RET原癌基因C634R突变合并G691S、R982C多态性致多发内分泌腺瘤病2A型的家系研究并文献复习

目的 对一个多发内分泌腺瘤病2A型(MEN2A)家系患者的临床特点及RET原癌基因突变情况进行分析.方法 收集先证者及其家系成员相关临床资料,提取1名先证者及10名家系成员的外周血基因组DNA,对RET基因所有外显子进行PCR扩增,对扩增产物进行测序分析.结果 家系中3位已发病患者的临床表现不同,但其RET原癌基因均同时存在3个错义突变,分别是位于11号外显子的C634R、G691S和位于18号外显子的R982C,而家系中其他成员则不存在上述突变.结论 当C634R与G691S、R982C多态性同时存在时,临床上主要表现为与单纯C634R突变一致的PET蛋白功能异常激活性疾病.     

7个肾上腺脑白质营养不良家系的基因突变分析

目的对7个肾上腺脑白质营养不良家系进行基因突变分析。方法应用RT-PCR技术，对7位患者的ABcDl基因编码区分4个片段进行扩增并对PCR产物直接测序。应用PCR-限制性酶切或DNA测序等方法分析相应的基因组DNA，进一步确证ABCD1基因的突变位点。结果在7位患者的ABCD1基因上存在6个不同的碱基置换（709C→A、807G→A、1161C→T、2065C→T、2113T→C和2235C→T）、1个碱基缺失（1801delAG）和1个碱基插人（1126insCCATCG），分别造成5个错义突变（A141T、R259W、P560L、L76P和R617C）、2个移码突变（fs I246和fs E471）和1个无义突变（S108X）。结论在中国人肾上腺脑白质营养不良患者中发现4个新的ABCD1基因突变，即S108X、fs I246、R259W和IA76P突变。不同家系具有不同的突变位点，且突变类型和表型之间无特殊的相关性。     

中国人群低钾型周期性麻痹家系CACNA1S和SCN4A基因突变状态分析

目的 检测中国人群中低钾型周期性麻痹(HPP)家系CACNA1S和SCN4A基因的突变情况,并与既往文献报道的西方白种人群HPP基因突变情况进行比较分析.方法 应用PCR和DNA测序技术,对2个家族性HPP家系、1个甲亢性HPP家系和4例散发性HPP患者的CACNA1S基因和SCN4A基因进行测序,与基因库中的参考序列比对,以确定是否存在突变.在PubMed数据库中,搜集1999年1月-2012年12月公开发表的关于HPP家系CACNA1S、SCN4A基因突变的相关文献,最终纳入9篇文献.结果 先证者均存在伴有血清钾降低的发作性肌无力、肌无力常累及四肢等典型的HPP临床表现,辅助检查证实血清钾降低,心电图提示低钾性改变,肌电图提示运动电位时限短、波幅低,诊断明确.3个家系的先证者和家族成员以及4例散发性HPP患者的CACNA 1S和SCN4A基因中未发现突变位点.既往文献显示,西方白种人群中HPP患者CACNA1S及SCN4A基因的突变阳性率远高于中国人群.结论 中国人群HPP患者CACNAIS和SCN4A基因突变率极低,与西方白人患者的检测结果存在差异.     

DHPLC在X-连锁肾上腺脑白质营养不良分子诊断中的应用(附12例报告)

目的探讨DHPLC在X-连锁肾上腺脑白质营养不良(X-ALD)分子诊断中的应用。方法提取12个X-ALD家系及成员的外周血基因组DNA,分15个片段扩增ABCD1基因的10个外显子,应用DHPLC技术对其进行突变筛查,并对出现异常洗脱峰的PCR产物进行DNA序列测定,证实突变位点的存在。结果12个X-ALD家系存在12种不同的ABCD1基因突变,包括8个错义突变、2个移码突变和2个无义突变,即P534R、G343V、R259W、A141T、R401Q、K276E、Y174C、A314P、fs E471、fs A247、S108X和Q177X。结论DHPLC筛查结合DNA序列测定能快速有效检测出ABCD1基因突变。不同的X-ALD家系有不同的ABCD1基因突变位点,突变类型和表型之间无特殊相关关系。     

