* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download CHD
X-inactivation wikipedia , lookup
Genomic imprinting wikipedia , lookup
Copy-number variation wikipedia , lookup
Fetal origins hypothesis wikipedia , lookup
Genetic drift wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Human genetic variation wikipedia , lookup
Population genetics wikipedia , lookup
Genome evolution wikipedia , lookup
Hardy–Weinberg principle wikipedia , lookup
History of genetic engineering wikipedia , lookup
Genetic engineering wikipedia , lookup
Saethre–Chotzen syndrome wikipedia , lookup
Epigenetics of diabetes Type 2 wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Point mutation wikipedia , lookup
Dominance (genetics) wikipedia , lookup
Gene desert wikipedia , lookup
Pharmacogenomics wikipedia , lookup
Gene expression profiling wikipedia , lookup
Epigenetics of neurodegenerative diseases wikipedia , lookup
Gene expression programming wikipedia , lookup
Gene therapy wikipedia , lookup
Helitron (biology) wikipedia , lookup
Neuronal ceroid lipofuscinosis wikipedia , lookup
Gene nomenclature wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Public health genomics wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Genome (book) wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Polymorphism (biology) wikipedia , lookup
Gene Polymorphisms and Coronary Heart Disease Fang Zheng Clinic Lab, Zhongnan Hospital, Wuhan University Coronary Heart Disease is still the No. 1 killer in the world. The prevention of CHD is based on the control of several factors associated with a disease or clinical condition and suspected to play a pathogenetical role, defined as risk factors.The risk factors of CHD included: Genetics Environmental Life style Emerged CHD Risk Factors Age Clotting factors Sex Fibrinolytic factors Hypertension Hyperhomocysteinaemia Smoking Inflammation factors Diabetes Endothelium factor Hyperlipidaemia Nutrition factor Obesity Post-menopausal status Genetic factors But only in 5% of hereditary CHD, the gene background was clear. In the others, each genetic factor played a minor role in occurrence and development of the disease. Rare mutations (e.g., in the LDLR and APOE genes) may have a major effect, whereas genes belonging to normal polymorphism have only a moderate effect. But even genes with only a slight effect can be clinically important in combination with other genes. The importance of polymorphism analyses will increase significantly in the near future. What’s normal polymorphism? The occurrence in a population (or among populations) of several phenotypic forms associated with alleles of one gene or homologs of one chromosome. The occurrence together in the same population of more than one allele or genetic marker at the same locus with the least frequent allele or marker occurring more frequently than can be accounted for by mutation alone. Polymorphism and Mutation They are both single nucleotide polymorphism,SNP. polymorphism--normal phenotype mutation --disease polymorphism--more mutation --less Cardiovascular disease is complex as a consequence of pleiotropy. These included environmental and genetics factors. Gene polymorphism played an important role in the occurrence and development of cardiovascular disease. And it can be applied on the prediction, diagnosis, treatment and prognosis. 1. The gene polymorphisms as independent risk predictors An HphI polymorphism in the E-selectin gene is associated with premature coronary artery disease. ApoE gene polymorphism is related to coronary heart disease. E23K polymorphism in KCNJ11 gene has relationships with coronary heart disease. Every gene variants that contribute to CHD like tiny weights in balance. 