腓骨肌萎缩症1A型的临床、神经电生理和疾病基因突变分析

目的　观察腓骨肌萎缩症 (CMT) 1A型的临床、神经电生理特点和疾病基因的突变分析。方法对一CMT家系中 9个成员进行详尽的临床检查、疾病基因突变分析 ,对先证者进行神经电生理检查和神经肌肉活检。结果　本家系中 5人发病 ,符合常染色体显性遗传模式 ,除 1例患者无临床症状外 ,其余 4例均在2 0岁前起病。临床特点为进行性四肢远端肌无力、肌萎缩 ,末梢型感觉障碍 ,腱反射减弱或消失 ,足部畸形(高弓足 )。神经电生理检查示运动和感觉神经传导速度减慢。基因突变分析发现 17号染色体短臂 11 2区(17p11 2 )包含周围髓鞘蛋白 (PMP) 2 2基因的正向串联重复突变。结论　CMT1A型是CMT最常见类型 ,多于儿童期或青少年期起病 ,表现为进行性四肢远端肌无力、肌萎缩 ,腱反射减弱或消失。神经电生理特点为运动神经传导速度均一性减低 (<38m/s)。 17p 11 2区包含PMP 2 2基因在内的 1 5Mb(偶尔 <1 5Mb)的正向串联重复突变是CMT 1A最主要的突变型。     

遗传性运动感觉性周围神经病Ⅰ型的临床及电生理特点

目的研究遗传性运动感觉性周围神经病I型(CMT1型)患者的临床特征、肌电生理特点及二者的相关性。方法观察临床确诊的36例CMT1型患者的临床特征,检测双侧上肢远端及下肢常规肌电图及周围神经传导速度及波幅改变情况,并探讨CMT1的肌无力、萎缩程度与胫神经、正中神经及尺神经CMAPs及MCV的关系。结果36例临床确诊的CMT1型患者,男性多于女性,均在青少年期起病,主要临床症状为进行性双下肢或四肢对称性远端肌无力和/或肌萎缩,本组患者症状局限于双下肢者20例(55.56%)。肌电图检查示所有患者均表现为神经源性损害,胫神经、腓神经、正中神经和尺神经均有不同程度的传导速度下降甚至不能引出,波幅降低。随起病年龄增大、病程延长,正中神经、尺神经及胫神经的MCV有下降的趋势并可能测不出(r=0.39,P0.05),CMAPs也出现类似的变化趋势(r=0.28,P0.05)。且肌肉萎缩、无力程度与CMAPs正相关而与MCV无相关关系。结论CMT1多为青少年起病,以慢性进行性双下肢或四肢远端肌无力和肌萎缩为主要特征,肌电图和周围神经传导速度是诊断CMT1的可靠方法,并能预测疾病的进展程度。     

腓骨肌萎缩症(CMT)1型的临床、神经电生理及CMT1A型基因诊断方法的研究

目的 观察腓骨肌萎缩症(CMT)1型患者的临床表现及神经电生理特点,同时利用两种不同方法检测CMT1A型相关基因是否存在突变,并分析两种方法的临床应用价值以进一步确定CMT1A型的诊断.方法 对临床确诊为CMT1型的5例患者进行详细的临床及神经电生理检查,同时对所有患者利用等位基因特异性PCR及MLPA两种方法进行PMP22基因重复突变检测.结果 4例患者20岁前发病,其中2例有家族史,1例患者30岁左右发病.临床特点为进行性四肢远端无力伴肌萎缩,四肢远端感觉减退,腱反射均减弱或消失,2例患者出现弓型足.神经电生理检查示神经传导速度减慢,波幅轻度降低.两种基因检测均发现1例患者存在PMP22基因重复突变.结论 CMT1型发病年龄较早,主要表现为进行性四肢无力伴肌萎缩,神经电生理可见神经传导速度明显降低,波幅略有降低.等位基因特异性PCR和MLPA两种方法检测基因突变结果一致.     

