小热休克蛋白22基因在腓骨肌萎缩症中的突变分析

目的 探讨小热休克蛋白22（small heat-shock protein 22，HSP22）基因在中国人腓骨肌萎缩症（Charcot-Marie-Tooth disease，CMT）中的突变特点。方法 应用聚合酶链反应和DNA直接测序方法，对1个发现HSP22基因423（G→T）突变的CMT2L家系外的114个CMT家系先证者进行了且HSP22基因的突变分析。结果 114个先证者中有2例患者在且HSP22基因的第3外显子发生了582（C→T）碱基改变，由于编码的氨基酸未改变，均为色氨酸（Thr），为一种同义突变。结论 HSP22基因突变在中国人的腓骨肌萎缩症患者中少见，突变率为0.87％（1／115）。     

中国人遗传性痉挛性截瘫spastin基因突变研究

目的 探讨中国人遗传性痉挛性截瘫（hereditary spastic paraplegia,HSP)spastin基因的突变特点，为该病的基因诊断提供依据。方法 应用聚合酶链反应—单链构象多态性(PCR—single strand conformation polymorphism，PCR—SSCP)结合DNA序列分析方法，对22个常染色体显性遗传HSP家系的先证者和9例散发性HSP患者的spastin基因进行研究，对发现异常SSCP条带的家系内成员进行突变研究。结果 在22例常染色体显性遗传HSP家系的先证者和9例散发性HSP患者中发现异常SSCP条带6例，进行DNA序列分析，共发现3种spastin基因突变，为外显子8的T1258A和A1293G，外显子14的1667delACT或1668delCTA或1669delTAC，均未见报道，突变位点均位于spastin基因功能区域，其中两个家系存在同一种突变(T1258A)，各突变家系内患者存在同样的异常SSCP条带。结论 中国人遗传性痉挛性截瘫患者存在spastin基因突变，该基因在中国人常染色体显性遗传的遗传性痉挛性截瘫家系中的突变率较低(18．2％)，点突变是主要的突变形式，外显子8可能是中国人spastin基因的突变热点。     

Van der Woude综合征家系IRF6基因突变分析

目的研究Van der Woude综合征（Van der Woude syndrome，VWS）干扰素调节因子6（interferon regulatory factor 6，IRF6）基因突变。方法提取3个VWS家系成员基因组DNA，聚合酶链反应扩增IRF6基因9个外显子及其侧翼内含子序列，直接测序对患者IRF6基因进行突变的检测。结果在3个家系患者IRF6基因中共发现国际上尚未报道的3个突变：无义突变981（T→A）（Cys327X）和1234（C→T）（Arg412X）；错义突变1214（T→C）（Met405Thr）。结论IRF6基因突变可能是VWS发病原因。     

神经丝轻链基因在腓骨肌萎缩症中的突变分析

目的：探讨神经丝轻链基因（neurofilament-light gene,NF-L）在中国人腓骨肌萎缩症（Charcot-Marie-Tooth disease,CMT）中的突变特点。方法：应用聚合酶链反应－单链构象多态性技术结合DNA序列分析方法，对32个来自全国5省汉族的CMT家系先证者进行了NF－L基因的突变分析。结果：32例先证者中只有1例患者出现异常条带，经DNA测序证实该患者在NF－L基因的外显子3发生了1329C→T碱基改变，由于编码的氨基酸未改变，均为酪氨酸（Tyr），为一种同义突变。结论：NF－L基因突变可能在中国人的腓骨肌萎缩症患者中少见。     

SACS基因复合杂合突变导致Charlevoix-Saguenay型痉挛性共济失调一家系两例CSCD

目的对1个常染色体隐性遗传痉挛性共济失调Charlevoix-Saguenay型（autosomal recessive spastic ataxia of Charlevoix-Saguenay, ARSACS）家系进行SACS基因突变分析,探讨其遗传学病因。方法应用目标区捕获高通量靶向测序对SACS基因进行突变筛查,用Sanger测序对突变位点进行验证。结果测序结果显示先证者和弟弟存在SACS基因C．13085T〉G（P．14362R）和C．5236dupA（P．T1746fs）复合杂合突变,父亲携带SACS基因c．5236dupA（P．T1746fs）杂合突变,母亲携带SACS基因C．13085T〉G（p．14362R）杂合突变,因此患者的C．5236dupA（P．T1746fs）和C．13085T〉G（P．14362R）突变分别来自父母。经检索人类基因突变数据库这两个变异均为未报道过的新突变,根据美国医学遗传学及基因组学会遗传变异解读指南,提示均为可能的致病性突变。结论C．5236dupA（P．T1746fs）和C．13085T〉G（P．14362R）突变为该ARSACS家系患者的遗传学病因,新突变的检出丰富了SACS基因突变谱。     

