X-连锁迟发性脊髓骨骺发育不良家系的基因诊断

ObjectiveTo investigate the molecular pathogenesis of a pedigree of X-linked spondyloepiphyseal dysplasia atarda (SEDL) and to establish methods of gene diagnosis. Methods Clinical diagnosis was made based on height measurement, radiological examination and pedigree analysis. Peripheral blood samples of relevant family members were collected. After genomic DNA extraction, single strand conformation polymorphism (SSCP) followed with DNA sequencing was used to detect SEDL gene exons 36. Microsatellite marker DXS16 was selected for linkage analysis. Results The abnormal electrophoretic bands were detected in exon 4 of probands by PCR-SSCP. A c. 218C ＞ T mutation in exon 4 of SEDL gene was found in three probands, which resulted in a change in amino acid sequence S37L. The heterozygous exon 4 mutation was identified in three carriers, but not in healthy individuals, and no mutations were detect in exon 3, 5 and 6 of probands. Three unmarried young females (Ⅲ10, Ⅳ6 and Ⅳ7) were found to harbor the mutation by DNA sequencing analysis. ConclusionsA c. 218C ＞ T missense mutation in exon 4 of SEDL gene is the cause of molecular pathogenesis of the pedigree. SSCP and DNA sequencing can be used for prenatal gene diagnosis.     

X-连锁迟发性脊髓骨骺发育不良家系的基因诊断

ObjectiveTo investigate the molecular pathogenesis of a pedigree of X-linked spondyloepiphyseal dysplasia atarda (SEDL) and to establish methods of gene diagnosis. Methods Clinical diagnosis was made based on height measurement, radiological examination and pedigree analysis. Peripheral blood samples of relevant family members were collected. After genomic DNA extraction, single strand conformation polymorphism (SSCP) followed with DNA sequencing was used to detect SEDL gene exons 36. Microsatellite marker DXS16 was selected for linkage analysis. Results The abnormal electrophoretic bands were detected in exon 4 of probands by PCR-SSCP. A c. 218C ＞ T mutation in exon 4 of SEDL gene was found in three probands, which resulted in a change in amino acid sequence S37L. The heterozygous exon 4 mutation was identified in three carriers, but not in healthy individuals, and no mutations were detect in exon 3, 5 and 6 of probands. Three unmarried young females (Ⅲ10, Ⅳ6 and Ⅳ7) were found to harbor the mutation by DNA sequencing analysis. ConclusionsA c. 218C ＞ T missense mutation in exon 4 of SEDL gene is the cause of molecular pathogenesis of the pedigree. SSCP and DNA sequencing can be used for prenatal gene diagnosis.     

遗传性凝血因子Ⅶ缺乏症的分子发病机制研究

目的 对一个遗传性FⅦ缺乏症家系进行F7基因突变检测,探讨其分子发病机制.方法 采用ELISA法检测先证者及家系成员FⅦ∶Ag,采用一期凝固法检测先证者及家系成员PT、FⅦ∶C等凝血指标进行实验表型诊断.基因检测采用DNA直接测序法分析先证者及家系成员F7基因的全部外显子及侧翼、5'和3'非翻译区,发现突变位点用反向测序加以证实;用CLC Protein Workbench软件分析基因突变位点的物种保守性和蛋白质二级结构改变.选择100名健康对照者以排除基因多态性.结果 先证者及其妹妹的PT、FⅦ∶C、FⅦ∶Ag明显异常,分别为36.3 s、5.0%、40.7%和33.4 s、5.0%、37.4%;先证者的父亲、母亲、女儿、外甥女的PT稍延长,分别为14.9 s、14.6 s、15.5 s、14.6 s;其FⅦ:C稍减低,分别为70%、85%、59%、79%.先证者F7基因8号外显子c.784T＞C杂合突变导致Ser269Pro,8号外显子c.964T＞G杂合突变导致Cys329Gly;先证者妹妹为c.784T＞C和c.964T＞G双重杂合突变,母亲为c.784T＞C杂合子,父亲、女儿、外甥女均为c.964T＞G杂合子.蛋白质生物学特性分析发现,Cys329Gly导致蛋白质空间构型发生改变,Ser269Pro导致氨基酸极性及疏水性发生改变.结论 F7基因Ser269Pro和Cys329Gly双重杂合突变是导致该例遗传性FⅦ缺乏症的分子发病机制.

