脐血干细胞移植治疗假肥大型肌营养不良症

目的比较假肥大型肌营养不良症(Duchennemusculardystrophy,DMD)患者经脐血干细胞移植治疗前后其肌肉再生、抗肌萎缩蛋白表达和运动功能的改变;以及评价治疗的安全性。方法对1例经基因分析和肌肉活检及抗肌萎缩蛋白检测确诊的、已丧失行走能力的DMD患儿,经HLA配型,在脐血库中寻找到一个全相合的脐血供体。采用白消安+环磷酰胺+兔抗胸腺淋巴细胞球蛋白预处理后进行异基因脐血干细胞移植;术后采用环孢素A和骁悉方案预防移植物抗宿主反应(graftversushostreaction,GVHD)。同时定期检测原发病的生化指标如血清肌酸激酶(creatinekinase,CK)、造血重建的植入证据(血型转变、肌肉和血液系统的聚合酶链反应短串联重复序列分析)、缺陷基因是否纠正、新生肌肉是否出现、肌肉中抗肌萎缩蛋白是否表达和运动功能是否改善。结果(1)中性粒细胞在脐血干细胞移植后第15天(+15天)达到0.5×109/L,白细胞在+25天达正常水平;血小板于+22天达到20×109/L;血红蛋白维持于85～100g/L。术后140天骨髓穿刺提示三系生长旺盛;(2)移植后140天血型转为供体AB型。至今没有出现移植物抗宿主反应。(3)术后18天、30天、43天、55天、74天、233天患者外周血DNA和术后140天、183天、235天骨髓细胞DNA经PCRSTR检测为供者独立植入;(4)患儿术后60天取外周血做基因分析,显示19号缺失的外显子得到完全纠正,患儿转变为正常基因型;(5)患儿在移植后75天的肌肉活检可见新生肌管形成,抗肌萎缩蛋白免疫组化呈弱阳性,少数为强阳性反应,DNA分析:供者基因DNA占1%～13%;移植后126天抗肌萎缩蛋白免疫组化检测显示阳性的肌纤维明显增多,供者基因DNA上升至2.5%～25%;(6)患儿血清CK从移植治疗前的5735U/L降至274U/L;(7)术后100天体检发现患儿肌力略有改善,肢端温暖。结论异基因脐血干细胞移植治疗DMD,可在移植后短期内重建造血功能、血清CK显著下降、肌肉抗肌萎缩蛋白表达,患儿运动有所改善,提示造血干细胞移植将有益于DMD的治疗。     

假肥大型肌营养不良基因诊断技术研究进展

假肥大型肌营养不良是由于Dystrophin基因突变而导致的X-连锁隐型遗传病,目前对这种疾病还没有有效的治疗方法。通过基因诊断技术对假肥大型肌营养不良患者以及携带者进行准确、全面的突变检测,进而进行产前诊断避免患儿的出生是目前解决这一问题的最有效途径。近几年来,一些常规的Dystrophin基因突变检测技术有了新的进展,同时也出现了一些全新的技术。该文对几种重要检测技术的研究进展进行综述。     

假肥大型进行性肌营养不良的诊断与遗传分析

目的总结假肥大型进行性肌营养不良患者的临床特征、病因及病理变化,提高其诊治水平。方法对患者进行肌电图、磷酸肌酸激酶浓度、肌肉活体组织、智力、神经反射等项检查,收集完整的家系资料进行遗传分析,判断致病基因携带者并评估再发风险。结果得到一假肥大型进行性肌营养不良的家系,并进一步确定其X连锁隐性遗传的遗传方式,明确了患者的表型特征,总结了目前的诊治方法,给与家系中相关人员以必要的遗传指导。结论假肥大型进行性肌营养不良是抗肌萎缩蛋白基因发生突变所致,目前应用PCR的相关技术、变性高效液相色谱结合测序技术可对突变基因进行筛查,从而预防患者的出生,对该病的治疗已取得了一定的进展。     

