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2A型肢带型肌营养不良家系CAPN3基因的突变分析

目的对一个2A型肢带型肌营养不良(limb-girdle muscular dystrophy type 2A)家系进行CAPN3基因的致病突变分析。方法收集先证者及家系成员的外周血,提取DNA,应用全外显子测序技术对先证者进行致病基因检测,然后用Sanger测序技术对先证者家系成员进行突变位点的验证。结果全外显子测序发现先证者携带CAPN3基因c. 1194-9A G和c. 1437C T (p. ser479=)的复合杂合突变。Sanger测序验证先证者母亲为CAPN3基因c. 1194-9A G变异携带者。家系中其他患者均存在相同的复合杂合突变,其未发病的姐姐和女儿为CAPN3基因c. 1437C T (p. ser479=)变异携带者,先证者的女婿未检测到上述位点变异。结论 CAPN3基因c. 1194-9A G和c. 1437C T (p. ser479=)的复合杂合突变为该家系的致病原因。     

短链烯酰辅酶A水合酶1基因突变导致线粒体短链烯酰辅酶A水合酶1缺乏症1例

目的总结1例短链烯酰辅酶A水合酶1(ECHS1)基因导致线粒体短链烯酰辅酶A水合酶1缺乏症(ECHS1D)患儿的临床特征及基因突变特点。方法回顾性分析2021年1月就诊于徐州市儿童医院神经内科的1例ECHS1D患儿的临床特点及基因检测结果, 并通过检索国内外相关文献对该疾病的临床特征进行复习。结果患儿男性, 年龄6个月4 d, 急性起病, 临床以肢体活动障碍为主要表现。患儿运动发育迟缓, 竖头尚可, 不能翻身、独坐, 不能追视, 不能逗笑出声, 四肢肌张力增高。入院检查示血乳酸水平升高至6.2 mmol/L, 提示代谢性酸中毒。头颅磁共振成像(MRI)示双侧基底节区异常信号, 左侧大脑半球脑膜异常强化。全外显子组测序发现该患儿ECHS1基因存在复合杂合突变, 分别为c.563C>T(p.A188V)和c.5C>T(p.A2V), 患儿父亲携带c.563C>T突变, 母亲携带c.5C>T突变, 均为错义突变。结论 ECHS1基因以错义突变为主, 大部分为复合杂合突变, 少部分为纯合突变。ECHS1基因突变导致线粒体ECHS1D常累及婴幼儿, 发病相对较早, 临床表...     

多巴反应性肌张力障碍患者的GCH1基因突变检测

目的分析多巴反应性肌张力障碍(dopa responsive dystonia,DRD)患者的GCH1基因突变。方法我们抽取21例来自医院门诊及住院的散发型多巴反应性肌张力障碍患者的肘静脉血,并提取外周血全基因组DNA。Primer3设计GCH1基因6个外显子的引物,PCR扩增GCH1基因的外显子及周边部分内含子序列,并对PCR产物进行测序。测序结果与正常序列进行比对,发现碱基变异后进行序列分析以确定是否多态。结果成功扩增21位DRD患者GCH1基因的6个外显子。经过分析,GCH1基因外显子序列未发现基因突变。仅在4个患者的1号外显子发现1个单核苷酸多态(SNP)c.68CT,该SNP没有产生氨基酸的改变。结论本地区多巴反应性肌张力障碍患者未发现GCH1基因突变,DRD患者可能存在其他致病基因。GCH1基因突变检测目前仍不能作为早期诊断的依据。     