Abstract：

Objective To identify gene mutations and explore the molecular mechanism of a pedigree with inherited coagulation F Ⅶ deficiency. Methods The levels of F Ⅶ: Ag in the proband and other family members were measured by ELISA assay. The values of PT, F Ⅶ: C and other coagulant parameters were determined by one-stage clotting for laboratory phenotype diagnosis. All the exons,exon-intron boundaries and 5',3' untranslated sequences of F7 gene were amplified by direct sequencing. The detected mutations were further confirmed by sequencing the other stand. The CLC Protein Workbench software was used to analyze the species conservation of the mutated site and the protein secondary structure. 100 healthy individuals were selected to exclude gene polymorphism. Results PT, FⅦ∶C and FⅦ: Ag in the proband and his sister were abnormal, which were 36. 3 s, 5.0%, 40. 7% and 33.4 s,5. 0%, 37.4%, respectively. Both PT and FⅦ∶C in the proband's father, mother, daughter and niece were slightly abnormal, which were 14.9 s, 14. 6 s, 15.5 s, 14. 6 s and 70%, 85%, 59%, 79%, respectively.The heterozygous mutations c. 784T ＞ C and c. 964T ＞ G in exon 8 of F7 gene were found in the proband,resulting in the substitutions of Ser269Pro and Cys329Gly respectively. Compound heterozygous mutations c. 784T ＞ C and c. 964T ＞ G were found in the proband's sister. The proband's mother was heterozygous for c. 784T ＞ C. His father, daughter and niece were heterozygous for c. 964T ＞ G. The protein biological characteristics analysis revealed that the Cys329Gly caused the change of spatial configuration, and Ser269Pro led to the change of amino acid polarity and hydrophobicity. Conclusion Compound heterozygous mutations of Cys329Gly and Ser269 Pro in F7 gene may be the underlying molecule mechanism of FⅦ deficiency in this pedigree.     

三个遗传性血管性血友病家系表型诊断和基因型研究

目的 对3个遗传性血管性血友病(vWD)家系进行表型诊断和基因型分析,探讨其分子发病机制.方法 分别采用出血时间(BT)、活化部分凝血活酶时间(APTT)、瑞斯托霉素诱导的血小板凝集试验(RIPA)、血管性血友病因子(vWF)瑞斯托霉素辅因子(vWF∶RCo)、vWF抗原(vWF∶Ag)、vWF活性(vWF∶A)测定,vWF胶原结合试验(vWF∶CB),vWF与FⅧ结合试验(vWF∶FⅧ∶B)和多聚体分析对3例vWD先证者和家系成员进行表型诊断.提取3例先证者外周血基因组DNA,用PCR法扩增vWF基因的52个外显子及侧翼序列,通过直接测序分析vWF基因变异.结果 3例左证者APTT均延长,BT除先证者3外均正常,血浆RIPA、vWF∶RCo、vWF∶Ag、vWF∶A和vWF∶CB均有不同程度的减低.多聚体分析结果显示先证者3中、高分子质量多聚体缺失,而先证者l、2基本正常.对3例先证者进行基因测序,共发现3个杂合突变,分别为vWF基因的G144067A(R2287Q)、G110374A(R1374H)、C110770T(S1506L)以及28号外显子G110667A(D1472H)杂合多态性.结论 R2287Q、R1374H和S1506L这3种杂合错义突变及D1472H杂合多态性是分别导致3例先证者发生遗传性vWD的分子发病机制.其中R2287Q是国际首次报道的新突变.

Abstract：

Objective To analyze phenotype and genotype of three Chinese pedigrees with von Willebrand disease (vWD), and explore the molecular mechanism. Methods Bleeding time (BT),activated partial thromboplastin time ( APTT), ristocetin-induced platelet aggregation ( RIPA ), von Willebrand factor timer analysis were used for phenotype diagnosis. Genomic DNA was extracted from the peripheral blood (PB). All the 52 exons and flanking sequences of the probands' vWF gene were amplified by PCR and analyzed by direct sequencing. Results APTT were prolonged in all three probands, while BT were normal exferent extents. In multimer analysis, proband 3 lost the large and intermediate molecular weight multimers,while proband 1 and 2 were normal. Gene analysis in the three probands revealed three heterozygous missense mutations of 144067 G→A(R2287Q) in exon 39 , 110374G→A (R1374H)and 110770C→T(S1506L) in exon 28 and heterozygous polymorphism 110667G→A (D1472H) in exon 28, respectively. Conclusion The three heterozygous mutations (R2287Q,R1374H and S1506L) and an heterozygous polymorphism (D1472H) are genetic defects of the hereditary vWD of the three pedigrees respectively. R2287Q is a novel mutation reported for the first time in the literature.     