1.1 The G98/T polymorphism in E-selectin gene and CHD E-selectin belongs to a family of structurally related "selectin' molecules including E-, P- and L-selectin and participates in the endothelial-leukocyte adhesion . Experiments using E-and P-selectin-double-knockout mice suggest that E- and P-selectin together play an important role in both early and advanced stages of the atherosclerotic lesion development. Several polymorphisms in the E-selectin gene have been identified as new risk factors for the early atherosclerosis. The transversion of G98T mutation abolishes the HphI recognition site. HphI NT 92 TTGGGTGAAAAG103 NT 92 TTGGGTTAAAAG103 HphI bp Kb 1.35 0.63 332 194 138 0.31 0.19 0.12 The PCR product was digested by HphI and separated on 2 % agarose gel electrophoresis. GG genotype: 98 TT genotype: 98 PCR amplification of the genomic DNA, subcloning and DNA sequencing were carried out. Table Frequency of the E-selectin G98T mutation in the angiographically documented premature CAD and controls (The original population: all males aged 50 yr.old, all females aged 60 yr. old; the subset: All males aged 45 yr.old, all females aged 55 yr. old) N The populationa Control 71 CAD 93 Pb The subsetc: Control 50 CAD 51 Pb G-allele (%) T-allele (%) Total alleles 128 (90.14) 160 (86.02) 14 (10.93) 26 (13.98) NS 142 186 90 (90.00) 80 (78.43) 10 (10.00) 22d (21.57) < 0.05 a: In control, 32 males, 39 females; in CAD, 51 males, 42 females. b: Chi-square statistical analysis was done using Sigma Stat (ver.2.0, SPSS Inc., Chicago, IL). c: In control, 21 males, 29 females; in CAD, 28 males, 23 females. d: Include 18 heterozygotes (GT) and two homozygotes (TT). 100 102 Multivariate Logistic Regression Analysis variable Odds Ratio (95%, CI) G98T 3.58 (1.20-10.67) =0.022 S128R 4.11 (1.24-13.56) =0.020 TC 0.99 (0.97-1.07) NS TG 1.00 (0.99-1.01) NS LDLB 1.02 (0.99-1.05) =0.071 Smoke, Y/N 5.87 (1.84-18.75) P =0.003 1.2 The E23K polymorphism in KCNJ11 gene and CHD The ATP-sensitive potassium channel (KATP) were complexes of two subunits, a regulatory sulfonylurea receptor (SUR) and an ATPsensitive and pore-forming inwardly rectifying K+ channel (Kir 6.X). The Kir 6.X subunits including Kir 6.1 and Kir 6.2 had two transmembrane domains and form the pore, conferring channel sensitivity to ATP and other cell metabolites such as ADP. The G to A mutation in the Kir 6.2, the ATP-sensitive potassium channel subunit, resulted a Glutamate (E) to Lysine (K) substitution at codon 23, and the A allele was shown to have a relationship with high risk to type 2 Diabetes in previous study. Table. Genotype and Allele Frequencies of the E23K Polymorphism of Kir6.2 Gene in CHD Patients and Controls Genotype(%) Group GG GA+AA Allele(%) G A CHD(n=119) 50(42.0) 69(58.0) 151(63.4) 87(36.6) Controls(n=101) 29(28.7) 72(71.3) 115(56.9) 87(43.1) χ2 4.202 1.940 P value 0.040 0.164 OR(95%CI) 1.799 (1.023~3.163)* 1.313 (0.895~1.927) ** *: The frequency of GG genotype was compared with that of GA+AA genotype; **: The frequency of G allele was compared with A allele. 1.3 The Apolipoprotein (Apo)E gene polymorphism and CHD Apolipoprotein E gene is located on chromosome 19q13.2. ApoE plays a critical role in the formation of very low density lipporotein(VLDL) and chylomicrons. Genetically, ApoE is polymorphic isoforms of proteins, E2, E3, E4 respectively. The ApoE alleles modulate the risk for CHD, cerebral aheroscerosis and Alzheimer’s disease. NH2 --------112---------158-----------COOH 2 5’---TGC--------TGC----------3’ Cys 3 HhaI 5’----TGC--------CGC---------3’ Cys 4 Cys Arg HhaI HhaI 5’-----CGC-------CGC---------3’ Arg Arg There were three alleles and six genotypes. ApoE PAGE/RFLP pattern M ε4/4 ε2/2 ε3/3 ε4/3 ε3/2 ε4/2 1.4 The Apolipoprotein (Apo)E and low density lipoprotein gene polymorphism and CHD There is a significant relationship between“ + ”allele of low density lipoprotein gene, ε4 and high total cholesterol, LDL cholesterol levels. The cholesterol levels of individuals with LDL-R AvaⅡ(-/-) and NcoI (-/-) genotype were lower than those with LDL-R AvaⅡ (+/+) and NcoI(+/+) genotypes. 