目标区域捕获测序检测常染色体隐性遗传性腓骨肌萎缩症GDAP1基因突变

研究背景腓骨肌萎缩症存在高度临床和遗传异质性,传统基因检测需对众多候选基因逐一筛查,存在效率低、耗时、费力等局限性。本文旨在探讨目标区域捕获测序技术诊断常染色体隐性遗传性腓骨肌萎缩症的可行性。方法采集5例临床拟诊常染色体隐性遗传性腓骨肌萎缩症患者的临床资料和外周血样本,采用目标区域捕获测序技术筛查腓骨肌萎缩症相关基因突变,Sanger测序对候选变异位点在患者及其父母外周血样本中进行验证。结果目标区域捕获测序显示,2例检出GDAP1基因复合杂合突变,余3例未检出致病性突变。经Sanger测序证实2例患儿存在GDAP1基因突变,例1为GDAP1基因复合杂合突变c.767AG(p.His256Arg)和c.866TA(p.Phe289Tyr),其父携带c.866TA(p.Phe289Tyr)突变,其母携带c.767AG(p.His256Arg)突变;例2为GDAP1基因复合杂合突变c.571CT(p.Arg191X)和c.589del C(p.Asp198IlefsX8),其父携带c.589del C(p.Asp198IlefsX8)突变,其母携带c.571CT(p.Arg191X)突变,最终明确诊断为常染色体隐性遗传性腓骨肌萎缩症。结论目标区域捕获测序技术是一项高效基因检测方法,适用于常染色体隐性遗传性腓骨肌萎缩症的基因诊断。     

ATP7B基因特殊的复合杂合突变致Wilson病1例报道

目的 探讨1例ATP7B基因特殊的复合杂合突变导致Wilson病的临床及影像学特征。方法 分析1例疑似Wilson病患者的临床表现及影像学特点,对其进行基因测序。结果 患者14岁开始即出现精神异常,17岁开始出现不自主震颤、写字过小等神经系统症状,血清铜蓝蛋白水平降低,瞳孔笔照射下可见双眼角膜色素环(Kayser-Fleischer ring,K-F环),肝脏彩超提示肝脏弥漫性损害; 具备Wilson病的典型影像学表现,即双侧丘脑、中脑、脑桥对称性长T₁长T₂信号,轻度脑萎缩改变; 基因检测提示ATP7B基因特殊的复合杂合突变,即c.1470C>A(p.C490*),4号内含子区域剪接突变c.1708-1G>C(splice-3), 启动子区域c.-157-u53A>T, c.1168A>G(p.I390V); 家系验证发现先证者父亲及弟弟存在杂合突变c.1708-1G>C(splice-3),c.-157-u53A>T(promoter), c.1168A>G(p.I390V)。根据美国遗传学与基因组学学会(American college of medical genetics and genomics, ACMG)指南,前3个变异位点均评级为致病性突变,证据分别为PVS1+PM2_支持+PP4; PVS1+PM2_支持+PM3_非常强+PP4; PS3+PM2_支持+PM3_强+PP4。变异位点c.1168A>G评级为临床意义未明(PM2_支持+PP4)。结论 该复合杂合突变患者具备Wilson病典型的临床及影像学特征。     

一个肌张力障碍-帕金森综合征的家系调查及致病基因研究

目的初步分析一个肌张力障碍-帕金森综合征家系的可能致病基因。方法对一个肌张力障碍-帕金森综合征的家系进行家系调查。在收集先证者相关血液生化指标、超声波、MRI影像学和PET核医学检查等临床资料基础上,对先证者及其家系三代共8人先后进行了目标基因以及全外显子基因测序加可疑位点Sanger测序验证。结果先证者临床表现为眼睑、口面、下肢肌张力异常,伴动作慢、肌张力高和震颤等典型肌张力障碍-帕金森综合征症状,多巴胺能药物不敏感及服药后罕见的阴道出血不良反应。血生化、铜蓝蛋白、肝脏超声及角膜裂隙灯照相、头颈及腰段脊髓MRI扫描均正常,头颅¹⁸F-dopa PET/MRI显像提示双侧豆状核多巴胺神经元受损。该家系三代共9人中出现症状2例(1例已死亡),基因检测显示先证者及另外3人携带父源的RYR1基因36号外显子c.5972C>T (p.T1911I)杂合突变;另有SETX基因外显子10的c.2439A>C (p.E813D)杂合突变;GCDH基因外显子10的c.1060G>A (p.G354S)杂合突变;ATP7B基因外显子18的c.3792G>C ...     