一个遗传性凝血因子Ⅶ缺陷症家系两种新的基因突变

目的 探讨遗传性凝血因子Ⅶ(FⅦ)缺陷症的分子发病机制.方法 用DNA直接测序法对1例FⅦ缺陷症家系成员FⅦ基因进行分析;将含突变序列克隆插入pMD19-T Simple TA载体中,对所得两条染色体相应序列分别测序,以确定不同突变在染色体上的分布.采用酶联免疫吸附试验(ELISA)和凝固法检测血浆中FⅦ:Ag和FⅦ:C.结果 家系中有3种基因突变:第8号外显子第15386位核苷酸存在A→C(Arg353Pro)和第15386位核苷酸G→C(Gln353Pro)突变;第8号外显子第15274位核苷酸A→T(Lys316Stop)突变,家系成员中发现的这3种突变均为杂合子;发现先证者父亲存在3种杂合多态性:即启动子区2050～2059位CCTATACCT 10 bp的缺失/插入多态性、1号内含子IVS1a+9 G→A及第15386位A→G(Arg353Gln),且均来自先证者祖父,3种多态性位于同一条染色体上.结论 发现该家系存在1种FⅦ基因的错义突变(Gln353Pro);1种无义突变(Lys316Stop),这两种突变均为国际上首次报道的新突变.

Abstract：

Objective To explore the mutations of coagulation factor Ⅶ ( F Ⅶ ) gene in one pedigree with hereditary F Ⅶ deficiency, and to investigate the molecular mechanisms of F Ⅶdeficiency. Methods FⅦ gene mutations were analysed in the pedigree by direct DNA sequencing. The mutated DNA fragments were cloned into pMD19-T simple TA vector, and sequenced to confirm their distribution on chromosome. The plasma activity of F Ⅶ of the probands and their family members was detected with coagulation assay. The antigen of F Ⅶ were identified with ELISA. Results Three gene mutations were detected in the pedigree: A/G to C at 15386 resulting in Arg353Pro/Gln353Pro, A to T at 15274 resulting in Lys316Stop, all three mutations were heterozygotes. Three kinds of polymorphisms were identified in his father: A to G transition at position 15386 resulting in Arg353Gln, heterozygotic deletion of 2050 -2059 cctatatcct in promoter and G to A mutation in intron 1a, the same polymorphisms were found in his grandfather. The three polymorphisms were located in the same chromosome of his father. Conclusion Two mutations were found in the pedigree with hereditary FⅦ deficiency. One is nonsense mutation( Lys316Stop), the other is missense one(Gln353Pro).Gln353Pro and Lys316Stop might be the molecular mechanisms of FⅦ deficiency. The two novel mutations were reported for the first time in the literature.     

四个遗传性凝血因子Ⅶ缺陷症家系的基因与表型分析

目的 研究4个遗传性凝血因子Ⅶ(FⅦ)缺陷症家系的临床表型及基因突变.方法 用一期法测定先证者及其家系成员的凝血酶原时间(PT)及FⅦ活性(FⅦ:C),用双抗夹心ELISA测定血浆中FⅦ抗原(FⅦ:Ag),用PCR结合测序分析各家系成员的基因突变情况.结果 各家系先证者PT明显延长,FⅦ:C与FⅦ:Ag明显降低.家系1先证者FⅦ基因为18041T→G纯合性突变,使未成熟FⅦ(ProFⅦ)的408位组氨酸(His)变为谷氨酸(Gln)(成熟蛋白的His348Gln);家系2先证者FⅦ基因测序发现5078-5079 CT双碱基的纯合性缺失,致使阅读框改变,在ProFⅦ的N端25位提前终止;家系3先证者FⅦ基因分析发现15975G→A与18093C→T双重杂合突变,前者为内含子6的3'端剪接位点突变(IVS6-1G→A),后者为无义突变,致使ProFⅦ蛋白的426位提前终止;家系4先证者FⅦ基因测序发现15975G→A与17908G→A双重杂合突变,后者使ProFⅦ364位Arg→Gln.结论 在4个遗传性FⅦ缺陷症家系中发现His408Gln与5078-5079 del CT两个纯合突变及IVS6-1G→A、Gln426stop与IVS6-1G→A、Arg364Gln两个双重杂合突变.其中His408Gln与5078-5079 del CT为国内首次报道的纯合突变,IVS6-1G→A、Gln426stop为国际首次报道的突变.

