线粒体融合蛋白2基因新突变导致的遗传性运动感觉性神经病6型一家系

目的 报道1个遗传性运动感觉性神经病6型家系的临床表现、病理改变以及基因突变特点。方法 先证者男性,15岁。患者5岁出现双下肢无力,症状进行性加重,伴随出现双足跟腱挛缩;11岁开始出现慢性进行性视力下降;12岁出现双手肌肉萎缩,无肢体麻木。周围神经传导速度检查显示诱发电位未能引出或波幅显著下降,感觉神经较运动神经改变更明显。视诱发电位提示双眼P100潜伏期均延长,波幅正常。眼底照相提示视神经萎缩,视网膜电图正常。患者母亲7岁时开始出现走路费力,10岁出现视力下降。对先证者进行腓肠神经活体组织检查。对先证者及其母亲进行线粒体融合蛋白2( MFN2)基因测序,100名健康人作为正常对照。结果 腓肠神经病理改变主要为有髓神经纤维显著减少,电镜检查发现个别有髓神经纤维出现洋葱球样结构和再生簇结构,个别神经纤维的轴索内可见线粒体聚集和空泡化。先证者和母亲的MFN2基因第19号外显子存在c.2218T＞C杂合突变,导致MFN2第740位的色氨酸由精氨酸替代(W740R)。100名健康对照没有发现该突变。结论 MFN2基因c.2218T＞C突变导致了遗传性运动感觉性神经病6型,其视力下降多出现在脊神经损害之后,周围神经可以存在髓鞘损害。     

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.     

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。     

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.     

替比夫定与聚乙二醇干扰素α-2a联用导致感觉神经病二例

目的 报道2例使用替比夫定和聚乙二醇干扰素α-2a联合治疗乙型肝炎导致的感觉神经病患者,对其临床、电生理和病理改变规律进行讨论.方法 2例男性患者分别为48岁和20岁,均为慢性乙型肝炎病毒感染者,在应用替比夫定和聚乙二醇干扰素α-2a治疗4个月后出现双下肢麻木和疼痛,症状进行性加重.体检发现均出现四肢远端痛觉减退,例2出现腱反射减低.2例均出现四肢远端无汗,例1出现手指和足趾的甲根部灰白样改变.例2伴随出现下肢轻度肌力下降和血清肌酸激酶轻度升高.对2例患者进行电生理检查及腓肠神经病理检查.结果 2例患者的电生理检查发现感觉神经动作电位波幅显著减低,传导速度轻度下降,其中1例出现运动神经动作电位波幅减低.腓肠神经活体组织检查显示有髓神经纤维中度减少、有髓神经纤维轴索变性和轻度再生簇形成.电镜检查进一步发现无髓神经纤维也出现减少.停止药物治疗并给予B族维生素、辅酶Q10和左旋肉碱治疗后症状好转.结论 替比夫定联合聚乙二醇干扰素α-2a治疗可以导致感觉神经病,出现轴索性神经病的电生理和病理改变特点.此病具有可逆性.     

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。     

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。     

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.     

周围髓鞘蛋白22基因重复突变致夏科-马里-图斯病1A亚型的临床变异性

目的 探讨夏科-马里-图斯病(CMT)患者周围髓鞘蛋白22(PMP22)基因重复突变特征及临床变异性.方法 联合应用改良的等位基因特异性PCR-双酶切和基于荧光标记毛细管电泳短串联重复序列(STR)分析对45例临床拟诊CMT患者进行PMP22基因重复突变的检测,详细分析其中阳性病例的临床特征.结果 在45例拟诊CMT患者中共检测出PMP22基因重复病例21例,包括10例临床特征符合四肢远端萎缩无力的典型CMT1型患者和11例不典型的CMT患者,后者具有特殊表型:1例仅以轻度头晕就诊;1例合并听力障碍;2例以反复发作性肢体无力起病;2例伴有上肢姿势性震颤;4例伴有小脑性共济失调;1例伴有癫(癎)发作.结论 PMP22基因重复突变为CMT病最常见的病因,改良的等位基因特异性PCR-双酶切提供了一种准确、可靠并易于操作的检测方法,有助于该病的诊断和鉴别.同时,通过综合分析PMP22重复突变阳性的CMT1A患者临床表现、电生理及病理特征,提示该组疾病具有高度的临床变异性.     

A FAMILY WITH AUTOSOMAL DOMINANT MUTILATING NEUROPATHY NOT LINKED TO EITHER 3q13-q22 OR 9q22 LOCI

The clinical separation of CMT2 from HSAN I may be difficult in some kindreds in which the sensory and motor symptoms and deficits are approximately alike. The genetic studies of CMT2 families are also controversial: one form of CMT2 was shown to map on chromosome 3q13-q22 and named CMT2B; the HSAN I locus was mapped to 9q22.1. We describe a family with an autosomal dominant inheritance in which at least three members, belonging to three generations, developed a progressive neuropathy that combined limb weakness, wasting, and severe distal sensory loss leading to prominent mutilating changes. The onset was in late childhood, with progressive weakness in the lower limbs and later in the hands, resulting in a severe paralysis in the feet in one patient. Sensory disturbances were pronounced in 2 patients, and led to poorly healing ulcerations with osteomyelitis and amputations in one foot and mutilating lesions of both hands. Electrophysiological investigation revealed an axonopaty with consistent motor damage. Sural nerve biopsy showed a reduction in the density of both myelinated and unmyelinated fibers, with regenerating clusters.
Linkage analysis using 5 microsatellite markers within to the critical 9q22 region was performed. Lod scores of this family calculated by LINKAGE package excluded association to this locus. We also performed linkage studies with chr. 3q13-q22 markers associated to the CMT2b locus. Lod scores excluded this locus as well as responsiblity of the familial phenotype. The severity of motor involvement would suggest classifying the disorder of this family as a form of HSMN II rather than HSAN, indicating that a new locus is involved in the pathogenesis of this disorder.     

