华人遗传性混合息肉病综合征BMPR1A基因种系突变检测

【目的】探讨遗传性混合息肉病综合征华人家系中BMPR1A基因是否存在种系突变。【方法】34个家系成员外周血提取基因组DNA，利用聚合酶链式反应分别扩增BMPR1A基因全部外显子，进行DNA测序与突变分析，对突变外显子PCR扩增产物作变性聚丙烯酰胺凝胶电泳鉴定。【结果】家系12和2所有发病成员BMPR1A基因2号外显子位于codon23处缺失11个碱基(AAAGTCAGAAA)，同时2号外显子PCR扩增产物变性聚丙烯酰胺凝胶电泳也发现异常迁移条带，而家系中正常成员的检测未发现这一突变。【结论】两华人HMPS家系中BMPR1A基因缺失突变与疾病共遗传，该基因极可能是HMPS华人家系的致病基因。     

一种新的 GPⅡb基因540A缺失移码突变引起的血小板无力症

目的:为了明确1例血小板无力症患者发生的分子机制.方法:用40对引物对血小板无力症患者GPⅡ/皿a (αⅡbβ3)基因的45个外显子序列及其剪切点进行全长扩增,用SSCP-聚丙烯酰胺凝胶电泳技术对扩增产物进行基因突变筛选,将筛选出的PCR产物进行直接测序.结果:患者GPⅡb基因Exon4的PCR产物经SSCP-聚丙烯酰胺凝胶电泳后出现异常条带,PCR产物直接测序显示GPⅡb基因540A缺失导致后面的氨基酸编码发生移码突变.结论:GP Ⅱb基因540A缺失发生移码突变是GP Ⅱb基因的一种新突变,是血小板无力症发病的分子基础之一.     

表皮松解性角化过度鱼鳞病COL7A1基因突变研究

目的探讨一个表皮松解性角化过度鱼鳞病家系基因的突变。方法提取表皮松解性角化过度鱼鳞病患者及家族成员的基因组DNA，采用PCR扩增COL7A1基因所有的外显子及其邻近的剪切点并进行双向直接测序，用PCR检测突变位点从而进一步确定家系的致病原因。结果发现患者COL7A1基因的一条等位基因第2号外显子上存在S48P的错义突变，而另一条等位基因第27号外显子上存在3625del 11缺失突变，造成编码区阅读框架的移位，最终导致蛋白终止密码（PTC）的生产。结论COL7A1基因的缺失突变和锆义突变引起该患者临床症状的特异突变。     

散发性早发帕金森病parkin基因1、2号外显子突变的研究

[目的]研究parkin基因1、2号外显子突变与散发性早发帕金林病发病的关系。[方法]应用聚合酶链反应（PCR）、琼脂糖凝胶电泳和单链构象多态性（SSCP）方法检测52例散发性早发帕金森病病人外周血白细胞DNA的parkin基因1、2号外显子突变情况,并对SSCP有异常泳动外显子进行DNA测序。[结果]发现1例病人（1.9％）存在parkin基因2号外显子缺失,2例病人（3.8％）分别存在parkin基因1、2号外显子PCR产物 SSCP发生泳动变位,测序发现1号外显子为杂合突变（T103C）,2号外显子 为纯合突变（G237C）。[结论]parkin基因1、2号外显子突变可能与部分散发性早发帕金森病发病有关。     

胃癌组织中S100A2基因的突变及杂合性缺失研究

目的 检测胃癌组织中S100A2基因的突变及杂合性缺失,从DNA水平探讨S100A2基因在胃癌发生发展过程中的作用.方法 采用PCR-SSCP和微卫星结合PCR-变性聚丙烯酰胺凝胶电泳技术,分析胃癌组织中S100A2基因的突变及缺失情况.结果 40例胃癌标本中,未发现S100A2基因缺失,亦未检测到S100A2基因第二外显子和第三外显子的突变.结论 S100A2基因在胃癌中的表达下调可能不是由S100A2基因杂合性缺失与突变所致.     