Abstract：

Objective To investigate the clinical manifestation and gene mutation in four Chinese pedigrees with the congenital coagulation factor Ⅶ deficiency. Methods Prothrombin time (PT), activated partial thromboplastin time, thrombin time and plasma fibrinogen were measured using STAGO STA-R automatic coagulation analyzer, and the coagulation activity of factor Ⅶ (FⅦ: C) was determined by a PT-based one stage method, and factor Ⅶ antigen (FⅦ: Ag) level by a sandwich enzyme-linked immunoabsorbsent assay. All exons, exon-intron boundaries and 3', 5'untranslated regions of the FⅦ gene from the genomic DNA of the probands and their families were amplified by PCR, and then sequenced. Results PT was significantly prolonged, and FⅦ: C and FⅦ: Ag were decreased and the following mutations were identified in the four probands: a homozygous transversion of 18041 T→G resulting in His408→Gln substitution in exon 8 in proband 1, a homozygous double nucleotide deletion, del CT (5078-5079) in exon 1 in proband 2, a double heterozygous of IVS6-1G→A and Gln426→stop in proband 3, and a double heterozygous of IVS6-1G→A and Arg364Gln in prohand 4. Conclusion Two missense mutations, His408Gln, Arg364Gln and one nonsense,Gln426stop in the catalytic domain of FⅦ and one double nucleotide deletion, del CT(5078-5079) in exon 1 and one splicesome mutation, IVS6-1G→A in intron 6 were separately identified in four Chinese pedigrees with inherited coagulation factor Ⅶ deficiency. The Gln426stop and IVS6-1G→A were first identified in the world and the homozygous del CT(5078-5079) and His408Gln were first found in China.     

酶切富集联合DHPLC检测肿瘤患者外周血EGFR和KRAS基因突变及其临床应用

Objective To establish a REDE-DHPLC method for detecting the EGFR and KRAS mutations in plasma DNA from tumor patients, and investigate its clinical significance. Methods Restriction endonucleases Mse Ⅰ , Msc Ⅰ , BstN Ⅰ and Bgl Ⅰ were used to digest the wild type fragments of exon 19,exon 21 of EGFR gene and coden 12, 13 of KRAS gene for enriching the mutation fragments, and REDE-DHPLC method was established to detect EGFR and KRAS mutations. The sensitivities of REDE-DHPLC and conventional DHPLC were analyzed by using a series of plasmids containing 50%, 10%, 5%, 1% and 0. 1% mutation genes. Then, Plasma samples and paraffin-embedded tissue samples of 120 NSCLC patients and 120 colorectal cancer patients were detected by REDE-DHPLC. Compared with conventional DHPLC and sequencing, the diagnostic efficiency of REDE-DHPLC method was evaluated by detecting the mutation status of 2 genes in plasma of NSCLC and colorectal cancer patients. Results The sensitivity values of REDE-DHPLC and conventional DHPLC for detecting mutations in 4 loci were 0. 1% and 1%respectively. Plasmid DNA containing 0.1% mutation gene was detected to be positive continually for 2 to 3 times by REDE-DHPLC. EGFR mutation rates of 120 plasma from NSCLC patients detected by REDE-DHPLC, conventional DHPLC and sequencing methods were 27. 5%, 16. 7% and 12.5% respectively, and KRAS mutation rates of 120 plasma from colorectal cancer patients were 38. 3%, 25. 8% and 16. 7%,respectively. The positive rates of EGFR and KRAS mutation detected by REDE-DHPLC were significantly higher than conventional DHPLC(x2 = 4. 092, 4. 301, all P ＜ 0. 05 ) and sequencing method (x2= 8. 438,14. 127,all P ＜ 0. 05 ). In comparison with conventional DHPLC, the sensitivities of REDE-DHPLC for detecting EGFR and KRAS mutation were 100% (20/20,31/31), the specificities were 87. 0% (87/100)and 83. 2% (74/89). In comparison with sequencing method, the sensitivities of REDE-DHPLC were 100%( 15/15,20/20), the specificities were 82.9% (87/105)and 74. 0% (74/100). The coincidence rate of the two methods for detecting EGFR and KRAS mutation were 89. 2% ( 107/120, Kappa = 0. 690, P ＜ 0. 05 ) and 87.5% ( 105/120, Kappa= 0. 718, P ＜ 0. 05 ). The Consistency of EGFR and KRAS mutation status in plasma and tissues detected by REDE-DHPLC were 91.7% (33/36, Kappa =0. 939,P ＜0. 05)and 90. 2 %(46/51, Kappa = 0. 914, P ＜ 0. 05 ), respectively. Conclusions The REDE-DHPLC method is highly sensitive and specific for detecting EGFR and KRAS mutations in plasma DNA from tumor patients. The results are easy to be interpreted without missing homozygous point mutation, which indicate that the detection of EGFR and KRAS mutations in plasma DNA by REDE-DHPLC could therefore extend to be usedin clinical laboratory.     

