姐妹2人同患家族性高胆固醇血症家系LDL-R基因突变分析

目的：对临床确诊的家族性高胆固醇血症（FH）两姐妹及其家系成员进行低密度脂蛋白受体（LDL-R）基因突变分析,探讨其发病机制。方法：提取患者外周血基因组DNA,聚合酶链反应分别扩增启动子和18个外显子片断,采用单链构象多态性（PCR-SSCP）结合银染技术,对异常电泳条带进行核苷酸序列分析。结果：姐妹2人及其父亲,叔叔,祖母均发现LDL-R基因第13外显子存在一个错义突变,与GeneBank对照证实第1879位G→A碱基置换,氨基酸的改变为丙氨酸→苏氨酸（A606T突变）,其母亲和女儿经测序并未发现此突变位点。结论：姐妹2人均为LDL-R基因存在A606T杂合错义突变,并均来自其父系亲属；可能是该家系发病的分子基础。     

一家族性高胆固醇血症家系低密度脂蛋白受体基因突变分析

为分析一家族性高胆固醇血症家系低密度脂蛋白受体的基因突变，提取患儿及其父母外周血基因组DNA，用聚合酶链反应扩增低密度脂蛋白受体基因的18个外显子。用单链构象多态性分析检测聚合酶链反应产物，对单链构象多态性分析电泳结果异常者进行DNA序列分析。结果发现，单链构象多态性分析发现患者及其母亲第10外显子存在一异常条带。DNA测序结果证实患者第10外显子的471位密码子由AGA同义突变为AGG，483住密码子由TGG突变为TAG，导致在483住提前出现终止密码子。本研究利用聚合酶链反应一单链构象多态性分析方法报道了一个新的低密度脂蛋白受体突变位点。     

家族性高胆固醇血症家系低密度脂蛋白受体活性及其基因突变分析

目的:对1例临床诊断为家族性高胆固醇血症(FH)纯合子患者家系进行低密度脂蛋白受体(LDL-R)活性研究及其基因突变分析,旨在探讨其分子病理机制。方法:对先证者及其父母进行血脂、颈动脉超声等检查;采用流式细胞仪检测先证者及其父母外周血淋巴细胞LDL-R表达量和功能;以先证者基因组DNA为模板,扩增载脂蛋白B100(ApoB100)基因3500区域片断,PCR产物进行核苷酸序列分析,排除由该突变导致家族性ApoB100缺陷症;用降落式PCR方法,在同一程序中分别扩增LDL-R基因的启动子和全部18个外显子片段,扩增产物进行核苷酸序列分析;发现突变后验证其父母是否存在相同基因突变。结果:先证者血清TC和LDL水平明显升高、颈动脉内中膜明显增厚;LDL-R的表达量和结合功能显著下降(分别为正常人的13.6%和21.1%);ApoB100基因3500区域未见突变,LDL-R基因第1864位碱基T取代了G发生纯合错义突变,导致第601位氨基酸天冬氨酸变成脯氨酸(D601Y)。其父母LDL-R基因发现了相同的杂合突变,经检索该突变在我国未见报道。结论:证实家系先证者存在LDL-R基因突变,分别来源于父系和母系的遗传,该突变可能是家系发病的分子基础;D601Y也可能是我国FH患者LDL-R基因一种新的突变类型。     

家族性高胆固醇血症姐妹二人基因突变分析

家族性高胆固醇血症（familial hypercholesterolemia，FH）是一种较为常见的常染色体显性遗传病，其主要特点为血浆胆固醇水平极度增高，多部位皮肤肌腱黄色瘤和过早发生冠心病，严重者青少年时期发生心肌梗死甚至死亡。本研究对临床确诊为纯合型家族性高胆固醇血症两姐妹进行聚合酶链反应—单链构象多态性（PCR—SSCP）结合银染技术、     

