两个中国常染色体显性遗传性多囊肾病家系的表型与基因型分析

目的研究中国人多囊肾病基因1（polycystic kidney disease 1 gene，PKD1）突变的特点，检测基因突变位点。方法25例多囊肾患者，正常对照16名，扩增PKD1基因的第44、45外显子的基因片段，变性梯度凝胶电泳突变检测系统进行初筛，然后测序。结果发现1个移码突变（12431delCT）、1个无义突变（C12217T）、1个多态性（A50747C），突变检测率为8％（2／25）。结论检测到2个新的可能的致病突变：1个移码突变（12431delCT）、1个无义突变（C12217T）。     

临床分离耐喹诺酮类铜绿假单胞菌gyrA基因单点突变研究

目的 研究临床分离铜绿假单胞菌耐喹诺酮类药物的分子机制，对PCR－RFLP－SSCP分析铜绿假单胞菌gyrA基因突变的可行性评价。方法 以铜绿假单胞菌gyrA基因序列为靶序列，用PCR、PCR－SSCP、PCR－RFLP、DNA测序、OMIGA软件分析等方法，对铜绿假单胞菌gyrA基因突变进行研究。结果 在铜绿假单胞菌10株耐药突变株中，有8株的gyrA基因的83位表现出高频的单点突变，其突变方式全为ACC→ATC。gyrA的PCR扩增产物Sac Ⅱ酶切片段与测序结果一致。SSCP带谱与测序结果比较，除1株（PSA2）其SSCP带谱与标准株相同，但测序结果有点突变外，其余菌株与测序结果一致。结论 临床分离的铜绿假单胞菌耐喹诺酮类药物分子机制主要表现为gyrA基因83位氨基酸密码子突变（Thr-83→Ile)，利用PCR－SSPC－RFLP系统，可快速、准确地检测耐喹诺酮类药物的铜绿假单胞菌gyrA中至少1个碱基的差异。     

应用变性高效液相色谱技术检测parkin基因突变

目的应用变性高效液相色谱技术(denaturing high performance liquid chromatography,DHPLC)检测早发性帕金森综合征(early-onset parkinsonism,EOP)致病基因parkin突变。方法散发EOP患者82例,提取外周血细胞DNA,通过PCR扩增parkin基因的12个外显子,应用DHPLC进行变异筛查,峰形异常者进行DNA测序以明确序列变异的种类和位置。结果以100名健康者为正常对照,在82例EOP患者中检测出3种突变,均为点突变,内含子区突变包括IVS1-39G→T和IVS9 18C→T;编码区突变为T1422C,导致所编码的441位氨基酸由半胱氨酸变为精氨酸(Cys441Arg)。结论在散发EOP患者中发现3个杂合型点突变,探讨应用DHPLC在EOP患者中开展parkin基因诊断的可行性。     

应用连锁分析对ADPKD进行基因诊断及产前诊断

目的应用聚合酶链法对常染色体显性遗传性多囊肾病(ADPKD)家系进行症状前基因诊断和产前诊断。方法提取家系成员外周血或羊水DNA,PCR扩增与PKD1紧密连锁的SM6、AC2.5、CW 2 4个微卫星遗传标记,采用聚丙烯酰胺凝胶电泳检测,对4个ADPKD家系的36名成员(包括1名胎儿)进行基因连锁分析,分析各成员与疾病连锁的单体型。结果36例家系成员中检出了3例临床无症状,B超未提示多囊肾的PKD1基因携带者,产前诊断显示胎儿为未携带致病基因的正常个体。结论联合应用多个微卫星位点对ADPKD进行连锁分析能够对ADPKD家系成员进行基因诊断和产前诊断。     

