A novel mutation in proprotein convertase subtilisin/kexin type 9 gene leads to familial hypercholesterolemia in a Chinese family / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>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 artherosclerosis. 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.</p><p><b>METHODS</b>Mutation detection was conducted for LDL-R, apolipoprotein B(100) (apoB(100)) 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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Functional analysis of low-density lipoprotein receptor in homozygous familial hypercholesterolemia patients with novel 1439 C-->T mutation of low-density lipoprotein receptor gene / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>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.</p><p><b>METHODS</b>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).</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Gene Mutation Analysis of A Child with Familial Hypercholesterolemia and His Family / 实用儿科临床杂志

Objective To screen the mutation of certain gene of a 10-years-old boy with multiple xanthomas and very high level of cholesterol who could be diagnosed as homozygous familial hypercholesterolemia (FH),to explore the relationship between the genotype and phenotype,and to discuss the molecular pathologic mechanism.Methods The basic information of life styles were asked from the boy and his familial members.The blood was drown to examine the lipid and genes.The boy was examined with electrocardiogram examination,ultrasonography and coronary CT angiography (CTA) to evaluate the degree of atherosclerosis.Peripheral blood DNA of the boy and his parents were extracted by phenol-chloroform method and investigated for mutations of promoter and all 18 exons of low density lipoprotein receptor(LDLR) gene.Screening was carried out by using Touch-down polymerase chain reaction (PCR) and single strand conformation polymorphism(PCR-SSCP),combined with DNA sequence analysis.In addition,the apolipoprotein B100 gene(apoB100) for known mutations (R3500Q) which caused familial defective apoB100 was screened by PCR-DNA sequence analysis.Results 1.The level of cholesterol of his parents were higher than the normal.2.Several clinical manifestations of atherosclerosis were detected from that boy.Increased intima-media thickness and plaques were detected in the common carotid artery.Mitral valve regurgitation was found by echocardiography.Coronary stenosis was confirmed by CTA.3.No mutations R3500Q of apoB100 was observed.4.A homozygous mutation in exon13 of the LDLR gene (D601Y) were identified in the boy and his parents harbour D601Y heterozygous mutation due to a single base pair substitution of G for T in the codon for residue 1864.Conclusions The final diagnosis of the boy with multiple xanthomas was homozygous FH.His disease was caused by D601Y homozygous mutation in exon13 of the LDLR gene inherited from his heterozygous parents.

Compound Heterozygosis Mutation of Low Density Lipoprotein Receptor Gene in Familial Hypercholestero-lemia Family / 实用儿科临床杂志

Objective To identify mutations site and clinical characteristics of a familial hypercholesterolemia(FH) proband diagnosed clinically through DNA sequencing and family analysis in the proband and his family members of 3 generations.Methods Blood samples and clinical data of the kindred of total 29 from 3 generations members were collected.Proband had a physical examination electrocar-diogrom and vascular ultrasound.The proband and his family members took routine clinical exams,and genomic DNA was isolated.The promoter region and the 18 exons of low density liporotein receptor(LDLR) gene were screened by Touch down polymerase chain reaction -single strand conformation polymorphism(PCR-SSCP) and DNA sequencing.The result of sequencing were matched gene sequence published in the BLAST database.Results 1.Increased intima-media thickness and plaque were detected in the common carotid artery,right subclavian artery of the proband.Aortic valve regurgitation was found by echocardiography.2.No mutation R3500Q of ApoB100 was observed.3.Two heterozygous mutations in exon 10 and 13 of LDLR gene (W462X and A606T) were identified.The proband and 5 members of paternal relatives showed W462X heterozygosis mutation in exon 10 of LDLR gene which introduced the change from tryptophone to a new stop codon.The proband's mother and grandmother harboured A606T heterozygous mutation in exon 13 of LDLR gene due to a single base pair substitution of G for A in the codon for residue 1 879.Conclusions Disease causing mutations of proband are W462X and A606T compound heterozygosis mutation in exon 10 and 13 of LDLR gene inherited from mother and father.Proband shows homozyous phenotype though the genotype analysis indicates heterozygous mutations.

