免疫荧光检测抗肌萎缩蛋白诊断肌营养不良症的临床应用

目的 采用免疫荧光技术对Duchenne型肌营养不良症（Duchenne muscular dystrophy,DMD),Becker型肌营养不良症（Becker muscular dystrophy,BMD)，面肩肱型肌营养不良症（facioscapulohumeral muscular dystrophy,FSHD)以及神经性肌萎缩患者骨骼肌细胞膜的dystrophin蛋白进行检测，为临床诊断、分类肌营养不良症提供简便的实验方法。方法 对47例患者选择3种dystrophin 的鼠抗单克隆抗体、羊抗和兔抗多克隆抗体，分别进行免疫荧光技术检测。结果 16例DMD患者均为阴性染色；11例BMD患者为弱阳性染色；10例FSHD和10例神经性肌萎缩患者均为阳性染色。结论 检测肌营养不良症患者骨骼肌膜dystrophin蛋白，有助于肌营养不良症的临床诊断和分型。     

T and B lymphocyte depletion has a marked effect on the fibrosis of dystrophic skeletal muscles in the scid/mdx mouse

Abnormal connective tissue proliferation following muscle degeneration is a major pathological feature of Duchenne muscular dystrophy (DMD), a genetic myopathy due to lack of the sarcolemmal dystrophin protein. Since this fibrotic proliferation is likely to be a major obstacle to the efficacy of future therapies, research is needed to understand and prevent the fibrotic process in order to develop an effective treatment. Murine muscular dystrophy (mdx) is genetically homologous to DMD, and histopatological alterations are comparable to those of the muscles of patients with DMD. To investigate the development of fibrosis, we bred the mdx mouse with the scid immunodepressed mouse and analysed fibrosis histologically; we used ELISA analysis to determine TGF-beta1 expression. Significant reduction of fibrosis and TGF-beta1 expression was found in the muscles of the scid/mdx mice. However, we observed similar centrally located nuclei, necrosis, muscle degeneration and muscle force compared to the mdx animals. These data demonstrate a correlation between the absence of B and T lymphocytes and loss of fibrosis accompanied by reduction of TGF-beta1, suggesting the importance of modulation of the immune system in DMD.     

The effects of glucocorticoid therapy on the inflammatory and dendritic cells in muscular dystrophies

Various clinical trials have documented the therapeutic benefit of glucocorticoids (GCs) in enhancing muscle strength and slowing disease progression of Duchenne and Becker muscular dystrophies (DMD/BMD). We hypothesized that GCs may have relevance to the differential anti-inflammatory effect on mononuclear inflammatory cells (MICs) and Dendritic cells (DCs) infiltrating the dystrophic muscles. In this prospective study, two muscle biopsies were obtained (before and after 6-month prednisone therapy) from 30 patients with dystrophies (DMD = 18; BMD = 6; and limb girdle muscular dystrophies (LGMD) = 6). MICs and DCs infiltrating the muscles were examined using mouse monoclonal antibodies and immunoperoxidase staining methods. Muscle strength was evaluated monthly by manual testing, motor ability and timed tests. Prednisone therapy was associated with: (i) functional improvement of overall motor disability, in upper limbs of DMD (P < 0.001) and BMD (P < 0.01) and lower limbs of DMD (P < 0.001) and BMD (P < 0.05); (ii) histological improvement such as fibre size variation (DMD, P < 0.01; BMD, P < 0.05), internalization of nuclei (DMD, P < 0.05), degeneration and necrosis (DMD and BMD, P < 0.01), regeneration (DMD, P < 0.001; BMD, P < 0.01) and endomysial connective tissue proliferation (DMD, P < 0.01; BMD, P < 0.05) and (iii) reduction of total MICs (P < 0.01) and DCs (P < 0.01). There was a positive correlation between the degree of improvement in overall motor disability and reduction of DCs numbers (In upper limbs; r = 0.638, P < 0.01 for DMD and r = 0.725, P < 0.01 for BMD, in Lower limbs; r = 0.547, P < 0.05 for DMD and r = 0.576, P < 0.05 for BMD). Such improvements and changes of MICs/DCs were absent in LGMD. In DMD/BMD, prednisone therapeutic effect was associated with reduced MICs and DCs numbers. Whether this therapeutic effect reflects targeting of the deleterious immune response produced by these cells mandates further investigations.     

