非缺失型DMD/BMD家系中基因携带者的短串联重复序列多态性连锁分析

目的 准确检出非缺失型杜氏／贝氏进行性肌营养不良症（Duchenne/Becker muscular dystrophy,DMD/BMD)家系中女性携带者，为产前基因诊断提供信息。方法 利用dystrophin基因中5个短串联重复序列多态位点（STR－44，STR－45，STR－49，STR－50和5'-DysⅡ）的特异寡核苷酸引物进行PCR扩增，经聚丙烯酰烯酰胺凝胶电泳分离，DNA片段的多态性用连锁分析其家系中各成员的基因单体型。结果 连锁分析了8个家中26名女性亲属基因型，检出16名女性DMD／BMD携带者和10名非携带者。结论 5个短串联重复序列多态位点的联合连锁分析，可较准确而简便地检出DMD／BMD家系中的女性携带者。     

内含子或外显子缺失DMD家系女性携带者的基因诊断

目的对内含子和(或)外显子缺失的Duchenne型肌营养不良症(Duchenne muscular dystrophy,DMD)家系女性成员进行致病基因携带者的诊断,为进一步行产前诊断或植入前遗传学诊断提供准确的信息。方法利用dystrophin基因5个微卫星位点(STR-44、45、49、40、5′DysⅡ)的多态性连锁分析,同时结合半定量PCR对1个内含子和外显子均缺失的DMD家系(家系5)和1个仅内含子缺失的DMD家系(家系4)的女性成员进行携带者基因诊断。结果家系5的Ⅱ2的STR-50位点基因型为245/245,不是DMD基因携带者。家系4的Ⅱ6、Ⅱ8的STR-45位点基因型为del/172,Ⅲ19为del/178,均为DMD基因携带者。结论STR-PCR多态性分析结合内含子半定量PCR可获得更多诊断信息,更准确地检出内含子缺失的女性携带者,提高诊断率。     

DMD基因内微卫星标记对女性携带者的诊断意义

目的对1临床诊断为Duchenne肌营养不良家系中两名女性个体进行连锁分析,以确定她们是否为Duchenne肌营养不良致病基因携带者。方法抽取家系成员外周血并提取基因组DNA,选取3个DMD基因内微卫星标记作引物进行PCR扩增,扩增产物经ABI PRISM377测序仪电泳后进行连锁分析。结果在我们所研究的Duchenne肌营养不良家系中,一女性个体为Duchenne肌营养不良致病基因携带者,而另一女性个体为正常基因型。结论基因内标记可以排除染色体交换,运用DMD基因内微卫星标记可以成功诊断Duchenne肌营养不良家系中女性个体是否为致病基因携带者。     

Duchenne和Becker肌营养不良的产前诊断

本文报道了自1985年12月以来40个家系的共53例Duchenne肌营养不良(DMD)或Becker肌营养不良(BMD)致病基因可疑携带者产前诊断的结果。其中43例为DMD致病基因可疑携带者,6例为BMD致病基因可疑携带者。     

假肥大型肌营养不良症家系的基因检测与产前诊断

目的 分析假肥大型肌营养不良症(Duchenne and Becker muscular dystrophy,DMD/BMD)家系的致病突变,对胎儿进行产前诊断,并确定家系中的女性成员是否为突变携带者.方法 收集43个DMD/BMD家系,用多重PCR方法分析DMD基因缺失热点区的18个外显子;用多重连接依赖性探针扩增(multiplex ligation-dependent probe amplification,MLPA)方法对43例患者及32个家系中的36位女性进行DMD基因全部79个外显子的定量检测,为其中27个家系提供产前诊断.结果 用多重PCR共检测到26例缺失突变.采用MLPA方法,除多重PCR检测到的突变外,还检测到3例缺失和6例重复突变,突变范围明确.用MLPA检测的36例女性中,32例为患儿母亲,共发现16例突变携带者,另有2名女性亲属也被确诊为携带者.10名女性排除了携带者的可能性,8例不能确定.经产前诊断,18例男性胎儿中3例为患者,9例女性胎儿中1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,同时明确女性携带者,从而为产前诊断提供准确信息.     

