迟发型先天性厚甲家系角蛋白17基因新突变位点的检测

目的探讨一迟发型先天性厚甲家系角蛋白17基因突变和临床表现的关系,为先天性厚甲的基因诊断和基因治疗奠定基础。方法用巢式PCR扩增了迟发型先天性厚甲家系中9例患者、1名正常人及与该家系无关的50名正常人外周血基因组：DNA角蛋白17基因第1外显子热点突变区,对PCR产物进行DNA序列分析。结果迟发型先天性厚甲家患者的角蛋白17基因第109位密码子由AAC突变为GAC,结果导致天冬酰胺由天冬氨酸替代(即N109D)。而该家系中的正常人及与该家系无关的50名正常人的DNA测序结果均未发现此突变。结论该家系存在角蛋白17N109D突变,为一新的错义突变。角蛋白17 1A区后半部的突变可表现为迟发型先天性厚甲Ⅱ型。     

一视网膜色素变性家系的基因检测分析

目的 通过对一个三代视网膜色素变性（RP）家系进行基因检测分析,找到其致病基因.方法 采用外显子捕获直接测序,检测家系成员40个RP相关基因,经与美国国立生物技术信息中心（NCBI）的SNP数据库（dbSNP）和国际人类基因组单体型图（Haplotype Map,简称HapMap）数据库进行比较,查找致病基因.结果 该家系的致病基因位于USH2A基因.该基因编码区存在2个错义突变（p.Tyr1279Asn、p.Cys934Trp）.结论 本研究在一个三代RP家系中发现了USH2A基因p.Tyr1279Asn、p.Cys934Trp两个新突变位点.     

广东人AGTR2突变热区的SNPs位点分析

[目的]研究广东汉族人群中血管紧张素Ⅱ2型受体基因(AGTR2)是否存在特有的SNPs位点.[方法]收集121例祖籍广东的汉族人.取外周静脉血以酚/氯仿法分离白细胞提取基因组DNA,根据AGTR2基因已知的SNPs的位点分布特点设计两对引物,PCR扩增目的片段.对PCR产物进行SSCP分析,银染显色.根据染色结果,随机抽取部分带型不同的PCR产物直接测序,对测序结果通过B1ASTn软件和ClustalW软件在线分析.[结果]发现5个SNPs位点:G300663A,A300672T,A300818T,G301404T和A301410G,除A301410G与GenBank dbSNP数据库中的位点(rs5194)相同外,其余4个位点为新发现的SNPs位点.[结论]AGTR2是一个高突变的基因,广东人AGTR2的SNPs位点多,与其他人群显著不同.     

良性家族性婴儿惊厥家系候选基因的突变检测

目的检测良性家族性婴儿惊厥—家系的致病基因。方法通过生物信息学查询选择HCRTR1、STX12、HPCA为候选基因,应用Primer 3引物设计、PCR扩增、直接测序的方法进行候选基因的突变检测。序列分析采用DNAStar软件。结果未发现与疾病表型共分离的致病突变,但其中发现1个已知的多态。结论排除HCRTR1、STX12、HPCA为该BFIS家系致病基因的可能。     

广东人AGTR2突变热区的SNPs位点分析

【目的】研究广东汉族人群中血管紧张素Ⅱ2型受体基因(AGTR2)是否存在特有的SNPs位点。【方法】收集121例祖籍广东的汉族人。取外周静脉血以酚／氯仿法分离白细胞提取基因组DNA，根据AGTR2基因已知的SNPs的位点分布特点设计两对引物，PCR扩增目的片段。对PCR产物进行SSCP分析，银染显色。根据染色结果，随机抽取部分带型不同的PCR产物直接测序，对测序结果通过B1ASTn软件和ClustalW软件在线分析。【结果】发现5个SNPs位点：G300663A，A300672T，A300818T，G301404T。和A301410G，除A301410G与GenBank dbSNP数据库中的位点(rs5194)相同外，其余4个位点为新发现的SNPs位点。【结论】AGTR2是一个高突变的基因，广东人AGTR2的SNPs位点多，与其他人群显著不同。     

乙型肝炎病毒基因耐药突变位点的异质性分析

目的 探讨乙型肝炎病毒(HBV)核苷(酸)类药物(NAs)相关基因耐药突变的异质性及其临床意义.方法 收集249例接受NAs治疗且出现病毒学突破的慢性乙型肝炎(CHB)患者的HBV逆转录酶区(RT区)耐药突变位点数据、临床数据及随访数据,根据NAs耐药突变与否分为非耐药组和耐药组.结果 非耐药组和耐药组年龄、治疗后HB...     

