2例不同遗传方式中央轴空病的临床、病理、影像及基因分析

目的分析2例不同遗传方式中央轴空病患者的临床、肌肉影像学、病理学及基因突变特点,比较其临床表型和分子遗传学的异同点。方法详细收集2例患者的临床资料、肌肉MRI及病理学,靶向捕获二代测序进行基因检测,Sanger测序验证及家系共分离分析。结果 2例分别为常染色体隐性(autosomal recessive,AR)和显性(autosomal dominant,AD)患者,表现儿童早期起病,四肢近端无力伴萎缩,面肌受累;双下肢肌肉MRI见广泛肌肉萎缩及脂肪浸润,股直肌回避;病理氧化酶染色见肌纤维典型的轴空结构,AR型存在偏心轴空;发现斯里兰卡肉桂碱受体1(Ryanodine receptor 1,RYR1)基因的3个错义突变,其中一个未报道。结论本研究的2例经典型患者存在不同遗传方式,在临床表型、受累肌群分布及病理存在诸多异同,可能与RYR1基因的不同突变形式相关,靶向二代测序可以提高确诊率。     

常染色体显性遗传中央核肌病一家系临床、病理和分子生物学特点

目的分析常染色体显性遗传中央核肌病（centronuclear myopathy，CNM）一家系中患者的临床、病理和基因突变特点。方法对家系中患者及其家属进行详细的神经系统检查，先证者行肌肉活检、组织学和酶组织化学染色，并进行动力蛋白2（dynamin 2，DNM2）基因突变检测。结果2例患者以双下肢无力为首发和主要症状，远端为著，伴有明显的全身肌肉萎缩，渐进性加重；先证者肌酸激酶轻度升高，2例患者肌电图均呈肌源性改变；家系中无其他类似患者。肌肉呈现中央核肌病的典型病理改变，90％的肌纤维中出现中央核，核周肌质带呈放射状排列，Ⅰ型纤维优势和萎缩。DNM2高频突变区域测序证实为外显子81105C→T突变。结论从临床、病理及基因等方面证实本家系为遗传性中央核肌病，致病基因为DNM2。     

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.     

细丝蛋白C肌病基因存在新的插入缺失突变

目的 报道在1个细丝蛋白C(filamin C,FLNC)肌病家系中发现的新的插入缺失突变.方法 该家系连续5代共有19例患者,临床和病理资料在前期研究中已经作为肌原纤维肌病进行了报道.现对包括先证者在内的3例患者、5名无症状家系成员和50名健康人进行FLNC基因的测序,利用质粒将FLNC基因的第18号外显子扩增产物进行克隆分离,然后进行电泳鉴定和直接测序.结果 先证者的FLNC基因的第18号外显子存在18个正常碱基缺失,同时插入6个异常碱基,导致FLNC蛋白第7个免疫球蛋白样杆状重叠结构异常,继而致FLNC蛋白结构的失稳.家系中另2例患者存在同样的突变,而5名无症状家系成员和50名健康对照均正常.结论 FLNC肌病存在FLNC基因第18号外显子新的插入缺失突变,我们发现该病可以出现在德国之外的其他种族.     

Bethlem肌病一家系临床表型及基因突变分析

目的分析Bethlem肌病临床表型和基因突变特点。方法报道一家系3例女性患者临床表型、肌电图、肌肉活检、肌肉病理学和基因检测结果,并结合相关文献进行分析。结果先证者于13岁发病,以进行性四肢近端无力为主要临床表现。血清学肌酸激酶水平显著升高,肌电图呈肌源性损害,肌肉病理学显示骨骼肌局灶坏死等非特异性肌源性损害。基因检测显示,先证者及其母、其妹存在相同基因突变,即COL6A3基因错义突变c.4270C>T。结论该家系Bethlem肌病患者为COL6A3基因突变致病,临床通过基因测序手段可提高诊断率,有助于产前诊断,减少遗传病发生率。     