Duchenne型肌营养不良症家系的多重PCR和STR—PCR基因诊断

目的该研究率先开展温州地区Duchenne型肌营养不良症（DMD）家系的缺失基因诊断特别是STR单体型连锁基因诊断,为基于DMD症状前、携带者基因诊断结果的遗传咨询和生育指导提供依据。方法针对4例DMD先证者,采用多重PCR检测常见18个外显子缺失,进行直接基因诊断。针对未能发现常见外显子缺失的DMD先证者及其有关家系成员,采用短串联重复序列（STR）PCR检测5个位点（3’CA、44CA、45CA、49CA和50CA）STR多态性,进行间接单体型连锁基因诊断。结果家系二的先证者缺失外显子3、4和6。其余3个家系的先证者的异常x染色体均肯定来源于其母亲。家系一先证者外婆肯定是携带者。家系三先证者年幼（4周岁）弟弟肯定为正常人,将来年龄大了也不会发病,先证者外婆肯定是携带者。家系四先证者刚出生的妹妹肯定是遗传携带者,将来其生育儿子有遗传患病风险。结论该研究的DMD家系的缺失和STR单体型连锁基因诊断,特别是对症状前男孩的诊断、对无患病后代的女性携带者的检出,具有非常重要的实际意义,可以为遗传咨询和生育指导提供可靠依据。     

MLPA联合遗传连锁分析在假肥大型肌营养不良症产前诊断中的价值

目的 探讨多重连接依赖探针扩增技术(multiplex ligation-dependent probe amplification,MLPA)联合短串联重复序列(short tandem repeat,STR)基因连锁分析用于Duchenne型假肥大型肌营养不良症(Duchenne muscular dystrophy,DMD)产前诊断的价值.方法 通过检测Y染色体性别决定基因(Y chromosome sex-determining gene,SR Y)判断胎儿性别;MLPA检测45个DMD家系中先证者、孕妇以及胎儿Dystrophin基因突变情况,并对家系成员和胎儿进行第45、49、50内含子以及5′和3 ′端STR的连锁分析.结果 45个进行产前诊断的家系中,SRY阳性31例,其中6例为DMD患病胎儿;阴性14例,其中4例为携带者,余未见异常.结论 MLPA能检测胎儿Dystrophin基因外显子突变情况,STR连锁能分析胎儿是否继承母源性风险X染色体,因此,STR连锁分析能发现MLPA技术检测不到的外显子突变胎儿.将两种方法结合起来用于DMD的产前诊断准确性更高.     

定量PCR结合STR多态连锁分析诊断缺失型DMD基因携带者

目的：直接定量PCR结合STR单体型连锁分析，以便更准确检出缺失型家系中DMD基因携带者。方法：在内标引物参照下，PCR扩增22个循环，产物在琼脂糖凝胶分离，EB显色，照相后，扫描定量，同时应用5个STR多态位点的单体型连锁分析，检测缺失型的DMD基因女性携带者。结果：直接定量PCR分析了6个家系中的8个外显子48缺失的DMD母亲或女性同胞，检出7个DMD为携带者；STR多态单体型连锁同样分析这6个家系中的8个女性亲属，亦检出7个DMD基因携带者，二种方法所得结果完全一致。结论：STR多态连锁分析与直接定量PCR法结合，可更准确，全面检出DMD基因携带者。     

Becker型肌营养不良的产前诊断

限制性片段长度多态(RFLP)在Duchenne型肌营养不良携带者检出和产前诊断的应用已有报道。有关连锁数据的最新资料表明Duchenne型肌营养不良(DMD)和Becker型肌营养不良(BMD)是同等位基因缺陷病。所以,用于DMD诊断用的DNA探针同样适用于BMD。目前已获得了位于DMD基因内的DNA探针,应用这些探针找到的限制性片段多态与DMD突变无任何重组现象。在基因的特异性突变及其功能弄清以前,对于有生育DMD和BMD患儿风险的家庭,这些紧密连锁的RFLP是有用的。     

