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

目的:对1例临床确诊为纯合型家族性高胆固醇血症(FH)先证者及其3代家系成员进行基因检测和系谱分析,探讨其发病机制.方法:先证者家中收集该家系3代共10例血标本及临床资料.对其家系成员进行血脂测定,酚氯仿法提取患儿及家系成员基因组DNA并鉴定,应用多聚酶链反应-单链构象多态性(PCR-SSCP)分析结合DNA直接测序方法,检测其低密度脂蛋白受体(LDL-R)基因的全部18个外显子和启动子及载脂蛋白B(ApoB100)26外显子,核苷酸序列分析结果与GeneBank比对寻找突变.结果:(1)先证者右锁骨下动脉起始,双侧颈总动脉分叉处,中段内一中膜轻度增厚,左房轻度增大,二尖瓣、三尖瓣及主动脉瓣轻度返流,冠脉血流储备减低;(2)该家系排除ApoB100基因26外显子3500附近位点突变;(3)核苷酸序列分析证实先证者LDL-R基因第13外显子发生D601Y纯合突变,为1864位G→T碱基置换,导致天冬氨酸改变为酪氨酸,先证者父亲和母亲LDL-R基因第13外显子均发生D601Y杂合突变.结论:该先证者LDL-R基因存在D601Y纯合突变,其父母LDL-R基因存在D601Y杂合突变,可能为该家系中FH的致病突变.     

1例家族性高胆固醇血症患者低密度脂蛋白受体基因新突变体功能研究

目的分析基因突变对低密度脂蛋白受体(LDLR)功能的影响,探讨其对家族性高胆固醇血症(FH)的可能致病机制。方法对1名FH患者进行基因检测,构建真核细胞表达载体,经定点诱变获得突变受体质粒,并将突变受体质粒转染入人胚肾(HEK293)细胞中,用激光共聚焦显微镜(CLSM)观察突变蛋白细胞定位,用流式细胞术检测突变蛋白表达及内吞活性变化。结果基因测序显示该名患者发生了LDLR基因Y398X突变;CLSM结果显示突变蛋白部分滞留于内质网中;流式细胞术结果显示细胞表面LDLR表达量减少至5.5%,内吞活性减少至20.1%。结论在临床确诊的FH患者中检测到LDLR致病性基因Y398X突变,在中国为首次报道。该突变造成LDLR转运缺陷,从而导致血浆中胆固醇代谢障碍,继而诱发FH的发生。     

一个纯合家族性高胆固醇血症家系低密度脂蛋白受体基因突变的检测

目的 检测家族性高胆固醇血症(familial hypercholestero-lemia,FH)患者低密度脂蛋白受体(low density lipoprotein receptor,LDLR)的基因突变.方法 提取家系中,临床通过典型特征和血脂检测诊断为家族性高胆固醇血症患者的基因组DNA,首先检测载脂蛋白B100(apoB100)基因R3500Q突变,以排除家族性apoB100缺陷症(Familial defective apoB100,FDB).然后用降落聚合酶链反应(TOUCH-DOWN PCR)扩增该基因的启动子和全部18个外显子,再用单链构象多态性(SSCP)方法分析PCR产物,并对电泳结果异常者进行DNA测序分析.用ANTHEPROT 5.0软件对突变LDLR进行二级结构分析,然后对突变LDLR进行SWISS MODEL在线三级结构预测.结果 通过SSCP和DNA测序发现该家系患者13号外显子存在A606T的纯合突变,采用ANTHEPROT5.0软件的GORⅠ法对突变型和野生型蛋白质进行二级结构分析,可见突变蛋白的突变区域部分螺旋结构被转角结构和无规卷曲取代,其二级结构发生了改变.突变LDLR三级结构预测未发现主链结构的变化.结论 结果表明.LDLR基因A606T的突变可能是此高胆固醇血症家系的致病原因所在.     

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。     

低密度脂蛋白受体基因全长cDNA 序列分析法检测1例家族性高胆固醇血症患儿基因突变

目的建立低密度脂蛋白受体(LDLR)基因全长cDNA序列分析方法并对1例家族性高胆固醇血症(FH)患儿进行基因检测。方法设计7对LDLR基因cDNA引物并验证;对1例临床诊断为FH的患儿进行家系调查和临床体检,提取外周血DNA和RNA,DNA扩增结合测序分析LDLR基因并找出其突变位点;RNA经PCR反转录为cDNA后扩增LDLR基因,将扩增产物进行正、反双向核苷酸序列分析,并与GenBank中LDLR基因的正常序列对比找出突变位点后与传统DNA测序方法结果比对。结果 LDLR基因全长cDNA序列分析方法检测LDLR基因为2 583个碱基,与标准序列完全一致;本例患儿确诊为"FH纯合子",cDNA测序结果与传统DNA测序结果相符,均为第2外显子终止突变和第6外显子点突变及框移突变。结论 LDLR基因全长cDNA序列分析法检测FH患儿突变,与传统DNA方法检测结果相符,可为FH的基因诊断提供新的方法依据。     

家族性高胆固醇血症的研究进展

家族性高胆固醇血症的研究进展朱大明综述陈保生陆宗良审校（中国医学科学院阜外心血管病医院，北京１０００３７）ＰｒｏｅｓｓｏｆＳｔｕｄｙｏｎＦａｍｉｌｉａｌＨｙｐｅｒｃｈｏｌｅｓｔｅｒｏｌｅｍｉａＺｈｕＤａｍｉｎｇ（ＦｕｗａｉＣａｒｄｉｏｖａｓｃｕｌａｒ...     

