眼咽型肌营养不良一家系临床、电生理、病理及基因分析

目的 报道1个出现神经源性骨骼肌损害的眼咽型肌营养不良(OPMD)家系的临床、骨骼肌病理和基因改变特点.方法 先证者为60岁男性,50岁时出现双下肢近端无力,53岁出现吞咽困难和构音障碍,57岁出现双眼睑下垂和眼球突出.肌酸激酶轻度增加,四肢肌电图为神经源性损伤,周围神经传导速度下降20%～43%.家系3代中除先证者外尚有5例在45岁后出现吞咽困难,4～20年后出现眼睑下垂,其中3例有肢体无力.对先证者左肱二头肌做肌肉活体组织检查,标本进行组织学、酶组织化学以及免疫组织化学染色(以抗结蛋白和泛素蛋白抗体作为一抗)和超微病理检查.对先证者和家系中另外18人进行多腺苷酸结合蛋白(PABPN1)基因检查.结果 先证者肌纤维内出现镶边空泡伴泛素阳性沉积物和成组分布的小角状萎缩肌纤维,个别肌纤维出现再生改变伴随结蛋白沉积,可见细胞色素C氧化酶阴性肌纤维.电镜检查发现约3%的肌纤维核内存在栅栏样细丝包涵体.先证者和另外11名家系成员的PABPN1基因存在(GCG)9异常扩增.结论 杂合(GCG).异常扩增性OPMD可先出现咽喉肌无力,伴随脱髓鞘性神经病.我国患者也存在肌纤维核内包涵体.     

眼咽型肌营养不良一家系临床与分子遗传学研究

目的探讨一考虑诊断眼咽型肌营养不良(oculopharyngeal muscular dystrophy,0PMD)家系的临床及分子生物学特点。方法收集该家系成员的临床资料,并经包括先证者在内的16位家族成员同意,收集其血样进行聚合酶链反应(PCR)基因验证分析。结果该家系成员男性患者起病以眼睑下垂为首发症状,而后开始逐渐出现以发音及吞咽困难为表现的咽部肌群和肢体乏力为表现的四肢近端肌群受累,而女性患者则往往以吞咽困难为首发表现。参与基因检测的家族成员中共发现10位存在多聚腺苷酸结合蛋白核l(PABPN1)基因的(GCG)6重复异常拷贝为(GCG)10,从而导致了丙氨酸的扩增。结论基因诊断及产前诊断是确诊及预防眼咽型肌营养不良的关键,眼睑下垂可能为携带(GCG)10突变男性OPMD患者的首发症状。     

结蛋白基因S12F新突变导致的结蛋白病一家系

目的 报道1个结蛋白基因新突变导致的结蛋白病家系,介绍其临床和病理改变特点.方法 1个常染色体显性遗传家系内共有8例患者,男7例,女1例.发病年龄20～50岁.其中7例有心脏损害,3例有肢体近端无力,1例伴慢性腹泻.先证者和其兄行左肱二头肌活体组织检查,进行组织学、酶组织化学、电镜观察及抗结蛋白等免疫组织化学染色.先证者和3例患者、5名无症状家系成员及50名健康人行结蛋白基因测序.结果 先证者的骨骼肌出现肌纤维直径变异加大伴结缔组织增生,少数肌纤维出现嗜酸性改变伴镶边空泡,其兄的骨骼肌仅在许多肌纤维内出现小圆状嗜酸性包涵体.肌纤维内包涵体和肌纤维膜下结蛋白阳性.电镜显示先证者肌纤维内颗粒物质沉积.4例患者存在结蛋白基因S12F突变,无症状家系成员和健康对照无此突变.结论 结蛋白S12F新突变导致的结蛋白病多出现在男性,以心脏病多见.病理改变在家系不同患者之间存在差异.     

眼咽型远端型肌病二家系的临床、病理及分子学特点

目的 探讨2个眼咽型远端型肌病(OPDM)家系的临床、病理及分子生物学特点.方法 对2个家系的先证者行血清肌酶、肌电图、肌肉活体组织检查、肌肉酶组织染色及电镜分析,并于复诊时提取其静脉血DNA样本,进一步行编码多聚腺苷酸结合蛋白核1(PABPN1)、GNE基因突变分析.结果 家系1为同代3兄弟发病,家系2为2代4人发病.起病以发音困难伴双下肢无力居多；以发音及吞咽困难为表现的咽部肌群受累较突出.肌肉超微结构电镜分析未见到眼咽型肌营养不良样核内包涵体,2家系先证者PABPN1基因GCN重复拷贝数均为正常(10次,GCG6GCA3GCG1),且GNE基因2～12号外显子均未发现突变.结论 2个OPDM家系起病年龄、形式与日本患者类似,但肌肉受累方式有所不同.家系1为中国首个常染色体隐性遗传OPDM家系.本研究结果证实OPDM是一个表型、病理、遗传学独立的肌病实体.     

