荧光原位杂交技术在检测假性肥大型肌营养不良症缺失型携带者中的应用

目的:应用荧光原位杂交(FISH)筛查技术检测假性肥大型肌营养不良症(DMD/BMD)缺失型携带者。方法:以外显子特异Cosmid DNA为探针(含18个外显子),采用中期和间期单色FISH技术,对9例正常男、女性及来自不同缺失型DMD/BMD家系的5例女性外周血标本、来自健康孕妇的2例羊水和2例绒毛标本进行分析。结果:72～100％外周血淋巴细胞中期相或间期核、60～70％羊水细胞间期核、95～99％绒毛细胞间期核显示预期信号。FISH检出1名、排除2名缺失型携带者。结论:充分利用FISH技术优点,结合现有其它技术,可有效筛查DMD/BMD缺失型携带者,并为女性胎儿DMD/BMD缺失型携带者产前诊断奠定基础。     

A novel and simple method for genotyping the mdx mouse using high‐resolution melt polymerase chain reaction

The mdx mouse mutation arises from a C‐to‐T point mutation, which terminates the translation of dystrophin and results in the loss of a functional dystrophin protein. mdx mice are used widely in studies of the role of dystrophin and of potential treatments for Duchenne muscular dystrophy, thus accurate genotyping is essential. Current methods require labor‐intensive efforts and can often lead to misconstrued results. This study describes a simple and highly reliable, sensitive, and user‐friendly, high‐resolution melt (HRM) assay that is able to utilize DNA obtained from a variety of sources in order to genotype the known sequence variant of the mdx mouse. Muscle Nerve 39: 603–608, 2009     

Dystrophin基因缺失检测微阵列构建及应用中技术优化的研究

目的建立Dystrophin基因缺失检测的DNA微阵列技术，并优化其构建及应用中的关键技术条件。方法提取样品基因组DNA，Klenow法随机引物扩增同时FITC荧光标记，并比较生物素标记法。将FITC荧光标记的核酸点样于不同方法活化处理的玻片上并用不同浓度的盐溶液洗脱，测试对DNA固定效率的影响。以分子克隆法获得的Dystrophin基因18个易缺失外显子cDNA片段为探针、APES和poly-Lys联合处理的玻片为基片，制备简易微阵列。分别与DMD/BMD患者及健康人荧光标记的基因组DNA杂交，检测微阵列的质量和评估结果的可靠性。结果APES和poly-Lys联合处理的玻片对核酸固定效率最高，核酸在洗涤过程中的脱落程度随洗液盐浓度的增加而增大；FITC标记步骤简便，生物素标记相对烦琐，但生物素标记杂交后的荧光强度明显高于FITC标记；微阵列杂交信号信噪比较好，各种对照结果满意，检测结果与PCR一致。结论优化了DNA微阵列构建及应用过程中基片表面活化、探针固定、靶基因DNA扩增标记、杂交条件、杂交信号检测分析等方法，为更好地应用微阵列进行Dystrophin基因诊断奠定基础。     

Muscular dystrophy

Muscular dystrophy is a group of genetically determined muscular disorders marked by progressive wasting and weakness of the skeletal muscle, but which often affect cardiac and smooth muscles or other tissues. The patterns of inheritance are either dominant or recessive although the gene may be defective because of a new mutation. Growing evidence revealed the marked heterogeneity of the muscle disorders, and considerable numbers of Japanese scientists and physicians have contributed to the research progress in muscular dystrophy. Among these the discovery of an increased serum creatine kinase activity in muscular dystrophy opened the way for the most reliable laboratory test for muscular dystrophy in 1959, and subsequently accelerated progress in a broad range of research areas in medicine. Progress in modern genetics and molecular pathology provided another breakthrough in muscular dystrophy research and, in 1987, dystrophin was identified, a deficiency of which causes DMD. The present review article highlights contributions of Japanese scientists to muscular dystrophy research.     

Detecting exon deletions and duplications of the DMD gene using Multiplex Ligation-dependent Probe Amplification (MLPA)

OBJECTIVES: To evaluate the efficacy of Multiplex Ligation-dependent Probe Amplification (MLPA) technique in comparison with the traditional multiplex PCR assay in detection of exon deletions and duplications of the DMD gene. DESIGN AND METHODS: The sensitivity and accuracy of MLPA were assessed and compared with the multiplex PCR in a total of 63 subjects including 43 subjects with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD) and 20 female carriers. RESULTS: MLPA was able to detect all the known deletions and duplications; it detected four additional mutations that had been missed by multiplex PCR. In addition, the extent of the deletions and duplications could be more accurately defined which in turn facilitated a genotype-phenotype correlation. CONCLUSIONS: MLPA is superior to multiplex PCR. It should be the method of choice for the detection of exon deletions and duplications of the DMD gene in patients with DMD or BMD, as well as in female carriers.     

Albumin targeting of damaged muscle fibres in the mdx mouse can be monitored by MRI

Increased sarcolemmal permeability has been implicated as a major pathological event in muscular dystrophies. In our study, we evaluated whether damaged muscle fibres can be specifically targeted using albumin as a carrier. We tagged human serum albumin (HSA) with Gadolinium (Gd) and systemically applied this compound (Gd-DTPA-HSA) to wildtype and dystrophin-deficient mdx mice. We performed magnetic resonance imaging before and after intravenous administration of Gd-DTPA-HSA and found localised signal enhancement only in mdx skeletal muscle. We also examined skeletal muscle after contrast enhanced magnetic resonance imaging using anti-human albumin antibodies and demonstrated intracellular accumulation of Gd-DTPA-HSA in clusters of damaged mdx muscle fibres. Comparison of magnetic resonance imaging and histological data emphasised the value of contrast agent enhanced magnetic resonance imaging for the in vivo assessment of fibre damage in muscular dystrophies. Furthermore, our data provide evidence that albumin can be used as a carrier to target covalently bound molecules to degenerating muscle fibres.     

散发型DMD/BMD家系突变分析及产前诊断研究

目的 分析散发型DMD/BMD家系中患者的致病突变,为部分家系的胎儿进行产前基因诊断,明确该类家庭中女性成员是否致病突变携带者,分析该类家系新发突变的比例.方法 共收集30个散发DMD/BMD家系,应用传统mPCR方法 分析DMD基因缺失热区中的18个外显子;应用MLPA方法,对家系中的30例患者及23个家系中的28位女性成员,进行DMD基因全部79个外显子的定量分析,并为其中19个家系进行20例产前诊断.结果 mPCR检测到19例缺失突变;MLPA检测到21例缺失突变和3例重复突变,并明确缺失突变范围.在检测到突变的家系中,10例母亲为缺失突变携带者,2例为重复突变携带者,9例母亲不是携带者,新发突变比例为37.5%.7例患者的姐妹中5例为携带者(3例缺失,2例莺复),2例不是携带者.经产前诊断,12例男性胎儿中5例为患者,8例女性胎儿中2例为携带者.结论 MLPA方法 可全面检测DMD基因缺失及重复突变、明确女性携带者,为产前诊断提供准确信息.     

含胎肌条件培养液的DMD原代肌组织培养体系的建立

应用含胎肌条件培养液的培养体系对 DMD 和正常肌组织进行原代培养。经倒置相差显微镜、透射电镜和 Desmin 免疫细胞化学技术鉴定,显示该培养体系能使肌组织成肌细胞生长并大量繁殖,分化良好,全部形成肌管。提示含胎肌条件培养液的培养体系能激活正常人及患者的肌卫星细胞,具有良好定向培养肌细胞的能力。