核黄素反应性脂质沉积性肌病20个家系的电子转移黄素蛋白脱氢酶基因存在热点突变

目的 报道20个核黄素反应性脂质沉积性肌病(RR-LSM)患者的电子转移黄素蛋白脱氧酶(ETFDH)基因检查结果.方法 对2003年1月至2010年5月我院神经科收治的24例RRLSM患者(来自20个我国大陆北方地区RR-LSM家系,其中16个家系各有1例患者,其余4个家系各有2例发病者)的临床特点进行分析.对24例患者、11名无症状家系成员以及100名健康人行ETFDH基因检查.结果 24例患者发病年龄为(27.9±9.9)岁,主要症状为四肢无力(21例,87.5%)、咀嚼困难(15例,62.5%)、颈肌无力(14例,58.3%)和肌痛(14例,58.3%)等.18例患者的血代谢筛查均提示脂酰肉碱升高,17例患者中有15例存在戊二酸尿症.我们发现19个家系存在17种ETFDH基因点突变,包括13种错义突变、2种剪切突变和2种无义突变.其中患者的c.998A>G、c.1450T>C、c.1703T>C、c.11717C>T、c.821G>A、c.643G>A、c.25IC>T、c.1763A>T、c.IVS7+2T>C、c.IVS6+1G>A没有出现在100名健康人中.有9个家系存在c.770A>G(P.Y257C)突变;5个家系存在c.1227A>C(P.L409F)突变.结论 诸多ETFDH基因新突变提示国人RR-LSM可能存在特殊的基因突变谱,其中P.Y257C与P.L409F突变可能为我国大陆北方地区的热点突变.

Abstract：

Objective To report the spectrum of electron transfer flavoprotein dehydrogenase (ETFDH)gene mutations in 20 Chinese RR-LsM families.Methods Twenty-four RR-LSM patients in the First Hospital of Peking University from January 2003 to May 2010 were collected and the clinical characteristics were analyzed.These patients came from 20 families in North Mainland China.Sixteen families had 1 patient each.and the other 4 families had 2 patients.ETFDH gene analysis was performed in all patients,11 family members and 100 healthy controls.Results The mean onset age was(27.9±9.9)years.The main symptoms were limb weakness(21,87.5%),dysmasesia(15,62.5%),neck weakness (14,58.3%)and myalgia(14,58.3%).Eighteen patients had high level of acyleamitine.Fifteen of 17patients had glutaric aciduria.Seventeen ETFDH mutations,including 13 missense mutations,2 splice mutations,and 2 nonsense mutations,were identified in 19 families:c.998A>G,c.1450T>C,c.1703T>C,c.1717C>T,c.821G>A,c.643G>A,c.251C>T,c.1763A>T,c.IVS7+2T>C and c.IVS6+1G>A were Hovel mutations which were not found in 100 healthy controls.Nine families had the mutation of c.770A>G(P.Y257C)and 5 families had the mutation of c.1227A>C(P.L409F).Conclusions The numerous novel mutations in ETFDH gene indicate that Chinese RR-LSM might have special mutation pattern.c.770A>G(P.Y257C)and c.1227A>C(p.L409F)may be hot spot mutations in North Mainland China.     

核黄素反应性脂质沉积性肌病两家系临床分析

目的探讨由ETFDH基因突变引起的核黄素反应性脂质沉积性肌病(Lipid storage myopathy,LSM)的临床特点以及核黄素的治疗效果。方法通过肌肉磁共振(MRI)、肌肉活检及基因检测确诊两家系3例LSM患者,并评估给予核黄素治疗前后患者运动症状的变化。结果 2例左侧三角肌肌肉MRI与肌肉活检提示肌肉脂质沉积,基因检测揭示1例存在ETFDH基因c.1395dupT(p.G466Wfs*24)和c.770AG(p.Y257C)复合杂合突变,2例存在ETFDH基因c.770AG(p.Y257C)纯合突变,3例经核黄素治疗1个月后运动症状均得到显著改善。结论对于无明显诱因引起的双下肢无力患者,可通过肌肉活检和基因检测进行确诊,且核黄素能够有效改善运动症状。     