家族性高胆固醇血症家系低密度脂蛋白受体基因突变分析

家族性高胆固醇血症(FH)是一种严重的常染色体单基因显性遗传性疾病,临床特点为血浆胆固醇大幅增高、特征性黄色瘤和早发冠心病,同时具有阳性家族史。低密度脂蛋白受体(LDLR)基因突变是引起FH最主要的原因。本研究对一临床诊断为纯合子FH先证者及其父母进行基因突变分析,以从分     

家族性高胆固醇血症患者低密度脂蛋白受体基因复合纯合突变一例

目的 检测家族性高胆固醇血症(FH)患者低密度脂蛋白受体(LDL—R)基因点突变，分析基因型与临床表型间的关系，探讨其分子病理机制。方法以1例临床诊断为FH纯合子患儿及其父母的基因组DNA为模板，用降落PCR方法，在同一程序中分别对LDL—R基因的启动子和全部18个外显子片段进行扩增，琼脂糖凝胶电泳检测，扩增产物直接进行核苷酸序列分析，并检索FH突变数据库(www．ucl．ac．uk／fh)。此外采用PCR-限制性内切酶技术，检测载脂蛋白(Apo)B100基因Q3500R突变，以排除家族性Apo B100缺陷症。结果该患儿及其父亲第4外显子发生Cys^122→Tyr(C122Y)杂合错义突变，同时患儿及其母第9外显子发生Thr^273→Ile(17383I)杂合错义突变，因此该患儿LDLR基因第4、9外显子各存在一个杂合突变，上述突变尚未在FH突变数据库见到。未检测出患儿及其父母Apo B100Q3500R突变。结论此患儿为LDL—R基因存在C122Y、T3831合纯合突变并分别来自其父母；以上两位点突变可引起FH；是FH患者LDL-R基因的一种新突变类型。     

家族性高胆固醇血症患者低密度脂蛋白受体基因新突变一例

目的 分析中国家族性高胆固醇血症（FH）患儿低密度脂蛋白受体（LDL－R）基因突变的情况，并为在婴幼儿时期此病的症前筛查提供确诊方法。方法 以患儿及其父母的基因组DNA为模板，首先用聚合酶链反应（PCR）扩增该基因的启动子和全部18个外显子，然后用单链构象多态性（SSCP）方法分析PCR产物，最后对电泳结果异常进行DNA测序。结果 在1个家系中检测出患儿和其父亲LDL－R基因的一种新突变，即在第4外显子的444位碱基发生杂合突变（T→A），相应的氨基酸由半胱氨酸变成终止密码子，其母亲LDL－R基因正常。结论 LDL－R基因此位点的突变可引起FH，PCR－SSCP方法可用于筛查出的高危人群的确诊。     

家族性高胆固醇血症低密度脂蛋白受体基因突变分析

目的:检测1例家族性高胆固醇血症(FH)先证者及其4代家系成员低密度脂蛋白受体(LDL-R)基因突变,探讨该家族FH可能发病分子机制.方法:收集先证者及其家系成员临床资料和基因组DNA,以基因组DNA为模板,用PCR方法扩增LDL-R基因的启动子和全部18个外显子,PCR产物进行限制性内切酶技术结合DNA测序,核苷酸序列分析结果与Gen Bank比对寻找突变;采用PCR-DNA测序技术检测apoB100基因R3500Q、R3531C和R3500W位点以及枯草溶菌素转化酶9(PCSK9)基因,以排除家族性apoB100缺陷症和PCSK9基因突变.结果:先证者及其部分家系成员第6号外显子发生Cys276X杂合无义突变,为半胱氨酸改变为提前终止密码子,使终止密码子在第276位提前出现,为致病性突变,国内尚无报道;另外,第15号外显子发生Arg744Arg同义突变.其母未发现上述突变,未检测出患者及其家系apoB100基因R3500Q、R3531C和R3500W突变以及枯草溶菌素转化酶9基因突变.结论:此患者及家系LDL-R基因存在Cys276X无义突变,可能是FH的致病突变,该突变是我国FH患者LDLR基因的一种新突变类型.     