甲亢性低血钾型周期性麻痹家系基因突变的初步研究

目的筛查甲亢性低血钾型周期性麻痹家系的钙离子通道α1亚基和电压门控钠离子通道α亚基基因是否存在突变。方法总结甲亢性低血钾型周期性家系Ⅵ代患者的临床特点,并应用酶联免疫测定和测序技术筛查编码钙离子通道α1亚基的528位及1239位精氨酸和钠离子通道α亚基669位及672位精氨酸基因的突变点。结果钠离子通道α亚基基因2012位碱基序列发生错义突变（T→C）,671位苯丙氨酸变为丝氨酸,而其他3个已知突变点的碱基序列完全正常。结论华人甲亢性低血钾型周期性麻痹家系患者中存在突变,致使钠离子通道α亚基基因671位苯丙氨酸为丝氨酸替代,该位点国内外未见报道,是一个新的突变位点。     

扩张型心肌病心脏移植患者全外显子测序分析

目的 探索与扩张型心肌病发生相关的突变基因,并分析其与临床特征的相关性。方法 回顾性分析自2016年9月至2020年9月就诊于北部战区总医院心血管外科的6例扩张型心肌病心脏移植患者的临床资料。采集患者的静脉血进行全外显子测序。应用人群基因突变数据库评估基因位点在人群中的突变频率。采用GERP++RS软件对核苷酸序列进行保守性分析。采用Mutation Taster、Fathmm MKL在线预测软件及CADD评分评估蛋白质的致病性。对筛选的基因突变位点进行美国医学遗传学与基因组学学会(ACMG)评级。结果 共筛选出3个与扩张型心肌病相关的基因突变位点：PSEN2基因在chr2:227078985位置发生T>C的错义突变;MYBPC3基因在chr11:47364625位置发生C>G的错义突变;LMNA基因在chr1:156104248位置发生C>T的错义突变。PSEN2基因突变位点在人群数据库中的最高突变频率为0.000 008 15。在线预测软件及CADD评分显示,3个突变基因位点均具有保守性、致病性。经ACMG评级,LMNA Arg190Trp突变为可能致病的突变,M...     

表皮松解性掌跖角化症家系基因突变研究

目的确定一个表皮松解性掌跖角化症家系的致病基因。方法收集该家系3例患者、3例表型正常个体和50名无亲缘关系的健康个体的外周血标本,抽提基因组DNA。选取角蛋白9(KRT9)基因邻近的3个STR多态性位点D17S1787、D17S579、D17S250进行连锁分析研究,并对KRT9基因所有外显子进行PCR扩增和Sanger测序分析。结果 3个STR位点均与患者表型共分离;患者的KRT9基因第1外显子均可见c.488 G>A(p.R163Q)杂合性突变,而家系中表型正常个体和50名正常对照个体均未检测到KRT9基因突变。结论 KRT9基因的c.488 G>A错义突变是导致该家系发生表皮松解性掌跖角化症的原因。     

GJB3基因在新疆维汉两民族遗传性非综合征耳聋患者的突变分析

目的耳聋具有高度的遗传异质性,分析GJB3基因在新疆地区维汉两族中的突变,了解其分子病因学机制。方法调查对象来自新疆地区非综合征耳聋患者（耳聋组）93例,其中维吾尔族43例。对照组为听力正常者110例．其中维吾尔族56例。所有受检者均采集外周血并提取DNA,应用聚合酶链反应（PCR）产物直接测序方法对各种感音神经性耳聋患者93名、对照组110名进行GJB3基因编码区突变检测及鉴定。结果在93名患者中发现GJB3基因的3种单核苷酸改变,其中有两种碱基变化导致了氨基酸的改变,为错义突变方式。其中1个突变（256G→A）,另1个突变形式（33C→T）为本研究首次发现。110名正常对照组中未发现同样突变。结论国人非综合征型遗传性聋者GJB3基因突变筛查研究发现了一个GJB3基因新的突变形式（256G→A）,为进一步开展耳聋相关基因的筛查研究打下了基础。     

应用基因芯片技术检测乙型肝炎病毒前-C区/BCP区基因突变的研究

目的　探讨利用基因芯片技术检测乙型肝炎病毒 (HBV)前 C区 /BCP区基因突变方法的临床价值及前 C区 /BCP区基因突变的临床意义。方法　应用基因芯片技术检测 4 6例急慢性肝病的HBV前 C区A1896 (nt1896G→A)、A1899(nt1899G→A)及HBVC基因启动子 (BCP)T176 2A176 4 (nt176 2A→T、nt176 4G→A)四位点突变 ,并探讨该技术的临床应用价值。结果　用基因芯片法测定HBV基因特定变异位点特异性强 ,阳性率为 87 0 %。A1896突变 18例 (4 5 0 % ) ,A1899突变 10例 (2 5 0 % ) ,T176 2A176 4联合突变 30例(75 0 % ) ,多位点突变 14例(35 0 % )。各变异组与未变异组比较 ,肝功损害均有显著性差异 (P <0 0 5～ 0 0 1)。前 C区 /BCP区基因突变在乙型肝炎肝硬化及慢性乙型肝炎中较为常见 ,在急性乙型肝炎中未检出。结论　应用基因芯片法测定HBV特定变异位点特异性强 ,可一次同时检测多个突变位点 ,具有一定的临床应用价值。     