应用荧光原位杂交技术诊断基因缺失型进行性假肥大性肌营养不良携带者

目的 建立应用荧光原位杂交(fluorescent in situ hybridization，FISH)方法检查进行性假肥大性肌营养不良(Duchenne／Becker muscular dystrophy，DMD／BMD))患者家系中女性亲属是否为携带者的方法。方法 采用多重聚合酶链反应对19例DMD／BMI)先证者进行基因诊断，从中筛选出两例缺失dystrophin基因外显子46的患者，其中l例有阳性家族史，另l例为散发病例，采用双色FISH对其女性亲属进行携带者的检查。结果 在有阳性家族史的1例患者的家系中检出4例携带者；在另一散发病例的家系中检出1例所缺失基因片段的体细胞嵌合体。结论 与多重PCR相结合，应用双色FISH检出基因缺失型DMD／BMD携带者是一个切实可行的诊断方法，对于所缺失基因片段的体细胞嵌合体的诊断是FISH方法的一个突出的优点，这对DMD／BMD家系的遗传咨询以及产前诊断指征的确立具有重要意义。     

Carrier detection of Duchenne/Becker muscular dystrophy by analysis of STRs loci linked to the gene of dystrophin in Venezuelan families

The Duchenne/Becker Muscular Dystrophy (DMD/BMD) is an X linked recessive lethal disease. The female carrier will transmit the disease gene to half of her sons and half of her daughters; half of the daughters will be carriers, while half will be normal. Half of the sons will be normal and, on average, half will have the disease. It is of particular relevance to be able to detect carrier status among female relatives of the patients for genetic counseling and prenatal diagnosis. The method of Short Tandem Repeat (STR) sequence polymorphism analysis can determine haplotype at normal status or at risk status and, to establish genetic linkage between the mutated gene and the segregated haplotype. We have analyzed 105 members from 15 unrelated Venezuelan families with one or more siblings affected with DMD/DMB and 7 unrelated males. Of the 105, 37 were male (26 affected and 11 normal) and 68 were female. STR sequences (STR44, STR45, STR49, STR50, STR3'DYS) of the gene of the Dystrophin were amplified by polymerase chain reaction (PCR) to analyze allelic polymorphism in the families. Five of the 15 families (33%) had a deletion of one or several of the exons. Of the 68 females, 27 (39.7%) were carriers, 27 (39.7%) were non-carriers and in 14 cases (20.58%) it was not possible to reach a definitive diagnosis. The definitive diagnosis could be established in 79% of the females. This analysis also shows that the mutation occurred on the grandpaternal X chromosome in one family. Hemizygocity was detected and carrier status ascertained in the mother of other patient and in one family we were able to do prenatal diagnosis. The germinal mosaicism could not be excluded in 3 patients.     

Carrier detection in Duchenne and Becker muscular dystrophy Argentine families

In order to offer carrier detection, genetic counseling, and prenatal diagnosis to families with Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) in our country, segregation analysis of highly polymorphic short tandem repeats (STR) (dC-dA)n: (dG-dT)n loci was utilized. The risks to females of 15 DMD/BMD families (9 familial and 6 sporadic) were evaluated on STR, pedigree and serum creatine kinase (SCK) data. From the 36 females at risk of being carriers (not including 8 obligate carriers), results of STR analysis were compatible with carrier status in 7 and not compatible in 20. In 9 females, no information regarding carriership was derived from the STR analysis. Prenatal diagnosis is now possible on the carrier females. Previously identified deletions in the central part of the gene were confirmed by STR analysis in 3 families. Five new alleles were identified in Argentine individuals; allele frequencies differed from those of North American people. Results derived from this study are useful for carrier detection and genetic counseling in DMD/BMD. One case of probable mosaicism in an unaffected father was detected on a pedigree basis in a family with DMD patients.     

Mutation analysis and prenatal diagnosis for 50 pedigrees affected with Duchenne/Becker muscular dystrophyCSCD

Objective To establish individualized prenatal diagnosis program for families affected with Duchenne/Becker muscular dystrophy (DMD/BMD) and different clinical background using a variety of methods. Methods Multiplex ligation-dependent probe amplification (MLPA) was performed on 50 patients suspected for DMD/BMD. For single exon deletions of the DMD gene, PCR was used for validating the results. For those without any deletion or duplication, Sanger sequencing was used to screen for DMD gene mutations in the children and their mothers. Prenatal genetic testing was provided to female carriers using chorionic villus, amniocentesis or cord blood samples. To ensure the accuracy of diagnosis, all prenatal specimens were also subjected to linkage analysis. Results Among the 50 patients with DMD/ BMD, 23 harbored large deletions, 11 only had single exon deletions, 10 harbored duplications, and 5 had small scare mutations. No mutation was detected in one family. For 37 women undergoing prenatal diagnosis, 10 fetuses were identified as affected males, 6 were female carriers, while 21 were not found to carry any mutation. Testing of creatine kinase was consistent with the results of prenatal diagnosis. For a patient harboring exon 51 deletion, the same mutation was found in a fetus but not in their mother. The proband and fetus had inherited the same haplotype, which suggested that the mother probably has germline mosaicism for the mutation. Conclusion Application of individualized methods for analyzing pregnant women with different clinical background can minimize the risk for giving birth to further children affected with DMD/BMD. © 2018 West China University of Medical Sciences. All rights reserved.     