A family of early childhood-onset Charcot-Marie-Tooth disease type 2]

We reported a man and his son with Charcot-Marie-Tooth disease (CMT) type 2. Their age at onset was about 5 years. Their clinical examinations revealed muscle atrophy and weakness of both distal lower limbs, foot-drop, a reduction of the reflex in both Achilles tendons and sensory impairment of the glove and stocking type. Nerve conduction studies revealed remarkably low amplitude of compound muscle action potential compared to conduction velocity. The nerve biopsy of their sural nerves revealed loss of large myelinated fiber. We presumed that the clinical features of their disease were compatible with CMT2A or 2B. DNA analysis of our family members performed with microsatellite markers linked to the candidate regions of CMT2A and 2B, did not show apparent positive results. We speculate that this family was a novel gene locus of CMT type 2.     

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.     

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。     

Two families of Charcot-Marie-Tooth disease with Adie's pupil, axonal neuropahy and the Thr124Met mutation in the peripheral myelin protein zero gene]

We reported two families of Charcot-Marie-Tooth disease (CMT) with Thr124Met mutation in the peripheral myelin protein zero (MPZ). The clinical features of the proband patients of both families showed Adie's pupil, severe sensory dominant neuropathy in lower extremities, and axonal changes in sural nerve biopsies and nerve conduction studies. Muscle atrophy and weakness was mild in the lower legs, while sensory impairment was marked. The proband patient of family 1 had four symptomatic siblings and one of them showed Adie's pupil. The elderly daughter of the proband of family 2 showed Adie's pupil and younger daughter showed photophobia. The biopsied sural nerves of both proband patients revealed prominent axonal sprouting, and sub-perineurial edema and mild fascicular enlargement. Segmental demyelination was not frequent in teased fiber assessment. The present two family cases strongly suggest that this MPZ gene mutation (Thr124Met) could be present among the patients with CMT type 2, axonal form. Furthermore, the patients showing sensory neuropathy and Adie's pupil may need to be reexamined with this mutation. It is also necessary to reassess genotype-phenotype correlation in CMT patients particularly in reference to type 1 and type 2.     

The phenotype of the Gly94fsX222 PMP22 insertion

Point mutations in PMP22 are relatively rare and the phenotype may vary from mild hereditary neuropathy with liability to pressure palsies (HNPP) to severe Charcot-Marie-Tooth type 1 (CMT1). We describe the phenotype of the Gly94fsX222 mutation in the PMP22 gene. Medical records of all patients were reviewed and 11 patients were re-examined. EMG was carried out in nine patients and nerve biopsy in one. Thirteen patients originating from seven families with a Gly94fsX222 mutation were included and consisted of 10 women and 3 men with a median age of 41 years (range 7-67). Five index patients were originally suspected of CMT1. Ten patients had abnormal motor skills during childhood. Nine patients had a history of pressure palsies. Involvement of the olfactory, trigeminal, facial, and pudendal nerves occurred in three patients. Twelve patients had pes cavus and one scoliosis. Distal anterior leg and distal arm weakness were found in 12 and 4 patients, respectively. Twelve patients had distal leg sensory abnormalities. Electrophysiological examination revealed a demyelinating sensorimotor neuropathy, both resembling CMT1 and HNPP. Sural nerve biopsy showed demyelinating neuropathy with presence of tomacula. More than three-fourths of the patients with Gly94fsX222 mutation demonstrated a CMT1 phenotype combined with transient deficits. Clinicians should test for this mutation in those patients exhibiting a generalised neuropathy combined with compressive like episodes.     

A novel mutation in PRPS1 causes X‐linked Charcot‐Marie‐Tooth disease‐5

X‐linked Charcot‐Marie‐Tooth disease‐5 (CMTX5) is a rare hereditary disorder caused by mutations in the gene for phosphoribosyl pyrophosphate synthetase‐1 (PRPS1). We investigated a boy with a novel PRPS1 mutation (c.334G>C, p.V112L) via genetic, neuropathological and enzymatic tests. The proband was a 13‐year‐old boy with congenital non‐syndromic sensorineural deafness. At 3 year old, he developed progressive distal weakness of all limbs with muscle atrophy of both hands and shanks. Nerve conduction study revealed the loss of sensory nerve action potentials, and slowing down of motor nerve conduction velocities with a decrease of amplitudes of compound motor action potentials. Visual evoked potentials and brainstem auditory evoked potentials were not bilaterally evocable. Sural biopsy proved the loss of myelinated nerve fibers, with axonal degeneration, regenerating clusters and onion bulbs. Enzymatically, PRPS1 activity was close to zero in the proband and mildly reduced in his mother, compared with controls. To our knowledge, this is the first report of CMTX5 in a Chinese population. The genetic finding has expanded the genotypic spectrum of PRPS1 mutations.