马凡综合征微纤维蛋白1基因突变检测及单倍型连锁分析

目的：检测中国人马凡综合征（Marfan syndrome,MFS)患者微纤维蛋白1（fibillin-1,FBN1)基因的突变及对马凡综合征患者的家系成员进行症状前诊断。方法：应用聚合酶链反应－单链构象多态性技术和测序方法，对汉族9个家系中共17个MFS患者进行基因突变检测；运用FBN1基因内4个内含子中的可变串联重复序列构建染色体单倍型，进行家系单倍型连锁分析和基因诊断。结果：发现MFS（A）家系Ⅱ1患者有单链构象改变，测序证实为位于FBN1基因第25号外显子3243－3256核苷酸之间有I个13bp的小片段缺失，为新位点基因移码突变，其序列为gcctctgcaccca;单倍型连锁分析发现MFS（B）家系Ⅲ1是1个无症状期患者。结论：中国人FBN1基因突变可以引起马凡综合征，应用突变检测与单倍型连锁分析方法能为马凡综合征基因诊断提供依据。     

中国人早发及多发糖尿病家系中HNF4A基因突变的筛查

目的探讨中国上海及周边地区早发及（或）多发糖尿病家系肝细胞核因子如基因（hepatocyte nuclear faetor-4α，HNF4A）的突变及变异发生情况。方法用PER-单链构象多态及序列分析的方法对154例早发及（或）多发糖尿病家系先证者进行HNF4A基因扫查。对发现的突变或变异采用PCR-限制性片段长度多态性方法在家系其他成员及93名正常对照者中进一步检测。结果在2例糖尿病家系先证者中发现2个同义突变，即N153N和A158A。其中N153N在1个早发性糖尿病家系中见到，且与糖尿病共分离。上述同义突变在正常者中未查到。此外，还发现3个变异位点：即IVS1＋308（A→G）（rs2071197），IVS1＋357（A→T）（rs2071198），IVS1-5（C→T）（rs745975）。3个位点基因型和等位基因频率在糖尿病先证者和正常对照者中无品著差别．结论HNF4A基因突变在中国人早发及（或）多发糖尿病家系中可能罕见。     

人类溶菌酶基因突变可导致遗传性系统的淀粉样变性

本文对两个遗传性非神经系统淀粉样变性症(Ostertag型)家系患者进行了研究,首次报告引起人类溶菌酶及溶菌酶相关的变异疾病的分子基础。对此两家系所有个体的溶菌酶基因作序列分析发现,患者均为溶菌酶基因突变的杂合子,此突变可引起高度保守的氨基酸残基发生替换:家系1先证者的该基因第二外显子中存在T→C转换,此突变可     

中国南方斑驳病一家系的一种新的KIT基因突变

目的研究1个斑驳病家系的基因突变情况。方法经组织病理、电镜检查结合典型的临床特征确立斑驳病的诊断。采用聚合酶链反应及DNA直接测序的方法对此家系进行基因突变检测。结果家系中先证者存在K／T基因第2528位G→A（或C→T），使密码子AGT〉AAT，导致A850N。100名健康对照组不存在此突变。结论S850N可能是引起该家系临床表型的原因。     

两个X连锁少汗性外胚层发育不良家系的基因突变分析

目的 对两个X连锁隐性遗传少汗性外胚层发育不良(X-linked hypohidrotic ectodermal dysplasia,XLHED)家系进行ED1基因突变分析,为罹患家庭提供遗传咨询及产前诊断.方法 综合应用序列分析及多重连接依赖性探针扩增方法,对两个家系的先证者进行ED1基因突变分析,并针对检测到的突变位点对女性成员进行检测.采集家系1胎儿的羊水细胞进行产前诊断,包括致病突变位点的分析、ED1基因内4个短串联重复序列(short tandem repeat,STR)位点的单倍型连锁分析、性别鉴定及核型分析.结果 家系1先证者缺失ED1基因第1外显子及下游2个STR位点DXS8269,DXS1422区域,其余外显子序列分析未见异常,其女儿为该缺失突变的携带者;结合连锁分析、性别鉴定及核型分析结果,家系1胎儿为男性非ED1基因缺失突变携带者,胎儿足月分娩后随访,为健康个体.家系2先证者经序列分析检测到ED1基因第3外显子c.463C＞T(R155C)错义突变,母亲为c.463C＞T(R155C)杂合突变携带者.结论 ED1基因第1外显子区域缺失和错义突变R155C是导致2个少汗性外胚层发育不全家系患者临床表型的主要原因,ED1基因的突变检测结合单倍型分析,能准确地对该类家系提供产前诊断.     