幽门螺杆菌感染与hMLH1和APC基因突变及hMLH1甲基化异常的关系

目的　探讨幽门螺杆菌 (H .pylori)感染与hMLH1和APC突变及甲基化异常的关系。方法　采用改良的Giemsa染色和PCR方法检测H .pylori;采用二维DNA电泳、DGGE电泳和DNA测序技术检测hMLH1和APC突变 ;采用甲基化特异性PCR检测hMLH1启动子区的甲基化状态 ;采用以PCR为基础的方法检测微卫星DNA不稳 (MSI)。结果　 6 8例胃癌中检出hMLH1基因突变 3例 ,突变率为 4 4 %。APC基因突变 15例 ,突变率为 2 2 1%。hMLH1突变与肿瘤大小、分化程度、组织学类型、浸润深度和临床病理分期无显著相关。APC突变率在肠型胃癌显著高于弥漫型胃癌 (P <0 0 5 )。正常胃黏膜未见hMLH1高甲基化。 6 8例胃癌中检出hMLH1高甲基化 11例 ,占 16 2 % ,均为去甲基化和高甲基化并存。将MSI分为高频率MSI(MSI H ,≥ 2个位点 ) 8例、低频率MSI(MSI L ,仅为 1个位点 ) 9例和MSI阴性 (MSS) 5 1例三组 ,结果 3例hMLH1基因突变均发生于MSI H组 ,而MSI L和MSS组未见 ;APC突变均发生于MSI L和MSS组 ,而MSI H组未发现有APC突变者 ;MSI H组hMLH1高甲基化的检出率显著高于MSI L和MSS组 (P <0 0 1)。hMLH1和APC基因突变及hMLH1甲基化在H pylori阳性组和H pylori阴性组及CagA 组和CagA-组检出率差异均无统计学意义 (P>0 0 5 )。结论　hMLH1突变和     

AKR1C3在放疗食管癌患者病理标本检测中的意义

目的 对单纯放疗食管癌患者病理标本进行检测,评估醛固酮类还原酶家族1成员C3(AKR1C3)表达与放疗效果的关系.方法 回顾性分析28例行单纯放疗的局部晚期食管癌患者的临床资料,通过免疫组化检测食管癌患者中AKR1C3的表达情况.结果 AKR1C3在不同分化程度的食管癌患者中表达程度不同,其表达水平与放疗短期疗效呈负相关(P=0.031,95%可信区间 0.151～0.914).结论 AKR1C3有可能成为食管癌放疗疗效判定的敏感性指标.     

自发性心室纤颤的基因基础和分子机制

 目的研究心脏钠离子通道基因SCN 5 A的突变是否能够引起自发性心室纤颤(IVF),以帮助IVF的基因诊断和合理治疗.方法用单链构型多态性(SSCP)和DNA序列分析法伴有IVF的6个小家系和2个散发的病人的血样,在已知离子通道基因,包括心脏钠离子通道基因SCN 5 A上进行了识别突变的研究.并通过测试突变通道和正常通道在卵母细胞中的电生理活动来判定突变对IVF发生机制的影响.结果在3个IVF家族中从SCN 5 A密码范围内识别了…个错义突变和一个读码突变.电生理研究显示含有错义突变的钠离子通道比正常通道从静止中恢复得更快,而读码突变使钠离子通道失去功能.结论我们的工作显示了伴有RBBB和ST段抬高的IVF是一种明显的综合征,并且心脏钠通道基因SCN 5 A与IVF的发生密切相关.     