酶切富集联合DHPLC检测肿瘤患者外周血EGFR和KRAS基因突变及其临床应用

Objective To establish a REDE-DHPLC method for detecting the EGFR and KRAS mutations in plasma DNA from tumor patients, and investigate its clinical significance. Methods Restriction endonucleases Mse Ⅰ , Msc Ⅰ , BstN Ⅰ and Bgl Ⅰ were used to digest the wild type fragments of exon 19,exon 21 of EGFR gene and coden 12, 13 of KRAS gene for enriching the mutation fragments, and REDE-DHPLC method was established to detect EGFR and KRAS mutations. The sensitivities of REDE-DHPLC and conventional DHPLC were analyzed by using a series of plasmids containing 50%, 10%, 5%, 1% and 0. 1% mutation genes. Then, Plasma samples and paraffin-embedded tissue samples of 120 NSCLC patients and 120 colorectal cancer patients were detected by REDE-DHPLC. Compared with conventional DHPLC and sequencing, the diagnostic efficiency of REDE-DHPLC method was evaluated by detecting the mutation status of 2 genes in plasma of NSCLC and colorectal cancer patients. Results The sensitivity values of REDE-DHPLC and conventional DHPLC for detecting mutations in 4 loci were 0. 1% and 1%respectively. Plasmid DNA containing 0.1% mutation gene was detected to be positive continually for 2 to 3 times by REDE-DHPLC. EGFR mutation rates of 120 plasma from NSCLC patients detected by REDE-DHPLC, conventional DHPLC and sequencing methods were 27. 5%, 16. 7% and 12.5% respectively, and KRAS mutation rates of 120 plasma from colorectal cancer patients were 38. 3%, 25. 8% and 16. 7%,respectively. The positive rates of EGFR and KRAS mutation detected by REDE-DHPLC were significantly higher than conventional DHPLC(x2 = 4. 092, 4. 301, all P ＜ 0. 05 ) and sequencing method (x2= 8. 438,14. 127,all P ＜ 0. 05 ). In comparison with conventional DHPLC, the sensitivities of REDE-DHPLC for detecting EGFR and KRAS mutation were 100% (20/20,31/31), the specificities were 87. 0% (87/100)and 83. 2% (74/89). In comparison with sequencing method, the sensitivities of REDE-DHPLC were 100%( 15/15,20/20), the specificities were 82.9% (87/105)and 74. 0% (74/100). The coincidence rate of the two methods for detecting EGFR and KRAS mutation were 89. 2% ( 107/120, Kappa = 0. 690, P ＜ 0. 05 ) and 87.5% ( 105/120, Kappa= 0. 718, P ＜ 0. 05 ). The Consistency of EGFR and KRAS mutation status in plasma and tissues detected by REDE-DHPLC were 91.7% (33/36, Kappa =0. 939,P ＜0. 05)and 90. 2 %(46/51, Kappa = 0. 914, P ＜ 0. 05 ), respectively. Conclusions The REDE-DHPLC method is highly sensitive and specific for detecting EGFR and KRAS mutations in plasma DNA from tumor patients. The results are easy to be interpreted without missing homozygous point mutation, which indicate that the detection of EGFR and KRAS mutations in plasma DNA by REDE-DHPLC could therefore extend to be usedin clinical laboratory.     

遗传性蛋白S缺陷症家系基因突变的研究

Objective To identify the clinical phenotypic diagnosis and gene mutation detection of two kindreds with PS deficiency. MethodsPS: A was measured by chromogenic substrate method;TPS:Ag, FPS: Ag levels were measured by ELISA method; PS gene(PROS1 gene)was detected by amplifying 15 exons and flanking intron sequences from the propositus with PCR method. PCR products were purified and directly sequenced. Results For propositus 1,PS: A was 48.6% ,TPS: Ag was 136 mg/L, FPS : Ag was 41 mg/L, PROSI gene exon 2 was in c. Heterozygous base substitutions was detected in C121T locus, which led to Arg-1Cys (R-1C) heterozygous roissense mutation encoded in PS proteins. For propositus 2, PS: A was 29.2%, TPS: Ag was 83 mg/L, FPS: Ag was 26 mg/L, PROSI gene exon 14 was in c. Heterozygous base substitutions was identified in CI687T locus, in which Gln.522Stop heterozygous nonsense mutation was encoded in PS proteins. Conclusions c. C121T is a novel mutation locus detected in PROS1 gene. This heterozygous mutation could lead to type Ⅱ PS hereditary deficiency, while c. C1687T heterozygous mutation could bring about type Ⅰ PS hereditary deficiency.     