The effects of polygoni multiflori total glycosides on the experimentally atherosclerotic formation in apoE-deficient mice / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effect of polygoni multiflori total glycosides (PMTG) on the expressions of ICAM-1 and VCAM-1 in the apoE-deficienct (ApoE-/-)mice with experimental atherosclerosis (AS) and underlying mechanism.</p><p><b>METHOD</b>Thirty-two female apoE-deficienct mice were randomized into four groups: high dose PMTG group (150 mg x kg(-1) x d(-1)), low dose PMTG group (25 mg x kg(-1) x d(-1)), atorvastatin positive control group (5 mg x kg(-1) x d(-1)) and model group. At the end of the tenth week of treatment, all mice were killed. The serum levels of total cholesterol (TC), triglyceride(TG), high-density lipoprotein-cholesterol (HDL-C) were measured by enzyme dynamics method. Light microscopy were adopted to assess the degree of atherosclerotic plaque of aortic wall and image analysis was performed with computer. The expressions of ICAM-1 and VCAM-1 were studied by SABC imunohistochemistry.</p><p><b>RESULT</b>In comparison with the model group, (1) PMTG reduced the levels of serum TC and TG significantly (P < 0.01), but elevated HDL level obviously (P < 0.01) . (2) PMTG increased the levels of serum NO and the anti-oxidation capacities significantly (P < 0.05 and P < 0.01), but reduced the levels of serum MDA markedly (P < 0.01). (3) PMTG reduced also the extent of atherosclerotic plaque of aorta areas were (P < 0.05). (4) PMTG deregulated the expressions of ICAM-1 and VCAM-1 in aortic wall.</p><p><b>CONCLUSION</b>PMTG could inhibit the occurrence and development of atherosclerotic lesions by the regulating lipid metabolism and anti-oxidation and deregulating the of expressiona of ICAM-1 and VCAM-1 in AopE-/- mice in aortic wall.</p>

Identification of a novel splice mutation of low density lipoprotein receptor gene in a Chinese family with familial hypercholesterolemia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify the mutation of low density lipoprotein receptor(LDLR) gene in a large Chinese family with familial hypercholesterolemia(F H) and make a discussion on the pathogenesis of FH at the molecular level.</p><p><b>METHODS</b>Investigations were made on a patient with the clinical phenotype of homozygous FH and his parents for mutations of promoter and all 18 exons of LDLR gene. Screening was carried out using Touch down PCR and a g arose gel electrophoresis, combined with DNA sequence analysis. The results were compared with the normal sequences in GenBank and FH database (www.ucl.uk/fh) t o find the mutation. Then the mutation was identified in other members of the family. In addition, the authors screened the apolipoprotein B(100) (apoB(100)) gene f or known mutations (R3500Q) that cause familial defective apoB(100) (FDB) by PCR-RFLP.</p><p><b>RESULTS</b>A novel homozygous IN III 5' GT --> AT mutation in the splice donor of LDLR intron 3 was detected in the homozygote propositus with FH. The mutation was also identified in four heterozygous carriers in his family. No mutations R3500Q of apoB(100)were observed.</p><p><b>CONCLUSION</b>A homozygous G --> A splice mutation in LDLR gene was first reported. The change of the splice donor in LDLR intron 3 may cause skipping of exon 3, which is responsible for FH. Perhaps it is a particular pathogenesis for Chinese people.</p>

Detection of W462X Mutation in Low Density Lipoprotein Receptor Gene of A Familial Hypercholesterolemia Patient and Its Clinical Significance / 实用儿科临床杂志

Objective To explore the molecular basis of familial hypercholesteraemia(FH)by analyzing the phenotype and genotype relationship through identify the low density liporotein receptor(LDL-r)gene mutation in a FH kindred.Methods A male patient of 15 years old was selected to examine the electrocardiogram,lipid.Color Doppler was used to examine heart and great vessels.The promoter region and the 18 exons of the LDL-r gene were screened by touch-down polymerase chain reaction(PCR)and DNA sequencing.Results The caro-tid intima-media thickness(IMT)was increased to 0.23 cm,while coronary flow velocity reserve(CFVR)was decreased to 1.57,and mode-rate mitral regurgitation was found in the proband.The genetic alteration G→A change at 1 448 of exon 10 causing premature stop codon(W462X).The same heterozygous nonsense mutation was also found in his father.The mutation had been reported in other Chinese patients.In vitro experiments showed that W462X mutation leads to low LDL binding and internalization ability.Conclusions The homozygous mutation(W462X)in exon 10 of the LDL-r gene were identified in the clinically heterozygous FH proband.The W462X mutation is the underl-ying cause of hypercholesterolaemia and clinical AS manifestations.W462X is recurrent mutation among Chinese FH patients.It might be a hot spot mutation in LDL-r in Chinese FH.J Appl Clin Pediatr,2009,24(1):18-20