人CYP3A4第9外显子基因突变频率的检测

目的建立一种简便、准确、实用的人CYP3A4第9外显子基因突变频率的检测方法，并了解汉族人CYP3A4第9外显子的分布特点．方法应用聚合酶链反应（PCR）特异性扩增人CYP3A4第9外显子基因序列，扩增产物用限制性内切酶Hinf Ⅰ酶切，琼脂糖凝胶电泳后，观察酶切位点的限制性片段长度多态性（RFLP）图谱．结果运用PCR—RFLP法检测了92名汉族人CYP3A4第9外显子基因点突变，其中野生型纯合子频率为85．9％，杂合子频率为14．1％，突变型纯合子频率为O．突变等位基因频率为0．0706．结论该方法简便、快速、准确，适合于一般实验室检测及大规模的人群调查，汉族人CYP3A4第9外显子也存在相同的突变位点．     

应用连锁分析法对常染色体显性遗传性多囊肾病进行基因诊断

目的：探讨常染色体显性遗传多囊肾病（autosomal dominant polycystic kidney disease，ADPKD）的症状前基因诊断方法。方法：PCR扩增PKD1基因两侧和基因内SM6、16AC2.5、HBAP、KG8共4个微卫星遗传标记，并采用中性聚丙烯酰胺电泳（polyacrylamide gel electrophoresis，PAGE）凝胶、常规变性PAGE凝肌、及含32%甲酰受、5.6mol/L尿素的PAGE凝胶进行电泳检测。结果：被检测家系疾病与PKD1连锁。在SM6位点上，中性胶检测Ⅲ4和Ⅲ1均为纯合子，在变性胶检测中则是杂合子。在常规变性PAGE凝胶电泳中，SM6位点扩增产物有很多杂带干扰结果分析，而在含32%甲酰受、5.6mol/L尿素电泳检测中无杂带干扰，主带很清楚。结论：联合应用多个微卫星标记对ADPKD进行连锁分析能有效地进行早期诊断。与中性胶相比，采用变性胶对微卫星标记PCR扩增产物进行电泳检测，所获得的信息含量高；而采用32%甲酰胺、5.6mol/L尿素的聚丙烯酰胺凝胶更能有效地消除杂带，优于常规变性胶。     

变性高效液相色谱检测 PKD2基因突变

目的　利用变性高效液相色谱分析技术 ( denaturing high- performance liquidchromatography,DHPL C) ,检测 2型常染色体显性遗传性多囊肾病致病基因 ( polycystic kidney diseasegene 2 ,PKD2 )突变。方法　收集临床确诊的汉族常染色体显性遗传性多囊肾病 ( autosomal dominantpolycystic kidney disease,ADPKD) 94个家系 ,提取外周血白细胞 DNA,用聚合酶链反应 ( polymerasechain reaction,PCR)扩增目的基因的全编码区 ,DHPL C对 PCR产物进行突变筛选 ,出现异常峰型的DNA片段进行核苷酸序列测定 ,明确突变位点和类型。结果　以 5 0名健康志愿者为正常对照 ,从 94例患者家系中成功检测出 8种突变 ,包括 2种无义突变、3种移码突变、3种错义突变。无义突变分别位于第 5和13外显子 ( 12 4 9C→ T,2 4 0 7C→ T) ,编码氨基酸分别在 4 17和 80 3位形成终止密码子。移码突变分别位于第2、12和 13外显子 ( 6 36 - 6 37ins T,2 348- 2 35 1del AGAA,2 4 0 1del A)。错义突变分别位于第 1、4和 5外显子 ( 5 6 8G→ A,96 4 C→T,116 8G→A) ,其编码氨基酸发生改变 ( 190 Ala→ Thr,32 2 Arg→Trp,390 Gly→ Ser)。结论　所检测出的 8种突变 ,为 ADPKD患者的基因诊断、产前诊断和囊肿前诊断积累了资料     

