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.     

缝隙连接蛋白B1基因I20T新突变导致伴有短暂性脑白质损害的X连锁Charcot-Marie-Tooth病1型

目的 报道1个伴有短暂性脑白质损害的X连锁Charcot-Marie-Tooth病1型(CMT1x)家系的临床、影像学和基因改变特点.方法 先证者为14岁男孩,出现短暂发作性言语不能和轻度肢体麻木无力2年5个月.其母亲存在弓形足.对先证者进行头颅MRI、神经电生理检查和腓肠神经活体组织检查;对先证者及其父母,50名女性无周围神经病及脑病对照者进行缝隙连接蛋白B1(GJB1)基因检测.结果 先证者周围神经的运动神经动作电位波幅显著下降,传导速度轻度减慢.听觉和体感诱发电位潜伏期明显延长.MRI显示胼胝体和大脑后部白质对称性异常信号,6个月后病变显著减轻.病理检查提示慢性轴索性周围神经病,电镜检查还可见有髓神经纤维的髓鞘施兰切迹加宽.先证者及其母亲GJB1基因存在I20T突变,其父和50名女性对照者无此突变.结论 伴短暂性脑白质损害的CMT1X可能与GJB1基因I20T新突变有关,其大脑白质的MR1改变具有可逆性.     

远端型遗传性运动神经病Ⅴ型一家系

目的 报道1个远端型遗传性运动神经病Ⅴ型(dHMN-Ⅴ)家系的临床、病理和基因改变特点.方法 该家系中连续4代有9例(4例男性,5例女性)在13～40岁之间发病,其中6例出现下肢无力;有2例女性患者仅出现双手肌肉无力和萎缩,其中1例出现锥体束征.先证者为20岁女性,13岁时发现双手肌肉萎缩和无力,15岁后出现下肢无力;肌电图提示神经源性损伤,神经传导速度检查显示运动神经复合肌肉动作电位波幅显著降低,伴随传导速度轻度减慢,感觉神经传导速度和动作电位波幅均正常.对先证者进行腓肠神经活体组织病理检查,并对先证者和其他4例发病者进行血Berardinelli-Seip先天性脂肪营养不良基因2(BSCL2)基因检查.结果 病理检查显示腓肠神经的有髓神经纤维数量轻度减少,伴随个别有髓神经纤维再生簇以及洋葱球样改变.基因检查显示BSCL2基因的第3号外显子存在263A→G杂合突变.结论 临床和基因检查证实该家系为dHMN-Ⅴ,其发病年龄和临床表现在同一家系中存在异质性,可以伴随轻微锥体束征和感觉神经损害.     

腓骨肌萎缩症2A2A型家系的神经电生理及基因突变分析

目的探讨一个腓骨肌萎缩症(charcot-marie-tooth,CMT)家系的临床表现、神经电生理学和基因突变特点。方法收集家系先证者及其他成员的临床资料,对先证者进行神经电生理学检查和全外显子组基因测序,用Sanger测序技术对先证者及其家系进行突变位点验证。应用计算机软件预测突变位点氨基酸进化保守性和突变可能导致的蛋白质结构和功能变化,分析突变位点的性质。结果先证者儿童期发病,出现双下肢对称性肌肉无力伴跟腱反射消失及足部畸形,其母亲有类似症状。先证者神经电生理检查示运动和感觉神经纤维脱髓鞘及轴索性改变。基因检测发现先证者和母亲MFN2基因第11个外显子均检出c.1066A>G(p.T356A)杂合错义突变;先证者姐姐和父亲未检测到该突变。用PolyPhen-2和MutationTaster软件预测该突变为致病性,突变区域序列在不同物种间高度保守。结论儿童CMT2A2A患者的神经电生理、临床特点、发病机制及相关基因表型均有改变,此可为儿童CMT的临床诊断提供依据。     