?1例家族性高胆固醇血症患者的apoB100基因型分析

目的对1例临床确诊为家族性高胆固醇血症(FH)、具有典型FH表型特征的患者进行载脂蛋白B100(apoB100)基因、低密度脂蛋白受体(LDLR)基因分析,探讨患者发病机制,分析基因型与临床表型间的关系。方法常规血脂测定,提取患者及其父母基因组DNA,扩增apoB100基因第26号外显子蛋白编码3500区域及LDLR基因全部18个外显子,对扩增目的片段进行核苷酸测序,结果与GenBank比对分析。结果患者血清TC 16.8 mmol/L,LDL-C 13.1 mmol/L,apoB100基因第26外显子10707位核苷酸C改变为T,导致apoB100基因3500位上精氨酸被色氨酸置换,为R3500W杂合突变;LDLR基因中第13外显子1879位核苷酸G改变为A,导致丙氨酸被苏氨酸置换,为A606T杂合突变。患者父亲存在与患者一致的apoB100基因R3500W杂合突变,母亲存在与患者一致的LDLR基因A606T杂合突变。结论患者的2个突变基因分别遗传自父母,基因突变导致患者同时发生apoB100缺陷症(FDB)及FH,是FDB/FH双基因复合杂合子,患者有严重的FH表型,临床确诊为纯合FH。     

家族性高胆固醇血症的临床和超声表现

家族性高胆固醇血症（familial hypercholesterolemia,FH）为常染色体显性遗传性疾病,是导致动脉粥样硬化和早发冠心病的重要危险因素,为脂质代谢疾病中最严重的一种。其发病机制是由于低密度脂蛋白受体（low-density lipoproteinreceptor,LDL-R）基因突变引起功能性LDL-R的减少,影响LDL-R与含有载脂蛋白B和载脂蛋白E的低密度脂蛋白（LDL）结合,从而使LDL从血中转移受阻,导致血清胆固醇浓度升高,尤其以血清LDL升高为主要特征,以致于大量LDL聚集于清除细胞中,并在组织内过度淤积,形成黄色瘤和动脉粥样硬化。     

变性高效液相色谱技术在家族性高胆固醇血症低密度脂蛋白受体基因突变检测中的应用

目的 以变性高效液相色谱(DHPLC)，分析检测家族性高胆固醇血症(FH)一汉族家系成员的低密度脂蛋白受体(LDLR)基因突变，以明确诊断。方法 收集临床诊断为家族性高胆固醇血症的汉族一个家系共37名成员，其中30人为一级和二级亲属，7名为亲属配偶作为对照，提取基因组DNA，聚合酶链反应(PCR)方法扩增LDLR基因包含启动子和全部基因编码区(1-18外显子)及临近的内含子序列共21个片段，琼脂糖凝胶电泳鉴定产物。采用DHPLC技术检测了LDLR基因，对洗脱曲线异常者进行核苷酸序列分析。结果 该家系中发现4处变异，其中1处经核苷酸序列测定明确了突变的性质为第3内含子的剪接突变，并在此家系5名成员中得到证实，而对照组中未检出。结论 成功地建立了以DHPLC筛查LDLR基因点突变的方法及技术参数，该方法简便，结果稳定，可作为大样本筛查突变位点的一种便捷可靠手段。     

降落聚合酶链反应技术在低密度脂蛋白受体基因点突变研究中的应用

目的 建立降落(TOUCHDOWN)聚合酶链反应(PCR)方法，快速检测家族性高胆固醇血症患者低密度脂蛋白受体(LDL-R)基因点突变。方法 设计LDL-R基因2l对引物，根据TOUCHDOWN原理设计包括启动子和18个外显子特异性片段在内的PCR程序，通过试验选择PCR最佳反应条件，在同一程序中分别对21个片段进行扩增，琼脂糖凝胶电泳检测扩增产物，纯化后DNA产物测序分析该方法的特异性。结果 编设退火温度范围从68℃降至54℃的PCR程序，优化PCR扩增条件，电泳检测采用同一程序同时分别扩增的LDL-R基因21个片段条带清晰，测序证实了此组片段的特异性。结论 成功建立降落PCR方法，提示此法为LDL-R基因突变筛查提供了快速可靠的手段。     

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.     