骨骼肌钠通道α1亚基基因R1129Q新突变导致正常钾和低钾性周期性瘫痪一家系

目的 报道1个骨骼肌钠通道α1亚基(SCN4A)基因新突变导致的正常钾和低钾性周期性瘫痪家系的临床和病理改变特点.方法 本家系为常染色体显性遗传,共有9例患者,男性4例,女性5例,发病年龄7～25岁.5例患者为正常钾性周期性瘫痪,其中4例伴随肌强直症状;3例患者为低钾性周期性瘫痪;1例发作时血钾浓度不详.对先证者进行左肱二头肌活体组织检查.先证者和7例家系患者、3名无症状家系成员以及50名健康人行SCN4A基因测序.结果 先证者的肌纤维出现轻度肥大和萎缩,伴随核内移和肌纤维内空泡,部分肌纤维内氧化酶分布异常.所有患者均存在SCN4A基因的R1129Q突变,3名无症状家系成员以及50名健康对照无此突变.结论 SCN4A基因R1129Q新突变在同一家系内可以导致低血钾性和正常血钾性周期性瘫痪共存.     

骨骼肌钠通道α1亚基基因R1129Q新突变导致正常钾和低钾性周期性瘫痪一家系

目的 报道1个骨骼肌钠通道α1亚基(SCN4A)基因新突变导致的正常钾和低钾性周期性瘫痪家系的临床和病理改变特点.方法 本家系为常染色体显性遗传,共有9例患者,男性4例,女性5例,发病年龄7～25岁.5例患者为正常钾性周期性瘫痪,其中4例伴随肌强直症状;3例患者为低钾性周期性瘫痪;1例发作时血钾浓度不详.对先证者进行左肱二头肌活体组织检查.先证者和7例家系患者、3名无症状家系成员以及50名健康人行SCN4A基因测序.结果 先证者的肌纤维出现轻度肥大和萎缩,伴随核内移和肌纤维内空泡,部分肌纤维内氧化酶分布异常.所有患者均存在SCN4A基因的R1129Q突变,3名无症状家系成员以及50名健康对照无此突变.结论 SCN4A基因R1129Q新突变在同一家系内可以导致低血钾性和正常血钾性周期性瘫痪共存.     

眼面咽喉肌受累的一个家系临床及其相关基因的初步研究

目的分析呈常染色体显性遗传，核心症状为眼外肌、面肌、咽喉肌肉瘫痪的一个家系，探讨其分类和病因。方法调查包括先证者在内的5例患者以及该家系中另外26名成员，收集其临床资料，进行电生理、肌肉病理检查，收集血样用PCR法进行基因验证。结果5例接受调查的患者经查体发现：眼睑下垂（5／5），眼外肌麻痹（5／5），面瘫（5／5），吞咽困难、声音嘶哑、咽反射迟钝（5／5），舌肌萎缩（3／5），颞肌萎缩（4／5），咬肌萎缩（4／5），近端肢体无力（3／5），肢体近端肌肉萎缩（4／5），远端肢体无力（3／5），肢体远端肌肉萎缩（4／5）。与眼咽型肌营养不良（OPMD）等疾病进行比较，电生理上确定病灶的性质为肌源性损害，肌肉病理为肌肉萎缩，但没有代谢性病变的表现，因此从电生理和肌肉病理两方支持肌营养不良的诊断。患者和表现健康的成员的PABPN1基因不存在（GCG）。（GCA），GCG的突变。结论该家系临床表现类似OPMD而不同于其他已知疾病，但是基因背景又完全不同于OPMD，可能属于肌营养不良的一种新亚型。     