Characteristic association between K-ras gene mutation with loss of heterozygosity in X-ray-induced thymic lymphomas of the B6C3F1 mouse

PURPOSE: To elucidate the characteristics of radiation carcinogenesis, the spectra of K- and N-ras oncogene mutations, loss of heterozygosity (LOH) and their association in X-ray-induced thymic lymphomas (TL) were determined by comparing with those of N-ethyl-N-nitrosourea (ENU)-induced and spontaneously occurring TL. MATERIALS AND METHODS: TL that arose in untreated, X-ray-irradiated and ENU-treated B6C3F1 mice were examined both for K- and N-ras mutations by PCR-SSCP and DNA sequencing and for LOH by PCR with polymorphic microsatellite markers. RESULTS: (1) ras gene mutations were found in a proportion of TL from X-ray-exposed (approximately 20%) and ENU-treated (30-40%) mice while no ras gene mutations were found in spontaneous TL. N-ras mutations were rare. (2) The spectrum of ras gene mutations was diverse and seemed to differ little between X-ray-induced and ENU-induced TL, even though there was a higher frequency of ras mutations in ENU-induced TL that clustered to K-ras codon 12. (3) The X-ray-induced TL showing K-ras mutation were associated with LOH on chromosome 6, while those showing no K-ras mutation were associated with high frequency of LOH on chromosomes 4, 11 and 12. CONCLUSION: These results demonstrate that, in the B6C3F1 mouse TL, X-ray-induced lymphomagenesis showed both the co-expression, yet low occurrence of allelic imbalance on chromosome 6 and K-ras mutation, and exclusive expression of frequent allelic imbalance on chromosomes 4, 11 and 12 and K-ras mutation.     

Abschätzung des Krebsrisikos durch genetische Analyse?

Background

The recent literature of familial cancer, specifically related to germline mutations of RB1, p53, NF1, ATM, BRCA1, Mismatch repair genes and APC is reviewed.

Results and Conclusions

Germline mutations do not relate to an increased tumor risk of any single tissue, but instead to spectra of neoplastic diseases. The genetic background plays a major role in modifying the cancer risk. Therefore, mass screening for mutations of single genes seems to be without practical value. Only in combination with an adaequate and informative family history can molecular genetic analysis significantly support the care for the individual. Comparison of the data of patients inheriting germline mutations and the experience from the corresponding “knockout” mouse demonstrate that only the p53 and APC knockout mice are useful models of human disease.     

Characteristic association between K- ras gene mutation with loss of heterozygosity in X-ray-induced thymic lymphomas of the B6C3F1 mouse

Purpose : To elucidate the characteristics of radiation carcinogenesis, the spectra of K- and N- ras oncogene mutations, loss of heterozygosity (LOH) and their association in X-ray-induced thymic lymphomas (TL) were determined by comparing with those of N -ethyl- N -nitrosourea (ENU)-induced and spontaneously occurring TL. Materials and methods : TL that arose in untreated, X-ray-irradiated and ENU-treated B6C3F1 mice were examined both for K- and N- ras mutations by PCR-SSCP and DNA sequencing and for LOH by PCR with polymorphic microsatellite markers. Results : (1) ras gene mutations were found in a proportion of TL from X-ray-exposed (~20%) and ENU-treated (30-40%) mice while no ras gene mutations were found in spontaneous TL. N- ras mutations were rare. (2) The spectrum of ras gene mutations was diverse and seemed to differ little between X-ray-induced and ENU-induced TL, even though there was a higher frequency of ras mutations in ENU-induced TL that clustered to K- ras codon 12. (3) The X-ray-induced TL showing K- ras mutation were associated with LOH on chromosome 6, while those showing no K- ras mutation were associated with high frequency of LOH on chromosomes 4, 11 and 12. Conclusion : These results demonstrate that, in the B6C3F1 mouse TL, X-ray-induced lymphomagenesis showed both the co-expression, yet low occurrence of allelic imbalance on chromosome 6 and K- ras mutation, and exclusive expression of frequent allelic imbalance on chromosomes 4, 11 and 12 and K- ras mutation.     

国人家族性Budd-Chiari综合征的影像学特点与介入治疗

目的 探讨国人家族性Budd-Chiari综合征（Budd-Chiari syndrome,BCS）的影像学特点与介入治疗的有效性。方法 对4例家族性BCS（两对姐妹,来自A、B两个家族）行血管造景,并对2例行经皮球囊血管成形术（percutneous transluminal angioplasty,PTA),2例行内支架置入术。结果 A家族姐妹、B家族姐妹分别为下腔静脉肝后段节段性闭塞和膜性闭塞。A、B家族姐姐分别行内支架置入术,妹妹分别行PTA。4例BCS行介入治疗后下腔静脉回流通畅。A家族姐妹随访2年后下腔静脉出现再狭窄,姐姐再行内支架治疗,妹妹再行PTA;7个月后姐姐因肝功能衰竭死亡,其妹妹至今未见复发。B家族姐妹随访4年未见复发。结论 （1）国人家族性BCS病类型多样。（2）静脉血栓是国人家族性发病的基本病因。（3）PTA、内支架置入术及严 格长期抗凝治疗的综合应用是治疗家族性BCS的有效方法。     