Genetic diagnosis of familial hypercholesterolemia using a DNA-array based platform

Objectives

The aim of this study was to validate the Lipochip^® genetic diagnostic platform by assessing effectiveness, sensitivity, specificity and costs for the identification of patients with familial hypercholesterolemia (FH) in Spain. This platform includes the use of a DNA micro array, the detection of large gene rearrangements and the complete resequencing of the low-density lipoprotein receptor gene.

Design and methods

DNA samples of patients with clinically diagnosed FH were analyzed for mutations by application of the Lipochip^® platform. Results obtained were confirmed by DNA sequencing and MLPA analysis by two other, independent laboratories.

Results

Of 808 patients tested, Lipochip^® detected a mutation in 66% of the cases and of these 78% were detected by the micro array. A specificity of 99.5% at a sensitivity of 99.8% was reached. A positive test result could be reported within 22 days after start of analysis. The total average screening costs of $ 350 per case were significantly lower compared to other existing screening programs.

Conclusion

Lipochip^® provides a reliable, fast and cheap alternative for the genetic testing of patients with clinically diagnosed FH.     

Is responsiveness to lovastatin in familial hypercholesterolaemia heterozygotes influenced by the specific mutation in the low-density lipoprotein receptor gene?

Abstract. Lovastatin is one of the most commonly used lipid-lowering drugs in familial hypercholesterolaemia (FH) heterozygotes. In order to study whether the response to lovastatin is influenced by the underlying mutation in the low-density lipoprotein (LDL) receptor gene, the authors compared the response in 24 heterozygotes in whom the mutation has been classified and in 34 heterozygotes in whom the mutation has not been classified. Those possessing a classified mutation had significantly higher pre-trial values of LDL-cholesterol than those possessing an unclassified mutation. However, no difference was found in the response to lovastatin. Nor were there any differences in the response between subjects possessing one of the three different classified mutations. Furthermore, irrespective of whether or not the mutation had been classified, no difference in the response was found between subjects in the upper and lower quartile with respect to pre-trial values of LDL-cholesterol. The authors conclude that the response to lovastatin is independent of both the specific mutation in the LDL receptor gene and the actual cholesterol level in FH heterozygotes.     

血液透析患者低密度脂蛋白受体Taq I位点基因多态性与血脂水平检测

目的 探讨血液透析患者脂代谢紊乱的临床特征及低密度脂蛋白受体(LDLR)基因多态性对脂代谢的影响。方法 生化方法检测血液透析血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDLC)、低密度脂蛋白胆固醇(LDLC)、载脂蛋白(Apo A1、ApoB、ApoE)及脂蛋白[Lp(a)]水平，多聚合酶链反应-限制性片断长度(PCR—RFLP)方法检测LDLR内含子4Taq I位点基因多态性。结果 血液透析患者脂代谢紊乱主要表现为血清，TG水平显著增高，HDLC水平显著降低。33％的患者血清TG水平高于正常水平，10．4％的患者HDLC低于正常水平。偏相关回归分析显示，TG水平与血清ALB水平、透析时体外循环血流量显著相关；HDLC与KT／V显著相关。血液透析患者高血压的发生率为73．6％，心血管疾病为25％。伴心血管疾病组TG水平显著高于无心血管疾病组，伴高血压组与无高血压组血脂水平无显著差异。LDLR基因多态性检测结果显示，血液透析组与对照组间LDLR内含子4Taq I位点基因型与等位基因分布频率无显著差异。LDLR基因多态性对血脂水平的影响表现为LDLR内含子4Taq I位点基因型-／-的血液透析患者甘油三酯水平较高。结论 血液透析患者脂代谢紊乱主要表现为血清TG、ApoB水平显著增高，HDLC等指标显著降低。伴心血管并发症的患者，TG水平显著高于无并发症的患者。，TG水平与血清ALB水平、透析时体外循环血流量显著相关；HDLC与KT／V显著相关。LDLR内含子4Taq I位点基因型-／-血液透析患者易发生血清甘油三酯水平增高。     

Clinical evaluation of three types of plasmapheresis in a patient with type IIa familial hypercholesterolemia

Long-term plasmapheresis (PP) therapy was studied in a 56-year-old patient with homozygous type IIa familial hypercholesterolemia also suffering from severe coronary heart disease. Three different PP techniques, plasma exchange (PE), double-membrane-filtration plasmapheresis (DFP), and the recently developed low-density lipoprotein adsorbent column (adsorption plasmapheresis, adsorption PP), were used in an attempt to develop better means of managing the disease. All three techniques showed similar elimination efficiency with respect to plasma total cholesterol level. Adsorption PP with minimal supplemental plasma protein managed the circulatory status of the patient better than DFP during extracorporeal treatment. In the course of PP therapy xanthoma tuberosum markedly regressed, and the cardiac status of the patient was clearly improved.