视网膜眼电图对DMD/BMD携带者的检测价值探讨

目的研究杜氏／贝氏进行性肌营养不良（DMD／BMD）携带者视网膜眼电图（ERG）的改变，探讨ERG对DMD／BMD携带者的诊断意义。方法对22个基因突变类型明确的DMD／BMD家系．用定量PCR法结合系谱分析将家系中女性成员分成肯定携带者和非携带者，对患者和家系女性成员进行详细的眼科检查和ERG检测，并用ERG国际测量标准记录结果。结果22名患者中17名出现异常ERG改变；11名肯定携带者中5名出现ERG异常，14名非携带者无ERG改变，两组无重叠。结论ERG是一项对DMD／BMD诊断非常敏感和特异的检查，而ERG对携带者的诊断也具有一定的临床意义。     

Rapid identification of female carriers of DMD/BMD by quantitative real-time PCR

Recently developed PCR systems offer online-monitoring of amplification and allow simple and reliable DNA quantification. We have used the LightCycler system to develop a simple and rapid method for direct identification of female carriers of deletions and duplications in the dystrophin gene. The challenge resides in the ability to identify the presence of a deleted or duplicated allele over the background contributed by the normal allele. Quantification is based on the determination of the ratio between potentially deleted/duplicated dystrophin exons and non-deleted/-duplicated reference exons using the unspecific dsDNA-dye SYBRgreen I. In a retrospective study, we evaluated our method in female relatives of DMD/BMD patients with known carrier status by comparative analysis of deleted or duplicated versus non-deleted/-duplicated exons. Carrier status was accurately attributed in 100% of cases, the mean ratios being 0.52+/-0.12 for deletion carriers (expected value: 0.5) and 1.56+/-0.18 for duplication carriers (expected value: 1.5) vs. 1.022+/-0.17 for non-carriers (expected value: 1.0). The method proved to be simple, rapid, reliable, and cost-effective. It may be used for direct determination of deletions/duplications in potential DMD/BMD carriers and may easily be adapted for other genetic conditions involving deletions and duplications.     

The value of deletion analysis for carrier detection in Duchenne muscular dystrophy (DMD)

We performed genetic analysis for carrier detection for several at-risk females in a four-generation Duchenne muscular dystrophy (DMD) pedigree using deletion analysis. We demonstrated that dosage analysis is a suitable alternative method to determine the carrier status of female relatives of DMD patients shown to have a deletion within the DMD gene. Subsequently, we diagnosed an affected male fetus for an at-risk female shown to be a DMD carrier by deletion analysis. The usefulness of deletion and linkage analysis are compared. In this family, linkage analysis was complicated by the unavailability of key family members, two recombination events and by previously undisclosed nonpaternity. We found that dosage analysis was more efficient than linkage for carrier evaluation in this family.     

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.     

DGGE-based whole-gene mutation scanning of the dystrophin gene in Duchenne and Becker muscular dystrophy patients

Duchenne and Becker muscular dystrophy (DMD and BMD) are caused by mutations in the dystrophin gene. Large rearrangements in the gene are found in about two-thirds of DMD patients, with approximately 60% carrying deletions and 5-10% carrying duplications. Most of the remaining 30-35% of patients are expected to have small nucleotide substitutions, insertions, or deletions. To detect these subtle changes within the coding and splice site determining sequences of the dystrophin gene, we established a semiautomated denaturing gradient gel electrophoresis (DGGE) mutation scanning system. The DGGE scan covers the dystrophin gene with 95 amplicons, PCRed either individually or in a multiplex setup. PCR and pooling were performed semiautomatically, using a pipetting robot and 384-well plates, enabling concurrent amplification of DNA of four patients in one run. Amplification of individual fragments was performed using one PCR program. The products were pooled just before gel loading; DGGE requires only a single gel condition. Validation was performed using DNA samples harboring 39 known DMD variants, all of which could be readily detected. DGGE mutation scanning was applied to analyze 135 DMD/BMD patients and potential DMD carriers without large deletions or duplications. In DNA from 25 out of 44 DMD patients (57%) and from 5 out of 39 BMD patients (13%), we identified clear pathogenic changes. All mutations were different, with the exception of one DMD mutation, which occurred twice. In DNA from 10 out of 44 potential DMD carriers, including four obligate carriers, we detected causative changes, including one pathogenic change in every obligate carrier. In addition to these pathogenic changes, we detected 15 unique unclassified variants, i.e., changes for which a pathogenic nature is uncertain.     

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.     