TTR Val50Leu突变导致家族性淀粉样多发性神经病的临床和电生理研究

目的分析TTR Val50Leu突变导致家族性淀粉样多发性神经病的临床和电生理特点。方法对一个由TTR Val50Leu突变导致的家族性淀粉样多发性神经病家系进行报道,先证者以足部疼痛为首发症状,2年内逐渐向小腿及上肢进展,并出现自主神经症状。通过对先证者及其家系中相关者进行临床表现、电生理检查及基因检测,分析该病的临床和电生理特点。结果先证者的外祖父、母亲、舅舅、弟弟(其外祖父、母亲、舅舅已故)与其具有相似症状。先证者电生理检查上肢正中神经感觉传导受累,运动正常,尺神经的感觉传导及运动传导均正常,但尺神经F波异常,下肢胫神经和腓总神经的感觉传导及运动传导均未见肯定波形,腓肠神经受累,交感皮肤反应未引出。其弟弟上肢正中神经及尺神经改变同先证者,下肢胫神经运动波幅下降,腓总神经运动正常,交感皮肤反应四肢波幅降低,余同先证者。其女儿上述电生理检查未见异常。基因检测发现三者均在TTR基因exon2存在c.148GT突变,TTR蛋白存在Val50Leu突变。结论 TTR Val50Leu突变导致的家族性淀粉样多发性神经病家系属早发型,以足部疼痛为首发症状,进展迅速,自主神经症状出现较早。电生理符合多发性神经病表现,早期可伴有交感皮肤反应波幅降低。     

遗传性感觉交感神经病Ⅰ型一家系的临床、电生理和病理改变

目的报道一个遗传性感觉交感神经病Ⅰ型（HSANⅠ）家系的临床、病理和电生理改变特点。方法先证者为28岁男性，出现双下肢痛觉缺失1年余，伴随双脚多发溃疡，先证者之母在30岁出现双足麻木和溃疡。对先证者的周围神经和自主神经进行电生理检查，对腓肠神经进行病理检查。结果先证者手部皮肤交感反应延长，在足部没有引出；感觉神经传导速度在上肢出现减慢，（右尺神经33m／s，左正中神经45m／s），在下肢无反应；运动神经传导速度在上肢正常或减慢，在下肢减慢或无反应。腓肠神经的有髓神经纤维完全脱失，无髓神经纤维出现严重脱失。结论我国存在HSANⅠ型家系，病理检查显示有髓神经纤维和无髓神经纤维均被严重累及。皮肤交感反应检查交感神经损害的程度有助于该病的诊断。     

X连锁Charcot-Marie-Tooth病1型六个家系的病理和基因突变特点

目的 报道6个X连锁Charcot-Marie-Tooth病1型(CMTX1)家系的神经病理和基因型改变特点.方法 6个CMTX1家系的先证者均为男性,发病年龄11 ～24岁,出现下肢远端为主的肌无力、腱反射减低和轻度感觉减退.先证者1伴随发作性白质脑病,先证者5伴随小脑性共济失调.12名家系成员也出现周围神经损害症状,另7名存在高弓足或腱反射减低.对6例先证者行腓肠神经活体组织检查,并对6例先证者、8名受累家庭成员和10名无症状家系成员及50名健康女性进行缝隙连接蛋白32( Cx32)基因测序.结果 6例先证者有髓神经纤维出现轻-中度减少伴轴索再生变性,5例出现薄髓鞘神经纤维,其中3例伴洋葱球样结构,2例伴炎细胞浸润.6个家系的Cx32基因存在5种新突变和1种同义突变,即L20T、I127F、D178G、A197V错义突变,403_404T insT插入突变和L10L沉默突变,10名无症状家系成员中有4名女性为携带者,6名男性和健康对照均没有这些基因突变.结论 该组CMTX1患者的周围神经病理改变以慢性轴索损害为主,Cx32基因较多新突变的出现提示我国CMTX1患者具有个体突变特点.     