核黄素反应性脂质沉积性肌病一家系ETFDH基因突变研究

目的探讨核黄素反应性脂质沉积性肌病一家系ETFDH基因的突变方式。方法分析核黄素反应性脂质沉积性肌病家系的临床资料,采用PCR方法对家系中的2例患者、先证者的儿子及孙子以及100名健康对照者的ETFDH基因所有外显子进行DNA测序。结果 2例患者的ETFDH基因第7及10号外显子各发现一个突变,分别是c. 770A G和c. 1270_1273del;先证者的儿子携带c. 1270_1273del突变。先证者的孙子及100名健康对照者未发现上述突变。结论该c. 1270_1273del突变为新发现的致病性突变,与c. 770A G突变共同作用导致核黄素反应性脂质沉积性肌病,基因检测有助于明确诊断及提供遗传咨询。     

中性脂肪沉积症合并肌病一家系

Objective To study the clinical,myopathological features in neutral lipid storage disease with myopathy (NLSDM) caused by a novel PNPLA2 mutation.Methods Two patients were siblings.The proband was a 40-year-old woman.She presented progressive limb weakness and muscle atrophy at 35 years old.Her 55-year-old brother presented deafness at 35 years old and limb weakness at 45 years old. He suffered from ventricular septal defect.Open biosies were performed on them and specimens were studied histologically enzymhistochemically.and ultrastructurally.All the exons of PNPLA2 gene were analyzed in the both patients and 3 healthy family individuals.Results Muscle biopsy in both patients revealed hypertrophy and atrophy of fibers with proliferation of connective tissue.There were numerous lipid droplets and plenty of rimmed vacuoles in the fibers.Electron microscopy revealed lipid droplets between sarcomeres as well as myelin figures.A single homozygous base substitution was detected at the beginning of intron 2(IVS2+1G＞A)of PNPLA2 in two patients.but not in the healthy family individuals. Conclusion The novel IVS2+1G＞A mutation of PNPLA2 causes NLSDM with prominent limb weakness.The disease may be associated with auditory nerve lesions and congenital heart disense.Rimmed vacuoles with lipid storage in the fibets might have indication for diagnosis of NLSDM.     

Paroxysmal kinesigenic dyskinesia and myotonia congenita in the same family：coexistence of a PRRT2 mutation and two CLCN1 mutations

Paroxysmal kinesigenic dyskinesia（PKD） and myotonia congenita（MC） are independent disorders that share some clinical features. We aimed to investigate the sequences of PRRT2 and CLCN1 in a proband diagnosed with PKD and suspected MC. Clinical evaluation and auxiliary examinations were performed. Direct sequencing of the entire coding regions of the PRRT2 and CLCN1 genes was conducted. Haplotype analysis confirmed the relationships among the family members. The proband suffered choreoathetosis attacks triggered by sudden movements, and lower-limb weakness a n d s t i ff n e s s t h a t w o r s e n e d i n c o l d w e a t h e r. Carbamazepine monotherapy completely controlled his choreoathetosis and significantly relieved his limb weakness and stiffness. His father, when young, had similar limb stiffness, while his mother and brother were asymptomatic. Genetic analysis revealed that the proband and his father harbored a PRRT2 c.649 dup C mutation, and CLCN1 c.1723C〉T and c.2492A〉G mutations. His brother carried only the two CLCN1 mutations. None of these mutations were identified in his mother and 150 unrelated controls. This is the first report showing the coexistence ofPRRT2 and CLCN1 mutations. Our results also indicate that both the PRRT2 and CLCN1 genes need to be screened if we fail to identify PRRT2 mutations in PKD patients or CLCN1 mutations in MC patients.     

Correlation between human seizure-related gene 6 variants and idiopathic generalized epilepsy in a Southern Chinese Han population

This study sought to analyze the genotype and gene mutations of human seizure-related gene 6 in 98 patients with idiopathic generalized epilepsy (non-febrile seizures), who were selected from three generations of the Chinese Han population living in Shanghai, Zhejiang Province, Wuxi of Jiangsu Province, and Jiangxi Province of Southern China. Twenty-six patients’ parents were available as a first-degree relatives group and 100 biologically unrelated healthy controls were collected as the control group. Based on the age of onset and seizure type, the patients were divided into six subgroups. Polymerase chain reaction and DNA direct sequencing analysis showed that the most frequent mutations c.1249dupC (p.Gly418Argfx31) and c.1636A > G (p.Thr546Ala) were detected in some idiopathic generalized epilepsy patients and their asymptomatic first-degree relatives (30.6% vs. 19.2% and 11.2% vs. 26.9%). A novel mutation c.1807G > A (p.Val603Met) was found in a patient with late-onset idiopathic generalized epilepsy. There was no significant difference in the incidence of these three mutations among the different subgroups of idiopathic generalized epilepsy and controls. Thus, further analysis of a larger population is needed to confirm the assumption that human seizure-related gene 6 is a susceptibility gene for idiopathic generalized epilepsy with various sub-syndromes.     