DNAJB6基因突变致显性遗传性肌病一家系并文献复习

目的总结常染色体显性遗传性DNAJB6基因突变所致肌病的临床表型和基因突变特点。方法回顾分析一家系2例DNAJB6基因突变所致肌病患者的临床表现、实验室、肌肉影像学、神经电生理学、肌肉病理学和基因检测结果,并进行文献复习。结果先证者主要表现为四肢远近端肌无力,下肢重于上肢、近端重于远端,其父呈姿势异常,上楼需扶持。二者血清肌酸激酶水平正常,MRI表现为不同程度肌肉脂肪化,组织病理学可见肌营养不良样改变,部分肌纤维内镶边空泡形成,核内移增多或个别肌纤维再生。基因检测提示先证者及其父均携带DNAJB6基因c.161A>C(p.Glu54Ala)杂合突变,为中国大陆首次报道,分别为肢带型肌营养不良症D1型(LGMD?D1型)和远端型肌病型,该家系明确为常染色体显性遗传性DNAJB6基因突变所致肌病家系。结合文献提示DNAJB6基因突变所致肌病临床表现存在异质性,同一家系可表现为不同的临床亚型。结论DNAJB6基因突变可导致肢带型肌营养不良症和远端型肌病两种表型,肌肉病理均呈现镶边空泡和肌营养不良样改变。该家系进一步扩展了DNAJB6基因突变的表型谱。     

MYOT基因变异相关肌原纤维肌病3型的临床、肌肉病理和分子遗传学分析

目的对MYOT基因突变致肌原纤维肌病3型的临床表型特点、肌肉病理、基因突变及相关蛋白进行分析, 并对该病进行文献复习和综述。方法回顾分析2018年12月于山东大学齐鲁医院确诊的1例MYOT基因突变致肌原纤维肌病3型患者的临床表型特点、肌肉病理和基因检测结果。应用全外显子测序对患者进行高通量致病基因筛查, 发现候选致病突变后应用Sanger测序技术对患者及家系成员进行突变位点的验证, 同时对发现的MYOT的基因突变位点进行功能学验证并结合相关文献进行复习综述。结果该患者为47岁女性, 因双下肢无力8年就诊。肌电图检查示肌源性损害;肌肉病理提示部分肌纤维内异常物质沉积及镶边空泡。外显子组测序和Sanger测序发现患者携带MYOT基因c.170C>T(p.Thr57Ile)杂合突变, 其儿子、女儿也存在着相同的突变位点。患者儿子肌酸激酶水平升高, 肌电图偶见自发电位, 患者女儿无异常;患者2名弟弟未检测到上述变异位点。蛋白功能研究提示MYOT基因c.170C>T突变可导致myotilin的部分空间结构发生改变, 且p62蛋白与myotilin的异常聚集参与疾病的致病过程。经文献复...     

一个肢带型肌营养不良家系的临床和分子遗传学分析

目的 研究1个肢带型肌营养不良(limb girdle muscular dystrophy,LGMD)家系的临床表现,并应用基因突变分析、基因组扫描技术和连锁分析对该家系进行分子遗传学分析.方法 对1个来自浙江的连续4代发病的LGMD家系进行家系调查和体格检查,先证者行电生理检查及肌肉病理活体组织检查分析;26名家系成员在知情同意的情况下抽取基因组DNA进行基因突变分析、基因组扫描和连锁分析.结果 家系分析证明该家系符合常染色体显性遗传,家系中存在遗传早现现象,主要表现为四肢近端肌无力,无构音障碍、肌强直;电生理检查和肌肉活体组织检查符合肌肉病变特点;基因突变分析未发现LGMD1A、1B、1C和面肩肱型肌营养不良(FSHD)基因的致病突变;基因组扫描和连锁分析显示该家系致病基因与已报道的LGMD1D和LGMD1F的染色体区间连锁关系不成立.结论 LGMD家系患者的临床表现具有高度异质性,该家系的致病基因不在已报道的位点内,推测可能存在新的致病位点或是一种新的LGMD遗传类型.     

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.     