中性脂肪沉积症合并肌病一家系

目的 报道1个中性脂肪沉积症合并肌病家系的临床和病理特点.方法 家系中同代2人发病,先证者为40岁女性,35岁出现缓慢发展的四肢肌肉无力和萎缩.其兄55岁,患先天性室间隔缺损,35岁出现双耳听力下降,45岁后出现四肢无力.对2例患者进行右肱二头肌活体组织检查,标本进行常规组织学、酶组织化学和电镜检查.对2例患者以及家系中其余3名健康成员进行三酯酰甘油水解酶-2(PNPLA2)基因检查.结果 2例患者均出现肌纤维肥大和萎缩伴随结缔组织增生,在许多肌纤维内可见镶边空泡以及大量脂肪滴沉积.电镜下可见空泡内出现髓样小体及细丝样包涵体,在肌原纤维之间可见大量脂肪滴.2例患者的PNPLA2基因2号内含子第1个碱基存在G＞A突变(IVS2+1G＞A).3名健康成员无此突变.结论 PNPLA2基因的2号内含子IVS2+1G＞A新突变导致的中性脂肪沉积症合并肌病出现明显的骨骼肌损害,该病可以伴随听神经损害以及先天性心脏病.肌纤维出现大量脂肪滴沉积和镶边空泡可能对诊断该病具有提示意义.     

眼咽型肌营养不良病理及分子遗传学研究

目的研究眼咽肌营养不良(ocu lopharyngeal muscu lar dystrophy,OPMD)的遗传学和病理形态学表现。方法应用透射电镜技术对6例患者提上睑肌进行超微结构观察和分析,并采用聚合酶链反应(PCR)产物直接测序法对来自3个家系的OPMD患者11例及其亲属共27名外周血进行检测。结果4例患者眼肌活检标本于电镜下可观察到特异性核内包涵体(intranuc lear inc lusions,INIs),在细胞核内出现率分别为18%、20%、34%及40%。而9例患者基因中存在(GCG)6重复序列拷贝数异常(GCG)8、(GCG)10,亲属中未发病者均未见重复序列的异常扩增。结论OPMD患者受累眼肌活组织检查于电镜下可见INIs,并且INIs出现比率与异常扩增数目成正比。OPMD患者存在(GCG)6重复序列的异常扩增,并且发病年龄与异常扩增数目成反比。     

ZASP基因突变所致肌原纤维病一家系报道及文献复习

目的通过对ZASP基因突变所致肌原纤维病一家系报道及文献复习,了解该病的临床、病理及基因突变特点。方法分析1例远端肌病患者的临床、肌肉MRI及肌肉病理特点,并追踪其家系家族史。先证者外周血提取DNA,进行目标区序列捕获二代测序(含58个肌病相关基因),明确存在ZASP基因变异。对家系其他成员进行Sanger测序进一步明确及验证突变位点。结果先证者为中年女性,52岁起病,表现为进行性双下肢无力伴双腿变细。先证者家系2代15名中,除先证者外共6名存在肌肉受累,4名为先证者同代亲属,临床特点与先证者类似;2名为先证者下一代亲属,其中1名仅有闭目肌受累及肌酸激酶(CK)轻度升高(291 U·L-1),另1名仅有CK轻度升高(199 U·L-1)。先证者肌肉病理发现肌细胞内有异常嗜伊红物质沉积和镶边空泡形成,免疫组化染色可见肌纤维内desmin蛋白沉积。电镜下可见Z线附近致密颗粒沉积。目标区序列捕获二代测序及Sanger测序确定该家系致病基因为ZASP基因已报道错义突变p.A147T(c.G439A)。结论 ZASP基因突变所致的肌原纤维病家系为国内首次报道。     

Oculopharyngeal muscular dystrophy with PABPN1 mutation in a Chinese Malaysian woman

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disorder of middle age presenting as progressive dysphagia and eyelid ptosis, due to short expansions of the GCG trinucleotide repeat (from GCG6 to GCG8-13) in the polyadenylate binding-protein nuclear 1 (PABPN1) gene. OPMD is rarely seen in Asians and morphologically and/or genetically confirmed cases have been reported in Japanese kindreds only. We report a 64 year old Chinese-Malaysian woman who presented with progressive dysphagia and bilateral ptosis for about 6 years. Her mother and elder brother (both deceased) were believed to be affected. Muscle histopathology revealed angulated fibres with rimmed vacuoles. Genetic analysis showed repeat expansion in one allele to (GCG)9 while normal in the other (GCG)6. This is the first non-Japanese Asian family with genetically confirmed OPMD.     