应用变性高效液相色谱技术检测三个遗传性多发性外生骨疣家系的EXT1与EXT2基因突变

目的建立一种应用变性高效液相色谱(denaturing high performance liquid chromatograph,DHPLC)技术检测遗传性多发性外生骨疣(hereditary multiple exostosis,EXT)基因突变的新方法,并研究3个EXT家系的基因突变情况。方法扩增EXT致病基因的所有外显子区及部分内含子与外显子交界区,联合连锁分析、DHPLC筛查及测序的方法进行分析。结果3个EXT家系中,共检测到两处已知EXT2基因的剪接位点突变IVS2 1G>A、IVS7 1G>T,一处28C>A变异和一处EXT1基因的IVS4 66G>A变异。结论EXT2基因的2个剪接位点突变分别是引起相应EXT家系的致病原因,应用DHPLC技术检测遗传性疾病基因变突是一种自动化、高通量、灵敏、快速且简便经济的好方法。     

常染色体显性遗传多囊肾病一个家系的基因检测及产前诊断

目的对一个常染色体显性遗传多囊肾病(autosomal dominant polycystic kidney disease,ADPKD)家系进行基因诊断和产前诊断。方法收集该家系成员的外周血标本及先证者妻子的羊水标本,提取基因组DNA,运用Sanger测序方法对家系成员进行PKD1基因全外显子测序,确定该家系突变位点后,对羊水标本进行产前诊断。结果我们检测出该家系4个病人的PKD1基因均有一个缺失突变C.393-394delTG,该缺失突变为致病突变。进而对先证者妻子的羊水标本进行检测,未发现该缺失突变,结果显示胎儿正常。结论应用Sanger测序技术明确了该家系PKD1基因的致病突变,并对该家系进行了产前诊断。     

PAX6基因5′端非编码区剪接突变能够引起先天性无虹膜症

目的对一先天性无虹膜症家系进行了致病基因PAX6的突变分析。方法PCR反应扩增PAX6基因的所有外显子,PCR产物进行SSCP（单链构象多态性）分析,通过患者与正常人带型的差异来确定突变发生的外显子,对有差异SSCP带型的PCR产物进行直接测序找到突变位点。PCR产物进一步亚克隆到pGEM-T载体,测序验证突变位点。结果发现基因突变为PAX6基因第2内含子和第3外显子之间的剪接识别位点＂AG＂中的碱基A的丢失（IVS2-2delA）。结沦PAX6基因5′端非编码区剪接突变能够引起先天性无虹膜症。     

两例常染色体显性多囊肾患者PKD1基因的突变检测

目的研究两例常染色体显性多囊肾患者的致病原因。方法对常染色体显性多囊肾患者的多囊肾病1基因(PKD1)3′端单拷贝区进行了聚合酶链反应-变性高效液相色谱(PCR-denaturing high-per-formance liquid chromatography,DHPLC)分析,并对有异常峰形的PCR产物进行测序。结果在1例患者中发现第42外显子的C11901A有一个无义突变,导致原丝氨酸3897变为终止密码子;而另一例患者第35外显子的C10737T有一个错义突变,导致原苏氨酸3509变为甲硫氨酸。在正常对照中发现两种同义突变分别为第42外显子的G11824A及C11860T。结论用DHPLC和DNA测序方法对两名患者进行PKD1的突变检测中,发现一个新的无义突变、一个错义突变以及两种同义突变。     

用与PKD2紧密连锁的微卫星DNA对2型常染色体显性多囊肾病进行基因诊断

目的　应用DKD2紧密连锁的微卫星DNA对 2型染色体显性多囊肾病进行基因诊断。方法应用聚合酶链反应 毛细管电泳 基因扫描方法对PKD2基因侧翼微卫星D4S15 3 4、D4S15 42、D4S15 63、D4S2 460和D4S42 3进行基因分型 ,对常染色体显性多囊肾病家系成员进行连锁分析 ,确定患病家系是否与PKD2连锁 ,并对未发病成员进行基因诊断。结果　通过连锁分析 2 0个家系 ,寻找到 3个与PKD2连锁的多囊肾病家系 ;在 3个家系的 4名未发病成员中发现 2例携带PKD2基因突变的症状前个体。结论　连锁分析是多囊肾病异质性研究和基因诊断的一种快速、简便的方法。     