常染色体显性遗传性微管聚集性肌病存在SCN4A基因突变(附1家系报告)

目的 探讨显性遗传性微管聚集性肌病的临床、骨骼肌病理和基因改变特点.方法 对显性遗传性微管聚集性肌病1家系进行分析研究,先证者为17岁男性,1岁开始出现发作性面肌、咀嚼肌和四肢肌无力,以及寒冷或活动诱发的肌肉僵硬,发作间期持续性肢体乏力.家族中连续4代10例出现类似临床表现.对先证者及其母亲进行肌肉活检.对母子及家族中无症状者行SCN4A基因序列检测.结果 在先证者和其母亲的Ⅱ型肌纤维肌纤维内均发现异常沉积物,分别占所有肌纤维的10%和3%.免疫组织化学染色见病变肌纤维内tau、dysferlin和泛素阳性表达.电镜检查显示沉积物为大量聚集的微管结构.基因测序发现母子两人的SCN 4A基因第13号外显子存在T704M突变.结论 病理检查证实显性遗传性微管聚集性肌病,该病和SCN4A基因突变有关,出现副肌强直性周期性瘫痪的临床表型.     

Nonaka肌病伴面部肌肉受累

目的 报道1个伴随面部肌肉受累及的Nonaka型远端性肌肉病家系的临床和病理特点，讨论其发病机制。方法 先证者在中年早期起病。主要临床表现为胫前肌为主的四肢远端肌无力和肌萎缩，伴随有面肌和胸锁乳突肌力弱以及眼睑下垂，股四头肌不受累。肌酶轻度升高。肌电图提示肌源性损害。对患者进行胫前肌活检，进行组织学，酶组织化学和超微结构检查。家族中其妹妹也具有相同的临床表现。出现下肢远端为主的肌无力和肌萎缩。结果 肌肉病理改变特点是出现肌纤维肥大和萎缩。伴随核内移和肌纤维分裂现象。在部分肌纤维内可见镶边空泡和胞浆体。电镜下可见肌纤维内和核内的管丝包涵体以及髓样小体，其中出现在膜下的管丝包涵体具有细胞核的轮廓，可以看到细胞核变性后形成致密破碎结构。结论 结合患者的家庭史，临床表现和病理学改变特点。此患者可以考虑为Nonaka肌病，我们证实此病可以伴随面部肌肉的受累及。其发病机制可能与肌核的变性有关。     

TWINKLE gene mutation: report of a French family with an autosomal dominant progressive external ophthalmoplegia and literature review

Background: Multiple mitochondrial DNA (mtDNA) deletions usually have a mendelian inheritance secondary to mutation in nuclear genes. One of these is the Twinkle gene whose mutation is responsible for autosomal dominant progressive external ophthalmoplegia (PEO). The number of reported cases with mainly myopathic symptoms and possible nervous system involvement related to Twinkle gene mutation is limited. We present a new French family of whom two members displayed myopathy and neuropathy associated with PEO, and we perform a clinical review in light of other observations reported in the literature. Methods: The proband, one son and the daughter have been investigated. Southern blot analysis and long‐range PCR assay have been performed from muscle biopsy specimens. Coding exons and flanking intron regions of polymerase gamma (POLG) and DNA helicase (Twinkle) genes were sequenced. Results: Multiple mitochondrial DNA deletions have been found and sequencing of the Twinkle gene showed the change p.R374Q. Conclusion: Two other families from the literature also had the R374Q mutation. Symptoms reported in association with this mutation were myopathy, peripheral neuropathy, dysarthria and/or dysphagia, respiratory insufficiency and parkinsonism. Respiratory insufficiency caused by chest wall weakness was reported in other families with different Twinkle gene mutations, and one might provide exercise intolerance, dysarthria and/or dysphagia as symptoms in favor of the diagnosis. Occurrence of impressive emaciation was a peculiarity in our family.     