Progress in understanding the pathogenesis of oculopharyngeal muscular dystrophy

Oculopharyngeal muscular dystrophy (OPMD) is an adult-onset disorder characterized by progressive eyelid drooping (ptosis), swallowing difficulties (dysphagia), and proximal limb weakness. The autosomal dominant form of this disease is caused by expansions of a (GCG)6 repeat to (GCG)8-13 in the PABPN1 gene. These mutations lead to the expansion of a polyalanine stretch from 10 to 12-17 alanines in the N-terminal domain of PABPN1. Mutated PABPN1 (mPABPN1) induces the formation of muscle intranuclear inclusions that are thought to be the hallmark of this disease. In this review, we discuss: 1) OPMD genetics and PABPN I function studies; 2) diseases caused by polyalanine expansions and cellular polyalanine toxicity; 3) mPABPN1-induced intranuclear inclusion toxicity; 4) role of oligomerization of mPABPNI in the formation and toxicity of OPMD intranuclear inclusions and; 5) recruitment of subcellular components to the OPMD inclusions. We present a potential molecular mechanism for OPMD pathogenesis that accounts for these observations.     

Identification of a novel mutation in a Korean patient with oculopharyngeal muscular dystrophy.

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset muscle disorder characterized by progressive dysphagia and bilateral ptosis. Mutations in the polyadenylate binding protein nuclear 1 (PABPN1) gene have been found to cause OPMD. The typical mutation is a stable trinucleotide repeat expansion in the first exon of the PABPN1 gene, in which (GCG)(6) is the normal repeat length. We investigated a Korean patient with OPMD and identified a novel mutation: a heterozygous insertion of a 9-bp sequence [(GCG)(GCA)(GCA); c.27_28insGCGGCAGCA] instead of the (GCG) repeat expansion, resulting in an in-frame insertion of three alanines (p.A10insAAA). To the best of our knowledge, this is the first report of a genetically confirmed case of OPMD in Korea.     

HnRNP A1 and A/B interaction with PABPN1 in oculopharyngeal muscular dystrophy

BACKGROUND: Oculopharyngeal muscular dystrophy (OPMD) is an adult-onset disorder characterized by progressive ptosis, dysphagia and proximal limb weakness. The autosomal dominant form of this disease is caused by short expansions of a (GCG)6 repeat to (GCG) in the PABPN1 gene. The mutations lead to the expansion of a polyalanine stretch from 10 to 12-17 alanines in the N-terminus of PABPN1. The mutated PABPN1 (mPABPN1) induces the formation of intranuclear filamentous inclusions that sequester poly(A) RNA and are associated with cell death. METHODS: Human fetal brain cDNA library was used to look for PABPNI binding proteins using yeast two-hybrid screen. The protein interaction was confirmed by GST pull-down and co-immunoprecipitation assays. Oculopharyngeal muscular dystrophy cellular model and OPMD patient muscle tissue were used to check whether the PABPN1 binding proteins were involved in the formation of OPMD intranuclear inclusions. RESULTS: We identify two PABPNI interacting proteins, hnRNP A1 and hnRNP A/B. When co-expressed with mPABPN1 in COS-7 cells, predominantly nuclear protein hnRNP A1 and A/B co-localize with mPABPN1 in the insoluble intranuclear aggregates. Patient studies showed that hnRNP A1 is sequestered in OPMD nuclear inclusions. CONCLUSIONS: The hnRNP proteins are involved in mRNA processing and mRNA nucleocytoplasmic export, sequestering of hnRNPs in OPMD intranuclear aggregates supports the view that OPMD intranuclear inclusions are "poly(A) RNA traps", which would interfere with RNA export, and cause muscle cell death.     

Oculopharyngeal muscular dystrophy

Autosomal dominant oculopharyngeal muscular dystrophy (OPMD) is an adult-onset disease with worldwide distribution. It usually presents in the fifth or sixth decades with progressive dysphagia, eyelid ptosis, and proximal limb weakness. Unique intranuclear filament inclusions in skeletal muscle fibers are its morphological hallmark. Surgical correction of the ptosis and cricopharyngeal myotomy are the only therapies available. Autosomal dominant OPMD is caused by short (GCG)8-13 riplet-repeat expansions in the polyadenylation binding protein 2 (PABP2) gene, which is localized in chromosome 14q11. Autosomal recessive OPMD is caused by a double dose of a (GCG)7 PABP2 allele. The GCG expansions cause lengthening of a predicted polyalanine tract in the protein. The expanded polyalanine domains may cause polyalanine nuclear toxicity by accumulating as nondegradable nuclear filaments.     