多巴反应性肌张力障碍三磷酸鸟苷环化水解酶Ⅰ基因突变检测

目的　检测多巴反应性肌张力障碍 (dopa responsivedystonia,DRD)三磷酸鸟苷环化水解酶Ⅰ(guanosinetriphosphatecyclohydrolaseⅠ, GCH1)基因编码区的突变。方法　对 2个DRD家系的 5例患者和 6例散发患者及其 18名亲属和 20名健康对照者的GCH1基因编码区进行聚合酶链反应 单链构象多态性(PCR SSCP)分析;对PCR SSCP异常的外显子进行PCR产物直接测序,若患者 6个外显子PCR SSCP均无异常,则对所有外显子测序;为了确证突变,引入SphⅠ限制性内切酶位点进行聚合酶链反应 限制性片段长度多态性 (PCR RFLP)分析。结果　在 1个呈常染色体显性遗传DRD家系中发现 1个新的杂合型点突变(A224G)。此突变位于 1号外显子,由酪氨酸错义突变为半胱氨酸(Tyr75Cys), 20名健康对照者等位基因无此突变。另 1家系和其他散发患者在GCH1基因编码区未发现基因突变。序列分析提示与 2号外显子邻近的 1号内含子部分和与 3号外显子邻近的 3号内含子部分存在基因多态性。结论　我们描述了一个新的错义突变Tyr75Cys,GCH1基因编码区突变能解释部分DRD患者的发病原因。     

儿童良性癫痫伴中央颞区棘波放电患者的GRIN2A突变筛查及遗传特征分析

目的对儿童良性癫痫伴中央颞区棘波放电(BECTS)患者进行GRIN2A基因突变筛查,分析其在BECTS患者中的致病性和遗传特征。方法收集2012年6月~2014年12月期间我院诊断的BECTS患者,采用PCR扩增和一代测序方法筛查GRIN2A基因突变。结果在收集的53例BECTS患者中,发现4例存在GRIN2A杂合突变,其中1例患者同时具有2个GRIN2A基因突变位点。突变包括4个错义突变(c.2627TC,p.I876T;c.1341TA,p.N447K;c.4322CA,p.T1441N;c.1271CT,p.P424L)和1个剪切位点突变(c.415-38CT),且均为未见报道的新突变位点。除c.1271CT为新生突变、c.1341TA未能验证突变来源外,其余3个突变均为遗传性突变。突变率为7.5%,外显率为75%。经保守性分析,发生错义突变的氨基酸变化位点均为高度保守。结论GRIN2A可能是BECTS的致病基因。GRIN2A突变存在不完全外显,临床进行遗传咨询时应引起高度重视。     

肌病型极长链脂酰辅酶A脱氢酶缺乏症患者临床、病理及遗传学特点分析

目的探讨肌病型极长链脂酰辅酶A脱氢酶缺乏症(VLCADD)的临床、病理及遗传学特点。方法回顾性分析2014年6月至2019年11月河南省人民医院和首都医科大学宣武医院收治的4例肌病型VLCADD患者的详细临床资料、肌肉活组织检查病理及基因检测结果。结果 4例患者均为晚发肌病型, 发病年龄在13～16岁(平均发病年龄14.5岁), 确诊年龄在21～54岁(平均确诊年龄42.5岁), 均表现为发作性横纹肌溶解症的相关症状(肌肉疼痛、无力、酱油色尿), 其中1例合并明显嗜睡。肌肉病理可见轻度脂滴增加, 未见空泡形成。在4例患者中基因测序发现6个ACADVL基因变异, 分别为c.1283G>A(p.R428H)、c.1532G>A(p.R511Q)、c.833₈35delAGA(p.K278del)、c.1843C>T(p.R615*)、c.1748C>T(p.S583L)和c.1391C>T(p.T464I), 其中c.1391C>T(p.T464I)为未报道过的错义突变, 预测为可能致病, 其余5个变异均为已报道的致病性变异。结论肌...     