The clinical and myopathological features of oculopharyngodistal myopathy in a Chinese family

Oculopharyngodistal myopathy is a rare type of hereditary myopathy characterised pathologically by the changes of muscular dystrophy with rimmed vacuoles and intra‐muscular tubulofilamentous inclusions. Here we report the clinical and myopathological changes in a Chinese family with oculopharyngodistal myopathy. The proband showed external ophthalmoplegia, dysphagia, distal weakness and atrophy in all extremities. Serum creatine kinase level was mildly elevated and a myopathic pattern with myotonic discharge was demonstrated by electromyography (EMG). Molecular genetic analysis showed that the number of trinucleotide repeat expansions in the polyadenylate‐binding protein nuclear 1 gene was within the normal limit. No mutations were indentified in the GNE gene. Five other persons with similar symptoms were found in the same generation. Muscle biopsy was performed on the tibialis anterior muscle in the proband. Muscular dystrophy changes with rimmed vacuoles were the main histopathological changes. Ultrastructural examination revealed numerous tubulofilamentous inclusions in both sarcoplasm and nucleus. EMG showed myotonic discharges in oculopharyngodistal myopathy. In addition to the sarcoplasm inclusions, we confirmed that tubulofilamentous inclusions appeared also in the nucleus.     

Markesbery Disease: Autosomal Dominant Late-Onset Distal Myopathy: From Phenotype to ZASP Gene Identification

In 1974, Markesbery et al. thoroughly characterized and reported a large kindred with distal muscle weakness of late adult-onset that was autosomal dominantly inherited. Clinical evidence supported myopathy rather than the usual neuropathy expected with distal weakness. Postmortem examination of two patients documented myopathy and excluded anterior horn cell disease or peripheral neuropathy as the cause. Distinctive morphologic changes were present in muscle. Widely accepted as a distinct disease entity, this disorder has recently been characterized as one of a group of myofibrillar myopathies resulting from mutations in several muscle proteins. Studies of members of the original family have now identified the molecular defect to be a mutation in ZASP, Z-band alternatively spliced PDZ-motif-containing protein. The specific mutation, A165V, was identified in all clinical affected family members by direct sequencing. Thus, Markesbery disease is a zaspopathy. Other families have been identified with the same mutation and a shared haplotype indicating a founder effect.     

A novel mutation in the PDZ‐like motif of ZASP causes distal ZASP‐related myofibrillar myopathy

Mutations in the LDB3 gene have been identified in patients with Z‐disc‐associated, alternatively spliced, PDZ motif‐containing protein (ZASP)‐related myofibrillar myopathy (ZASP‐MFM) characterized by late‐onset distal myopathy with signs of cardiomyopathy and neuropathy. We describe an autosomal dominant inherited pedigree with ZASP‐MFM that is in line with the typical phenotype of distal myopathy without cardiomyopathy and neuropathy, while mild asymmetrical muscle atrophy can be observed in some affected members. Muscle MRI revealed considerable fatty degeneration involved in the posterior compartment of thigh and lower leg, but relatively preserved in rectus femoris, sartorius, gracilis, adductor longus and biceps femoris breve muscles in the later stage. In addition, fatty infiltration of medial gastrocnemius muscle can be initiated as early as in the third decade in asymptomatic individuals. Myopathological features showed sarcoplasmic accumulation of multiple protein deposits and electron dense filamentous bundle aggregates. A novel heterozygous missense mutation (p.N155H) in a highly conserved PDZ‐like motif of ZASP was identified. The results indicate that typical ZASP‐MFM presenting with late‐onset distal myopathy is commonly associated with mutations in PDZ‐like motif of ZASP. The development of fatty degeneration is consistent with the typical pattern of ZASP‐MFM, and the initial fatty infiltration might be started from medial gastrocnemius muscle. Our study expands the clinical and mutational spectrum of ZASP‐MFM.     

