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1、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 pl
2、ay a pathogenetical role, defined as risk factors.The risk factors of CHD included:,Emerged CHD Risk 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
3、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 t
4、he near future.,Whats 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 w
5、ith 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 poly-morphism，SNP. polymorphismnormal phenotype mutation disease polymorphismmore mutation less,Cardiovascular disease is complex a
6、s 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 independ
7、ent 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 CH
8、D like tiny weights in balance.,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
9、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.,1.1 The G98/T polymorphism in E-selectin gene and CHD,The transversion of G98T mutation abo
10、lishes the HphI recognition site.,The PCR product was digested by HphI and separated on 2 % agarose gel electrophoresis.,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
11、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),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.
12、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).,variable Odds Ratio (95%, CI) P 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.
13、02 (0.99-1.05) =0.071 Smoke, Y/N 5.87 (1.84-18.75) =0.003,Multivariate Logistic Regression Analysis,The ATP-sensitive potassium channel (KATP) were complexes of two subunits, a regulatory sulfonylurea receptor (SUR) and an ATP-sensitive and pore-forming inwardly rectifying K+ channel (Kir 6.X). The
14、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) substi
15、tution at codon 23, and the A allele was shown to have a relationship with high risk to type 2 Diabetes in previous study.,1.2 The E23K polymorphism in KCNJ11 gene and CHD,*: The frequency of GG genotype was compared with that of GA+AA genotype; *: The frequency of G allele was compared with A allel
16、e.,Table. Genotype and Allele Frequencies of the E23K Polymorphism of Kir6.2 Gene in CHD Patients and Controls,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(V
17、LDL) and chylomicrons. Genetically, ApoE is polymorphic isoforms of proteins, E2, E3, E4 respectively. The ApoE alleles modulate the risk for CHD, cerebral aheroscerosis and Alzheimers disease.,There were three alleles and six genotypes.,ApoE PAGE/RFLP pattern,There is a significant relationship bet
18、ween“ + ”allele of low density lipoprotein gene, 4 and high total cholesterol, LDL cholesterol levels. The cholesterol levels of individuals with LDL-R Ava(-/-) and NcoI (-/-) genotype were lower than those with LDL-R Ava (+/+) and NcoI(+/+) genotypes.,1.4 The Apolipoprotein (Apo)E and low density l
19、ipoprotein gene polymorphism 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 didnt find any relationship between four polymorphism in fibronectin gene and CHD. But a non difference does not imply a
20、 non effect. But we found pFN levels in circulation were decreased significantly in patients with CHD.,1.5 Fibronectin gene and 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.
21、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,Fig The sequence reports. a: genotype AA for 3076A/C; b:genotype CC for 3076A/C (Eco81I: CCTNAGG) ; c: g
22、enotype CC for MspI(MspI: CCGG) allele was designated as C (CCAG), D(CCGG) for the MspI polymorphism,1.6 Interleukin-1 gene and CHD,Interleukin-1 (IL-1 ) belongs to a family of cytokines including IL-1, IL-4, IL-8, IL-10, and IL-13. IL-1 plays a dominant role in several immune reactions IL-1 also wa
23、s found to associate to atherosclerotic events in vitro and in vivo.,Polymorphism analyze,CC CT TT PCR,Comparison of distribution of IL-1 3954C/T genotypes between CHD group and control group,(P0.05),The concentrations of C-reactive protein in different genotype groups,* (P0.05),The Taqpolymorphism
24、of IL-1 was associated with the concentrations of CRP in normal people The Taqpolymorphism of IL-1 was not associated with with 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 pat
25、hogenesis and prediction of CHD.,1.7 CRP gene and 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 homozy
26、gous CC,Comparison of distribution of +1444 C/T genotypes and alleles between CHD group and control group,*: genotype CC vs CT+TT；：allele C vs T,The concentrations of C-reactive protein in different groups,The +1444 C/T polymorphism of CRP was associated with the basal concentrations of CRP in norma
27、l 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 leve
28、l of lipid. The polymorphisms of IL-1and CRP genes influenced the CRP baseline. We didnt find any association between polymorphism in fibronectin gene and CHD.,Patients with an acute myocardial infarction are of high risk to develop ischemia induced ventricular arrhythmias, leading to sudden cardiac
29、 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
30、 studies and may therefore influence the outcome of AMI patients. However they didnt 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.,2.Gene polymorphis
31、m and prognosis,From: Johnson J. A. TRENDS in Genetics 2003 Vol.19 No.11:660-666,3. Gene polymorphism and pharmacogenomics,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
32、 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
33、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.,The HMG-CoA reductase is the rate-limited enzyme in
34、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.,For Example:,Recently, investigation in the relationship of statins effects and gen
35、e 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 a
36、nd LDL-C level. It showed the best effects to reduce LDL-C in2 carriers. The4 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 in4 carriers was poor may be due to
37、 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 potentia
38、l 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,Identification of all gene variants that contribute to CHD appears possible; this may considerably improve our understanding of the aetiology an
39、d 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.,In a word,From: Pfost D R et al. TIBTECH, 2000 (Vol. 18):334-338,Aknowlegement！,Aknowlegement！,Aknowlegement！,Aknowlegement！,Prof. Xin Zhou Prof. Li Xia Yin Zhang Chenling Xiong Xiaobo Sun,