dystrophin基因第45～54外显子缺失连接片段的克隆和测序

目的通过对dystrophin基因第45-54外显子缺失后连接片段的克隆和测序分析，探讨dystrophin基因缺失的发生机理。方法先以外显子PCR反应检测证实1例杜氏肌营养不良症（Duchenne muscular dystrophy，DMD）患者第45～54外显子缺失，然后在第44和第54内含子上用PCR步移方法寻找断裂位点，最后用靠近断裂位点处设计的引物，以PCR法直接扩增dystrophin基因的缺失连接片段并测序，测序结果和正常内含子序列作对比分析。结果对扩增连接片段的PCR产物测序获得2716bp有效序列。本例基因缺失片段长达402kb。5’端断裂点位于第44内含子长散在元件（long interspersed elements，LINE）L1序列内，邻近基质附着区（matrix attachment region，MAR），3’端断裂位点在第54内含子较可能形成MAR的一个次级区域内，附近有拓扑异构酶Ⅱ识别位点，断裂点两旁存在6bp的回文序列。连接片段通过4bp的微小同源序列AGAG连接断裂点两端。结论由L1重复序列、断裂点附近拓扑异构酶Ⅱ酶切位点、MARs以及微小同源序列的非同源末端连接修复等综合因素引起的非同源基因重组可能是导致此一大片段基因缺失的重要原因。     

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。     

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。     

疑似假性肥大性肌营养不良症患儿Dystophin基因缺失突变分析

目的了解中国汉族假性肥大性肌营养不良症(DMD/BMD)患儿基因缺失突变的特点。方法经PCR和20对引物,对964例疑似DMD/BMD患儿Dystophin基因外显子缺失突变类型及断裂点进行检测分析。结果有491例患儿(491/964,51.0%)存在基因缺失突变:其中75例基因缺失突变位于基因5’端区域(15.2%),402例基因缺失突变位于基因中央区域(81.7%),13例基因缺失突变范围跨越了以上两个区域(2.6%)。检测到以50、49、48号外显子缺失突变最为常见。74%患儿的Dystophin基因断裂点位于44～50号内含子,以44号内含子最多(21%)。结论 20对引物的PCR法能够检测超过半数的Dystrophin基因缺失突变,基因中央区缺失是中国汉族DMD/BMD患儿病例的主要基因缺失突变类型。     

应用间期细胞原位PCR检测基因缺失型杜氏肌营养不良

目的：建立原位PCR技术,用于检测遗传性疾病。方法：应用抗肌萎缩蛋白（dystrophin)的基因48及51号外显子的引物,使用直接法原位PCR,检测正常人及Duchenne型肌营养不良症（DMD）患者。结果：正常男性96％间期淋巴细胞出现信号斑点,而DMD缺失型患者间期淋巴细胞均未出现信号斑点。结论：原位PCR技术不破坏细胞形态结构,能精确定位靶基因,兼有PCR及原位杂交技术两者优点。可作为检测缺失型DMD患者及产前诊断的手段。     

假肥大型肌营养不良症15例家系的基因检测及产前诊断

目的 对15例假肥大型肌营养不良家系进行基因型分析.并为其家庭提供产前分子诊断评估再生育风险.方法 联合多重连接依赖性探针扩增(MLPA)检测和单体型连锁分析分别对15例家系行假肥大型肌营养不良(DMD)的DMD基因诊断.所有产前诊断标本均通过STR位点检测排除母血污染.结果 MLPA检测结果显示,15例先证者中DMD...     