Genetic heterogeneity in 30 German patients with oculopharyngeal muscular dystrophy

Oculopharyngeal muscular dystrophy (OPMD) is due to short elongations of a polyalanine tract in the poly(A) binding protein nuclear 1 (PABPN1) gene. Originally GCG expansions in which (GCG)₆ is extended to (GCG)_7–13 were found. Subsequently five further genotypes with additional GCA– and GCG–trinucleotides were identified in single OPMD patients. This indicated larger genetic heterogeneity and showed that unequal crossing–over and not replication slippage must be the underlying mechanism of elongation.We performed sequencing of the PABPN1 gene in 30 German OPDM index patients to determine the exact genotype. The original GCG expansion ranging from (GCG)₈ to (GCG)₁₁ was found in 22 patients. In 8 patients, however, three different elongated alleles other than classical (GCG)_7–13 were observed. Two of these genotypes had already been identified in Japanese patients. One genotype was recently identified showing (GCG)₆ followed by inserted (GCA)₃GCG in four unrelated patients. This study further supports the theory of unequal crossing over as the molecular mechanism leading to elongation. It shows that other genotypes than classical (GCG)_7–13 are rather common in German OPMD patients. The data imply that there is no single founder effect in German OPMD patients. Drs. Müller and Deschauer contributed equally to this work.     

Mutation and haplotype analysis of oculopharyngeal muscular dystrophy in Thai patients

Oculopharyngeal muscular dystrophy (OPMD) is an inherited neuromuscular disease associated with a short trinucleotide repeat expansion in Exon 1 of the PABPN1 gene. OPMD is uncommon in East Asian populations, and there have been no previous reports of Thai patients. We studied clinical and molecular genetic features of six unrelated Thai patients with autosomal dominant OPMD. All patients had expansions of the guanine-cytosine-guanine (GCG) repeat ranging from three to seven additional repeats in the PABPN1 gene. Haplotype analysis showed that these mutations might have originated independently. Analysis of the size of the GCG repeat in the PABPN1 gene in 200 Thai control patients showed that 0.5% of the control subjects possessed (GCG)₇, thereby suggesting that the prevalence of autosomal recessive OPMD in the Thai population was approximately 1 in 160,000. In conclusion, our data suggest that OPMD in Thailand may be more common than previously thought.     

A late-onset case of oculopharyngeal muscular dystrophy carrying a (GCG)8 repeat expansion in the PAPBN1 gene]

We report a sporadic case of a female patient with oculopharyngeal muscular dystrophy (OPMD). Her father died at age 86 and mother at age 74. There was no familial occurrence of the disease. The patient initially developed a nasal voice at age 66. Neurological examinations on admission at age 72 revealed bilateral ptosis, a limitation of ocular movement without diplopia, dysphagia, and proximal muscle weakness. Serum creatine kinase level was slightly increased. Biopsied muscle specimens showed variation in fiber size as well as the occasional presence of rimmed vacuoles. On the basis of these clinical and laboratory findings, we suspected a diagnosis of OPMD, although a family history was absent. To confirm the diagnosis of OPMD, we performed a gene analysis for poly A binding protein, nuclear 1 (PABPN1; PABP2), which revealed a mild expansion of GCG repeat (8 repeats) as a heterozygous state. Clinical features of the patient were consistent with those in a previous literature reporting that patients carrying (GCG)8 repeat as a heterozygous state show a relatively late onset and a mild phenotype. The case of this patient emphasizes the importance of the PABPN1 gene analysis for patients showing muscular weakness involving oculopharyngeal and proximal limb muscles even when a familial occurrence of the disease is not apparent.     

Okulopharyngeale Muskeldystrophie Genetische Diagnostik einer Familie in Deutschland

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant myopathy with almost benign course. Its clinical features include ptosis, dysphagia, and proximal limb muscle weakness. The OPMD gene has been localized to chromosome 14, causing expansions of GCG triplets. Scattered families with OPMD belonging to different ethnic groups have been described worldwide. We describe one from northern Germany. In genetic diagnosis, expansion of GCG triplets to 11 was observed, which proved that myopathy, which is very rare in Germany.