遗传性蛋白S缺陷症家系基因突变的研究

Objective To identify the clinical phenotypic diagnosis and gene mutation detection of two kindreds with PS deficiency. MethodsPS: A was measured by chromogenic substrate method;TPS:Ag, FPS: Ag levels were measured by ELISA method; PS gene(PROS1 gene)was detected by amplifying 15 exons and flanking intron sequences from the propositus with PCR method. PCR products were purified and directly sequenced. Results For propositus 1,PS: A was 48.6% ,TPS: Ag was 136 mg/L, FPS : Ag was 41 mg/L, PROSI gene exon 2 was in c. Heterozygous base substitutions was detected in C121T locus, which led to Arg-1Cys (R-1C) heterozygous roissense mutation encoded in PS proteins. For propositus 2, PS: A was 29.2%, TPS: Ag was 83 mg/L, FPS: Ag was 26 mg/L, PROSI gene exon 14 was in c. Heterozygous base substitutions was identified in CI687T locus, in which Gln.522Stop heterozygous nonsense mutation was encoded in PS proteins. Conclusions c. C121T is a novel mutation locus detected in PROS1 gene. This heterozygous mutation could lead to type Ⅱ PS hereditary deficiency, while c. C1687T heterozygous mutation could bring about type Ⅰ PS hereditary deficiency.     

FH clinical phenotype in Greek patients with LDL-R defective vs. negative mutations

BACKGROUND: Familial hypercholesterolaemia (FH) is caused by mutations in the low-density lipoprotein receptor gene and the gene encoding apolipoprotein B-100, affecting one in 500 individuals. METHODS: One hundred and eighty-three Greek FH patients were screened for mutations on the LDLR and ApoB genes. RESULTS: We identified mutations in 67 probands and 11 relatives. Sixteen mutations located in eight different exons and the promoter of the LDLR were discovered. Among them 10 were missense mutations (C6W, S265R, A370T, Q363P, D365E, V408M, A410T, A517T, G528D, G571E), two were nonsense mutations (Q363X and C660X), three were splice defects (2140 + 5G-->A and 2140 + 9C-->T, 1706 - 10G-->A), and one was a nucleotide substitution (- 45delT) on the promoter. None of the subjects carried any apoB mutation. The detection rate of mutations in this study was 43%. From the above mutations, A410T, A519T and the splice site defects 2140 + 9C-->T were detected for the first time in the Greek population. Among them V408M, G528D, C6W and S265R account for 73% of heterozygous FH probands. V408M mutation is more common in Central West, while C6W is more common in Central East. Separating the patients into two groups (receptor defective and receptor negative) we found that the receptor negative group had higher levels of total cholesterol, low-density lipoprotein cholesterol and higher prevalence of tendon xanthomas compared with the receptor-defective group. DISCUSSION: The homogenous molecular basis of familial hypercholesterolaemia in Greece facilitates the application of a DNA diagnostic strategy based on the origin of the patient. The early mutation analysis would add valuable information on the severity of the disease.     

单链构象多态性技术在家族性高胆固醇血症患者低密度脂蛋白受体基因13外显子点突变筛查中的应用

目的 探讨单链构象多态性(SSCP)技术在家族性高胆固醇血症患者低密度脂蛋白受体(LDLR)基因13外显子点突变筛查上的应用价值.方法 以16例临床诊断为家族性高胆固醇血症(FH)患者为研究对象,提取外周血DNA,扩增LDLR基因第13号外显子片段,组合最优条件进行SSCP电泳并银染.对异常条带进行DNA序列测定确定其突变性质和位置.结果 优化SSCP电泳条件为:不含甘油8%凝胶,在10℃条件下电泳;含5%甘油的8%凝胶,在常温条件下电泳(交联度均为49:1).凝胶厚度均不超过0.4 mm,电泳电压为5 V/cm,在此条件下进行SSCP电泳均可以得到满意电泳图谱.对发现的异常条带,结合DNA测序证实有4例患者LDLR基因第13外显子分别发生A606T,D601N,Y601D,或G636V错义突变,同时均存在1959碱基C→T同义突变.另外4例患者13外显子仅存在1959碱基C→T同义突变.结论 通过优化各种条件进行的PCR-SSCP银染方法,是高胆固醇血症病LDLR基因13外显子点突变初步筛查的有效手段.     

Novel stop mutation causing familial hypercholesterolemia in a Costa Rican family

Combined heteroduplex single-strand conformation polymorphism (HEX-SSCP) analysis of the promoter and coding region of the low density lipoprotein receptor (LDLR) gene revealed a novel C to T mutation at nucleotide position 2056 in a Costa Rican patient with heterozygous familial hypercholesterolemia (FH). This nonsense mutation, Q665X, results in a termination codon in the epidermal growth factor (EGF) precursor homology domain of the mature LDLR.     