显性遗传性运动感觉性神经病Ⅱ型一个家系分析

目的本文报道一个在老年期发病的遗传性运动感觉性周围神经病Ⅱ型家族。方法对家族成员进行临床和电生理检查,其中１例病人进行腓肠神经活检。结果家族成员在老年期出现四肢无力和感觉减退。老年病人和无症状年轻病人的电生理检查均发现周围神经的诱发电位波幅显著下降。腓肠神经活检证实轴索性周围神经病。结论检查结果符合显性遗传性运动感觉性周围神经病Ⅱ型的诊断,电生理检查可以发现家族中的亚临床病人。     

常染色体显性遗传性脑动脉病伴皮质下梗死和白质脑病的周围神经改变

目的报道常染色体显性遗传性脑动脉病伴皮质下梗死和白质脑病（CADASIL）患者的周围神经电生理和病理改变特点。方法7例经病理和基因检查确诊的CADASIL患者，女性5例，男性2例。年龄在33～46岁之间，病程从4个月到3年不等。其中1例出现手套袜套样痛觉减退及四肢腱反射减弱。除1例有长期饮酒史外，所有被检者均无其他导致周围神经损害的危险因素。其中3例进行了周围神经电生理检查。7例患者均进行了腓肠神经活体组织的光镜和电镜检查。结果电生理检查显示1例患者的感觉和运动神经以及另1例患者的运动神经传导速度减慢。腓肠神经病理检查显示7例患者均出现轻到中度的有髓神经纤维脱失，6例出现薄髓鞘有髓神经纤维，4例出现个别小有髓神经纤维变性改变，3例伴随小有髓神经纤维的再生簇结构。1例可见血管周围少量炎细胞浸润，5例患者神经滋养动脉的血管平滑肌细胞出现脱失，2例出现增生改变，5例毛细血管基底膜肥厚。结论CADASIL周围神经病多存在亚临床的神经纤维脱失，髓鞘损害比较突出。周围神经的病理改变可能主要与组织缺血有关，不同Notch3基因突变者周围神经损害程度存在差异。     

腓骨肌萎缩症2型的临床特点研究

目的研究腓骨肌萎缩症2型(CMT2)的临床特点。方法回顾性分析9例CMT2患者的临床资料。结果本组男5例,女4例;平均发病年龄21.7岁。平均神经病残疾评分32.6分,平均CMT评分13.3分。均为隐匿性起病,缓慢进展,主要表现为慢性对称性四肢远端肌无力和肌萎缩,感觉症状轻微。1例患者伴有限制性心肌病,临床罕见。9例患者神经电生理检查示运动、感觉神经传导动作电位波幅降低或消失,1例患者伴神经传导速度减慢(<38 m/s),周围神经病变严重。4例腓肠神经及腓短肌肌肉病理学检查符合CMT2典型神经肌肉病理表现。MFN2基因突变分析发现,1例MFN2基因第18外显子发生L710P突变。结论 CMT2的主要临床特点为对称性四肢远端肌无力和肌萎缩,周围神经损害严重但功能相对良好。限制性心肌病可能是该病的表现型之一。MFN2基因L710P突变可能为CMT2致病基因的突变型之一。     

Late‐onset hereditary sensory and autonomic neuropathy expands the phenotypic spectrum of MFN2‐related diseases

Mutations in the Mitofusin 2 (MFN2) gene have been identified in patients with autosomal dominant axonal motor and sensory neuropathy or Charcot–Marie‐Tooth 2A (CMT2A). Here we describe clinical and pathological changes in an adult patient with sporadic hereditary sensory and autonomic neuropathy (HSAN) due to an MFN2 mutation. The patient was a 53‐year‐old man who had sensory involvement and anhidrosis in all limbs without motor features. The electrophysiological assessment documented severe axonal sensory neuropathy. The sural nerve biopsy confirmed the electrophysiological findings, revealing severe loss of myelinated and unmyelinated fibers with regeneration clusters. Genetic analysis revealed the previously identified mutation c.776 G > A in MFN2. Our report expands the phenotypic spectrum of MFN2‐related diseases. Sequencing of MFN2 should be considered in all patients presenting with late‐onset HSAN.     

