低密度脂蛋白受体的变异与家族性高胆固醇血症

低密度脂蛋白受体主要功能是摄取血中的胆固醇至细胞内，家族性高胆固醇血症与患者低密度脂蛋白受体的缺陷有关，低密度脂蛋白受体基因的不同突变可突变可造成受体的不同缺陷，故对家族性高胆固醇血症患者可进行基因诊断和基因治疗。     

家族性高胆固醇血症致病基因PCSK9的研究进展

家族性高胆固醇血症(FH)是一种常染色体单基因显性遗传性疾病,其主要的临床特征为血浆低密度脂蛋白胆固醇(LDL-C)水平明显升高、肌腱或皮肤黄色瘤、早发冠状动脉粥样硬化和冠状动脉粥样硬化性心脏病等。人类枯草溶菌素转化酶9(PCSK9)基因是FH的致病基因之一。PCSK9通过调节低密度脂蛋白受体在肝脏降解,从而间接调节LDL-C水平。PCSK9基因突变可分为失功能性突变和功能获得性突变,是目前降脂药物的研究热点。     

LDLR基因突变致家族性高胆固醇血症家系分析

目的 对一家族性高胆固醇血症家庭成员进行医学外显子测定,揭示分子病因。方法 先证者4岁,女孩,因皮肤肌腱多处大小不等黄色瘤、高血浆总胆固醇(TC) 和高低密度脂蛋白胆固醇(LDL-C)就诊,随后检测发现先证者父母、弟弟均有不同程度的高TC和LDL-C。利用高通量测序技术对先证者及其父母进行了医学外显子测序,并进行基因序列比对分析,检测其中可能存在的基因变异,最后对先证者姐姐和弟弟进行了相关位点验证。结果 先证者低密度脂蛋白受体(LDL-R)基因有 2个杂合突变:(1)c.727T>A(编码区第 727 号核苷酸由胸腺嘧啶变异为腺嘌呤),导致氨基酸改变 p.C243S(第 243 号氨基酸由半胱氨酸变异为丝氨酸),经家系验证分析,该突变源自父亲,母亲该位点无变异。对先证者姐姐和弟弟进行验证,结果显示先证者弟弟该位点同先证者父亲为杂合变异,先证者姐姐该位点无变异。(2)c.1003G>T(编码区第 1003 号核苷酸由鸟嘌呤变异为胸腺嘧啶),导致氨基酸改变 p.G335C(第 335号氨基酸由甘氨酸变异为半胱氨酸),经家系验证分析,该突变源自母亲,父亲该位点无变异。对先证者姐姐和弟弟进行验证,结果显示先证者姐弟俩该位点均无变异。上述两个突变经蛋白功能预测软件预测为有害,可以改变蛋白质的结构,从而对LDL-R蛋白功能造成影响。结论 LDL-R基因c.727T>A 和c.1003G>T突变可以导致家族性高胆固醇血症。     

一个家族性高胆固醇血症家系基因突变分析

目的:对临床确诊的一个家族性高胆固醇血症(FH)纯合子家系进行基因突变分析,分析基因型与临床表型之间的关系,探讨其发病机制。方法:在这个包括48名成员的家系中,16例患者有高胆固醇血症。提取患者及家系成员外周血基因组DNA,对患者聚合酶链反应扩增ApoB100基因Q3500R位点并进行测序,确定有无常见突变,同时对包括患者在内的48名成员针对与PCSK9基因相连锁的微卫星位点D1S417,D1S2797,D1S2890以及与LDL-R基因相连锁的微卫星位点D19S221,D19S394进行连锁分析。结果 :核苷酸序列分析未发现ApoB100基因Q3500R突变,数个常见的与LDL-R基因或PCSK9基因相连锁的微卫星多态位点与此FH无连锁。结论:对该FH家系,未发现常见的ApoB100突变,微卫星多态性分析未发现与LDL-R基因,PCSK9基因连锁的多态性存在。是否存在新的突变基因,尚需下一步通过全基因组扫描验证。     