家族性高胆固醇血症一家系基因突变分析和临床治疗

目的]总结1例家族性高胆固醇血症(FH)家系的基因突变分析和临床治疗方案。 [方法]先证者因“反复气喘伴胸痛4个月,加重2天”入院,血浆低密度脂蛋白胆固醇(LDLC)异常升高,且早发冠心病,对先证者进行全外显子测序和载脂蛋白E(ApoE)、对氧磷酶1(PON1)、前蛋白转化酶枯草溶菌素9(PCSK9)等位点进行测序分析,针对可疑致病突变在家系成员中进行检测,对先证者及其父亲进行了冠状动脉介入治疗和降脂治疗。 [结果]先证者、其父亲和其儿子在低密度脂蛋白受体(LDLR)基因中均检出了6个突变位点,分别为c.191+13G＞A(rs200621482)、c.1598G＞T(rs200427089)、c.883T＞G(rs553235458)、c.3536A＞G(rs201300867)、c.2215+6G＞A(rs540060615)、c.162+5A＞T(rs146596406)。这3例患者的6个位点均为杂合突变。3例患者的ApoE基因型结果如下:先证者及其儿子的ApoE基因型均为ε3/ε3型,蛋白表型为E3(ApoE2位点为CC型,ApoE4位点为TT型);其父亲的ApoE基因型为ε2/ε3型,蛋白表型为E2(ApoE2位点为CT型,ApoE4位点为TT型)。3例患者的PON1(A575G,rs662)位点基因型均为AG型,3例患者的PCSK9基因型为GG、CC、CC、GG型。基于该家系遗传学检测结果,给予先证者及其父亲个体化的降脂治疗方案,阿托伐他汀钙与依折麦布联合PCSK9抑制剂,且先证者及其父亲成功行冠状动脉介入治疗术,随访两年LDLC控制较好,未出现药物不良反应。 [结论]本研究中该家系患者的LDLR基因均发现6个位点突变,其中LDLR c.191+13G＞A、c.162+5A＞T在国内尚未见报道,丰富了中国人群的LDLR基因突变谱。本研究有利于阐明FH的发病机制,进一步指导FH患者的临床治疗。     

载脂蛋白E基因多态性与家族性高胆固醇血症

家族性高胆固醇血症 (familialhypercholesterolemia ,FH)是低密度脂蛋白受体 (lowdensitylipoproteinreceptor,LDLR)基因突变导致的常染色体显性遗传病。国外报道杂合子患病率为 1/5 0 0 ,纯合子患病率为 1/10 0万[1] ,目前国内还未见有关FH患病率的报道。本文就FH的临床诊断标准、载脂蛋白E(apolipoproteinE ,ApoE)基因多态性在FH患者中的分布及其对血脂水平和调脂药的影响一些最新研究进展进行综述。一、FH的临床诊断标准FH的临床诊断标准如下[2 ] :纯合子FH ,血中总胆固醇(TC)浓度超过 9 1mmol/L ( 35 0mg/dl) ,若同时包括以…     

The Trp-Stop and Trp-Gly mutations in the LDL receptor gene: common causes of familial hypercholesterolemia in Denmark

Mutations in the gene for the low density lipoprotein (LDL) receptor cause the autosomal dominant disease familial hypercholesterolemia (FH), the prevalence of which is about 0.2% in most populations. By PCR-SSCP analysis and direct sequencing, we identified the receptor-negative Trp²³-Stop LDL receptor mutation (FH Cincinnati-5) in 10 of 63 FH probands and the receptor-defective Trp⁶⁶-Gly LDL receptor mutation (FH French Canadian-4) in another 10 of the 63 FH probands. These two mutations thus account for 30% of diagnosed FH families in Denmark. Comparison of the mean lipid concentrations (unadjusted and adjusted for age), including serum total cholesterol and LDL-cholesterol, showed no significant differences between the two groups of FH heterozygote probands (cholesterol: 10.7 mmol/l vs. 10.7 mmol/l) and between the probands and 16 and 22 non-proband family members with the Trp²³-stop (cholesterol: 10.1 mmol/l) and Trp⁶⁶-Gly (cholesterol: 10.7 mmol/l) mutations, respectively.     