一例Ⅰ型成骨不全家系的基因定位及突变检测

目的对国内1例成骨不全(OI)家系进行基因突变及突变效应分析,为研究中国人群的成骨不全基因突变特点提供线索。方法对成骨不全Ⅰ型胶原基因COL1A1和COL1A2所在的17号染色体和7号染色体分别进行连锁分析,对致病基因做初步判断,然后用聚合酶链反应扩增致病基因外显子,并测序检出基因突变。结果该家系为COL1A1基因突变,所有患者在该基因的第8个内含子剪切受体位点处为AG→GG(IVS8-2A>G)突变。结论对比COL1A1基因突变数据库,该突变为一新发现突变。     

一例Ⅰ型成骨不全家系的基因定位及突变检测

目的 对国内1例成骨不全(OI)家系进行基因突变及突变效应分析,为研究中国人群的成骨不全基因突变特点提供线索.方法 对成骨不全Ⅰ型胶原基因COL1A1和COL1A2所在的17号染色体和7号染色体分别进行连锁分析,对致病基因做初步判断,然后用聚合酶链反应扩增致病基因外显子,并测序检出基因突变.结果 该家系为COL1A1基因突变,所有患者在该基因的第8个内含子剪切受体位点处为AG→GG(IVS8-2A＞G)突变.结论 对比COL1A1基因突变数据库,该突变为一新发现突变.     

一个中国Usher综合征2型家系中USH2A基因的2个新的致病突变

目的为了扩大USH2A突变的范围并进一步揭示USH2A基因在2型Usher综合征（Usher syndrome type 2, USH2）中的作用,对中国的USH2患者进行了USH2A基因突变筛选。方法从收集到的中国USH2患者及其家属的外周血中提取基因组DNA,设计特异性引物扩增USH2A基因编码区（外显子2-72）并使用Sanger测序研究等位基因并与NCBI数据库中的标准序列进行比对。使用PolyPhen-2等预测软件对筛选出来的突变的致病性进行预测。结果在1例患者中检测到2个之前未报道过的致病的杂合突变c.230dupA(Phe78Valfs*30)和c.4085C＞T(p.Pro1362Leu)。结论通过全外显子测序鉴定了可能导致USH2的2个新的杂合USH2A基因致病突变。这一结果扩大了已知的USH2A基因致病突变的范围。     

智力障碍小家系中致病基因的研究

目的 研究一个智力发育障碍家系中的致病基因突变.方法 染色体核型G显带方法分析先证者染色体核型,用全基因组外显子测序的方法探究致病基因,并在先证者家系中用Sanger测序法进行验证.结果 G显带核型分析未显示先证者染色体核型的数目和结构异常.全基因组外显子测序的方法共从先证者外显子基因中鉴别出1 455个单核苷酸多态性(single nucleotide polymorphisms,SNPs)和187个indels,结合家系信息筛选出X染色体上ARHGAP4基因突变与智力障碍表型相关,Sanger测序法验证结果一致,符合孟德尔家系遗传.结论 X染色体上ARHGAP4的C2822T突变位点可能与家系中的智力障碍疾病表型相关.     

A novel mutation of the KIT gene in a Chinese family with piebaldism

Background Human piebaldism is a rare autosomal dominant condition characterized by congenital white forelock and depigmented patches of skin,typically on the forehead,anterior trunk and extremities.Mutations in the KIT gene have been proposed to be responsible for the underlying changes in this disorder.The aim of this study was to identify gene mutation in a Chinese family with piebaldism.Methods A Chinese family with piebaldism presenting with white forelock and large depigmented skin macules on the abdomen,arms and legs was collected.DNA was isolated from peripheral blood of the family members.The encoding exons with flanking intron regions of the KIT gene were analyzed by polymerase chain reactions (PCR) and direct DNA sequencing.Besides,DNA extracted from 100 ethnically matched population individuals was as controls.Results A heterozygous missense mutation c.2590T＞C was identified in the patients of the family.This mutation converted a serine residue to proline (p.Ser864Pro).The mutation was not found in their unaffected family members or normal controis.Conclusion A novel missense mutation c.2590 T＞C was found and it might play a significant role in the piebaldism phenotype in the family.     

一例GNB1基因突变致神经发育障碍患儿的临床及基因突变分析

目的：应用全外显子测序技术（whole exome sequencing, WES）对患有语言运动发育迟缓及严重智力障碍的患儿及其父母进行分析,探讨基因水平的遗传学病因并明确临床诊断,进一步指导妊娠。方法：提取患儿及其父母外周血DNA,采用外显子捕获结合高通量测序技术进行检测。根据美国医学遗传学与基因组学学会（ACMG, 2015）标准对患儿及父母检测出的变异进行致病性判定,结合患儿表型寻找致病基因及位点。利用Sanger测序法对致病位点进行验证。结果：患儿GNB1基因第7号外显子c.346 G>A (p.G116S)位点杂合错义突变为致病位点,患儿父母该位点均为野生型,此变异为患儿的新发突变。Sanger测序验证结果与外显子捕获测序结果一致。患儿为常染色体显性智力低下42型（Autosomal dominant mental retardation-42, MRD42）患者。结论：应用全外显子测序技术可对语言运动发育迟缓伴严重智力低下的患儿进行诊断,明确了该患儿的致病原因,有助于家系的遗传咨询并为再生育提供指导。     