Serum CK-MB activity in progressive muscular dystrophy: Is it of nosologic value?

Serum creatine-kinase (CK) isoenzyme MB was measured in 53 patients affected by different types of myopathies (20 with Duchenne muscular dystrophy (DMD), eight with the Becker form (BMD), ten with the limb-girdle form (LGMD), six with the facioscapulohumeral form (FSH), and nine affected by polymyositis and in 21 normal control subjects). The aim of this study was to compare each group with the control individuals and to assess the nosologic value of CK-MB activity among some clinically similar dystrophies, which may have an important application for genetic counseling. A statistically significant increased CK-MB activity was found only in the Duchenne and Becker patients when compared with control persons (p < 0.05). When the different groups of patients were compared among themselves, no significant difference was found between DMD and BMD or LGMD and polymyositis. However, a significant difference was found between BMD and LGMD. Based on these data, it is possible, through discriminant analysis, to estimate the relative biochemical probability of an isolated male patient belonging to either group.     

女性假肥大型肌营养不良症家系的临床病理和基因分析

目的研究女性假肥大型肌营养不良症(Duchenne muscular dystrophy，DMD)患者的临床特征，探讨其发病机理。方法对一个女性DMD家系患者的临床表现进行跟踪随访，并作肌肉组织的免疫组化检测及基因分析。结果该家系的DMD患儿临床表现及辅助检查均符合典型的DMD特征。先证者母亲的临床特点类似良性假性肥大型肌营养不良(Becker muscular dystrophy，BMD)，肌肉免疫荧光分析提示dystrophin蛋白染色阳性的纤维与阴性纤维并存。该家系的dystrophin基因分析为非缺失型。先证者母亲核型分析正常。结论本家系中的39岁女性具有类似BMD的临床表现，病理检查及图像分析提示dystrophin蛋白为正常的1／3。此例女性患者的核型分析正常，故倾斜的X染色体模式为其可能的机理。     

Epidemiology of dystrophinopathies in North-West Tuscany: a molecular genetics-based revisitation

A molecular genetics-based epidemiological investigation was carried out in 1997 in the territory of North-West Tuscany, central Italy, to calculate incidence and prevalence rates of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). Results were compared with a previous epidemiological study conducted in the same area in 1981, in the pre-dystrophin era. Routine adoption of methods of molecular diagnosis determined an increase in prevalence of BMD from 1.06 x 10(-5) to 2.42 x 10(-5) inhabitants, while cumulative incidence of DMD was markedly decreased from 23.12 x 10(-5) during the period 1965-1976 to 10.71 x 10(-5) male live births during the period 1977 1994. The combined reduction of DMD/BMD diagnostic error rate and familial recurrence could explain these results, providing the bases for a consistent redefinition of dystrophinopathy carrier frequency in the area considered.     

PGD for dystrophin gene deletions using fluorescence in situ hybridization

Duchenne muscular dystrophy and Becker muscular dystrophy (DMD and BMD) are caused by mutations in the dystrophin gene (Xp21). In two-thirds of DMD/BMD cases, the mutation is a large deletion of one or several exons. We have established PGD for DMD/BMD using interphase fluorescence in situ hybridization (FISH) analysis on single nuclei from blastomeres for the detection of deletions of specific exons in the dystrophin gene. We performed PGD for two carrier females; one had a deletion of exons 45-50 (DMD), and the other had a deletion of exons 45-48 (BMD). An exon 45-specific probe was used in combination with probes for the X and Y centromeres. Using this straightforward approach, we can distinguish affected and unaffected male embryos as well as carrier female and normal female embryos. Three cycles were performed for each patient, which resulted in a pregnancy and the birth of a healthy girl. To the best of our knowledge, this approach for PGD has not been previously reported. The use of interphase FISH is an attractive alternative to sexing or PCR-based mutation detection for PGD patients with known deletions of the dystrophin gene.     