两个家系中X连锁视网膜色素变性的RP2 基因无义突变

目的 检测引起2个家系产生X连锁视网膜色素变性的RP2基因突变。方法 根据RP2基因外显子的内含子DNA序列合成8对引物，以人基因组DNA为模板，PCR扩增出包含RP2基因所有外显子的8个片段。扩增产物化后直接测序。通过比较病人和正常人相应的DNA序列，检测基因突变位点。结果 在2个家系中首次检测到RP2基因的同一个无义突变38C→T。突变位于RP2基因的第2外显子。它使该基因编码精氨酸的遗传密码CGA变为终止密码TGA，引起发病。结论 该突变的检出有助于RP2蛋白的功能分析和X连锁视网膜色素变性的基因诊断。     

一例原发性肺动脉高压家族的临床与遗传学特点

目的 阐明家族性原发性肺动脉高压(PPH)的临床与遗传学特点。方法 对河南省驻马店地区1例PPH家系成员进行了详细的临床及实验室检查。采集所有家系成员外周血并提取DNA,设计BMPR2基因外显子1-13含侧翼内含子序列引物,对聚合酶链式反应(PCR)扩增产物纯化后测序,与正常BMPR2基因序列比较。以100名正常志愿者的临床检查和测序结果作为对照。结果 发现先证者及其弟弟和先证者之女共3人患有重度肺动脉高压,肺源性心脏病,心脏扩大,心功能Ⅲ级。其中以先证者病情最为严重,35岁时发病。先证者之母于42岁发病,43岁去世;而先证者之女13岁即已发病。先证者其他家系成员临床检查未见异常。测序证实先证者等3例患者的BMPR2基因11号外显子的第491位密码子发生C—T转换,导致该位置编码的精氨酸(R)变为色氨酸（W),而其他家系成员没有发现此突变。对照组未见临床及遗传学检查的异常。结论 BMPR2基因的R491W错义突变可致汉族人群家族性PPH的发生,提示与白种人一样,BMPR2基因也是我国PPH重要的致病基因。此突变表型在本家系中表现出症状严重,外显率高的特征,且没有健康携带者,并有发病年龄逐渐提前的趋势。     

中国家系FBN1基因频繁突变(R62C)孤立表现为晶状体异位

目的:检测孤立表现为晶状体异位的一中国家系中原纤维蛋白1(FBN1)基因的突变。设计:临床相关试验研究。方法:家系成员均进行临床检查。提取家系成员和100例对照者外周血粒细胞中的基因组DNA进行分析。通过PCR扩增FBN1的65个外显子,用变性高效液相色谱法和直接DNA测序筛查突变基     

常染色体显性遗传性听神经病MPZ基因序列分析

目的:了解MPZ基因是否与1个常染色体显性遗传性听神经病中国家系的发病相关.方法:选择1个现存3代9人的常染色体显性遗传性听神经病家系为研究对象,用基因组DNA抽提试剂盒提取外周血DNA.首先.对所有家系成员DNA进行MPZ基因第3外显子的PCR扩增,扩增产物经纯化后直接测序;然后,采用相同方法对1名家系听神经病患者进行MPZ基因全部6个外显子的PCR扩增和测序分析.测序结果与标准序列对照进行突变检测.结果:所有研究对象的基因区域均扩增成功,序列分析在MPZ基因第3外显子上未检测到Thr124Met和Tyr145Ser 2个已知的突变,整个MPZ基因编码区也未见新的致聋突变.结论:该家系成员MPZ基因上未发现有意义的突变位点,提示新基因参与家系耳聋的发生.     