羊水细胞低密度脂蛋白受体基因突变分析在家族性高胆固醇血症产前诊断中应用

目的探讨羊水细胞低密度脂蛋白受体（low density lipoprotein receptor,LDLR）基因突变分析在家族性高胆固醇血症（familial hypercholesterolemia,FH）产前诊断中的应用价值。方法 3例曾生育FH重症患儿并再次妊娠的妇女及其核心家系成员,提取其外周血基因组DNA,筛查LDLR基因突变;于妊娠16～20周在超声引导下行羊膜腔穿刺术抽取羊水,提取胎儿脱落细胞DNA,分别对家系存在的LDLR基因突变进行检测,判断胎儿是否为重症FH。结果 3个家系均符合FH诊断,并分别在LDLR基因检测到2个互不相同的杂合突变位点;胎儿LDLR基因核苷酸序列分析证实,1号家系胎儿仅携带该家系1个突变位点判断为杂合（轻症）,2号家系胎儿携带该家系2个突变位点判断为复合杂合（重症）,3号家系胎儿未检到该家系的突变位点推测为正常个体。结论 FH孕妇羊水脱落细胞LDLR基因分析安全有效,可尽早发现FH纯合子患儿。     

Mutation analysis in a small cohort of New Zealand patients originating from the United Kingdom demonstrates genetic heterogeneity in familial hypercholesterolemia

Familial hypercholesterolemia (FH) and familial defective apolipoprotein B-100 (FDB) are relatively common lipid disorders caused by mutations in the low-density lipoprotein receptor (LDLR) and apolipoprotein B (apo B) genes, respectively. Molecular analysis at these loci was performed in eight New Zealand subjects with clinical features of heterozygous FH. Utilization of an in vitro lymphocyte receptor assay demonstrated normal receptor function in four patients, three of whom screened positive for the founder-type apo B mutation, R3500Q, causing FDB. Four patients with reduced LDLR function, consistent with heterozygous FH, revealed three previously documented mutations in exons 3 (W66X), 6 (C292Y) and 7 (G322S) of the LDLR gene and, a novel 2-bp deletion (TC or CT) after nucleotide 1204 (or 1205) in exon 9. The remaining patient was found to be FH/FDB negative after extensive mutation screening using both denaturing gradient gel electrophoresis and heteroduplex-single strand conformation polymorphism analysis. Haplotype analysis at the LDLR and apo B loci finally excluded the likelihood that mutations in these two genes underlie the FH phenotype in the molecularly uncharacterized New Zealand family originating from the United Kingdom. This family represents a valuable source of material for future genetic dissection of autosomal dominant hypercholesterolemia (ADH), shown to be a heterogeneous disease through molecular analysis.     

Mutational heterogeneity in low-density lipoprotein receptor gene related to familial hypercholesterolemia in Morocco

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant disorder caused by mutations in the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB) and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. Until now, molecular data concerning FH in Morocco is still limited. To gain more information in this field and to assess the contribution of these three genes in the cause of FH determinism, we analyzed six unrelated Moroccan probands and twenty-five of their family's members. METHODS: After LDLR and APOB genotype analysis, we screened the LDLR gene for mutations using southern blot and PCR-sequencing analysis. We also screened the APOB gene for the two common mutations R3500Q and R3531C by PCR-mediated site-directed mutagenesis. The PCSK9 gene was analyzed by direct sequencing. RESULTS: We identified three novel mutations (C25X, IVS3+5G>T, D558A) and two mutations previously described (D151N, A480E) in the LDLR gene. The R3500Q and R3531C mutations are absent in our probands and for 1 proband, the implication of LDLR, APOB and PCSK9 genes was excluded, supporting the implication of a fourth gene in the determination of FH. CONCLUSION: These data are in agreement with our previous study that suggests a heterogeneous mutational spectrum of FH in Morocco.     