家族性高胆固醇血症

家族性高胆固醇血症是一种常染色体显性遗传疾病。该病的发病机制是细胞膜表面低密度脂蛋白受体基因突变，导致LDLR缺如，低密度脂蛋白代谢障碍。过量的LDL-C沉积于细胞中，形成黄色瘤和粥样斑块。本病的特征性临床表现为血LDL-C水平增高、黄色瘤、角膜弓和冠心病，主要是血胆固醇升高及其导致的一系列病理生理变化，特别是心血管方面的症状。对FH有效的预防重点是查出携带者，早期治疗，对家系成员进行婚育指导，并对高危胎儿进行产前检测。     

家族性高胆固醇血症的治疗研究现状及进展

家族性高胆固醇血症(FH)是一种常见的遗传代谢性疾病,其最主要的特征为低密度脂蛋白胆固醇(LDL-C)水平从出生之后就较正常水平明显升高,从而提高了动脉粥样硬化性心血管疾病早发的风险。这极大影响了患者的生活质量及寿命。目前,在传统的降脂疗法(LLT)基础上,随着前蛋白转化酶枯草溶菌素9(PCSK9)单克隆抗体在临床上的应用,FH患者血浆LDL-C水平得到进一步控制。尽管近年对该疾病的治疗取得了一定进展,但仍有大量患者无法达到治疗目标。本文从FH的特征、国内外指南及患者治疗现状入手,围绕PCSK9、血管生成素样蛋白3(Angptl3)等其他潜在的治疗靶点,对FH患者目前应用及尚在进行研发的降脂疗法和最新进展进行综述。     

家族性高胆固醇血症纯合子患者低密度脂蛋白受体缺陷的研究

目的：研究家族性高胆固醇血症纯合子患者的发病机理。方法：在临床研究和家系调查的基础上，培养患者皮肤成纤维细胞，采用放射性配体结构受体分析技术研究其低密度脂蛋白受体。结果：患者低密度脂蛋白受体对低密度脂蛋白的高亲和性结合为正常人的78．2％，高亲和性内移和降解则分别为正常人的3．6％和1．7％。结论：本例家族性高胆固醇血症纯合子患者的发病机制为低密度脂蛋白受体内移功能障碍。     

A novel mutation in proprotein convertase subtilisin/kexin type 9 gene leads to familial hypercholesterolemia in a Chinese family

Background Familial hypercholesterolemia （FH） is an autosomal disorder associated with elevated plasma low density lipoprotein （LDL） levels leading to premature coronary heart disease （CHD）. As a result of long-term hyperlipemia, FH patients will present endarterium thickening and atherosclerosis. In the present study we scanned the related gene of a clinically diagnosed autosomal genetic hypercholesterolemia family for the possible mutations and established eukaryotic expression vector of mutation of proprotein convertase subtilisin/kexin type 9 （PCSK9） gene with gene recombination technique to investigate the contributions of the variation on low density lipoprotein receptor （LDL-R） metabolism and function alternation.Methods Mutation detection was conducted for LDL-R, apolipoprotein B100 （apoB100） and PCSK9 gene with nucleotide sequencing in a Chinese FH family. The full-length cDNA of wild type PCSK9 gene （WT-PCSK9） was obtained from Bel-7402. Site mutagenesis was used to establish the recombinant eukaryotic expression vector carrying pathogenic type of PCSK9 gene and the inserted fragment was sequenced. With the blank vector as control, liposome transfection method was used to transfect the Bel-7402 cells with recombinant plasmid. The expression of LDL-R mRNA was examined by RT-PCR. PCSK9 and the expression of LDL-R protein were determined by Western blotting. Results The G→T mutation at the 918 nucleotide of PCSK9 gene resulted in the substitution of the arginine by a serine at the codon 306 of exon 6. After sequencing, it was confirmed that the inserted fragment of established expression vector had correct size and sequence and the mutant was highly expressed in Bel-7402 cells. There was no significant variation in the levels of LDL-R mRNA. LDL-R mature protein was decreased by 57% after the cells were transfected by WT-PCSK9 plasmid. Mature LDL-R was significantly decreased by 12% after the cells were transfected by R306S mutant as evidenced by gray scale scanning, suggesting that the new mutant R306S can significantly decrease the expression of mature LDL-R protein.Conclusions A novel missense mutation of PCSK9 gene, R306S, was found and the eukaryotic expression vectors of mutant and wild-type of PCSK9 gene were established. There was no significant variation in the levels of LDL-R mRNA. The R306S mutation could significantly lead to the decrease of LDL-R mature protein expression, which might be the pathogenic gene of the FH family.     