一甲状腺激素抵抗综合征伴桥本甲状腺炎家系TRβ基因突变分析

目的:分析1例甲状腺激素抵抗综合征伴桥本甲状腺炎患者及家系的甲状腺激素β受体(thyroid hormone receptor-β,TRβ)基因的突变情况。方法:收集患者、9例家系成员及随机抽取的9名健康对照者的外周血标本,检测甲状腺功能并提取基因组DNA,PCR扩增TRβ基因的第1～10个外显子,PCR产物纯化后直接测序检测TRβ基因是否发生突变。结果:TRβ基因的10个外显子未发现碱基替换、插入、缺失等突变情况。结论:TRβ基因突变不是RTH致病的唯一原因。     

肌萎缩侧索硬化症SOD1基因突变特点

 【目的】 探讨中国南方人群肌萎缩侧索硬化症铜锌超氧化物岐化酶（CulZnsuperoxidedismutase；SOD1）基因突变的特点。【方法】 采用SOD1基因的5对引物对4个家系的15例家族性肌萎缩侧索硬化症（FALS）患者、56例散发性肌萎缩侧索硬化症（SALS）患者和46例正常对照DNA进行PCR扩增，重复三次应用单链构象多态性方法分析各外显子的多态性。【结果】 SOD1基因的5个外显子未发现异常泳动。【结论】 中国南方人群肌萎缩侧索硬化症患者可能不存在SOD1基因第1-5号外显子突变或突变率极低，可能存在其他位点的基因突变。     

蛋白C基因复合杂合突变导致的肺栓塞及家系研究

目的了解1例肺栓塞患者及其家系成员发生蛋白C缺陷症的分子发病学机制。方法收集先证者及其家系成员的枸橼酸钠抗凝血,采用发色底物法检测PC活性(PC∶A)、蛋白S活性(FPS∶A)和抗凝血酶活性(AT∶A),采用ELISA方法检测PC抗原(PC∶Ag)水平。采用PCR方法对先证者PC基因所有9个外显子及其侧翼序列进行扩增、测序,发现突变后,对先证者家系成员的PC基因有关外显子片段进行PCR扩增和测序。结果先证者及其父亲、母亲和妹妹均为Ⅱ型PC缺陷症患者。PC基因测序结果显示先证者的PC基因分别出现了位于3号外显子第5540位碱基的G→A的杂合突变和位于第7号外显子第10230位碱基C→T的杂合突变,导致PC E29K和R147W双杂合突变。先证者父亲携带PC E29K杂合突变,而先证者母亲和妹妹均为PCR147W杂合突变的携带者。结论先证者为PC E29K和R147W基因复合杂合突变携带者,且这两种突变分别遗传自其父母。其中,PC E29K错义点突变为目前国际上尚未见报道的新突变,而PC R147W是一种已报道的常见于遗传性易栓症患者的可导致Ⅱ型PC缺乏的错义点突变。     

杂合突变的PCR产物中包含异源双链DNA片段的研究

目的:验证杂合突变的PCR产物中包含异源双链DNA片段.方法:采用PCR、PAGE电泳和变性高效液相色谱分析的方法,对中国人表皮松解性掌跖角化症致病基因KRT9第1外显子的杂合的碱基插入/缺失突变(497delAinsGGCT)进行实验验证.结果:KRT9基因第1外显子碱基插入/缺失突变(497delAinsGGCT)杂合子的PCR产物,本身包含2种异源双链DNA片段和2种同源双链DNA片段,不需要经过额外的变性、退火处理.结论:在用DGGE、TGGE、DHPLC和HA等需要形成杂合双链体的基因突变检测技术进行突变检测时,如果突变为杂合子,则PCR产物可以直接进行突变检测,不需要预先加热/冷却等预处理以形成异源双链DNA分子.     

Biochemical activity and gene analysis of inherited protein C and antithrombin deficiency in two Chinese pedigrees