食管反流大鼠肿瘤诱发过程中p53基因突变的研究

通过动物实验研究不同反流状态下食管肿瘤诱发过程中 p5 3基因的突变情况。选用SD大鼠进行不同手术 ,制作单纯胃食管反流 (G组 )、单纯十二指肠食管反流 (D组 )、胃十二指肠混合液食管反流 (DG组 )及无反流对照 (C组 )模型 ,于术后 4周开始注射食管致癌剂甲基戊基亚硝胺 (MANA) ,共 15周 ,于术后 2 0、2 6、40周分批取得食管组织 ,进行基因组DNA抽提 ,合成 p5 3基因的第 5、6、7、8外显子的 4对引物 ,进行PCR扩增。扩增产物变性后进行非变性聚丙烯酰胺凝胶电泳 (PCR SSCP) ,电泳后凝胶以硝酸银染色。结果显示PCR扩增未见 p5 3基因缺失。 2 0周时D组及DG组各有 1只 (10 % )标本检测出p5 3突变。此后随时间延长各组突变增加 ,40周时D组 (31 6 % )、DG组 (33 3 % )的突变率显著高于C组 (15 4% )和G组 (11 7% ) ,P均 <0 0 5 ,后两者差异无显著性意义 (P >0 0 5 )。提示十二指肠内容物食管反流可导致食管粘膜上皮p5 3基因的突变率增加 ,这可能是它促进食管肿瘤发生的机制之一。而单纯胃液反流不增加食管的 p5 3基因突变     

Diagnostic criteria for testing for BRCA1 and BRCA2: the experience of the Department of Defense Familial Breast/Ovarian Cancer Research Project

The Department of Defense Familial Breast/Ovarian Cancer Research Project has offered genetic counseling and testing for BRCA1 and BRCA2 on a research basis to patients meeting specific diagnostic criteria, with risk for BRCA1 and BRCA2 mutations calculated based on the Couch model. In 2.5 years, 250 patients were evaluated and 101 patients met criteria requirements, including 33 who met criteria in more than one category. Ninety patients elected to undergo DNA testing. In this group of 90 patients, 14 mutations (15.5%) and 16 unclassified variants (17.7%) were identified. The most common inclusion criteria were onset of breast/ovarian cancer before age 45 years (n = 32) and onset of breast/ovarian cancer before age 45 years with strong family history (n = 21). However, when number of mutations and unclassified variants found were compared separately across all diagnostic criteria (including those of more than one capacity) using the chi 2 statistic, no significant differences were seen among the categories to suggest that one criterion was more predictive of mutations or variants than another. Couch risk values for patients with mutations showed a mean of 14% and ranged from 3.2 to 43.5% (range for all patients, 1.2-69.7%). These findings emphasize the importance of using multiple diagnostic criteria and suggest that a Couch risk value of > 3% may be useful in selecting patients for testing. The data also underscore the necessity of genetic counseling in the testing process, particularly given the large number of unclassified variants diagnosed and their uncertain status for disease predisposition.     

Diagnosing CADASIL using MRI: evidence from families with known mutations of Notch 3 gene

Clinical data and MRI findings are presented on 18 subjects from two families with neuropathologically confirmed CADASIL. DNA analysis revealed mutations in exon 4 of Notch 3 gene in both families. All family members with mutations in Notch 3 gene had extensive abnormalities on MRI, principally lesions in the white matter of the frontal lobes and in the external capsules. Of several family members in whom a diagnosis of CADASIL was suspected on the basis of minor symptoms, one had MRI changes consistent with CADASIL; none of these cases carried a mutation in the Notch 3 gene. MRI and clinical features that may alert the radiologist to the diagnosis of CADASIL are reviewed. However, a wide differential diagnosis exists for the MRI appearances of CADASIL, including multiple sclerosis and small-vessel disease secondary to hypertension. The definitive diagnosis cannot be made on MRI alone and requires additional evidence, where available, from a positive family history and by screening DNA for mutations of Notch 3 gene. Received: 17 February 1999 Accepted: 23 July 1999