Functional analysis of low-density lipoprotein receptor in homozygous familial hypercholesterolemia patients with novel 1439 C→T mutation of low-density lipoprotein receptor gene

Background Familial hypercholesterolemia （FH）, caused by low density lipoprotein （LDL） receptor （LDL-R） gene mutations, is associated with increased risk of premature coronary heart disease. Until now, limited molecular data concerning FH are available in China. The present study described the clinical profiles and cell biological defects of a Chinese FH kindred with novel LDL-R gene mutation. Methods The patient＇s LDL-R gene coding region was sequenced. The patient＇s lymphocytes were isolated and the LDL-R expression, binding and up-take functions were observed by immunohistochemistry staining and flow cytometry detection. The patient＇s heart and the major large vessels were detected by vessel ultrasound examination and myocardial perfusion imaging （MPI）. Results The patient＇s LDL-R expression, LDL binding and up-take functions were significantly lower than normal control （39%, 63% and 76% respectively）. A novel homozygous 1439 C→T mutation of the LDL-R gene was detected in the patient and his family. ECG showed atypical angina pectoris. Echocardiogram showed stenosis of the coronary artery and calcification of the aortic valve and its root. Blood vessel ultrasound examination showed the thickness of large vessel intima, and the vessel lumen was narrowed by 71%. MPI showed ischemic changes. Conclusions The LDL-R synthesis dysfunction of FH patients leads to arterial stenosis and calcification, which are the major phenotype of the clinical disorder. The mutation of the LDL-R gene is determined. These data increase the mutational spectrum of FH in China.     

家族性高胆固醇血症(FH)致病基因的研究进展

 家族性高胆固醇血症(familial hypercholesterolemia,FH)的临床特征为血总胆固醇升高,尤其是低密度脂蛋白胆固醇(low density lipoprotein cholesterol,LDL-c)升高,沉积于组织,形成皮肤或肌腱黄色瘤,导致动脉粥样硬化甚至早发冠心病。FH的发病机制为LDL受体(LDL receptor,LDLR)或apoB基因突变引起LDL受体途径功能缺陷,主要为常染色体显性遗传疾患,具有基因剂量效应;部分患者为常染色体隐性遗传,机制为LDL受体衔接蛋白1(LDL receptor adaptor protein 1,LDLRAP1)失功能型突变,导致LDL内化活性降低。罕见的人类枯草溶菌素转化酶9 (proprotein convertase subtilisin/kexin type 9,PCSK9)发生功能型突变也可引起严重的FH表型。PCSK9通过降解LDLR蛋白间接下调LDL受体途径,其失功能突变可致血浆LDL水平下降。因此PCSK9是目前降脂药物的研究热点。     

Analysis of low-density lipoprotein receptor gene mutations in a Chinese patient with clinically homozygous familial hypercholesterolemia