常染色体显性遗传腓骨肌萎缩症的临床与基因突变特点

目的:探讨常染色体显性遗传腓骨肌萎缩症(CMT)患者的临床与基因突变的特点。方法:对43个常染色体显性遗传CMT家系共106例患者的临床表现、电生理和病理特点进行回顾性分析,并进行PMP22的大片段重复突变和PMP22、MPZ、SIMPLE、EGR2、RAB7、NEFL、MFN2、Hsp27及Hsp22基因突变分析。结果: CMT1A和CMT1B致病基因分别为PMP22的大片段重复突变和MPZ基因,这两型患者起病较早,临床表现多见起始于下肢远端的肌无力萎缩,伴感觉减退或缺失,神经系统检查可见小腿肌肉明显萎缩,膝、踝反射减低或消失,弓形足,神经电生理检查示神经传导速度减慢,病理改变可见髓鞘脱失。CMT2A2、CMT2F和CMT2L致病基因分别为MFN2、Hsp27及Hsp22基因,发病率较CMT1低,发病年龄比CMT1较迟,临床症状与CMT1相比,运动系统受累较感觉系统更明显,神经传导速度常在正常范围,病理改变呈轴索变性。结论:基因突变分析结果与临床特点一致,准确性高、损伤小,可早期诊断,值得广泛应用于临床,特别是有家族史的患者或高危亲属。     

一种罕见的运动神经元病:远端型脊肌萎缩症（附1例报道）

目的 探讨远端型脊肌萎缩症(Distal spinal muscular atrophy,dSMA)的临床特征及诊断。方法 对1例双下肢远端肌无力伴萎缩的患者进行临床、实验室、电生理、影像学检查。结果 患者幼年起病,表现为对称性双下肢无力,病情缓慢进行性加重,逐渐出现双下肢远端对称性肌肉萎缩,血清肌酶基本正常,电生理检查提示四肢神经源性损害,感觉、运动神经传导正常。结论 远端型脊肌萎缩症的临床特征与腓骨肌萎缩症、运动神经元病极为类似,实验室、电生理检查及基因检测有助于疾病的诊断。     

腓骨肌萎缩症的神经电生理及病理学特点(附2例报告)

目的 探讨腓骨肌萎缩症(CMT)的神经电生理及病理学特点.方法 回顾性分析2例腓骨肌萎缩症患者的神经电生理及病理学资料.结果 本组患者主要表现为慢性进行性双下肢远端肌无力和肌萎缩,弓形足,伴有双上肢受累,腱反射消失,四肢感觉障碍.神经电生理检查显示神经传导速度减慢,神经源性损害；神经活检显示节段性脱髓鞘,部分区域“洋葱球样”改变；电镜显示有髓神经密度中度减少,髓鞘破坏；肌活检显示肌纤维萎缩呈角形.结论 CMT的神经电生理特点为神经源性损害；病理学特点为周围神经节段性脱髓鞘和神经源性肌萎缩.     

夏科-马里-图斯病2A2型一家系的临床病理特点

目的 报道一个早发型夏科-马里-图斯病(CMT)2A2家系,探讨其临床和病理特点.方法 该家系共有5例患者,呈常染色体显性遗传,先证者为36岁女性,6岁开始出现下肢进行性无力,8岁出现双足内翻.家族中另有2例男性和2例女性发病,发病年龄3～7岁,主要表现为缓慢进展的四肢远端肌肉无力、萎缩,伴随四肢远端感觉减退、腱反射减退及关节挛缩.先证者和其儿子的上肢感觉神经、下肢感觉和运动神经诱发电位波幅不能引出.对先证者左侧腓肠神经进行活体组织病理检查.对先证者和其他4例家系患者、3名无症状家系成员行MFN2基因测序.结果 病理检查可见腓肠神经有髓纤维数目重度减少,以大有髓神经纤维减少为主,伴随个别有髓神经纤维再生簇结构以及不典型的洋葱球样结构.电镜下可见轴索中线粒体聚集,未发现线粒体结构异常.5例患者存在MFN2基因R94W突变,无症状家系成员无此突变.结论 我国存在早发型CMT2A2家系,患者周围神经缺乏有髓神经纤维再生改变,提示MFN2基因突变对神经元的损害更大.     