一个遗传性血管水肿家系C1抑制物基因突变的检测分析

目的 对一个遗传性血管水肿(HAE)家系患者C1抑制物(C1 INH)基因的突变类型进行检测分析。方法 用聚合酶链反应扩增产物直接测序法检测HAE患者C1 INH基因8个外显子及旁侧内含子序列,将检测结果与GenBank公布的C1 INH基因序列相比较,确定突变。为除外多态性可能,在30名正常人中对该突变进行分析。结果 该家系中的5例患者外显子8中均检测到1种新的突变类型(核苷酸序列17839 del C),正常人中无此改变。结论 在该家系中发现C1 INH基因核苷酸序列17839 del C突变,该突变可能是此家系发病的分子基础。     

A novel nonsense mutation in BBS4 gene identified in a Chinese family with Bardet-Biedl syndrome

Background Bardet-Biedl syndrome (BBS) is a genetically heterogeneous disease, and information about BBS in Chinese populations is very limited. The purpose of the present study was to determine the genetic cause of BBS in a Chinese Han family.

Methods Clinical data were recorded for the 4-year-old female proband and the available family members. The proband was screened for mutation by Sanger sequencing for a total of 142 exons of the 12 BBS-causing genes (BBS1-BBS12). The variants detected in the proband were further confirmed in the other family members.

Results We identified a novel homozygous nonsense mutation (c.70A>T, p.K24X) in the BBS4 gene exon 2 in the proband. Such mutant allele was predicted to cause a premature truncation in the N-terminal of the BBS4 protein, and probably induced the nonsense-mediated decay of BBS4 messenger RNAs. The proband’s parents and brother were heterozygous for the nonsense mutant allele. It was absent in 50 Chinese control subjects. An additional rare heterozygous missense single nucleotide polymorphism (SNP) named rs200718870 in BBS10 gene was also detected in the proband, her father and her brother. Some manifestations of the proband including atypical retinitis pigmentosa, choroidal sclerosis, high myopia, and early onset of obesity might be associated with this mutation in BBS4 gene. The proband’s father also reported surgical removal of an extra finger during childhood.

Conclusions The present study described a novel nonsense mutation in BBS4 gene in a Chinese family. This homozygous mutation was predicted to completely abolish the synthesis of the BBS4 protein. We also detected a rare heterozygous missense SNP in BBS10 gene in the family, but did not ?nd sufficient evidence to support the triallelic inheritance.

     

A novel deletion mutation of ATP7A gene in a Chinese family with Menkes disease

Menkes disease is a rare X-linked recessive .hereditary disorder first described by Menkes et al in 1962.1 including The gene mutation results in clinical features pili torti, unusual facies, mental/growth retardation and metabolic dysfunction. The pathogenic gene ATP7A was identified in 1993.2 It is located on chromosome X and encodes a transmembrane Cu^2＋ transporter. Here we reported the clinical manifestations and results of genetic study of a family with Menkes disease. In this family, a deletion mutation in ATP7A gene is responsible for the disease.     

A novel mitochondrial tRNA gene mutation in a chinese family with dilated cardiomyopathy and sensorineural deafness

Objective： To determine whether a mutation of mitochondrial DNA induces familial dilated cardiomyopathy in Chinese families with cardiomyopathy, and analyzed the correlation between the genotype and phenotype. Methods： Affected members in three Chinese families of the familial dilated cardiomyopathy underwent clinical evaluation and DNA analysis. Polymerase chain reaction and direct DNA sequencing were used to screen for mitochondrial DNA mutation. The type of mtDNA variations and clinical situation were analysed on the patients with mitochondrial DNA mutation. Results： The mitochondrial A3434G mutation was identified in one of the three families,the 3434 th nucleotide A was replaced by G, which led to change of amino acid. No mutations were identified in the clinically unaffected members of the family and all members of the other two families. Conclusion： This study indicates that the mitochondrial A3434G mutation maybe related with familial dilated cardiomyopathy and deafness.     

先天性脊柱骨骺发育不良家系COL2A1基因的突变

目的：报道1个涉及四代9例患者因患有常染色体显性遗传的先天性脊柱骨骺发育不良的家系COL2A1基因突变。方法：发现18个月的先证者未出现股骨头的继发性骨化中心。其父骨骼改变主要表现为椎骨椎体扁平、股骨颈结构不规则、股骨头骨化缺如、髋臼顶扁平和髋内翻。该家系的其他患者均有类似改变。在明确诊断为先天性脊柱骨骺发育不良后，对该家系进行12号染色体上5个微卫星标记物的单倍体分型。在确定COL2A1基因为疾病的候选基因后，对该家系所有患者及获得血样的正常成员进行该基因54个外显子和启动子的测序。同时对10名健康对照者的第23外显子测序。结果：所有患者COL2A1基因第23外显子的1510G→A，使第504个氨基酸由甘氨酸→丝氨酸（GS04S），但家系中健康者和无血缘关系的10名健康对照者均无此改变。结论：COL2A1基因第23外显子的1510G→A的改变是该家系患者先天性脊柱骨骺发育不良的原因。该家系详细的影像学资料将扩大人们对Ⅱ型胶原病表型的认识。