ARSA gene mutations in five Chinese metachromatic leukodystrophy patients

The objective was to identify arylsulfatase A mutations, if any, in five Chinese patients with metachromatic leukodystrophy. This would be the first such study in China. All eight exons and exon-intron boundaries of the arylsulfatase A gene (ARSA) were amplified with polymerase chain reaction, which was followed by direct DNA sequencing. Patient 1 exhibited a homozygous mutation at c.954G>A (p.W318X) in exon 5. Patient 2 exhibited compound heterozygous mutations, identified as one allele with the c.862C>T (p.R288C) missense mutation in exon 5 and the other allele with the c.1338dupC frameshift mutation in exon 8. Patient 3 exhibited only a c.179_180dupCA frameshift mutation in exon 1 in one allele. Patients 4 and 5 exhibited identical compound heterozygous mutations, identified as one allele with the c.296G>T (p.G99V) missense mutation and the other allele with the c.251G>A (p.R84Q) missense mutation in exon 2. Six DNA variants of the arylsulfatase A gene were identified: two novel frameshift mutations (c.179_180dupCA and c.1338dupC), one known nonsense mutation (p.W318X), and three known missense mutations (p.R84Q, p.G99V, and p.R288C).     

Novel mutations in the C-terminal region of the MECP2 gene in Tunisian Rett syndrome patients

Rett syndrome (RTT), an X-linked dominant neurodevelopmental disorder in females, is caused mainly by de novo mutations in the methyl-CpG-binding protein 2 gene (MECP2). Rett patients present an apparently normal psychomotor development during the first 6 to 18 months of life. Thereafter, they show a short period of developmental stagnation followed by a rapid regression in language and motor development. In the present study, we performed a mutational analysis of the MECP2 gene in 2 typical Rett syndrome patients and in 1 atypical Rett syndrome girl. The results showed the presence of 3 de novo point mutations in the C-terminal region: 2 novel mutations: c.1065C>A (p.S355R) and c.1030C>G (p.R344G) in the 2 typical Rett syndrome girls, but also the c.996C>T (p.S332S) mutation first described in the atypical Rett syndrome patient.     

Mutation and polymorphism analysis of TSC1 and TSC2 genes in Indian patients with tuberous sclerosis complex

OBJECTIVE: To find the mutation and polymorphism spectrum of TSC1 and TSC2 genes in patients affected with tuberous sclerosis complex from the Indian population. MATERIAL AND METHODS: All coding exons and promoter regions of both TSC genes were screened for mutations and polymorphisms in 24 TSC families using polymerase chain reaction-single strand conformation polymorphism and DNA sequencing techniques. RESULTS: A single previously known mutation, c.2111_2112delAT was identified in the TSC1 gene. A total of 11 mutations were identified in the TSC2 gene. Of these, seven mutations, c.137_138delGA, c.2070delC, c.2087_2088insAA, c.3080T>C (p.L1027P), c.648+1G>A, c.3131+1G>A and c.5034C>G were novel. The remaining four mutations, c.4544_4547delACAA, c.1941_1942insT, c.1831C>T (p.R611W) and c.1832G>A (p.R611Q) had been reported previously in other populations. The novel mutation, c.137_138delGA was predicted to result in the production of a very small tuberin protein of 64 amino acids lacking all seven functional domains. In addition, we also detected three and 10 polymorphisms in the TSC1 and TSC2 genes respectively. DNA sequence analysis of promoter regions of both TSC genes in 24 families did not show any variation. CONCLUSIONS: This is the first molecular genetic study of TSC in an Indian population. A total of 12 mutations were detected in 24 Indian TSC families in TSC genes. All except one mutation were detected in the TSC2 gene. No variation was found in the promoter regions of either gene. As observed in the western and Japanese populations, the mutations were scattered across the TSC2 gene.     