腓骨肌萎缩症电生理、病理和基因定位研究

目的研究腓骨肌萎缩症(CMT)临床特征、基因测定、病理及神经电生理检查在其诊断和分型中的价值。方法收集50例CMT患者临床资料,对其进行肌电图检查及腓肠神经活检,并采用PCR技术直接测序进行基因突变分析。结果 40例CMT患者双下肢运动及感觉传导速度减慢(双胫、腓总神经为15~28 m/s,腓肠神经为12~30 m/s),10例双下肢未引出反应电位;50例正中神经运动及感觉传导速度亦减慢分别为19~48 m/s和20~52 m/s。CMT患者神经传导速度减慢的程度和临床表现的严重程度并不平行。腓肠神经活检符合慢性脱髓鞘部分伴轴索改变性周围神经病。PMP22、Cx32、MPZ、MFN2、GDAP1致病基因的突变分析发现14例患者存在PMP22基因的大片段重复突变(28%),13例患者存在Cx32基因的点突变(26%),4例患者存在MPZ基因的点突变(8%),3例患者存在MFN2基因的点突变(6%),未发现GDAP1基因的突变,16例患者未检测出上述基因突变。结论电生理、病理、基因测定在CMT的诊断及分型中有重要价值。     

腓骨肌萎缩症的临床、病理学及遗传学特点(附1家系报告)

目的:探讨腓骨肌萎缩症(CMT)的临床、病理学及遗传学特点.方法:对1例CMT患者及其家系的临床资料进行回顾性分析.结果:本家系患者主要表现为先天性慢性进行性双下肢远端肌无力和肌肉萎缩,部分伴双上肢受累;腱反射消失,双下肢感觉减退;弓形足.神经电生理检查示周围神经损害,正中神经传导速度＞38m/s.先证者肌肉病理示I型...     

小热休克蛋白27基因突变所致腓骨肌萎缩症患者的临床、电生理和病理特点

目的探讨小热休克蛋白27基因(smallheat shockprotein27,Hsp27)突变所致腓骨肌萎缩症(Charcot Marie Toothdisease,CMT)患者的临床、电生理和病理特点。方法对发现Hsp27基因同一突变(C379T)的4个常染色体显性遗传CMT2家系的7例患者的临床表现、电生理和病理检查进行回顾性分析。结果患者主要临床特点为35～60岁发病,平均病程(17.6±6.6)年,发病后平均(12.6±4.9)年需要扶拐杖行走,平均(20.7±5.7)年完全丧失行走能力;患者感觉障碍轻,神经电生理示下肢神经传导速度呈中至重度减慢,但上肢正常或轻度减慢,神经活检证实为慢性轴突性神经病,肌肉活检显示神经原性肌萎缩。结论Hsp27基因C397T突变可引起CMT2表现型,突变家系的临床表现与文献报道的该基因突变CMT2F家系有所不同。     

MFN2‐related genetic and clinical features in a cohort of Chinese CMT2 patients

Charcot‐Marie‐Tooth disease 2A (CMT2A), caused by mutations in the mitofusin 2 gene (MFN2), is the most common CMT2 subtype. The aim of our study is to assess the frequency and summarize the genetic and clinical characteristics of Chinese CMT2A patients. A total of 17 coding exons of MFN2 were detected by direct sequencing in 82 unrelated Chinese families diagnosed as CMT2. Clinical evaluations were analyzed among CMT2A patients. We identified 14 missense variants in 9 sporadic and 6 familial cases, including four novel mutations (T129A, S249F, Q367P, and Q674L), 4 known mutations (R94W, R94Q, T105M, C132Y, M376V and Q751X), and 4 rare missense variants (K120E, C217F, K307E and T356S). A total of 23 patients had early‐onset phenotype. Two patients had a CMTNS score of 0 to 10; 16 had a score of 11 to 20; and 7 had a score greater than 20. Five patients were confirmed a de novo origin. Six of 14 variants were located or closed to the GTPase domain. We report four novel mutations and four rare missense variants. MFN2 mutations account for 18% of CMT2 families in mainland China. The common characteristics of Chinese pedigree are early disease onset and moderate phenotypes.     