1.5 Fibronectin gene and CHD The results presented here do not suggest a positive association between HindIII, TaqI, MspI, and 3076A/C polymorphisms in FN gene and CHD. We didn't find any relationship between four polymorphism in fibronectin gene and CHD. But a non difference does not imply a non effect. But we found pFN levels in circulation were decreased significantly in patients with CHD. Figure. MspI (a), Taq I (b), (3076A/C c), and HindIII (d) digestions of the PCR product showing different genotypes. The size of each fragment is indicated on the gel. M1:A 100-bp DNA ladder, MBI Fermentas. M2:A 50-bp DNA ladder, MBI Fermentas. P: PCR products Table Genotype and Allele Frequencies of the Polymorphisms of the FN Gene in CHD Patients and Controls Genotype P value Allele MspI in intron 26 Phenotype CC CD DD CHD (n=109) 62 (56.9) 47 (43.1) 0 (0) Controls (n=123) 75 (61.0) 48 (39.0) 0 (0) C D 0.527 171 (78.4) 47 (21.6) 3076A/C in exon20 Phenotype AA AC CC CHD (n=109) 96 (88.0) 12 (11.0) 1 (1.0) Controls (n=123) 108 (87.8) 15 (12.2) 0 (0) A C 204 (93.6) 14 (6.4) 0.95 Fig The sequence reports. a: genotype AA for 3076A/C; b:genotype CC for 3076A/C (Eco81I: CC↓TNA↑GG) ; c: genotype CC for MspI﹡(MspI: C↓CG↑G) ﹡allele was designated as C (CCAG), D(CCGG) for the MspI polymorphism 1.6 Interleukin-1β gene and CHD Interleukin-1β (IL-1 β) belongs to a family of cytokines including IL-1, IL-4, IL-8, IL-10, and IL-13. IL-1 β plays a dominant role in several immune reactions IL-1β also was found to associate to atherosclerotic events in vitro and in vivo. Polymorphism analyze 1 CC 2 CT 3 TT 4 PCR Comparison of distribution of IL-1β 3954C/T genotypes between CHD group and control group group n Gene type(%) CC CT TT Allele frequency C T control 130 0.931 0.069 0.000 0.965 0.035 CHD 78 0.897 0.090 0.013 0.942 0.058 (P>0.05) The concentrations of C-reactive protein in different genotype groups Gene type n CRP median Inter-quartile range CC 121 2.05 * 0.67-3.64 * CT 9 3.98 1.69-6.68 * (P<0.05) The TaqⅠpolymorphism of IL-1β was associated with the concentrations of CRP in normal people The TaqⅠpolymorphism of IL-1β was not associated with with CHD 1.7 CRP gene and CHD CRP, The first acute-phase protein to be described, its plasma concentration increases during inflammatory states. Recently, CRP might have an important role in the pathogenesis and prediction of CHD. Polymorphism analysis Figure 1-1 Determination of the +1444 C/T polymorphism in the CRP gene by PCR-RFLP. Lane M:DNA Marker; Lane A:PCR product; Lane B:homozygous CC; Lane C:heterozygous CT; Polymorphism analysis Figure The chromatogram of homozygous CC Comparison of distribution of +1444 C/T genotypes and alleles between CHD group and control group Group s n CHD Contro l Genotype Distribution(%) Allele Distribution(%) CC CT+TT C T 128 114(89.1) 14(10.9) 242(94.5) 14(5.5) 119 107(89.9) 12(10.1) 226(95.0) 12(5.0) 2 0.048 0.045 P 0.827 0.832 OR(95%CI) 0.913(0.404¬2.063) * 0.918(0.416¬2.027) △ *: genotype CC vs CT+TT;△:allele C vs T The concentrations of C-reactive protein in different groups Groups n median Inter-quartile range CHD 128 1.21 0.63~2.58 CC 114 1.21 0.67~2.48 CT+TT 14 1.52 0.51~3.73 Control 119 0.77 0.59~1.22 CC 107 0.75 0.59~1.15 CT+TT 12 1.42 0.66~3.05 The +1444 C/T polymorphism of CRP was associated with the basal concentrations of CRP in normal people. The +1444 C/T polymorphism of CRP was not associated with CHD. 1.8 Conclusion for the study on polymorphisms as predictors of CHD We found the polymorphisms of E-selectin, ApoE gene and KCNJ11 