线粒体基因G13513A突变导致的线粒体脑肌病六例临床表型分析

目的 报告6例mtDNA G13513A点突变引起的线粒体脑肌病患者的临床、影像学特点,总结mtDNA G13513A突变所致的线粒体病的临床表型.方法 对35例mtDNA常见突变(包括大片段缺失及A3243G、T3271C、A8344G、T8993G/C点突变)检查为阴性的线粒体脑肌病患者,用线粒体DNA全长测序和(或)聚合酶链反应-限制性片段长度多态法检测mtDNA G13513A点突变,分析阳性患者的临床特点,复习文献报道的mtDNA G13513A所致线粒体病的病例.结果 35例患者中有6例存在mtDNA G13513A突变.该6例患者均出现偏盲、轻偏瘫或偏身感觉障碍等卒中样发作表现,其中3例成人发病者以卒中样发作为主要症状,伴随癫痫、头痛、身材矮小、神经性耳聋等,头颅MRI显示以顶-枕-颢叶受累为主的大片病灶,符合成人型线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)的临床和影像学特点;3例青少年发病者除卒中样发作外,还有构音障碍、共济失调、眼外肌瘫痪等脑干受累的症状,MRI检查可见枕-颞叶大脑皮质非对称性病灶,以及双侧基底节和脑干的对称性病灶,符合青少年型MELAS-Leigh叠加综合征的临床和影像学特点.肌肉病理检查在5例患者发现不整红边纤维.经复习文献,发现mtDNA G13513A突变患者还存在婴幼儿型Leigh或Leigh样综合征表型.结论 mtDNA G13513A点突变是线粒体脑肌病较常见的致病性突变,主要导致Leigh综合征、MELAS-Leigh叠加综合征或MELAS综合征,其临床表型具有年龄依赖性.

Abstract：

Objective To report 6 Chinese patients with mitochondrial encephalomyopathy caused by mitochondrial DNA(mtDNA)G13513A mutation and discuss the mitochondrial phenotype associated with this mutation based on the data of our patient series as well as the reports by others.Methods Direct sequencing of polymerase chain reaction(PCR)products or PCR-RFLP analysis Was performed to screen mtDNA G13513A mutation in 35 cases with mitoehondrial encephalomyopathy.who carried no mtDNA common mutations(1arge 8eale deletion,A3243G,T3271 C,A8344G,or T8993G/C).The clinical features,MRI changes were retrospectively collected and analyzed.Published studies of all patients with mtDNA G13513A mutation were also reviewed.Results Six patients were identified carrying mtDNA G13513A mutation.All patients presented stroke-like episodes with hemianopsia.hemiparesis or hemiparesthesia.Three adult patients presented clinical and radiological features of adult-onset mitochondrial myopathy,encephalopathy,lactic acidosis,and stroke-like episodes(MELAS),including stroke-like episodes,epilepsy,headache,short stature,sensorineural deafness,multifocal lesions on parietal,occipital and temporal lobes on cranial MRI scans.Three iuvenile.onset patients presented the clinical and brain MRI features of MELAS-Leigh syndrome(LS)overlap syndrome.In addition to the stroke-like episodes,they also showed brain stem lesions with dysarthria,ataxia,and ophthalmopJegia. Brain MRI revealed asymmetrical lesions in the cortex of the oecipital and temporal lobes,as well as symmetrical lesions in the bilateral basal ganglia and brainstem.Muslce biopsy showed ragged redfibem in 5 patients.The infant-onset LS or Leigh-like syndrome with mtDNA G135 13A was described in the English literature.Conclusions mtDNA G13513A mutation is a common pathogenic mutmion for mitochondrial encephalomyopathy,which can result in Leigh syndrome,MELAS-LS overlap syndrome and adult MELAS.The onset of various phenotypes is relatively age-dependent.     