Additional dystrophin fragment in Becker muscular dystrophy may result from proteolytic cleavage at deletion junctions

Becker muscular dystrophy is usually caused by intragenic dystrophin gene deletions that result in production of an internally deleted protein. Previous studies have detected what appears to be a unique dystrophin degradation product that appears only in muscle biopsies from patients with Becker muscular dystrophy. This dystrophin fragment is always seen in addition to the “full-size” dystrophin of the expected size for a given gene deletion. It is only found in biopsies from patients with mutations in the deletion-prone region encompassing exons 45–53, but it does not appear to correlate with any observable phenotype at the clinical level. By correlating the size and locations of dystrophin gene deletions with the size of this degradation product, together with use of region-specific dystrophin antisera, we find that proteolytic cleavage may occur at the deletion breakpoints, perhaps due to alterations of the secondary and/or tertiary structures of the protein. This cleavage results in loss of the carboxy-terminal domains that are thought to be important for interactions between dystrophin and other membrane-bound proteins. © Wiley-Liss, Inc.     

面肩肱型肌营养不良症基因诊断

目的 观察面肩肱型肌营养不良症(facioscapulohumeral muscular dystrophy，FSHD)患者p13E—11标记的4q35 EcoR Ⅰ／B1n Ⅰ片段分子量变化特点，对FSHD进行基因诊断。方法 提取基因组DNA，EcoR Ⅰ／B1n Ⅰ双酶切后进行脉冲凝胶电泳，用同位素标记的探针p13E—11进行Southern印迹，以小于38kb为诊断FSHD标准，观察4q35 EcoR Ⅰ／B1n Ⅰ片段分子量大小的分布。结果 FSHD组26例患者中，20例4q35 EcoR Ⅰ／B1n Ⅰ片段小于38kb，基因诊断阳性率为76．92％。FSHD亲属组12例，其中两例该片段小于38kb。对照组21人，该片段均大于38kb。结论 以小于38kb为诊断标准较满意，FSHD基因诊断阳性率与文献基本吻合。     

Amplification of ten deletion-rich exons of the dystrophin gene by polymerase chain reaction shows deletions in 36 of 90 Japanese families with Duchenne muscular dystrophy

We analyzed DNA samples taken from 95 Duchenne muscular dystrophy (DMD) patients belonging to 90 different families in Japan using the polymerase chain reaction. Ten different regions at the 5′ end or in the central region of the dystrophin cDNA gene that were previously shown to be prone to deletion were selected for amplification and analysis. Patients in 36 of the 90 families (40%) had deletions in at least one of these segments of the gene. Identical deletions were detected in the dystrophin gene of patients from the same family. The deletions were heterogeneous in size and location. One patient had deletions in 7 of the 10 amplified regions, while 19 patients from 18 families had a deletion in only one of the regions studied. Deletions at the 5′ end were generally larger and more heterogeneous than those in the central region of the gene. One third of deletions had their proximal end breakpoints between exons 44 and 45. This region seems to be particularly vulnerable to gene breakage in DMD patients.     

ERG phenotype of a dystrophin mutation in heterozygous female carriers of Duchenne muscular dystrophy

PURPOSE: Mutations in the dystrophin gene result in Duchenne muscular dystrophy (DMD). DMD is associated with an abnormal electroretinogram (ERG) if the mutation disrupts the translation of retinal dystrophin (Dp260). Our aim was to determine if incomplete ERG abnormalities would be associated with heterozygous carriers of dystrophin gene mutations. METHODS: Ganzfeld ERGs were obtained under scotopic and photopic testing conditions from a family which includes the heterozygous maternal grandmother, the heterozygous mother, and her children, two affected boys and dizygotic twin sibs, an unaffected male and heterozygous female. Southern blot analyses were done to characterise the dystrophin mutation. RESULTS: The dystrophin gene was found to contain a deletion encompassing exon 50. The ERGs in the two affected boys were abnormal, consistent with the DMD ERG phenotype. Serial ERGs of the heterozygous females were abnormal; however, they were less severely affected than the DMD boys. The ERG of the female sib showed a greater abnormality than her mother and maternal grandmother. The unaffected twin had a normal ERG. CONCLUSIONS: The ERG shows abnormalities associated with carrier status in this family with a single exon deletion. A large study of confirmed obligate carriers is planned to clarify further the value of the ERG in detecting female heterozygous carriers of dystrophin gene mutations.     