常染色体显性成人多囊肾病两家系PKD1、PKD2基因的突变鉴定

目的 鉴定两个常染色体显性成人多囊肾病家系的致病突变.方法 采用酚氯仿法提取家系成员及无亲缘关系的100名健康对照个体的外周血白细胞DNA,PCR扩增先证者致病基因PKD1、PKD2的所有外显子序列及其侧翼内含子剪切区域,直接测序确定DNA序列的变异.通过家系和正常对照的比较分析,对检测到的变异是否与疾病相关进行了初步探讨.结果 在两个家系中共检测到5个序列变异:PKD1:c.2469G＞A,PKD1:c.5014_5015 delAG,PKD1:c.10529C＞T,PKD2:c.568G＞A和PKD2:c.2020-1_2020 delAG.其中PKD1:c.2469G＞A和PKD2:c.2020-1_2020 delAG为新发现的变异.此外,检测到的移码突变和剪切突变未见于家系中健康成员及无亲缘关系的正常对照.结论 PKD1:c.5014_5015 delAG和PKD2:c.2020-1_2020 delAG分别为家系A和B的致病突变,且PKD2:c.2020-1_2020 delAG为先证者新发生的突变.     

Mutation detection in the duplicated region of the polycystic kidney disease 1 (PKD1) gene in PKD1-linked Australian families

Screening for disease-causing mutations in the duplicated region of the PKD1 gene was performed in 17 unrelated Australian individuals with PKD1-linked autosomal dominant polycystic kidney disease. Exons 2-21 and 23-34 were assayed using PKD1-specific PCR amplification and direct sequencing. We have identified 12 novel probably pathogenic DNA variants, including five truncating mutations (Q563X, c.5105delAT, c.5159delG, S2269X, c.9847delC), two in-frame deletions (c.7472del3, c.9292del39), and two splice-site mutations (IVS14+1G>C, IVS16+1G>T). Three of the mutations (G381C, Y2185D, G2785D) were predicted to lead to the replacement of conserved amino acid residues, with ensuing changes in protein conformation. Defects in the duplicated region of PKD1 thus account for 63% of our patients. Together with the previously detected mutations (Q4041X, R4227P) in the 3 region of the gene, the study has achieved an overall mutation detection rate of 74%. In addition, we have detected 31 variants (nine novel and 22 previously published) that did not segregate with the disease and were considered to be neutral polymorphisms. Three of the nine novel polymorphisms were missense mutations with a predicted effect on protein conformation, emphasizing the problems of interpretation in PKD1 mutation screening.     

Evaluation and application of denaturing HPLC for mutation detection in Marfan syndrome: Identification of 20 novel mutations and two novel polymorphisms in the FBN1 gene

Mutations in the human fibrillin 1 gene (FBN1) cause the Marfan syndrome (MFS), an autosomal dominant connective tissue disorder. Knowledge about FBN1 mutations is important for early diagnosis, management, and genetic counseling. However, mutation detection in FBN1 is a challenge because the gene is very large in size ( approximately 200 kb) and the approximately 350 mutations detected so far are scattered over 65 exons. Conventional methods for large-scale detection of mutations are expensive, technically demanding, or time consuming. Recently, a high-capacity low-cost mutation detection method was introduced based on denaturing high-performance liquid chromatography (DHPLC). To assess the sensitivity and specificity of this method, we blindly screened 64 DNA samples of known FBN1 genotype exon-by-exon using exon-specific DHPLC conditions. Analysis of 682 PCR amplicons correctly identified 62 out of 64 known sequence variants. In three MFS patients of unknown FBN1 genotype, we detected two mutations and eight polymorphisms. Overall, 20 mutations and two polymorphisms are described here for the first time. Our results demonstrate 1) that DHPLC is a highly sensitive (89-99%, P = 0.05) method for FBN1 mutation detection; but 2) that chromatograms with moderate and weak pattern abnormalities also show false positive signals (in all 45-59%, P = 0.05); 3) that the difference in the chromatograms of heterozygous and homozygous amplicons is mostly independent of the type of sequence change; and 4) that DHPLC column conditions, additional base changes, and the amounts of injected PCR products influence significantly the shape of chromatograms. A strategy for FBN1 mutation screening is discussed.     