X-linked recessive Charcot-Marie-Tooth neuropathy: clinical and genetic study.

We describe three families with X-linked recessive Charcot-Marie-Tooth (CMT) neuropathies. The disease phenotype in family 1 was characterized by infantile onset, weakness of lower legs, areflexia, pes cavus, and mental retardation (2 of 5 patients). The disease phenotype in families 2 and 3 was characterized by late onset, distal weakness, and normal intelligence. Hereditary spastic paraparesis was also present in the CMT patients of family 2. Thirty X-linked DNA markers were used for linkage studies. A maximum lod score of +3.48 was obtained by multipoint linkage analysis for the DXS16 locus mapped at Xp22.2 in family 1. In families 2 and 3, there was suggestion of linkage of Xq26 markers; the peak multipoint lod score for these 2 CMT families was 1.81, at DXS144. These results were suggestive of heterogeneity. The joint analysis including both regions (Xp22.2 and Xq26) provided evidence against homogeneity (chi 2 = 9.12, P less than 0.005).     

Increased severity over generations of Charcot-Marie-Tooth disease type 1A

BACKGROUND: Charcot-Marie-Tooth type 1A (CMT1A) is an autosomal dominant polyneuropathy due to a 1.5 Mb tandem duplication in chromosome 17p11.2, containing the PMP22 gene. This mutation is not modified during inheritance. OBJECTIVES: We set forth to test the hypothesis that in a subgroup of CMT1A patients there is clinical anticipation, namely an increase in disease severity over generations. METHODS: Thirty-nine CMT1A mutation-positive patients in 16 families and 23 parent-offspring pairs were evaluated. This included 14 families with 2 generations and 2 families with 3 generations. Age of presentation was assessed by interviewing the patients and clinical severity was measured using the CMT neuropathy score (CMTNS). RESULTS: In 21/23 parent-child pairs and 14/16 families, there was an earlier age of presentation in children of genetically affected parents. The mean age of onset in the progeny was 12.61 years compared to 41.22 years in the parent generation, (p < 0.001).Mean severity in the younger generation was slightly higher than that of the parent generation. When corrected for the age difference, the trend for a worse phenotype in the younger generation became statistically significant (p < 0.02,Wilcoxon signed rank test). CONCLUSIONS: Our findings suggest that in a subgroup of CMT1A patients there is an increase in clinical severity over generations. The mechanism responsible for this observation remains unknown. Our findings should be validated on a larger cohort of CMT1A families.     

Comparison of CMT1A and CMT2: similarities and differences

To evaluate the clinical and electrophysiological similarities and differences between two large groups of patients with Charcot-Marie-Tooth disease, i.e. CMT1A and CMT2, we performed a post hoc comparison of clinical and electrophysiological data.Most CMT1A and CMT2 patients had the classical CMT phenotype. Age of onset was significantly later in CMT2. Total areflexia was present in approximately half of the CMT1A patients whereas it was rare in CMT2. Foot deformities and weakness of knee extensor and foot dorsal flexor muscles were more frequent in CMT1A. Median nerve motor nerve conduction velocities (MNCV) were always less than 38 m/s in CMT1A patients, whereas this was also the case in 16% of the CMT2 patients. Sensory nerve conduction velocities showed less overlap. In both CMT1A and CMT2 CMAP and SNAP amplitudes were often reduced or not obtainable in the legs. In CMT1A, SNAP amplitude was more reduced and SNAP duration more prolonged than in CMT2.We conclude that there are no robust clinical signs or symptoms that differentiate between CMT1A and CMT2 patients. Electrodiagnostical studies show a length-dependent motor and sensory axonal dysfunction in both CMT-types. Additional SNAP and SNCV evaluation may be helpful in focusing molecular genetic analysis in the occasional case of CMT2 showing slow motor nerve conduction velocities overlapping with CMT1A values. The reduction of CMAP and SNAP amplitudes in CMT1A is probably a combined effect of demyelination and axonal dysfunction.     