Objective To screen the point mutation of the low-density lipoprotein receptor （LDL-R） gene in Chinese familial hypercholesterolemia (FH) patients, characterize the relationship between the genotype and the phenotype and discuss the molecular pathological mechanism of FH. Methods A patient with clinical phenotype of homozygous FH and her parents were investigated for mutations in the promoter and all eighteen exons of the LDL-R gene. Screening was carried out using Touch-down PCR and direct DNA sequencing; multiple alignment analysis by DNASIS 2.5 was used to find base alteration, and the LDL-R gene mutation database was searched to identify the alteration. In addition, the apolipoprotein B gene (apo B) was screened for known mutations (R3500Q) that cause familial defective apo B100 (FDB) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).Results Two new heterozygous mutations in exons 4 and 9 of the LDL-R gene were identified in the proband (C122Y and T383I) as well as her parents. Both of the mutations have not been published in the LDL-R gene mutation database. No mutation of apo B100 (R3500Q) was observed. Conclusion Two new mutations (C112Y and T383I) were found in the LDL-R gene, which may result in FH and may be particularly pathogenetic genotypes in Chinese people.     

2代3人同患家族性高胆固醇血症及其低密度脂蛋白受体基因突变分析

目的　调查姐妹二人同患家族性高胆固醇血症的家系并进行系谱分析。方法　根据患者及其家系的血缘关系绘制家系图谱,分析临床症状和血脂检查资料。结果　先证者女性,17岁,血清胆固醇浓度为18.89 mmol/L,3岁时即有臀部黄色瘤, 17岁时首次发生前壁心肌梗死,其姐血清胆固醇浓度为15.23 mmol/L,全身多处黄脂瘤。初步诊断先证者为纯合子型,其姐为杂合型。检查患儿4代29人,根据血脂和临床表现确诊2例杂子型家族性高胆固醇血症患者,系谱分析该家系遗传方式符合常染色体显性遗传规律。结论　初步证实一个纯合子型家族性高胆固醇血症系谱。     

酸性多糖治疗高胆固醇血症的实验研究

目的　评估酸性多糖降低血总胆固醇 (TC)和低密度脂蛋白胆固醇 (LDL -c)的效果。方法　 (1)体外实验 :10ml血清加 0 .3ml 1‰酸性多糖溶液 ,混匀 ,观察吸附效果。 (2 )体内实验 :32只家兔随机分成两组 ,服药组基础饲料中加 1‰酸性多糖 ;对照组仅服用基础饲料。分别于 1周、3周抽血 ,以酶法和聚乙烯硫酸沉淀法查TC、LDL -c。结果　体外实验 :血清经酸性多糖吸附后上清液中TC下降 80 %以上。体内实验 :1周后服药组兔子血TC、LDL-c(分别为 0 .47± 0 .0 7mmol·L-1和 0 .2 5± 0 .0 3mmol·L-1)明显低于对照组 (0 .5 6± 0 .0 6mmol·L-1和 0 .32± 0 .0 2mmol·L-1) ,差异极显著 (P均 <0 .0 0 1)。服药组家兔TC值降低11% ,LDL -c降低 15 % ;3周后服药组家兔血TC、LDL -c(分别为 0 .41± 0 .0 6mmol·L-1和0 .18± 0 .0 1mmol·L-1)明显低于对照组 (TC、LDL -c分别为 0 .5 7± 0 .0 7mmol·L-1和 0 .34±0 .0 3mmol·L-1) ,差异极显著 (P值均 <0 .0 0 1) ,TC降低 2 1% ,LCL -c降低 39%。结论　酸性多糖有明显降低TC、LDL -c的作用     

Fluvastatin prevents renal injury and expression of lactin-like exidized low-density lipoprotein receptor-1 in rabbits with hypercholesterolemia