Axonal neuropathy with optic atrophy is caused by mutations in mitofusin 2

OBJECTIVE: Charcot-Marie-Tooth (CMT) neuropathy with visual impairment due to optic atrophy has been designated as hereditary motor and sensory neuropathy type VI (HMSN VI). Reports of affected families have indicated autosomal dominant and recessive forms, but the genetic cause of this disease has remained elusive. METHODS: Here, we describe six HMSN VI families with a subacute onset of optic atrophy and subsequent slow recovery of visual acuity in 60% of the patients. Detailed clinical and genetic studies were performed. RESULTS: In each pedigree, we identified a unique mutation in the gene mitofusin 2 (MFN2). In three families, the MFN2 mutation occurred de novo; in two families the mutation was subsequently transmitted from father to son indicating autosomal dominant inheritance. INTERPRETATION: MFN2 is a mitochondrial membrane protein that was recently reported to cause axonal CMT type 2A. It is intriguing that MFN2 shows functional overlap with optic atrophy 1 (OPA1), the protein underlying the most common form of autosomal dominant optic atrophy, and mitochondrial encoded oxidative phosphorylation components as seen in Leber's hereditary optic atrophy. We conclude that autosomal dominant HMSN VI is caused by mutations in MFN2, emphasizing the important role of mitochondrial function for both optic atrophies and peripheral neuropathies.     

Clincial and pathological study of distal motor neuropathy with N88S mutation in BSCL2

Seipinopathy is an autosomal dominant inherited distal motor neuropathy caused by Berardinelli‐Seip congenital lipodystrophy 2 (BSCL2) gene mutations. We describe a Chinese family with seipinopathy in which nine patients from four successive generations were involved. The onset of age was from 13 to 40 years. Among them six were distal hereditary motor neuropathy type II with predominant weakness of lower extremities, while one of them was accompanied by pyramidal signs. The other three women were distal hereditary motor neuropathy type V with predominant atrophy of hands. Electrophysiological results in one patient demonstrated reduction of amplitude of compound muscle action potentials. Sural nerve biopsy showed loss of large myelinated fibers and fiber regeneration. Gene analysis revealed a heterozygous 263A→G mutation in BSCL2 gene resulting in amino acid substitutions in N88S. This report suggests that a different type of distal hereditary motor neuropathy could exist within one family carrying N88S mutations. The axonal degeneration of sensory nerves appeared also in the disease.     

A case of hereditary motor and sensory neuropathy of neuronal type with retardation of motor development

An atypical case of hereditary motor and sensory neuropathy of neuronal type with retardation of motor development was described. The patient was a 15-year-old boy who had suffered from distal muscle weakness with atrophy of four limbs and deformities of hands and feet since age 6 months. These symptoms were slowly progressive. He had never walked. His parents were not consanguinous. His parents and two siblings were unremarkable on neurological examination and on nerve conduction studies. On neurological examination, he showed severe degree of muscle weakness and atrophy in the distal upper and lower limbs, moderate degree of muscle weakness and atrophy in the proximal upper limbs and slight degree of made weakness and atrophy in the proximal upper limbs. Deep tendon reflexes in four limbs were decreased or absent. Vibration sensation was moderately decreased in the distal parts of four limbs. On the nerve conduction studies, no sensory nerve potential was recorded in the median, ulnar and sural nerves bilaterally. Motor nerve conduction velocity of the right tibial nerve was 21 m/sec and the amplitude of the compound muscle action potential (M-wave) was 0.15 mV, and no M-wave was elicited with the electrical stimulation of the median, ulnar and peroneal nerves. Neelde EMG showed fibrillation potentials and giant spikes with a reduction of the number of motor units. On sural nerve biopsy, the densities of both myelinated and unmyelinated fibers were severely decreased.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical and pathological features of an autosomal recessive neuropathy

Two siblings are described, ages 49 and 45 years, having a distinct hereditary motor and sensory neuropathy (HMSN) with severe peroneal nerve involvement. The neuropathic symptoms began in childhood. Both patients have sensorineural deafness. The proband was found to have a cardiac conduction abnormality in the absence of known ischemic heart disease. Electrodiagnostic studies were consistent with a demyelinating peripheral neuropathy. The presence of parental consanguinity and absence of affected individuals in succeeding or preceding generations suggested that the sensorimotor neuropathy in this family is inherited in an autosomal recessive manner. The sural nerve of the proband had significant loss of myelinated fibers and demyelination but few regenerating myelinated fibers and no onion-bulbs. The pathological findings, while nonspecific, are not characteristic of the hypertrophic, neuronal or intermediate types of HMSN.     