Dissecting the Structure and Mechanism of a Complex Duplication–Triplication Rearrangement in the DMD Gene

Pathogenic complex genomic rearrangements are being increasingly characterized at the nucleotide level, providing unprecedented opportunities to evaluate the complexities of mutational mechanisms. Here, we report the molecular characterization of a complex duplication–triplication rearrangement involving exons 45–60 of the DMD gene. Inverted repeats facilitated this complex rearrangement, which shares common genomic organization with the recently described duplication‐inverted triplication–duplication (DUP–TRP/INV‐DUP) events; specifically, a 690‐kb region comprising DMD exons from 45 to 60 was duplicated in tandem, and another 46‐kb segment containing exon 51 was inserted inversely in between them. Taking into consideration (1) the presence of a predicted PRDM9 binding site in the near vicinity of the junction involving two inverted L1 elements and (2) the inherent properties of X–Y chromosome recombination during male meiosis, we proposed an alternative two‐step model for the generation of this X‐linked DMD DUP–TRP/INV‐DUP event.     

亚临床甲状腺功能减退与2型糖尿病慢性并发症的关系

目的 探讨亚临床甲状腺功能减退 （SCH）与T2DM慢性并发症的关系。 方法 将1294例T2DM患者分为SCH组和甲状腺功能正常组,比较两组间慢性并发症患病率及患者的甲状腺功能,采用Logistic多元回归分析SCH与糖尿病慢性并发症的关系。 结果18.8%的T2DM患者合并SCH。SCH组糖尿病慢性肾脏疾病（CKD）、DR、糖尿病周围神经病变（DPN）和糖尿病足病（DF）患病率均高于甲状腺功能正常组（P〈0.05）;CKD、DR和DPN患者FT3下降,促甲状腺激素（TSH）升高（P〈0.05）。Logistic多元回归分析显示,SCH为CKD的独立危险因素（OR=3.39,P=0.012）。 结论 T2DM合并SCH 患者CKD、DR、DPN和DF患病率升高。SCH是CKD的独立危险因素。     

Suramin attenuates dystrophin‐deficient cardiomyopathy in the mdx mouse model of duchenne muscular dystrophy

Introduction: The purpose of this study was to determine the effects of suramin, an antifibrotic agent, on cardiac function and remodeling in mdx mice. Methods: mdx mice (8 months old) received intraperitoneal injections of suramin twice a week for 3 months. Control mdx mice (8 months old) were injected with saline. Results: Suramin improved the electrocardiography profile with the main corrections seen in S‐ to R‐wave ratio, PR interval, and Q amplitude, and a significant decrease in the cardiomyopathy index. Suramin decreased myocardial fibrosis, inflammation, and myonecrosis. Conclusions: These findings suggest that suramin may be a new adjunctive therapy to help improve cardiomyopathy in DMD. Muscle Nerve 48 : 911–919, 2013     

假肥大型肌营养不良患者血清酶学与肌电图改变的相关性研究

目的研究假肥大型肌营养不良（DMD）患者血清酶学、肌电图改变,进一步分析之间的相关性。方法选择DMD患者45例,平均年龄（7．14±2．92）岁,分别测定血清磷酸肌酸激酶（cK）、乳酸脱氢酶（LDH）、肌酸激酶同工酶（CK—Mb）、肌红蛋白（Mb）等。并进行肌电图检测。结果所有DMD患者血清酶学均增高,平均CK（13109．38±3023．99）U／L,LDH（1258．99±331．5）U／L,CK—Mb（494．22士121．75）U／L,Mb（1417．07±461．47）U／L。共检测肌肉169块,发现肌源性损害肌肉73块,其中1DO％股四头肌存在肌源性损害。33．3％（15／45）存在肱二头肌肌源性损害,26．7％（12／45）三角肌存在肌源性损害。股四头肌时限下降百分比平均为（42．31±8．74）％。CK与Mb、CK—Mb、LDH均呈正相关,差异有统计学意义（P〈0．01）。Mb与CK—Mb、LDH均呈正相关,差异有统计学意义（P〈0．01）、CK—Mb与LDH呈正相关,差异有统计学意义（P〈0．01）。股四头肌时限下降百分比与CK、Mb、CK—Mb呈正相关,差异有统计学意义（P〈0．05）。CK、CK—Mb、股四头肌时限下降百分比等与病程明显相关,差异有统计学意义（P〈0．05）。结论血清CK、Mb是早期诊断DMD的特异性指标。联合肌电图检查,可提高诊断的敏感性和特异性和评估病程的进展速度。