以横纹肌溶解为表现的脂质沉积性肌病临床、病理与基因改变特点

目的研究以横纹肌溶解(rhabdomyolysis,RM)为表现的脂质沉积性肌病(lipid storage myopathies,LSM)临床、病理及基因改变特点,提高对其诊断的警惕性。方法回顾分析我院诊断的3例临床表现为急性横纹肌溶解的脂质沉积性肌病临床、病理及基因改变特点,结合相关文献复习进行讨论。结果 2例以急性横纹肌溶解为首发表现,1例是诊断为LSM后,因停药后出现上呼吸道感染诱发急性横纹肌溶解。3例患者肌肉病理HE染色均可见筛状空泡,ORO染色证实肌纤维内有大量脂滴。其中2例可见较严重的肌纤维坏死。其中2例患者行ETFA、ETFB、ETFDH基因突变检测,ETFA基因正常,均发现ETFB基因第5外显子c.734CT(Thr245Met)和ETFDH基因第2外显子c.92 CT(Thr3Ile)杂合突变。结论不明原因及反复出现肌肉酸痛、无力伴肌酸激酶明显增高、肌红蛋白尿等横纹肌溶解表现时,应考虑LSM可能,及时行肌肉活检明确诊断。以RM为表现的LSM出现相关ETFB与ETFDH基因的杂合突变,可能为多态性位点,意义未知。LSM患者停药或合并上呼吸道感染可诱发急性横纹肌溶解。     

Progressive Neuronal Degeneration of Childhood with Liver's Disease (Alpers' Disease) Clinical Features and Neuropathological Studies of 4 Sibling

We report four siblings of a family with Alpers' disease. Three of four siblings occurred diarrhea and myoclonus at the ages of 7 to 8 years old. During the disease evolution, symptoms of subacute encephalopathy such as headache, visual disturbance, cortical blindness, progressive seizures and mental retardation were presented at the ages of 15 to 20 years old. Downhill progression led them to death in multiple organ failure within six to eight months of onset. CT showed hypodensity lesions in the bilateral oc cipital and temporal lobes. Spongiform changes, which characterized by diffuse neuronal degeneration or loss and astrocytosis, were most severe in the gray matter. White matter was slightly involved, while basal ganglia, pons, brain stem and cerebellum were not involved. Physical examination of the only live brother of the four siblings showed short status (165 cm), arched feet and improper nose-pointed test of the left side. Muscle biopsy of him showed a large amount of Red-Ragged (RR) fibers and abnormal mitochondria. Clinical features and pathological findings of autopsy in all the four siblings were consistent with progressive neuronal degeneration of childhood with liver disease (PNDC) - Alpers' disease. The muscle biopsy showed the characteristic findings of mitochondrial myopathy. Our report confirmed the classification of late onset Alpers' disease as a mitochondrial disorders.     

Evaluation of the Revertant Phenomenon in Patients with DMD by Immunostaining and Molecular Biology

Objective To evaluate the significance of revertant phenomenon in patients with Duchunnes muscular dystrophy(DMD). Methods In the present study, the muscles from the patients with DMD were detected by immunofluoresce staining and anti dystrophin antibody, and the 25 pairs of exons in the serum of patients were measured by repetitive PCR test. Results Fifty-one patients had progressive general weakness, especially in proximal and trunk, and hypertrophy calves. Four of them had absent reaction for sarcolemma, which was called as rcvertant phenomenon. The finding was unique and quite rare. The measurement of molecular biology showed no dystrophin deletion in these 4 cases. Conclusions The revertant phenomenon may involve the different mechanism from the conventional medical wisdom. The symptoms and signs of these patients might be improved by a newly therapeutic approach.     

核黄素反应性脂质沉积性肌病伴感觉共济失调性神经病3例报告

目的研究核黄素反应性脂质沉积性肌病伴感觉共济失调性神经病的临床、电生理、病理和基因改变特点。方法 3例男性患者来自2个家系,其中2例为兄弟,发病年龄41～43岁,主要症状是四肢肌无力,伴随双足麻木和行走不稳。查体发现四肢近端肌力下降、末梢性感觉丧失和Romberg征阳性。3例患者的血尿代谢筛查均提示存在血多种脂酰肉碱水平升高和尿戊二酸水平增高。3例患者均进行了神经电生理、肌肉活检以及电子转移黄素蛋白脱氢酶(ETFDH)基因检查,2例进行腓肠神经活检。结果 3例患者的肌电图分别出现肌源性损害、可疑神经源性损害和无异常。3例患者的四肢感觉神经传导速度显著减慢或不能引出,运动神经传导速度仅在1例出现轻度减慢。3例患者的骨骼肌均可见肌纤维内脂肪滴显著增多,2例有个别破碎红纤维,2例出现小角状肌纤维。2例患者的腓肠神经均可见有髓神经纤维中-重度减少,伴随有髓神经纤维轴索变性和再生。3例患者均携带ETFDH基因的复合杂合突变,其中2兄弟为c.65A>G和c.242T>C,另1例为c.770A>G和c.1450 T>C。结论 ETFDH基因突变导致的核黄素反应性脂质沉积性肌病可以伴随感觉共济失调性神经病。     