gene were related to CHD disease. The polymorphisms in LDL-R gene and ApoE gene effected the level of lipid. The polymorphisms of IL-1βand CRP genes influenced the CRP baseline. We didn't find any association between polymorphism in fibronectin gene and CHD. 2.Gene polymorphism and prognosis Patients with an acute myocardial infarction are of high risk to develop ischemia –induced ventricular arrhythmias, leading to sudden cardiac death in about one third of all AMI patients. The individual susceptibility to ischemia-induced arrhythmias may be modified by polymorphisms in genes encoding ion channels. A.Jeron studied the Kir6.2 gene. Opening of the KATP channel during ischemia results in action potential shortening in various studies and may therefore influence the outcome of AMI patients. However they didn’t find any significant influence of Kir6.2 gene polymorphism on the risk of SCD in patients with CHD.But they identified two novel missense mutations in a highly conserved region of the Kir6.2 gene. 3. Gene polymorphism and pharmacogenomics From: Johnson J. A. TRENDS in Genetics 2003 Vol.19 The new pharmacogenetics uses powerful experimental and data-handling techniques in DNA analysis to discover and assemble a comprehensive list of the variations within the human genome – specifically, SNPs – and then defines complex genetic profiles of these SNPs that predict the use of new or existing therapeutic agents with maximal efficacy and minimal toxicity. A genetic test for certain single nucleotide polymorphisms(SNP) will predict you that: • You should suffer a severe adverse reaction to it. • You are expected to shown an excellent response to a different medication with little chance of side effects. This is the promise of pharmacogenetics— The optimization of drug therapy based on the individual genetic profile. For Example: The HMG-CoA reductase is the rate-limited enzyme in the biosynthesis of cholesterol. Statins, the HMG-CoA reductase inhibitors, are widely designed to reduce de novo cholesterol biosynthesis. The efficacy and toxicity of Statins are different in different individuals. Recently, investigation in the relationship of statins effects and gene polymorphisms related to the lipoprotein metabolism has been developed. These genes included the apolipoprotein E gene, hepatic lipase gene, lipoprotein lipase gene and CETP gene. In 2000, Siest G et al used different HMG-CoA reductase inhibitors to detect the relationship of apo E polymorphisms and LDL-C level. It showed the best effects to reduce LDL-C inε2 carriers. Theε4 carriers has elevated level of plasma cholesterol. And the affinity of LDL particles to LDL receptor was increased, the activity of HMG-CoA reductase was decreased. The effect of statins inε4 carriers was poor may be due to the low base level of HMG-CoA reductase activity. In 2003, Carlquist et al had concluded that the Taq1B polymorphism in the CETP gene is associated with CETP activity, HDL concentration, atherosclerosis progression, and response to statins. Their findings suggested, for the first time, the potential of CETP Taq1B genotyping to enable more effective, pharmacogenetically directed therapy. From: Johnson J. A. TRENDS in Genetics 2003 Vol.19 No.11:660-666 In a word, Identification of all gene variants that contribute to CHD appears possible; this may considerably improve our understanding of the aetiology and mechanisms of this disease. Furthermore, simultaneous analysis of several predisposing alleles may help to identify high-risk individuals and assess prognosis. And the treatment of CHD could be guided by screening certain SNP using pharamcogenetic methods. ……. From: Pfost D R et al. TIBTECH, 2000 (Vol. 18):334-338 Aknowlegement! Prof. Xin Zhou Prof. Li Xia Yin Zhang Chenling Xiong Xiaobo Sun