low-frequency electrical stimulation (LFES) of the right tibialis anterior (TA) muscle. Muscle strength and muscle fatigue were estimated by measuring torques in the ankle during attempts of maximal voluntary contraction (MVC) in the direction of dorsal flexion of the foot and during electrically evoked contractions (EEC). No important increase in the strength of the stimulated muscles was noticed in 4 boys whose muscles were stimulated for 3 months. The muscles of 5 boys who were subjected to electrical stimulation for 9 months showed an improvement; 6 measurements made during the stimulation program revealed that changes of torques in the ankle of the right stimulated extremity were significantly different (P less than 0.001) from the changes of torques in the ankle of the left nonstimulated extremity.     

Molecular deletion patterns in Duchenne and Becker muscular dystrophy patients from KwaZulu Natal

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.     

Parental attitudes toward newborn screening for Duchenne/Becker muscular dystrophy and spinal muscular atrophy

Introduction: Disease inclusion in the newborn screening (NBS) panel should consider the opinions of those most affected by the outcome of screening. We assessed the level and factors that affect parent attitudes regarding NBS panel inclusion of Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), and spinal muscular atrophy (SMA). Methods: The attitudes toward NBS for DMD, BMD, and SMA were surveyed and compared for 2 categories of parents, those with children affected with DMD, BMD, or SMA and expectant parents unselected for known family medical history. Results: The level of support for NBS for DMD, BMD, and SMA was 95.9% among parents of children with DMD, BMD, or SMA and 92.6% among expectant parents. Conclusions: There was strong support for NBS for DMD, BMD, and SMA in both groups of parents. Given advances in diagnostics and promising therapeutic approaches, discussion of inclusion in NBS should continue. Muscle Nerve 49 : 822–828, 2014     

Inefficient dystrophin expression after cord blood transplantation in Duchenne muscular dystrophy

We report a boy who received two allogeneic stem cell transplantations from umbilical cord donors to treat chronic granulomatous disease (CGD). The CGD was cured after the second transplantation, but 2.5 years later he was diagnosed with Duchenne muscular dystrophy (DMD). Examinations of his DNA, muscle tissue, and myoblast cultures derived from muscle tissue were performed to determine whether any donor dystrophin was being expressed. The boy was found to have a large‐scale deletion on the X chromosome that spanned the loci for CYBB and DMD. The absence of dystrophin led to muscle histology characteristic of DMD. Analysis of myofibers demonstrated no definite donor cell engraftment. This case suggests that umbilical cord–derived hematopoietic stem cell transplantation will not be efficacious in the therapy of DMD without additional interventions that induce engraftment of donor cells in skeletal muscle. Muscle Nerve, 2010     

Becker and limb-girdle muscular dystrophy associated with pituitary dwarfism

Summary In 1981 a report appeared of a patient with Duchenne muscular dystrophy associated with dwarfism caused by growth hormone deficiency, in whom the muscular disease was unusually benign. The authors suggested that the benign course might be related to the growth hormone deficiency and dwarfism. Other authors later supported this idea, having observed that in dystrophic mice and hamsters with congenital and experimentally induced pituitary dwarfism, respectively, pathological expressions of the dystrophy were markedly reduced. In this paper one case of Becker and one of limb-girdle dystrophy, each associated with short stature and growth hormone deficiency are described. In these cases the disease did not have a particularly benign course. It is concluded that caution is necessary, at least in certain cases, before an association between reduced muscular growth and the dystrophic process can be assumed.     

Gene expression profiling of Duchenne muscular dystrophy skeletal muscle

The primary cause of Duchenne muscular dystrophy (DMD) is a mutation in the dystrophin gene, leading to absence of the corresponding protein, disruption of the dystrophin-associated protein complex, and substantial changes in skeletal muscle pathology. Although the primary defect is known and the histological pathology well documented, the underlying molecular pathways remain in question. To clarify these pathways, we used expression microarrays to compare individual gene expression profiles for skeletal muscle biopsies from DMD patients and unaffected controls. We have previously published expression data for the 12,500 known genes and full-length expressed sequence tags (ESTs) on the Affymetrix HG-U95Av2 chips. Here we present comparative expression analysis of the 50,000 EST clusters represented on the remainder of the Affymetrix HG-U95 set. Individual expression profiles were generated for biopsies from 10 DMD patients and 10 unaffected control patients. Two methods of statistical analysis were used to interpret the resulting data (t-test analysis to determine the statistical significance of differential expression and geometric fold change analysis to determine the extent of differential expression). These analyses identified 183 probe sets (59 of which represent known genes) that differ significantly in expression level between unaffected and disease muscle. This study adds to our knowledge of the molecular pathways that are altered in the dystrophic state. In particular, it suggests that signaling pathways might be substantially involved in the disease process. It also highlights a large number of unknown genes whose expression is altered and whose identity therefore becomes important in understanding the pathogenesis of muscular dystrophy. Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.     