A novel type of familial hypercholesterolemia: double heterozygous mutations in LDL receptor and LDL receptor adaptor protein 1 gene

Background

Autosomal recessive hypercholesterolemia (ARH) is an extremely rare inherited hypercholesterolemia, the cause of which is mutations in low-density lipoprotein (LDL) receptor adaptor protein 1 (LDLRAP1) gene.

Methods

A total of 146 heterozygous familial hypercholesterolemic (FH) patients with a mutation in LDLR gene were screened for genes encoding proprotein convertase subtilisin/kexin type 9 (PCSK9) and LDLRAP1.

Results

Among the 146 subjects, we identified a 79-year-old Japanese female with double mutations in LDLR gene (c.2431A > T) and LDLRAP1 gene (c.606dup). Two other relatives with double mutations in those genes in her family were also identified. Although the proband exhibited massive Achilles tendon xanthoma and coronary and aortic valvular disease, serum LDL-C level of subjects with double mutations was similar with that of subjects with single LDLR mutation (284.0 ± 43.5 versus 265.1 ± 57.4 mg/dl).

Conclusion

Additional mutation in LDLRAP1 may account for severer phenotype in terms of xanthoma and atherosclerotic cardiovascular disease in FH patients.     

低密度脂蛋白受体基因二核苷酸串联重复序列(TA)n在正常中国汉族人群的多态性分布

目的　研究 LDL- R基因二核基酸串联重复序列 (TA) n在正常中国汉族人群的多态分布。方法　应用 PCR扩增 (TA) n所在区域的 DNA,通过变性聚丙烯酰胺凝胶电泳 ,结合银染技术检测扩增产物 ,测定了 2 0 6例正常中国汉族人的等位基因片段。结果　检测到 5种不同长度的等位基因片段和 1 0种不同基因型 ,多态信息容量 (PIC)为 0 .51 97,杂合度 0 .52 0 9。结论　该位点在中国人群中具有长度多态性 ,且其多态性分布与西方人群存在明显差异。     

Influence of LDL receptor gene mutation and apo E polymorphism on lipoprotein response to simvastatin treatment among adolescents with heterozygous familial hypercholesterolemia

The efficacy of the inhibitors of HMG CoA reductase shows considerable interindividual variation and intense research has focused in the recent years to identify the genetic loci and environmental factors responsible for this variability. A randomized, double-blind, placebo-controlled clinical trial with simvastatin, an HMG CoA reductase inhibitor, was conducted in 63 adolescents (47 treated versus 17 controls) with heterozygous FH. The patients were grouped according to known low-density lipoprotein (LDL) receptor gene mutation class. After 6 weeks of treatment with 20 mg/d of simvastatin, the mean reduction in plasma LDL-cholesterol in patients with a receptor-negative mutation (n=33) was 39% whereas, in the receptor-defective mutation group (n=14), it was 31% (P=0.01). Multiple regression analyses showed that there was a significant association between the apo E polymorphism and LDL-cholesterol response to simvastatin only among heterozygotes for a receptor-negative mutation. In subjects carrying a receptor-defective mutation, however, we observed that 51% of the variability in LDL-cholesterol response was explained by variations in the dosage of simvastatin expressed in mg/kg/day (P=0.0028). There was no significant association between LDL-cholesterol response and the dosage of simvastatin among heterozygotes for a receptor-negative mutation. The results of the present study have shown that the contribution of apo E polymorphism and the dosage of simvastatin to the LDL-cholesterol responsiveness is influenced by the nature of the LDL receptor gene mutation.     