Background Lipid abnormalities are often complicated by renal dysfunction. 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are the first-line choice for lowering cholesterol levels. The present study was designed to investigate whether statins could prevent and invert the development of renal injury in cholesterol-fed rabbits and to find the possible mechanism of their effects by detecting gene and protein expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in the renal artery.Methods Twenty-four male New Zealand white rabbits were divided into three groups: (1) control group, regular granules chow; (2) HC-diet group, granules chow with 1% cholesterol and 5% lard oil; and (3) fluvastatin group, 1% cholesterol and 5% lard oil diet plus fluvastatin ［10 mg·kg（-1）·d（-1）］ . After 16 weeks, serum total cholesterol (TC), low-density lipoprotein(LDL) and creatinine (Cr) levels were measured. Renal hemodynamics and function, mainly including glomerular filtration rate (GFR) in vivo were quantified using 99mTc-DTPA single photon emission computed tomograph (99mTc-DTPA SPECT). The thickness of the renal artery intima was quantitated in HE-stained segments by histomorphometry. Gene expression of LOX-1 in the renal artery was examined by semi-quantitative RT-PCR and its protein expression was evaluated by immunohistochemistry.Results High cholesterol diet induced hypercholesterolemia (HC) complicated by renal dysfunction with increased levels of serum lipid and Cr, decreased GFR and delayed excretion and extensively thickened renal arterial intima in the HC-diet group. Rabbits in the control group showed a minimal LOX-1 expression (mRNA and protein) in the endothelium and neointima of the renal artery. Intimal proliferation of the renal artery in the HC-diet group was associated with a marked increase of LOX-1 expression (protein and mRNA). Treatment with fluvastatin improved renal function, attenuated intimal proliferation of the renal artery and markedly decreased the enhanced LOX-1 expression in the endothelium and neointima of the renal artery in rabbits. Conclusions Fuvastatin treatment could prevent the development of renal injury in patients with HC and early atherosclerosis (AS). This beneficial effect might be mediated by its pleiotropic effects including a decrease in total cholesterol exposure level and prevention of LOX-1 expression in atherosclerotic arteries.     

钙拮抗剂MN9202对高脂血症大鼠的影响

研究ＭＮ９２０２（６－二甲基－４（３－硝基苯基）－１,４－二氢－３,５－吡啶二羧酸－３－甲酯－５－正酯）对高脂血症和动脉粥样硬化的治疗效果及其机制。方法４０只ＳＤ大鼠随机分为正常组,高脂组,ＭＮ９２０１１,３和５ｍｇ．ｋｇ＾－１组。每日记录饮食,体质量;每月测量血压．３ｍｏ后测血浆胆固醇（ＣＴ）,甘油三脂（ＴＧ）,低密度脂蛋白（ＬＤＬ－ｃ,高密度脂蛋白（ＨＤＬ－ｃ）,血清丙二醛（ＭＤＡ）和超氧化物     

家族性高胆固醇血症的药物治疗现状和进展

家族性高胆固醇血症(FH)是基因突变所致血脂紊乱,常见的致病基因有低密度脂蛋白(LDL)受体基因、载脂蛋白B(ApoB)基因、前蛋白转换酶枯草溶菌素9型(PCSK9)基因等.FH是早发冠心病的重要原因.诊断主要根据血清LDL-C升高、早发冠心病、黄色瘤、基因检查结果等.目前,治疗FH的药物主要是他汀类,可联合胆固醇吸收抑制剂或胆汁酸螯合剂.近年,多种新型降胆固醇药物已被批准用于FH的治疗,包括PCSK9抑制剂、微粒体甘油三酯转运蛋白(MTTP)抑制剂和ApoB合成抑制剂等.     

脂康调节高脂血症家兔肝脏LDL-R mRNA水平的实验研究

目的通过建立新西兰家兔高脂血症模型，探讨肝脏低密度脂蛋白受体基因水平与高脂血症形成的关系。方法（1）建立高脂血症家兔模型；（2）应用原位杂交方法检测肝脏低密度脂蛋自受体基因水平。结果（1）成功建立高脂血症家兔模型；（2）脂康方剂可有效降低血脂水平，并能有效上调肝脏低密度脂蛋白受体基因水平。结论脂康方剂可激活肝脏细胞膜LDL—R基因表达，使LDL—R的活性增强，从而加速脂蛋白的分解，有效调节血脂水平。