IQ, prognosis and Duchenne muscular dystrophy

The verbal scales (VS-IQ) of the IQs of 25 boys with Duchenne muscular dystrophy, the total population in Western Australia older than five yrs, were recorded. All the results of those 20 yrs of age and older lay within the normal range. The mean VS-IQ of those less than 20 yrs and less than 18 yrs is compared with the mean VS-IQ of those 20 yrs and older, and 18 yrs and older, respectively. The differences between the groups are statistically significant, and it is postulated that an active management programme has revealed a population of boys with normal intelligence who have an increased chance of prolonged survival.     

自噬在Duchenne型肌营养不良中的研究

目的检测Duchenne型肌营养不良症(DMD)患者骨骼肌中LC3和p62的表达情况,分析自噬在DMD骨骼肌细胞坏死中的作用。方法收集2008年1月~2015年5月在我院就诊的病理确诊为DMD的患者(DMD组,81例),另以怀疑为肌病,但肌肉病理未见明显病变者为对照组(6例)。所有入选者均行心肌酶学、肌电图、骨骼肌活检常规组织学和酶学染色、抗dystrophin-N,-C,-R和抗dysferlin免疫组织化学染色。检测其中6例DMD患者及对照组骨骼肌中LC3和p62的表达。结果 81例DMD患者均为男性,起病年龄(4.60±2.35)岁,首发症状多以双下肢起病为主。血清肌酸激酶值的高峰出现在患者年龄的6~8岁,随着肌细胞明显坏死,肌酸激酶水平下降,但仍高于正常。在DMD患者骨骼肌中,组织病理均示典型肌营养不良改变。半定量Western blot提示DMD患者骨骼肌中LC3-II的表达降低,而p62表达显著升高。结论自噬功能障碍可能参与了DMD骨骼肌细胞坏死的病理生理过程。     

Dystrophin-associated protein abnormalities in dystrophin-deficient muscle fibers from symptomatic and asymptomatic Duchenne/Becker muscular dystrophy carriers

The absence of dystrophin in muscle fibers is associated with a major reduction in dystrophin-associated proteins (DAPs) and disruption of the linkage between the subsarcolemmal cytoskeleton and the extracellular matrix. We investigated the expression of the DAPs β-dystroglycan, α-sarcoglycan, γ-sarcoglycan and syntrophin as well as utrophin in the muscles of 13 Duchenne muscular dystrophy (DMD) carriers (with variable percentages of dystrophin-deficient fibers and with a range of clinical symptoms), 2 Becker muscular dystrophy (BMD) carriers (expressing a highly truncated protein in some fibers), 2 girls with a DMD-like phenotype, and 11 BMD carriers with almost normal dystrophin expression (reduced or patchy distribution in a few fibers only and rare dystrophin-deficient fibers). DAPs were highly reduced in all fibers lacking dystrophin in the DMD carriers, but were almost normal in the dystrophin-deficient fibers of the 2 BMD carriers with highly truncated dystrophin. In the 11 BMD carriers with nearly normal dystrophin, the few fibers with reduced or patchy dystrophin immunostaining also showed reduced DAP expression in correlation with dystrophin expression. Immunoblot for β-dystroglycan and α-sarcoglycan confirmed the immunohistochemical findings. Utrophin expression was slightly increased in a proportion of fibers in the DMD and BMD carriers with dystrophin mosaicism. We found no correlation between utrophin expression and DAP expression. We conclude that absence or reduction of dystrophin in muscle fibers of DMD and BMD carriers causes a reduction of DAPs in the same fibers, as observed in DMD and BMD patients, while utrophin does not seem to play a role in DAP expression in adult muscle. Received: 11 January 1996 / Revised, accepted: 16 April 1996     

Scoliosis in Duchenne muscular dystrophy (DMD)

Scoliosis is a frequent complication in the non-ambulant patient with Duchenne muscular dystrophy (DMD). Weakness of the paraspinal muscles leads to trunk and body positional changes facilitating the development of a progressive collapsing scoliosis which inevitably interferes with comfortable sitting and may exacerbate deteriorating respiratory function. The recommended international standard of care for management of DMD includes strategies to prolong ambulation which may delay the onset of scoliosis. In the non-ambulant child there should be regular monitoring for scoliosis and, when present, surgical treatment should undertaken at an early stage. Careful multi-disciplinary pre-operative assessment and peri-operative care are essential.