Significant clinical heterogeneity with similar <Emphasis Type="Italic">ETFDH</Emphasis> genotype in three Chinese patients with late-onset multiple acyl-CoA dehydrogenase deficiency

Late-onset multiple acyl-CoA dehydrogenase deficiency (MADD) with electron transfer flavoprotein dehydrogenase (ETFDH) gene mutations is the most common lipid storage myopathy (LSM) in China. Its clinical features vary widely and pose a challenge for diagnosis. We presented the significant clinical heterogeneity among three Chinese late-onset MADD patients with similar ETFDH genotype by collecting clinical information, muscle histology, and genetic analysis. Three novel compound heterozygous variants of ETFDH gene were identified: c.892C > T (p.Pro298Ser), c.453delA (p.Glu152ArgfsTer15), and c.449_453delTAACA (p.Leu150Ter). Moreover, all patients carried a hotspot mutation c.250G > A (p.Ala84Thr). Western blot analysis of the patients’ muscular tissue showed a significantly reduced ETFDH expression, and normal electron transfer flavoprotein A (ETFA) and electron transfer flavoprotein B (ETFB) expression. Two patients with similar genotypes (c.453delA and c.449_453delTAACA) presented a significant clinical heterogeneity. Among them, one exhibited muscle weakness and exercise intolerance as initial and major symptoms, and the other showed episodic recurrent gastrointestinal symptoms before a serious muscle weakness appeared in later life. The novel variants in ETFDH and the corresponding clinical features enrich the variant spectrum of late-onset MADD and provide a new insight into the genotype-phenotype relationship. Late-onset MADD should be included in differential diagnosis for adult myopathy along with chronic digestive disease.     

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.     

电子转移黄素蛋白脱氢酶基因突变所致的核黄素反应性脂质沉积性肌病的临床、病理和基因特征分析

目的分析电子转移黄素蛋白脱氢酶(ETFDH)突变所致的核黄素反应性脂质沉积性肌病(RR-MADD)的临床特点、肌肉病理以及血、尿质谱筛查结果和基因突变特点,旨在为早期诊断和治疗提供帮助。方法回顾性分析该院2009年至2019年确诊的15例ETFDH突变所致的脂质沉积性肌病患者的各项资料。结果 15例患者平均发病年龄为(32.1±13.6)岁,均以肢体无力为首发症状,其中四肢起病者占53.3%,双下肢起病者占46.7%。所有患者的肌酶水平均升高;肌电图结果提示80%呈肌源性损害,13.3%为肌源性合并神经源性损害,6.7%结果正常。血、尿质谱的阳性检出率分别为66.7%和22.2%;基因检测提示所有患者存在ETFDH基因不同位点突变,其中单一杂合突变和复合杂合突变各占40%,纯合突变占20%。结论该病以波动性肌无力伴肌酶升高为主要表现,患者应尽快行肌肉病理检查,同时联合血、尿代谢筛查和基因检测有助于RR-MADD患者早期诊断和及时治疗。     

A new case of limb girdle muscular dystrophy 2G in a Greek patient,founder effect and review of the literature

Limb girdle muscular dystrophy (LGMD) type 2G is a rare form of muscle disease, described only in a few patients worldwide, caused by mutations in TCAP gene, encoding the protein telethonin. It is characterised by proximal limb muscle weakness associated with distal involvement of lower limbs, starting in the first or second decade of life.We describe the case of a 37-year-old woman of Greek origin, affected by disto-proximal lower limb weakness. No cardiac or respiratory involvement was detected. Muscle biopsy showed myopathic changes with type I fibre hypotrophy, cytoplasmic vacuoles, lipid overload, multiple central nuclei and fibre splittings; ultrastructural examination showed metabolic abnormalities. Next generation sequencing analysis detected a homozygous frameshift mutation in the TCAP gene (c.90_91del), previously described in one Turkish family. Immunostaining and Western blot analysis showed complete absence of telethonin. Interestingly, Single Nucleotide Polymorphism analysis of the 10 Mb genomic region containing the TCAP gene showed a shared homozygous haplotype of both the Greek and the Turkish patients, thus suggesting a possible founder effect of TCAP gene c.90_91del mutation in this part of the Mediterranean area.     