The diagnosis and prognosis of autosomal dominant polycystic kidney disease

BACKGROUND. Autosomal dominant polycystic kidney disease is usually caused by a mutant gene at the PKD1 locus on the short arm of chromosome 16, but in about 4 percent of families with the disorder it is caused by unknown mutations elsewhere in the genome. The natural course of the disease in both genetic forms is not well characterized. METHODS. We studied 17 families with autosomal dominant polycystic kidney disease to compare presymptomatic diagnosis by ultrasonography with diagnosis by genetic-linkage studies and to relate clinical variation of the disease to whether the PKD1 mutation was implicated. RESULTS. In 10 families the disorder was found to cosegregate with polymorphic DNA markers flanking the PKD1 locus, in 2 families it did not, and in 5 families linkage could not be determined. In the 10 families with the PKD1 mutation, 46 percent of the members less than 30 years old who had a 50 percent risk of inheriting a mutation had renal cysts, as compared with 11 percent of the members of the two families without linkage (P less than 0.001). In the PKD1 families, all 67 diagnoses made by ultrasonography were confirmed by determination of the genotype as inferred from linkage. Forty of 48 members (83 percent) less than 30 years old who inherited the PKD1 mutation had renal cysts. All 27 members 30 years old or older who inherited the mutation had renal cysts, suggesting that the probability of a false negative diagnosis did not exceed 0.13 in this age group (P less than 0.05). The mean (+/- SE) age at the onset of end-stage renal disease among members of the PKD1 families was 56.7 +/- 1.9 years, as compared with 69.4 +/- 1.7 years among members with cysts in the families without linkage (P = 0.0025). Hypertension and renal impairment were less frequent and occurred later in the families without the PKD1 mutation. CONCLUSIONS. At present, in most persons with a 50 percent risk of autosomal dominant polycystic kidney disease, imaging techniques are the only mode of reaching a diagnosis before symptoms appear. In such persons a negative ultrasonographic study during early adult life indicates that the likelihood of inheriting a PKD1 mutation is small. In the few who inherit a non-PKD1 mutation for polycystic kidney disease, renal failure is likely to occur relatively late in life.     

Prenatal diagnosis of autosomal dominant polycystic kidney disease (PKD1) presenting in utero and prognosis for very early onset disease.

We describe four prenatal diagnoses in a family with autosomal dominant polycystic kidney disease. Two pregnancies were terminated following the detection of enlarged echogenic fetal kidneys with cysts. Histopathological examination confirmed the diagnosis of polycystic kidney disease. Linkage to PKD1 was obtained by the analysis of DNA from relatives in three generations and from paraffin blocks and formalin fixed fetal tissues. Prenatal DNA analysis in subsequent pregnancies identified one unaffected fetus and one fetus carrying the high risk PKD1 allelle. Information on survival and subsequent outcome of PKD cases presenting in utero was requested by this family before prenatal testing was performed. Of 83 reported cases of ADPKD presenting in utero (excluding termination of pregnancy) or in the first few months of life, 43% died before 1 year. Longitudinal follow up of 24 children in two studies showed that 67% of survivors developed hypertension, of whom three had end stage renal failure at a mean age of 3 years.     

Haplotype analysis in autosomal dominant polycystic kidney disease.

Haplotype analysis was performed in 35 autosomal dominant polycystic kidney disease (ADPKD) families typed with 13 markers close to the PKD1 locus. The identification of recombinants close to the PKD1 gene on chromosome 16p indicates that PKD1 lies between CMM65 distally and 26-6 proximally. In addition, three unlinked (PKD2) families and two families with potential new mutation were identified.