Clinical, electrophysiological and pathological findings of a patient with CMT2 due to the p.Ala738Val mitofusin 2 mutation

Mutations in the gene encoding mitofusin 2 (MFN2) are responsible of about 20% of Charcot-Marie-Tooth disease type 2 (CMT2) case. A great variability exists among CMT2A concerning severity and associated clinical features. Generally patients with an early onset CMT2A disclose a severe phenotype while the cases with a late onset present a more benign clinical course. We describe clinical, electrophysiological and pathological findings of a patient with a mild CMT2A due to the c.2213C>T, p.Ala738Val MFN2 mutation. This mutation has been already described to be only associated with an early onset and moderately severe CMT2A phenotype.     

Influence of comorbidities on the phenotype of patients affected by Charcot–Marie–Tooth neuropathy type 1A

Charcot–Marie–Tooth type 1A (CMT1A) is the most common inherited neuropathy. The phenotype of patients affected by CMT1A is highly variable and may be influenced by several conditions. We evaluated how comorbidities such as diabetes, hypothyroidism, exposure to toxins and obesity can modify or exacerbate the clinical and neurophysiological phenotype of CMT1A patients. Disability was measured using the classic CMT neuropathy score. Compared to controls, all groups of CMT1A patients with comorbidities had higher CMT neuropathy score. In particular, patients with CMT1A and diabetes mellitus show motor subscores which are significantly higher than in control CMT1A. Amplitudes of ulnar CMAP are lower in patients with CMT1A and diabetes mellitus, but not at a significant level. As expected, motor nerve conduction velocity is not influenced by any of the comorbidities. The presence of concomitant diseases shows a tendency to worsen the clinical and neurophysiological CMT1A phenotype, especially in patients with CMT1A and diabetes mellitus, where higher values in the CMT neuropathy score and clinical motor subscore have been observed.     

腓骨肌萎缩症2F型1家系临床分析

目的探讨腓骨肌萎缩症(CMT)2F型的临床特点。方法对1家系内3例患者的临床表现和神经电生理资料进行回顾性分析。结果该家系为晚发(37~60岁),感觉障碍轻,1例伴右侧听力下降;神经传导速度检查示下肢感觉和运动传导速度减慢,甚至引不出反应波,但上肢正常或接近正常;躯体感觉诱发电位示中枢神经和周围神经均受累,运动诱发电位示运动通路周围段传导减慢,脑干听觉诱发电位示一侧听通路周围段严重受累。结论CMT2F型患者的临床特征有助于CMT患者的诊断和分型。     

Sensory manifestations in Charcot-Marie-Tooth disease

Involvement of sensory nerves in Charcot-Marie-Tooth (CMT) disease is well known, however, sensory symptoms are usually overlooked. To assess the frequency and features of sensory symptoms in a cohort of patients with CMT, we investigated in a prospective study 52 consecutive CMT patients, diagnosed on the basis of clinical, neurophysiological, and genetic features and classified in CMT type 1 (CMT1) (20 patients, including 14 with CMT1A) and CMT type 2 (CMT2) (32 patients). Positive sensory symptoms were reported by 28 patients (54%), including neuropathic pain in 6 patients. Pain, either neuropathic or nociceptive, was present in 29 patients (56%) and in 15 patients as a main symptom. Positive sensory symptoms were present in 24 of 32 CMT2 patients (75%) and in 4 of 20 CMT1 patients (20%) (p < 0.001); there was a presenting manifestation in 11/32 CMT2 patients vs. 1/20 in CMT1 patients (p = 0.018), and one of the main features in 6/32 CMT2 patients vs. 1/20 CMT1 patients. Frequency of positive sensory symptoms in CMT1A patients was similar to that of the entire CMT1 group. Within the CMT2 group, patients with positive sensory symptoms as a main or onset feature (11 patients) had significantly later onset (median 57 vs. 25 years; p = 0.042) and less severely impaired motor action potentials than CMT2 patients without positive sensory symptoms (8 patients). Nociceptive pain was especially frequent in CMT1A patients (10/14, 71%). Sensory manifestations in CMT seem more frequent than previously thought, especially in CMT2; however, their frequency may be different in the genetic subtypes of the disease and/or an expression of phenotypic variability. Sensory symptoms, and in particular pain, may represent an important issue in the management of CMT patients, especially in a physical medicine approach.     