X inactivation and dystrophin studies in a t(X;12) female: Evidence for biochemical normalization in Duchenne muscular dystrophy carriers

A 4-year-old girl was identified with high creatine kinase (CK) values, and mild muscle weakness in a limb-girdle distribution. Results of dystrophin analysis of the muscle biopsy were consistent with a manifesting heterozygote for Duchenne muscular dystrophy. In peripheral lymphocytes she had a t(X;12) (p21.2;q24.33). Late DNA replication studies demonstrated inactivation of the normal X chromosome in 99.4% of cells. Dystrophin immunofluorescence showed 64% dystrophin-negative muscle fibers. Dystrophin content of muscle by immunoblot was approximately 5% of normal. The discordance between the percent of normal X inactivation and percent of dystrophin-negative cells may be explained by compensatory protection of dystrophin by rare nuclei with the normal X active in multinucleated muscle fibers with shared cytoplasm. © 1992 Wiley-Liss, Inc.     

Duchenne muscular dystrophy and spinal muscular atrophy type I segregating in the same family

We report on a family with two severe neuromuscular diseases: Duchenne muscular dystrophy (DMD) and acute infantile spinal muscular atrophy (SMA I). One boy has DMD, and his brother died of SMA I at 11 months of age. Both boys had received the same DMD allele from their mother. Analysis of dystrophin by immunohistochemistry and Western blot showed complete lack of dystrophin in both brothers. The mother had a partial deficiency of dystrophin. The boy with SMA I had increased levels of creatine kinase in serum, compatible with DMD, but the muscle biopsy and post-mortem examination of the spinal cord showed the typical changes of SMA I. There were no cytogenetic abnormalities explaining the occurrence of both DMD and SMA I in this family. Molecular genetic prenatal diagnosis of DMD and SMA I, using analysis of RFLPs and dinucleotide repeats, has been performed in one foetus in the family. The results showed that the foetus had a high risk of developing SMA I. An abortion was planned but the pregnancy was terminated by miscarriage.     

Increase in fetal breech presentation in female carriers of Duchenne muscular dystrophy

Female carriers of Duchenne muscular dystrophy (DMD) may demonstrate elevated serum creatine kinase (CK) and reduction of muscle dystrophin in all muscle types. We hypothesized that decreased dystrophin in uterine or pelvic girdle musculature might affect the obstetrical performance of females heterozygous for a dystrophin mutation. We reviewed the outcome of 34 deliveries resulting in 35 children from 13 women who were mothers of males attending a muscular dystrophy clinic. Obstetrical performance was examined retrospectively by chart review and patient contact. Of 35 children, 6 (17%) were delivered in the breech position, which is a fivefold increase above the national standards for term pregnancies. Of the six infants with breech presentation, two were males affected with DMD, one was a female heterozygote, one was a male who died perinatally, and the carrier status of the other two females is unknown. Most DMD affected males (12/14) were delivered in the vertex position. Thus, it is likely that maternal, rather than fetal, muscle weakness was the significant factor in determination of fetal position at term. We speculate that subtle changes in uterine or pelvic girdle muscle tone may contribute to a higher rate of fetal breech position in carriers of the DMD gene. Am. J. Med. Genet. 73:276–278, 1997. © 1997 Wiley-Liss, Inc.     

面肩肱型肌营养不良症的基因诊断

目的 对中国人面肩肱型肌营养不良症进行基因诊断。方法 用EcoRI以及EcoRI/BlnI消化基因组DNA,0.6%琼脂糖凝胶电泳,P13E11探针进行Southern印迹杂交。结果 患者所得EcoRI BlnI/P13E11DNA片段长度在15-33kb之间,而正常对照在41kb以上,发现两个症状前患者。结论 以P13E11探针通过Southern印迹杂交探测EcoRi/BlnI双酶消化的基因组DNA可对中国人绝大部分面肩肱型肌营养不良症进行基因诊断,并可进行症状前诊断。