核黄素反应性脂质沉积性肌病的临床和病理特征

目的 探讨核黄素反心性脂质沉积性肌病的临床和病理特征。方法 回顾性分析4例核黄素反应性脂质沉积性肌病患者的临床资料结果本组4例患者表现为亚急性起病的四肢近端和躯干肌无力,不能耐受疲劳,3例患者有颈肌和脊旁肌萎缩、无力,2例有明显的咀嚼肌无力。2例肌电图示肌源性损害,1例示双侧胫神经传导速度轻度减慢。肌肉活检发现肌纤维内大量脂肪沉积,未见肌纤维坏死和再生,改良Gomorii色染色、琥珀酸脱氢酶和细胞色素C氧化酶染色以及电镜观察未发现有线粒体酶活性缺失,以及线粒体结构和数量的异常改变。应用维小素B2单药治疗后2例明显好转,2例痊愈。2例患者分别在治愈后1年、5年复发,重新给予维生素B2治疗仍然有效。结论 本病多以颈肌、脊旁肌和咀嚼肌受累,病理特征为肌肉脂肪沉积,无线粒体异常改变。维生素B2单一治疗对本病有显著疗效,此亦可与其他肌病鉴别。     

A myopathy with unusual features caused by PNPLA2 gene mutations

Introduction: The PNPLA2 gene encodes the enzyme adipose triglyceride lipase (ATGL), which catalyzes the first step of triglyceride hydrolysis. Mutations in this gene are associated with an autosomal recessive lipid‐storage myopathy, neutral lipid‐storage disease with myopathy (NLSD‐M). Results: A 72‐year‐old woman had late‐onset myopathy, with mild weakness, cramps, and exercise intolerance. Electromyography showed myotonic discharges. A few leukocytes showed lipid droplets (Jordan anomaly). Deltoid and quadriceps muscle biopsies showed no lipid storage. Genetic analysis of PNPLA2 detected 2 heterozygous mutations: c.497A>G (p.Asp166Gly) in exon 5 and c.1442C>T (p.Pro481Leu) in exon 10. Expression of mutant PNPLA2 plasmids in HeLa cells resulted in impaired enzyme activity, confirming the pathological effects of the mutations. Conclusions: In this case of NLSD‐M, the myopathy may be due to a metabolic defect rather than to a mechanical effect of lipid storage. This suggests that more than 1 mechanism contributes to muscle damage in NLSD‐M. Muscle Nerve 51: 609–613, 2015     

Identification of eight novel mutations of the acid α-glucosidase gene causing the infantile or juvenile form of glycogen storage disease type II

Glycogen-storage disease type II (GSDII; OMIM #232300), an autosomal recessive disorder caused by a deficiency of the glycogen hydrolysis enzyme acid alpha-glucosidase (acid GAA; acid maltase, EC. 3.2.10.20), results in the accumulation of glycogen in the lysosome. We performed a molecular genetic study on 29 patients with infantile-onset glycogen-storage disease type II (GSDII), 6 with juvenile-onset GSDII and one carrier for GSDII. Seventeen different mutations were identified among them; 8 were novel mutations: c.421C > A (p.L141M), c.872T > C (p.L291P), c.893A > C (p.Y298S), c.1375G > A (p.D459N), c.1437G > C (p.K479N), c.1509_1511del (p.A504del), c.1960T > C (p.S654P), and c.2174G > C (p.R725P). One of the mutations identified, c.2238G > C (p.W746C), which was a sequence change of unknown pathogenic significance causing diminished enzyme activity,was found homozygously in a juvenile-onset patient. We also found a juvenile-onset patient with homozygote c.1935C > A mutation which was frequently found in infantile-onset patients. In addition to mutations, we also identified 14 new polymorphisms in the acid alpha-glucosidase gene. The genotype/phenotype correlations indicated that c.2238G > C (p.W746C) is correlated with juvenile- onset GSDII and that c.872T > C (p.L291P) and c.1411_1414del (p.E471fsX5) are correlated with infantile-onset GSDII. Mutational analysis of GAA is useful in genetic counseling and prenatal diagnosis of the disease.     

<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.