Background We identified the gene mutations in two Chinese pedigree of type Ⅰ hereditary protein C deficiency and type Ⅰ hereditary antithrombin deficiency.Methods The plasma level of protein C activity (PC: A), protein C antigen ( PC: Ag) , protein S activity, antithrombin activity (AT: A) and antithrombin antigen (AT: Ag) of propositi and two family members were detected using ELISA and chromogenic assay, respectively. All exons and intron-exon boundaries of protein C gene and antithrombin gene were analyzed by direct sequencing of the corresponding amplified PCR products in DNA from the propositus.Results The plasma PC: A and PC: Ag of propositus 1 was 26% and 1.43 mg/dl, respectively. The PC: Ag and PC: A of his father were normal. The decreased PC: A level was seen in his mother and 4 of his maternal pedigree. PS: A and AT: A were all normal in pedigree 1 members. A C5498T heterozygous mutation in exon 3 of protein C gene, resulting in the substitution of Arg for Trp at the 15th amino acid, was identified in propositus 1 and 8 of his relatives. The plasma AT: A and AT: Ag of propositus 2 was 48.6% and 10.4 mg/dl, respectively. The reduced AT: A and AT: Ag levels were found in his father and 5 of paternal pedigree. PC: A, PC: Ag and PS: A were all in normal range. A heterozygous 13387-9G deletion in exon 6 of antithrombin gene was identified in propositus 2. This mutation introduced a frameshift and a premature stop at codon 426 and existed in 6 members of pedigree 2.Conclusion The C5498T heterozygous mutation in exon 3 of protein C gene, first reported in China,leads to type Ⅰ hereditary protein C deficiency. The 13387-9G deletion, a novel mutation, can cause antithrombin deficiency and thrombosis.     

China aims for national chain of anti-smoking clinics

Background Familial pulmonary arterial hypertension （FPAH） is an autosomal dominant disorder characterized by plexiform lesions of endothelial cells in pulmonary arterioles which leads to elevated pulmonary arterial pressure, right-sided heart failure and death. Heterozygous mutations in the bone morphogenetic protein type II receptor gene （BMPR2） have been found to underlie a majority of FPAH cases. More than 140 distinct mutations have been identified in FPAH cases and in idiopathic pulmonary arterial hypertension （IPAH） cases, but only one mutation has been reported in Chinese patients. Methods A three-generation pedigree of FPAH and another 10 patients with IPAH were collected. In the family, two of the 9 surviving and one deceased family member were diagnosed as FPAH. The entire protein-coding region and intron/exon boundaries of the BMPR2 gene were amplified by PCR using DNA samples from affected individuals. Direct sequencing of PCR products was performed on both the sense and antisense strands. To confirm the segregation of the mutation within the family and exclude the presence of the mutation in normal subjects, the relevant exon was amplified by PCR, followed by mutation-specific RPLP analysis. Results In the Chinese pedigree with FPAH an A-to-T transition at position 1157 in exon 9 of the BMPR2 gene was identified which resulted in a Glu386Val mutation. We confirmed the segregation of the mutation within the family and excluded the presence of the mutation in a panel of 200 chromosomes from normal subjects. No mutation was detected in BMPR2 in the other 10 patients with IPAH. Conclusions This amino acid substitution occurs at a glutamic acid that is highly conserved in all type Ⅱ TGF-β receptors. The nearly invariant Glu forms an ion pair with an invariant Arg at position 491 thereby helping to stabilize the large lobe. Substitution of Arg at position 491 is the most frequently observed missense mutation in FPAH, but until now no mutations at position 386 have been found in FPAH. The pr     

家族性阿尔茨海默病早老素-1基因突变位点的检测

目的：探讨早老素－1基因突变在家族性阿尔茨海默病（FAD）发病中的作用。方法：应用聚合酶链反应－单链构象多态性（PCR－SSCP）、变性高效液相（DHPLC）及DNA直接测序技术检测技术,对130人的阿尔茨海默病（AD）家系和50例正常对照组的早老素－1（PS－1）基因第4、5外显子进行了检测。结果：在早老素基因的第5外显子上发现除5例AD患者外,还有4例家系内正常人（Ⅳ－30、37、41、43）PCR－SSCP出现泳动异常。DHPLC检测进一步验证以上9例均表现双峰,提示可能有突变存在。DNA序列分析表明,这9例的早老素－1基因第5外显子的136号密码子发生了GCT→GGT错义突变,使氨基酸由丙氨酸变为甘氨酸（Ala136Gly);第4外显子未发现突变。家系内其他人及正常对照组的PS1基因第4、5外显子经以上检测均未发现异常。结论：PS1基因第5外显子的突变点可能为中国FAD患者早老素基因突变位点之一。     

R25G mutation in exon 1 of LMNA gene is associated with dilated cardiomyopathy and limb-girdle muscular dystrophy 1B