腓骨肌萎缩症 GDAP1基因突变分析

目的　分析神经节苷酯诱导分化相关蛋白 1( ganglioside- induced differentiation- associatedprotein- 1,GDAP1)基因在中国人腓骨肌萎缩症的突变特点。方法　应用多聚酶链反应 -单链构象多态性分析结合 DNA直接测序的方法 ,对 8个常染色体隐性遗传的腓骨肌萎缩症家系先证者和 15个散发病例共 2 3例患者进行了 GDAP1基因 6个外显子及其侧翼区的突变检测。结果　在 1个常染色体隐性遗传家系中发现 GDAP1基因的 A5 33G、A76 7G的复合杂合突变。纯合、杂合 T5 0 7G为人群常见多态。结论　GDAP1基因 A5 33G、A76 7G为新发现的突变     

Clinical,In Silico,and Experimental Evidence for Pathogenicity of Two Novel Splice Site Mutations in the SH3TC2 Gene

Abstract: Charcot-Marie-Tooth (CMT) neuropathy is the most common inherited neuromuscular disorder. CMT is genetically very heterogeneous. Mutations in the SH3TC2 gene cause Charcot-Marie-Tooth neuropathy type 4C (CMT4C), a demyelinating form with autosomal recessive inheritance. In this study, two novel splice site mutations in the SH3TC2 gene have been studied (c.279G → A, c.3676–8G → A). Mutation c.279G → A was detected on one allele in two unrelated families with CMT4C in combination with a known pathogenic mutation (c.2860 C →T in one family, c.505T → C in the other) on the second allele of SH3TC2 gene. Variant c.3676–8G → A was detected in two patients from unrelated families on one allele of the SH3TC2 gene in combination with c.2860C →T mutation on the other allele. Several in silico tests were performed and exon trap experiments were undertaken in order to prove the effect of both mutations on proper splicing of SH3TC2. Fragments of SH3TC2 were subcloned into pET01 exon trap vector (Mobitec) and transfected into COS-7 cells. Aberrant splicing was predicted in silico for both mutations, which was confirmed by exon trap analysis. For c.279G → A mutation, 19 bases from intron 3 are retained in cDNA. The mutation c.3676–8G→ A produces a novel splice acceptor site for exon 17 and complex changes in splicing were observed. We present evidence that mutations c.279G → A and c.3676–8G →A in the SH3TC2 gene cause aberrant splicing and are therefore pathogenic and causal for CMT4C.     

Three novel mutations in the gap junction beta 1 (GJB1) gene coding region identified in Charcot-Marie-Tooth patients of Greek origin: T55I, R164Q, V120E. Mutation in brief no 236. Online

Charcot-Marie-Tooth (CMT) disease type CMTX has been linked with mutations in GJB1, a gene on chromosome X coding for a gap junction protein, Connexin 32. We screened the GJB1 gene for mutations by SSCP analysis and sequencing of candidate regions, in five unrelated CMT affected individuals, members of families presenting a mode of transmission and clinical findings compatible with CMTX. Mutations were detected in all five patients. Three not previously reported mutations were identified: C164T, G491A and T359A. Two patients shared the same mutation (C164T) while one had a reported mutation (C43T). Restriction enzyme digestion confirmed the sequencing results, as well as the co-segregation of the mutation with the disease. The same method was used to screen 150 control X chromosomes and the variations were not detected.     