凝血因子Ⅴ及凝血因子Ⅷ联合缺陷患者四例的基因诊断

目的 对4例FⅤ及FⅧ联合缺陷患者及其家系成员进行基因诊断及分子发病机制研究.方法 测定先证者及家系成员APTT、PT、FⅧ:C及FⅤ:C等进行表型诊断;采用凝血酶生成试验检测先证者及健康对照者的凝血酶生成情况;Tiangen试剂盒法抽提先证者及家系成员全血基因组DNA;平衡酚-乙醚法抽提羊水DNA;PCR扩增4例先证者及家系成员的LMAN1基因及MCFD2基因,用末端标记双脱氧法检测核酸序列查找基因突变.结果 先证者1的APTT显著延长,为88.2 s,PT 延长至19.6 s,FⅧ:C降至24.2%,FⅤ:C为9.1%.先证者2与先证者3为亲姐妹,两人的APTF均明显延长,分别为71.6 s及74.6 s,PT分别延长至22.1 s及18.3 s,FⅧ:C均降低,分别为25%及19.6%,FⅤ:C分别降至7.6%及14.5%.先证者4的AFTT及PT均延长,分别为70.3 s及18.2 s,其FⅦ:C降至15.7%,FV:C降至9.4%,4例先证者的其余实验室表型检测指标均正常,临床诊断为FⅤ及FⅧ联合缺陷性疾病.对先证者1进行LMAN1及MCFD2基因直接测序,显示其LMAN1基因存在双杂合突变:突变1位于第8号外显子,为插入突变:nt912insA(X71661.1),导致第305位氨基酸发生移码突变,并在编码20个氨基酸后终止,其母亲该位点亦为杂合突变;先证者1的另一个杂合突变位于第11号外显子:nt1366C>CT(X71661.1),导致第456位精氨酸发生无义突变(p.Arg456X),其父亲及胎儿该位点均为杂合突变.先证者1及其父母的MCFD2基因测序均未发现突变.先证者2及3的LMAN1基因测序均未发现突变,MCFD2基因直接测序检测发现两者均在该基因的第4号外显子处存在1个纯合突变:nt411T>C(NM_139279),导致第136位异亮氨酸突变成苏氨酸(p.Ile136Thr).先证者2的女儿该位点为杂合突变.先证者4的LMAN1基因测序显示其在该基因的第5号外显子存在1个纯合突变:nt615C>T,导致第202位的精氨酸无义突变;其MCFD2基因测序未发现突变.凝血酶生成试验检测显示4例FⅤ及FⅧ联合缺陷患者的凝血酶生成潜力较健康对照者均有不同程度的下降.结论 先证者1是由LMAN1基因的双杂合突变nt1366C>CT及nt912insA引起,突变分别遗传自其父亲及母亲,对其母亲进行产前基因诊断发现胎儿为1名女性携带者,该胎儿遗传了其父亲的1个杂合突变nt1366C>CT.先证者2及3是由MCFD2基因上的纯合突变(nt411T>C,p.ne136Thr)所导致的.先证者2的女儿遗传了其母亲的一个杂合突变,为携带者.先证者4是由LMAN1基因的纯合无义突变(nt615C>T,p.Arg202X)所导致的.     

家族性高胆固醇血症黄色瘤的家系遗传分析

目的:检测中国汉族家族性高胆固醇血症(familial hyper-cholesterolemia,FH)家系低密度脂蛋白受体(LDLR)基因突变,探讨FH发病的分子机制。方法:采用PCR扩增结合核苷酸序列分析检测1例临床诊断为FH纯合子患者及其家系成员LDLR基因启动子和全部18个外显子片段,结果与GenBank公布的该基因正常序列对比找出突变,同时检测载脂蛋白B100(apoB100)基因Q3500R突变,以排除家族性apoB100缺陷症。结果:该患者LDLR基因第12外显子的第1747位和1773位碱基发生替换,前者导致H583Y突变,而后者未发现氨基酸改变。同时未检测出患者及其核心家系成员apoB100Q3500R突变。结论:FH是一常染色体显性遗传性疾病,为基因突变导致LDLR缺陷所致的遗传性疾病。检测相关基因突变对临床干预和遗传指导有参考价值。     

Use of denaturing HPLC to provide efficient detection of mutations causing familial hypercholesterolemia

BACKGROUND: Autosomal dominant familial hypercholesterolemia (FH) attributable to mutations in the LDL receptor (LDLR) gene is one of the most common genetic disorders associated with significant morbidity and mortality. Definitive diagnosis would help to initiate appropriate treatment to prevent premature cardiovascular disease. Currently, clinical diagnosis of FH is imprecise, and molecular diagnosis is labor-intensive and expensive because of the size of the LDLR gene and number of coding exons. METHODS: We used PCR to amplify all exons, including exon/intron boundaries, and the promoter of the LDLR gene. Nine individuals from five families with typical findings for a clinical diagnosis of heterozygous FH, 2 heterozygous FH cell lines, and 50 control individuals were screened for mutations by denaturing HPLC (DHPLC) followed by direct sequencing of aberrantly migrating fragments. RESULTS: Mutations that were previously reported to be disease causing were identified in eight of nine individuals with FH and both cell lines (V502M, C146X, E207X, C660X, C646Y, and delG197), but none were found in controls. The one individual with FH in whom no mutation was found had a previously unreported change in the 5'-untranslated region of unknown significance. In addition, we identified several previously reported polymorphism both in controls and individuals with FH. CONCLUSIONS: DHPLC can be used to detect mutations causing FH. On the basis of our current experience with DHPLC, this method combined with confirmatory DNA sequencing is likely to be sensitive and efficient.