Molecular deletions in the Duchenne/Becker muscular dystrophy gene

To gain further information relating to the frequency, position and size of DNA deletions in the Duchenne/Becker muscular dystrophy (D/BMD) gene region, and to detect any correlation of these deletions with phenotype, a large clinic-based population of DMD and BMD patients has been investigated using 13 cloned intragenic sequences. Our of 263 separate patients studied, 75 showed a deletion of at least one locus (28.5%). These represented 25.6% (55/215) of DMD patients and 41.7% (20/48) of BMD patients, suggesting that the milder phenotype is more often likely to be due to a deletion. The deletions range from 6 kilobases (kb) to greater than 1000 kb in size. The distribution of deletions across the gene region shows at least one region (detected by P20) prone to deletion mutations in both DMD and BMD patients. There is no simple correlation of position or extent of deletions with DMD or BMD, although deletion of a specific region towards the 5' end of the gene may be more often associated with a milder phenotype. Apparently similar deletions can give rise to phenotypes differing significantly in severity, presumably indicating further complexities in the molecular or cellular pathology.     

Duchenne/Becker muscular dystrophy in the family: have potential carriers been tested at a molecular level?

Duchenne muscular dystrophy (DMD) is the most common inherited neuromuscular disease. After identification of the mutation in the index patient, family members can be reliably investigated. Carriers should be informed about their risk of having offspring with the disease and about their own risk for cardiomyopathy for which regular cardiac surveillance is recommended. In a small country like the Netherlands with well-organized genetic services, one would expect that most DMD families are adequately informed about the above mentioned risks for carriers. We have investigated whether women at risk had been tested at a molecular level. In the national Duchenne/Becker database 311 DMD and 99 Becker muscular dystrophy (BMD) patients had been registered up to 1 July 2009. These patients were asked to give information about the number of sisters and maternal aunts of the DMD/BMD patient and anything that was known about their genetic status and that of the mother. This information was compared with the information known at the genetic laboratory. Thirty-five of 104 adult sisters/maternal aunts of DMD patients with a 50% risk of being a carrier and 45 of 148 adult women with a 4.3% risk because of germ line mosaicism for DMD had not been tested by DNA analysis. Our study indicates that about one third of the potential carriers have not been tested. Given the possible far-reaching clinical consequences of being a carrier, further studies are needed to investigate the reasons why potential female carriers have not been tested.     

Clinical features of patients with Becker muscular dystrophy and deletions of the rod domain of dystrophin geneCSCD

Objective: To explore the clinical features of patients carrying deletions of the rod domain of the dystrophin gene. Methods: Clinical data of 12 Chinese patients with Becker muscular dystrophy (BMD) and such deletions was reviewed. Results: Most patients complained of muscle weakness of lower limbs. Two patients had muscle cramps, one had increased creatine kinase (CK) level, and one had dilated cardiomyopathy. Conclusion: Compared with DMD, the clinical features of BMD are much more variable, particularly for those carrying deletions of the rod domain of the dystrophin gene. Muscular weakness may not be the sole complaint of BMD. The diagnosis of BMD cannot be excluded by moderately elevated CK. For male patients with dilated cardiomyopathy, the possibility of BMD should be considered. © 2018 West China University of Medical Sciences. All rights reserved.     

Deletions, duplications and novel restriction fragment length polymorphism in Duchenne and Becker muscular dystrophies

To determine the mutations of Southern Chinese with Duchenne and Becker muscular dystrophies (DMD, BMD), we analysed 28 DMD and BMD patients in 24 unrelated families for intragenic deletions and duplications by using cDNA probes covering the entire 14 kb of the dystrophin gene. Deletions were detected in nine unrelated patients (seven patients by probe 8 and two by probe 2b-3). Gene duplications were detected by probe 1-2a in two patients with the duplication bands confirmed in both Hind III and Bgl II digests and by densitometry. A third patient was found to have a junction fragment with Bgl II and a duplication band with Hind III by probe 5b-7. Therefore 50% of the 24 unrelated families were found to have either deletions or duplications. A previously undescribed restriction fragment length polymorphism (RFLP) was found in one family with probe 5b-7 in Bgl II digests which was found to segregate with the disease phenotype. This new RFLP was not detected in over 70 unrelated X chromosomes we have examined so far, and appeared to be "private" for this family. The presence of this new restriction site may or may not be the mutation responsible for the disease phenotype.     