促甲状腺激素受体胞内环基因突变与乳头状甲状腺癌发病的相关性研究

目的探讨乳头状甲状腺癌的发病与促甲状腺激素受体(TSHR)基因突变的相关性。方法采用巢氏-多聚酶联反应-单链构象多态性分析(NEST-PCR-SSCP)和DNA测序方法,对65例乳头状甲状腺癌和44例正常甲状腺组织TSHR3个胞内环基因进行检测。结果NEST-PCR-SSCP检测乳头状甲状腺癌促甲状腺激素受体(TSHR)3个胞内环未发现明显带型异常;DNA测序后,检测的第3胞内环2例对照组织和3例甲状腺癌组织TSHR2000位点碱基均由C→T,使得所编码的601位氨基酸由组氨酸(CAT)→酪氨酸(TAT)(His→Tyr),余胞内环未发现基因突变。结论乳头状甲状腺癌TSHR3个胞内环未发现基因突变,提示乳头状甲状腺癌发病与TSHR胞内环基因突变无关;5例标本601位氨基酸均为酪氨酸,考虑中国人TSHR基因可能与国外人群存在差异,TSHR2000位点碱基存在基因多态性。     

结核分支杆菌耐异烟肼分子机制的研究

目的了解结核分支杆菌耐异烟肼（ＩＮH）分离株ＫａtG基因完全缺失或突变的情况，探讨其在ＩＮＨ耐药性中的可能作用。方法应用ＰＣＲ和ＰＣＲ－ＳＳＣＰ方法对５８株结核分支杆菌临床分离株的ＫａｔＧ基因进行分析。结果以Ｈ３７，ＲＶ标准株为对照，１２株敏感株的ＫａｔＧ基因扩增产物，１１株SSCP泳动正常，1株（８．３％）异常；２４株耐ＩＮＨ株中，３株（ｌ．５％）PCR扩增阴性，ＺＩ株ＫａtG扩增阳性，其中１６株（７６．２％）SSCP泳动异常；２２株耐其它抗结核药物株中，也有７株（３１．８％）SSCP异常。结论某些结核分支杆菌ＩＮＨ耐药性产生可能是由于其ＫａｔＧ基因完全缺失或ＫａｔＧ基因突变所致，但某些菌株也可能与ＫａｔＧ基因无关，是其它耐药基因所致或存在多种机制，尚需进一步探讨。     

Type 2 (non-insulin-dependent) diabetes mellitus associated with a mutation of the glucokinase gene in a Japanese family

Summary Mutations were screened for in the glucokinase gene of 25 Japanese patients with Type 2 (non-insulin-dependent) diabetes mellitus. Each exon was scanned by electrophoresis of enzymatically amplified DNA segments under non-denaturing conditions and variants were sequenced. A variant pattern was detected in exon 5 of one patient. Direct sequencing of this exon revealed a single nucleotide substitution in codon 188 (GCTACT) of one of two alleles resulting in the mutation of Ala¹⁸⁸Thr, an invariant residue in the sequence of all mammalian glucokinases and hexokinases. This mutation was not found in 40 normal control subjects. The proband had been diagnosed with Type 2 diabetes at the age of 62 years. Four other members of her family have the same mutation and all have Type 2 diabetes or impaired glucose tolerance. The youngest age at diagnosis of Type 2 diabetes in these other members was 13 years, suggesting that her pedigree was maturity-onset diabetes of the young (MODY). All subjects with the Thr¹⁸⁸ mutation show a decreased insulin secretory response during oral glucose tolerance testing. Mutations in the glucokinase gene associated with Type 2 diabetes have been previously identified in Caucasian (French and British) subjects. This study indicates that mutations in this gene are also implicated in the development of Type 2 diabetes in Asians. Further studies are required to determine the frequency of mutations in glucokinase among Japanese patients with Type 2 diabetes.