Novel mutations at carboxyl terminus of CIC-1 channel in myotonia congenita

OBJECTIVES: Myotonia congenita (MC), caused by mutations in the muscle chloride channel (CLCN1) gene, can be inherited dominantly or recessively. The mutations at the carboxyl terminus of the CLCN1 gene have been identified in MC patients, but the functional implication of these mutations is unknown. MATERIAL AND METHODS: Direct sequencing of polymerase chain reaction products covering the whole coding region of the CLCN1 gene was performed in a MC family. This study was designed to investigate the clinical manifestations and genetic analysis of the CLCN1 gene. RESULTS: We identified two novel mutations, 2330delG and 1892C>T, from a genetic screening of the CLCN1 gene in the MC family. The 2330delG mutant allele producing a fs793X truncated protein was identified in a heterozygous state in all the patients. The 1892C>T nucleotide change induced a missense mutation (T631I) found in several asymptomatic individuals, indicating that it may not be associated with MC. Intriguingly, the 2330delG mutation was also found in an asymptomatic subject who also carried the 1892C>T mutation. CONCLUSION: The data indicate that the fs793X mutant protein causes dominantly inherited MC. Because the mutation has been found in a recessive pedigree, the fs793X mutation may have a dual inheritance pattern.     

A novel point mutation in PMP22 gene associated with a familial case of Charcot-Marie-Tooth disease type 1A with sensorineural deafness

Charcot-Marie-Tooth disease with deafness is a clinically distinct entity and is associated with mutations or deletions in several genes including PMP22 gene. Here, we report a large family showing characteristic phenotypes of Charcot-Marie-Tooth type 1A along with deafness in an autosomal dominant fashion. We detected a sequence variation (c.68C>G) co-segregating with the disease phenotype and leading to a T23R missense mutation in PMP22.     

Muskeldystrophie infolge Anoctamin-5-Mutationen

Recessive mutations in the anoctamin 5 (ANO5) gene have been recently identified in families with limb girdle muscular dystrophy (LGMD2L) and distal non-dysferlin Miyoshi myopathy. Anoctamin 5 is supposed to be a putative calcium-activated chloride channel. We report five German patients (four index patients) with muscle dystrophy due to mutations in the ANO5 gene. Sequencing of the ANO5 exons 5, 13 and 20 was performed to screen for a common c.191dupA mutation and two other reported mutations (c.1295C>G and p.R758C). The whole coding region of the ANO5 gene was sequenced to identify new mutations. Phenotypically, three patients showed LGMD and one patient Miyoshi type distal myopathy. One sibling had asymptomatic hyperCKemia. The age at onset was 64, 38 and 40 years in patients with LGMD and 23 years in the patient with distal myopathy. The four symptomatic patients showed remarkable asymmetric muscle involvement. There was marked CK elevation (11 to 30 times). Electron microscopy showed multifocal gaps in the sarcolemmal membrane. All patients harboured the common c.191dupA mutation in at least one allele. Two patients with LGMD were homozygous and the third patient and his asymptomatic sister were compound heterozygous for the c.191dupA mutation and a novel p.T548I mutation. The patient with distal myopathy harboured the p.R758C mutation in the second allele. Mutations in the ANO5 gene seem to be a relatively common cause of muscular dystrophy in Germany. Cases with late onset or asymptomatic hyperCKemia can occur. Clinically, asymmetric manifestation is typical.     

Low frequency of Parkin, Tyrosine Hydroxylase, and GTP Cyclohydrolase I gene mutations in a Danish population of early-onset Parkinson''s Disease

Autosomal recessive Parkinson's disease (PD) with early-onset may be caused by mutations in the parkin gene (PARK2). We have ascertained 87 Danish patients with an early-onset form of PD (age at onset < or =40 years, or < or =50 years if family history is positive) in a multicenter study in order to determine the frequency of PARK2 mutations. Analysis of the GTP cyclohydrolase I gene (GCH1) and the tyrosine hydroxylase gene (TH), mutated in dopa-responsive dystonia and juvenile PD, have also been included. Ten different PARK2 mutations were identified in 10 patients. Two of the patients (2.3%) were found to have homozygous or compound heterozygous mutations, and eight of the patients (9.2%) were found to be heterozygous. A mutation has been identified in 10.4% of the sporadic cases and in 15.0% of cases with a positive family history of PD. One patient was found to be heterozygous for both a PARK2 mutation and a missense mutation (A6T) in TH of unknown significance. It cannot be excluded that both mutations contribute to the phenotype. No other putative disease causing TH or GCH1 mutations were found. In conclusion, homozygous, or compound heterozygous PARK2 mutations, and mutations in GCH1 and TH, are rare even in a population of PD patients with early-onset of the disease.