Detection of partial deletion and partial duplication of dystrophin gene in Japanese patients with Duchenne or Becker muscular dystrophy

Summary The dystrophin gene was analyzed in 59 Japanese patients with Duchenne muscular dystrophy (DMD) from 48 unrelated families, including 11 pairs of siblings, and three patients with Becker muscular dystrophy (BMD) from two unrelated families, including one pair of siblings. The relationship between the type of gene abnormality and clinical symptoms was examined. Twenty-seven of 50 (54.0%) unrelated DMD or BMD patients were found to have partial deletions, and five (10%) appeared to have partial duplications in the dystrophin gene. Nine DMD patients, including three pairs of siblings, showed mental retardation, the existence of which was coincident in each pair of siblings, but deletion of an identical exon was not always related to mental retardation in unrelated patients.     

Exon Deletion Patterns of the Dystrophin Gene in 82 Vietnamese Duchenne/Becker Muscular Dystrophy Patients

Abstract

Duchenne and Becker muscular dystrophies (DMD/BMD) are the most common inherited muscle diseases caused by mutations in the dystrophin gene. The reading frame rule explains the genotype-phenotype relationship in DMD/BMD. In Vietnam, extensive mutation analysis has never been conducted in DMD/BMD. Here, 152 Vietnamese muscular dystrophy patients were examined for dystrophin exon deletion by amplifying 19 deletion-prone exons and deletion ends were confirmed by dystrophin cDNA analysis if necessary. The result was that 82 (54%) patients were found to have exon deletions, thus confirming exact deletion ends. A further result was that 37 patterns of deletion were classified. Deletions of exons 45–50 and 49–52 were the most common patterns identified, numbering six cases each (7.3%). The reading frame rule explained the genotype-phenotype relationship, but not five (6.1%) DMD cases. Each of five patients had deletions of exons 11–27 in common. The applicability of the therapy producing semifunctional in frame mRNA in DMD by inducing skipping of a single exon was examined. Induction of exon 51 skipping was ranked at top priority, since 16 (27%) patients were predicted to have semifunctional mRNA skipping. Exons 45 and 53 were the next ranked, with 12 (20%) and 11 (18%) patients, respectively. The largest deletion database of the dystrophin gene, established in Vietnamese DMD/BMD patients, disclosed a strong indication for exon-skipping therapy.     

DMD exon 1 truncating point mutations: Amelioration of phenotype by alternative translation initiation in exon 6

Mutations in the DMD gene result in two common phenotypes associated with progressive muscle weakness: the more severe Duchenne muscular dystrophy (DMD) and the milder Becker muscular dystrophy (BMD). We have previously identified a nonsense mutation (c.9G>A; p.Trp3X) within the first exon of the DMD gene, encoding the unique N‐terminus of the 427‐kDa muscle isoform of the dystrophin protein. Although this mutation would be expected to result in severe disease, the clinical phenotype is very mild BMD, with ambulation preserved into the seventh decade. We identify the molecular mechanism responsible for the amelioration of disease severity to be initiation of translation at two proximate AUG codons within exon 6. Analysis of large mutational data sets suggests that this may be a general mechanism of phenotypic rescue for point mutations within at least the first two exons of the DMD gene. Our results directly demonstrate, for the first time, the use of alternate translational initiation codons within the DMD gene, and suggest that dystrophin protein lacking amino acids encoded by the first five exons retains significant function. Hum Mutat 0:1–8, 2009. © 2009 Wiley‐Liss, Inc.     