Comparison between Clinical Disabilities and Electrophysiological Values in Charcot-Marie-Tooth 1A Patients with PMP22 Duplication

Background and Purpose

Charcot-Marie-Tooth disease (CMT) type 1A (CMT1A) is the demyelinating form of CMT that is significantly associated with PMP22 duplication. Some studies have found that the disease-related disabilities of these patients are correlated with their compound muscle action potentials (CMAPs), while others have suggested that they are related to the nerve conduction velocities. In the present study, we investigated the correlations between the disease-related disabilities and the electrophysiological values in a large cohort of Korean CMT1A patients.

Methods

We analyzed 167 CMT1A patients of Korean origin with PMP22 duplication using clinical and electrophysiological assessments, including the CMT neuropathy score and the functional disability scale.

Results

Clinical motor disabilities were significantly correlated with the CMAPs but not the motor nerve conduction velocities (MNCVs). Moreover, the observed sensory impairments matched the corresponding reductions in the sensory nerve action potentials (SNAPs) but not with slowing of the sensory nerve conduction velocities (SNCVs). In addition, CMAPs were strongly correlated with the disease duration but not with the age at onset. The terminal latency index did not differ between CMT1A patients and healthy controls.

Conclusions

In CMT1A patients, disease-related disabilities such as muscle wasting and sensory impairment were strongly correlated with CMAPs and SNAPs but not with the MNCVs or SNCVs. Therefore, we suggest that the clinical disabilities of CMT patients are determined by the extent of axonal dysfunction.     

Validation of the Italian version of the Charcot‐Marie‐Tooth Health Index

The Charcot‐Marie‐Tooth Health Index (CMT‐HI) is a disease‐specific patient‐reported outcome measure measuring overall disease burden in Charcot‐Marie‐Tooth (CMT) patients, designed for natural history studies and clinical trials in English‐speaking affected individuals. We developed and validated its Italian Charcot‐Marie‐Tooth Health Index (I‐CMT‐HI) version. The questionnaire was translated and culturally adapted from source into Italian by two neurologists experienced in CMT and neuromuscular disorders (NMDs). The two translations were reviewed by a panel of seven experts in CMT and NMD. The provisional version was back‐translated into English by a professional translator. The definitive Italian version was developed during a consensus teleconference by the panel and a patient representative from ACMT‐Rete. A series of clinically and genetically characterized CMT patients completed the final questionnaire; 11 participated in a test‐retest reliability assessment of the instrument. The I‐CMT‐HI was administered to 30 CMT patients (13 CMT1A, eight CMTX1, two CMT1B, two CMT1E, two CMT2I, one CMT2A, one CMT2N, one distal Hereditary Motor Neuropathy), with test‐rest in 11:14 females and 16 males, aged (mean ± SD) 48.0 ± 16.4 years (range 18‐81), with CMT Examination Score (CMTES) = 10.0 ± 4.4 (range 2‐18). The I‐CMT‐HI mean total score was 29.4 ± 21.2 (range 0.1‐60.3). The I‐CMT‐HI showed a high test‐retest reliability: intraclass correlation coefficient = 0.95 (95% confidence interval, 0.84‐0.99). No patient had difficulty in completing the questionnaire and none reported any problem with the questions' formulation. The total CMT‐HI score was positively correlated with age and CMTES, with higher disease burden with increasing age and disease severity according to the CMTES. The I‐CMT‐HI is now ready for use in clinical studies in the Italian population.