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。     

反转录与套式PCR技术在DMD／BMD杂合子基因诊断中的应用

以外周血为标本提取细胞质总ＲＮＡ，应用ＤＭＤ基因的反转录多聚酶链反应技术（反转录ＰＣＲ，ｒｅｖｅｒｓｅｔｒａｎｓｃｒｉｐｔｉｏｎＰＣＲ，ＲＴ－ＰＣＲ）检测了１０个ＤＭＤ／ＢＭＤ家系。结果在４个家系中发现６个患者获得较短的ＰＣＲ片段，其中在２个家系中发现部分女性同时获得正常大小和相应较短的ＰＣＲ片段，而得到了满意的患者和杂合子携带者的诊断。该法有利于ＤＭＤ／ＢＭＤ患者、尤其是杂合子携带者的确诊，为产前基因诊断和遗传咨询提供了科学的依据。     

Detection of carriers of Duchenne and Becker muscular dystrophy using the fluorescence in situ hybridization method

Duchenne and Becker muscular dystrophies (DMD/BMD) are X-linked recessive disorders caused by mutations in the dystrophin gene. A large intragenic deletion has been described in about 65% of DMD/BMD patients. Mothers of affected males are DMD/BMD carriers in two thirds of the cases. Routine deletions detection in DMD/BMD males is performed using multiplex polymerase chain reaction (mPCR), RT-PCR with a protein truncation test (PTT) or using Southern blotting. In females the deletions detection is complicated by the presence of a normal gene copy on the second X-chromosome. We are presenting the diagnostic strategy using FISH for the deletions detection in the dystrophin gene of female DMD/BMD carriers. We have used a set of six cosmid probes for the detection of the most frequently deleted areas of the dystrophin gene from the Department of Human Genetics, Leiden University Medical Center. We have examined 14 mothers of DMD/BMD males with a deletion in the dystrophin gene identified using mPCR. Four mothers of affected males have been diagnosed as carriers of a deletion in the dystrophin gene. We have revealed no deletion mutations in the exons examined in a control group of four healthy females. No discrepancy has been found between the FISH analysis results and the results of mPCR. Our results indicate that FISH is an effective and direct method for the identification of DMD/BMD carriers and we suggest this method as a method of a first choice in the identification of DMD/BMD carriers.     

Gene-deletion and carrier detections, and prenatal diagnosis of Duchenne muscular dystrophy by analysis of the dystrophin gene amplified by polymerase chain reaction.

Polymerase chain reaction (PCR)-based diagnosis was carried out in 62 patients (57 probands) with Duchenne or Becker muscular dystrophy (DMD or BMD) and 226 members in 57 families. The PCR studies were also performed for carrier detection in 57 mothers and 58 sisters, and prenatal diagnosis of 4 fetuses at risk of DMD. The PCR with 7 sets of primers, which amplify 7 different exon-sequences of the dystrophin gene, detected gene deletion of at least one exon in 49% of the probands. The PCR with the other 4 primer sets, which amplify 3 intragenic loci, and subsequent endonuclease digestion detected in 84% of the mothers a heterozygous pattern in at least one such locus/segment. Using the same primer sets, carrier detection was successful in 5 sisters of familial DMD cases, while recombination between the ERT87 and the 3' end intragenic loci was observed in 11% of family members studied. Prenatal diagnosis was made in all the 4 fetuses; two males were affected, one male fetus non-affected, and the remaining one female fetus a carrier. Thus, the PCR study and the primers used in the present study are useful and convincing for rapid diagnosis of DMD and/or BMD.