实时荧光定量PCR在周围髓鞘蛋白22基因重复或缺失检测中的应用

目的 应用实时荧光定量PCR在腓骨肌萎缩症和遗传性压力易感性神经病患者中检测周围髓鞘蛋白22基因（peripheral myelin protein 22，PMP22）重复或缺失。方法 采用实时荧光定量PCR检测113个腓骨肌萎缩症家系先证者、4个遗传性压力易感性神经病家系先证者和50名正常人PMP22基因重复或缺失突变。结果 113个腓骨肌萎缩症家系中发现有36个存在PMP22基因重复，4个遗传性压力易感性神经病先证者均存在PMP22基因缺失，50名正常人未发现异常。结论 我国PMP22基因重复突变的致病频率为31．9％（36／113），PMP22基因缺失突变是遗传性压力易感性神经病常见的致病原因。     

两个新RUNX2基因突变引起家族性锁骨颅骨发育不全

目的 探讨RUNX2基因突变在锁骨颅骨发育不全病因研究中的意义及两个中国家族性锁骨颅骨发育不全家系发病的分子机制.方法 提取收集到的2个锁骨颅骨发育不全家系中4例患者和4名家系健康成员、102名无关正常对照外周血基因组DNA,应用PCR扩增产物双向直接测序方法 检测RUNX2基因第1～7外显子及相邻侧翼区的DNA序列,测序结果 与RUNX2基因正常序列对比分析.对发现的突变位点用酶切方法 证实.结果 测序结果 发现一家系中两例父子患者的RUNX2基因第1外显子发生错义突变c.346T＞A(W116R),该错义突变通过Bsr Ⅰ限制性内切酶对PCR扩增产物行酶切分析得到进一步确认.另一家系中两例患者的RUNX2基因第3外显子发生无义突变c.610A＞T(K204X).在两个家系中的正常家系成员和无关正常对照RUNX2基因DNA序列中没有发现上述突变.结论 通过RUNX2基因,检测在中国人群中发现两个RUNX2基因新致病突变,扩展了遗传性锁骨颅骨发育不全的基因突变谱,对阐明该病发病机制及其基因诊断和遗传咨询有重要意义.     

High frequency of SH3TC2 mutations in Czech HMSN I patients

La??uthová P, Mazanec R, Vondrá?ek P, ?i?ková D, Haberlová J, Sabová J, Seeman P. High frequency of SH3TC2 mutations in Czech HMSN I patients. Charcot–Marie–Tooth (CMT) neuropathy type 4C (CMT4C) is an autosomal recessive (AR), demyelinating neuropathy with early spine deformities caused by mutations in the SH3TC2 gene. To determine the spectrum of SH3TC2 mutations in the Czech population, the entire coding region of SH3TC2 was sequenced in 60 unrelated Czech patients. The prevalent mutation was shown to be the p.Arg954Stop. Therefore, 412 additional patients referred for CMT testing were tested for the presence of p.Arg954Stop only. Of 60 patients in whom the SH3TC2 gene was sequenced, at least one mutation was detected in 13 (21.7%) patients and biallelic pathogenic mutations were detected in 7 (11.6%) patients. Of the 412 patients tested for p.Arg954Stop, the mutation was found in 8 patients (1.94%), 6 were homozygous and 2 were heterozygous. The second causative mutation was detected by sequencing in one of the patients but not in the other. Nine novel sequence variants were detected. Their pathogenicity was further tested in silico and in control samples. Mutations in the SH3TC2 gene are a frequent cause of demyelinating hereditary neuropathy among Czech patients. In total, at least one mutation was found in 21 unrelated patients. CMT4C seems to be the most frequent type of AR CMT and one of the most frequent of all CMT types. Mutation p.Arg954Stop is highly prevalent in the Czech population. Patients with demyelinating neuropathy along with non‐dominant mode of inheritance and negative for CMT1A/hereditary neuropathy with liability to pressure palsy should be tested for the presence of the p.Arg954Stop mutation or other mutations in the SH3TC2 gene.     

Small heat shock protein 27 mutation in a Japanese patient with distal hereditary motor neuropathy

Heat shock protein 27 (HSP27) belongs to a family of small heat shock proteins that play significant roles in the cellular stress response and are also involved in the control of protein–protein interactions as chaperons. Mutation in HSP27 has been identified as the cause of axonal Charcot–Marie–Tooth disease (CMT) and distal hereditary motor neuropathy (HMN). Heat shock protein 22 (HSP22) is a molecular counterpart of HSP27, and its mutation is another cause of distal HMN. We screened the mutation of HSP27 and HSP22 in 68 Japanese patients with axonal CMT or unclassified CMT and six Japanese patients with distal HMN. We detected a heterozygous P182S mutation of HSP27 in a patient with distal HMN, but we found no mutations in HSP22. Mutation in HSP27 may impair the formation of the stable neurofilament network that is indispensable for the maintenance of peripheral nerves.