Background Mutations of the LMNA gene encoding lamin A and C are associated with dilated cardiomyopathy （DCM）, conduction system defects and skeletal muscle dystrophy. Here we report a family with a mutation of the LMNA gene to identify the relationship between genotype and phenotype. Methods All 30 members of the family underwent clinical and genetic evaluation. A mutation analysis of the LMNA gene was performed. All of the 12 exons of LMNA gene were extended with polymerase chain reaction （PCR） and the PCR products were screened for gene mutation by direct sequencing. Results Ten members of the family had limb-girdle muscular dystrophy （LGMD） and 6 are still alive. Two patients suffered from DCM. Cardiac arrhythmias included atrioventricular block and atrial fibrillation; sudden death occurred in 2 patients. The pattern of inheritance was autosomal dominant. Mutation c.73C〉G （R25G） in exon 1 encoding the globular domains was confirmed in all of the affected members, resulting in the conversion of arginine （Arg） to glycine （Gly）. Conclusions The mutation R25G in exon 1 of LMNA gene we reported here in a Chinese family had a phenotype of malignant arrhythmia and mild LGMD, suggesting that patients with familial DCM, conduction system defects and skeletal muscle dystrophy should be screened by genetic testing for the LMNA gene.     

先天性眼外肌纤维化伴少年白发家系的KIF21A基因突变分析

目的对先天性眼外肌纤维化(Congenital fibrosis of the extraocular muscles,CFEOM)伴少年白发家系进行候选致病基因KIF21A突变筛查。方法应用Wizard Genomic DNA Purification试剂从家系成员外周静脉血中提取基因组DNA;以先证者基因组DNA为模板,PCR扩增KIF21A基因外显子8、20和21的DNA序列,PCR产物纯化后进行DNA直接测序筛查突变位点。一旦发现可疑性变异,则采用DNA双向测序方法在其他家系成员进行疾病与突变共分离分析以及进一步确认其是否为致病性突变位点。结果该家系三代呈常染色体显性遗传,临床表型大致相同,可确诊为CFEOM1型。KIF21A基因突变筛查发现患者在第21外显子携带c.C2860T杂合性突变,正常成员没有,临床表型与基因型呈共分离。该突变为一个已知突变,可导致KIF21A蛋白第954位的精氨酸变为色氨酸(p.R954W)。结论 KIF21AR954W突变是导致该家系患者眼外肌纤维化致病的遗传基础,是否与少年白发相关尚待进一步研究。     

Identification of a novel lethal fibrillin-1 gene mutation in a Chinese Marfan family and correlation of 3’ fibrillin-1 gene mutations with phenotype

Background Mutations in the fibrillin-1 gene have been identified in patients with Marfan syndrome （MFS）. This study aimed to identify the molecular defects in the fibrillin-1 gene in a Chinese family with Marfan syndrome, accompanied by aortic aneu rysms/dissection. Methods Two patients and one non-carrier in the family underwent complete physical, ophthalmic, and cardiovascular examinations. Genomic DNA was extracted from leukocytes of venous blood of these individuals in the family as well as 50 healthy normal controls. Polymerase chain reaction amplification and direct sequencing of all 65 coding exons of fibrillin-1 gene were analyzed. Results We found a novel mutation （c.8547T〉G, p.Tyr2849X） in exon 65 of fibrillin-1 gene in a Chinese proband with Marfan syndrome, accompanied by aortic aneurysms/dissection. Sudden death at a young age of affected members was seen due to aortic aneurysms/dissection. By evaluating genotype-phenotype correlations of patients with mutations in the 3＇ end of fibrillin-1 gene （exons 64 and 65）, we also found that the presence of nonsense mutations occurring in exons 64 and 65 appeared to be an indicator of early-onset aortic risk and sudden death. Conclusions These results expand the mutation spectrum of fibrillin-1 gene and help in the study of the molecular pathogenesis of Marfan syndrome, indicating that mutations occurring in the 3＇ end of fibrillin-1 gene may play an independent functional role in the pathogenesis of Marfan syndrome.