Hereditary motor sensory neuropathy type I presenting as scapuloperoneal atrophy (Davidenkow syndrome) electrophysiological and pathological studies

A 14 year old boy with scapuloperoneal muscular atrophy, pes cavus, areflexia and distal sensory loss (Davidenkow syndrome) is described. Nerve conduction velocities were diminished. Sural nerve biopsy demonstrated a reduction in the number of myelinated fibers and early "onion-bulb" formation. These observations support the hypothesis that the scapuloperoneal amyotrophy associated with distal sensory loss may represent a variant of type I hereditary motor sensory neuropathy.     

Hereditary motor and sensory neuropathy with spastic paraplegia and optic atrophy: report on a family

We describe two siblings affected by a motor and sensory neuropathy starting in childhood. Already in infancy, a spastic gait disturbance had become obvious, leading later to multiple surgical interventions. In adolescence, progressive loss of vision developed. At the time of our examination, both siblings showed severe weakness and atrophy of the distal muscles of legs and arms. Tendon jerks were brisk in proximal muscles; in the lower extremities, muscle tone was increased. Visual acuity was severely decreased. Nerve conduction studies revealed an axonal degeneration. This finding was confirmed by evaluation of a sural biopsy specimen in one patient, showing only few remaining myelinated fibres without signs of demyelination. This combination of hereditary motor and sensory neuropathy with spastic paraplegia and optic atrophy shows features of both hereditary motor and sensory neuropathy V and VI according to the classification of Dyck, indicating that these subtypes may not represent distinct entities. Received: 24 February 1997 Received in revised form: 30 May 1997 Accepted: 26 July 1997     

Hereditary motor and sensory neuropathy with optic atrophy. Ultrastructural and morphometric observations on nerve fibers, mitochondria, and dense-cored vesicles

Nerve biopsy specimens from three cases of hereditary motor and sensory neuropathy with optic atrophy were studied by light and electron microscopy and by morphometry. All cases had a chronic neuropathy of the neuronal/axonal type with little, presumably secondary, demyelination. There was predominant reduction of the large-caliber population of myelinated and unmyelinated nerve fibers. The number of dense-cored vesicles in unmyelinated and small myelinated fibers was increased. Abnormal mitochondria in Schwann cells with paracrystalline inclusions, prominent cristae including paracrystalline material (cases 1 and 2), and axonal mitochondria with presumable hydroxyapatite crystals (case 3) were found. The morphologic results suggest that hereditary motor and sensory neuropathy with optic atrophy should be regarded as a separate entity within the hereditary motor and sensory neuropathy group.     

Charcot-Marie-Tooth disease: a novel Tyr145Ser mutation in the myelin protein zero (MPZ,P0) gene causes different phenotypes in homozygous and heterozygous carriers within one family

Charcot-Marie-Tooth disease type 1B (CMT 1B) is caused by mutations in the gene coding for peripheral myelin protein zero (MPZ, P0) that plays a fundamental role in adhesion and compaction of peripheral myelin. Here we report a Costa Rican family with a hereditary peripheral neuropathy due to a novel Tyr145Ser MPZ mutation. Four family members were heterozygously affected; two siblings of two heterozygous carriers were homozygous for this mutation. On neurological examination the heterozygous parents and their homozygous children both showed distal sensory deficits. The mother and the siblings displayed impaired deep tendon reflexes and mild sensory ataxia. The homozygous individuals were more severely affected with an earlier age of onset, distal motor weakness, and pupillary abnormalities. Electrophysiological studies revealed both signs of demyelination and axonal nerve degeneration. The sural nerve biopsy of one sibling showed thinly myelinated nerve fibers, onion bulb formation, and clusters of regenerating fibers. On electron microscopy axonal degeneration and decompaction of inner myelin layers were found. This Costa Rican family shows phenotypic variability depending on the homozygous or heterozygous state of the Tyr145Ser mutation carriers.A. Leal and C. Berghoff contributed equally to this work.