ZASPopathy with childhood-onset distal myopathy

We report on a German family presenting with a predominantly distal myopathy primarily affecting anterior compartments of lower legs in childhood. Proximal lower limb and hip girdle weakness developed later in early adulthood in the female index patient and likewise in her mother. Consecutive muscle biopsy findings were first attributed to a mild congenital myopathy and later on interpreted as neurogenic changes without clear signs of a myopathy. Molecular genetic analysis was performed because of the clinical impression of a distal myopathy combined with dominant inheritance. The heterozygous mutation c.349G>A (p.D117N) in the ZASP gene could be found. This mutation had been previously associated with an adult-onset, isolated, dilated left ventricular non-compaction cardiomyopathy (OMIM*605906.0007), which was not present in our patients. Our data show that this mutation can be associated with an isolated skeletal muscle phenotype. Second, mutation analysis of the ZASP gene is suggested for distal myopathies of any age, even in cases of uncharacteristic muscle biopsy findings on routine analysis.     

FHL1-mutated reducing body myopathy

Here, we report about reducing body myopathy, associated with a mutation in the four and a half LIM domain 1 gene (FHL1), identified in a 40-year-old woman who was suffering from subtle muscle weakness since the age of six and a limping gait since the age of 22 years. In addition to her elevated muscle enzyme level and magnetic resonance imaging, myopathy was highly suspected considering progression of symptoms. Nerve conduction studies and electromyogram suggested myopathy. The muscle biopsy revealed severe dystrophic features with many reducing bodies on hematoxylin and eosin, nicotinomide adenine dinucleotide dehydrogenase-tetrazolium reductase (NADH-TR), and modified Gomori stains and ubiquitin immunohistochemistry. Whole-exome sequencing revealed Xq26.3 encoding FHL1 missense mutations (NM_001159704) in exon 4: p.C150R, c.T448C. FHL1-mutated “reducing body myopathy” is worth reporting based on its rarity and unique clinicopathologic features including ultrastructure. The confirmative diagnosis is still very difficult before gene analysis because clinical and pathological features of this disease overlap with other myofibrillar myopathies. We stress the importance of genotype-phenotype correlation to obtain a precise diagnosis.     

<Emphasis Type="Italic">MYH7</Emphasis> mutation associated with two phenotypes of myopathy

The mutations of MYH7 (slow skeletal/β-cardiac myosin heavy chain) are commonly found in familial hypertrophic/dilated cardiomyopathy, and also can cause Laing early-onset distal myopathy (LDM), myosin storage myopathy (MSM), and congenital myopathy with fiber-type disproportion (CFTD). Here we report two cases whose diagnosis was hereditary myopathy according to clinical feature and muscle pathology analysis. High-throughput genomic sequencing (next generation sequencing) was performed to validate the diagnosis. Two MYH7 mutations, p.R1845W and p.E1687del, were identified. p.R1845W was found in a male patient showing weakness of both terminal lower legs without foot drop. Muscle pathology stainings characteristically showed the hyaline body in the intracytoplasmic location. The novel mutation p.E1687del was found in a family with seven patients. The proband showed foot drop, scoliosis, and winged scapula, while his mother only showed mild foot drop and winged scapula. Muscle pathology analysis showed congenital centronucleus myopathy. Both cases only showed muscular disorder and had no cardiomyopathy. This study, for the first time, reports the MYH7 mutations associated with centronucleus myopathy.     

Progress and challenges in diagnosis of dysferlinopathy

Dysferlin‐deficient limb girdle muscular dystrophy type 2B, distal Miyoshi myopathy, and other less frequent phenotypes are a group of recessive disorders called dysferlinopathies. They are characterized by wide clinical heterogeneity. To diagnose dysferlinopathy, a clinical neuromuscular workup, including electrophysiological and muscle imaging investigations, is essential to support subsequent laboratory testing. Increased serum creatine kinase levels, distal or proximal muscle weakness, and myalgia with onset in the second or third decades are the main clinical features of the disease. In muscle biopsies, severe dysferlin deficiency by immunoblot or its abnormal localization by immunohistochemistry are the gold standard, as they have a high diagnostic value. Dysferlin testing on monocytes is a valuable alternative to muscle immunoblotting. Molecular techniques for gene mutation detection, such as next generation sequencing, have improved the genetic diagnosis, which is crucial for treatment and genetic counselling. Muscle Nerve 54 : 821–835, 2016