Relatively low proportion of dystrophin gene deletions in Israeli Duchenne and Becker muscular dystrophy patients

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are allelic disorders caused by mutations in the X-linked dystrophin gene. The most common mutations in western populations are deletions that are spread non-randomly throughout the gene. Molecular analysis of the dystrophin gene structure by hybridization of the full length cDNA to Southern blots and by PCR in 62 unrelated Israeli male DMD/BMD patients showed deletions in 23 (37%). This proportion is significantly lower than that found in European and North American populations (55–65%). Seventy-eight percent of the deletions were confined to exons 44–52, half of these to exons 44–45, and the remaining 22% to exons 1 and 19. There was no correlation between the size of the deletion and the severity of the disease. All the deletions causing frameshift resulted in the DMD phenotypes. © 1994 Wiley-Liss, Inc.     

假肥大型肌营养不良症与HLA-A、B、DR等位基因的相关性研究

目的研究南方汉族人群中假肥大型肌营养不良症(Duchenne muscular dystrophy,DMD)患者的HLA-A、B、DR基因多态性,探讨免疫遗传因素在DMD发病机制及肌纤维坏死中的作用。方法采用PCR反向序列特异性寡核苷酸杂交技术(polymerase chain reaction-reverse sequence specific oligonucleotide,PCR-RSSO)和美国骨髓库编码软件(National Marrow Donor Program,NMDP),对113例DMD患者和406名健康对照的HLA-A、B、DR等位基因进行多态性分析。结果DMD组HLA-A24、A30等位基因的频率分别为11.25%和5.46%,与对照组的22.16%和0.87%相比差异有统计学意义(P=0.001,<0.01);DMD组HLA-B13、B15、B61、B62等位基因频率12.26%、16.92%、0.44%、0.44%,与对照组6.76%、1.49%、4.79%、5.05%相比差异有统计学意义(P=0.016,<0.01,0.001);DMD组HLA-DR04、DR07、DR12等位基因频率17.45%、6.40%、19.62%,与对照组10.67%、2.24%、11.92%相比差异有统计学意义(P=0.018,<0.01,0.012)。结论DMD患者HLA等基因表达与正常对照组有显著差异,HLA基因型可能与DMD的肌纤维坏死和发病机制相关。     

Juvenile polymyositis or paediatric muscular dystrophy: a detailed re-analysis of 13 cases

Aims:  There has been much debate about the existence of juvenile polymyositis (JPM) as an entity distinct from muscular dystrophy (MD). The aim of this study was to retrospectively analyse muscle biopsies and clinical features of 13 Australian children given an initial diagnosis of JPM, to determine their clinicopathological, immunohistochemical and molecular characteristics.
Methods and results:  The muscle biopsies on 13 cases were reviewed using detailed morphological and immunoperoxidase studies, with additional protein and molecular analyses, in conjunction with clinical review. Only one case had a true connective tissue disease inflammatory myopathy. Twelve (92.3%) cases with an initial diagnosis of JPM were found on clinical, pathological and molecular review to be MD.
Conclusions:  Inflammatory changes in apparently sporadic juvenile myopathies should prompt consideration of an early presentation of MD. Detailed analysis of muscle histopathology, specifically the detection of subsarcolemmal blebbing, isolated fibre degeneration occurring independent of inflammatory infiltrates, patchy clustered major histocompatibility complex-I expression and a CD68+/CD3+ perimysial infiltrate, assists in the diagnosis of early MD. Specific protein and gene analysis adds support to the pathological diagnosis of dystrophy. This series adds weight to suggestions that JPM may not represent a discrete clinical or pathological entity.     

假肥大型肌营养不良症基因诊断及遗传分析

目的对假肥大型肌营养不良症（DMD／BMD）患者进行基因诊断并对家系进行遗传分析,以提高对DMD／BMD的基因诊断水平及有效的遗传咨询。方法对40例DMD／BMD患者应用18对引物多重PCR技术进行Dystrophin基因缺失诊断,收集完整家系资料进行遗传分析以判断致病基因携带者及评估风险。结果40例DMD／BMD患者基因诊断有27例至少存在一个外显子片段缺失（67．5％）,13例未检测到缺失（32．5％）。通过对家系的遗传分析判断出致病基因携带者。结论多重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;对风险家系进行遗传分析、判断致病基因携带者以进行有效的遗传咨询,进而控制遗传病。