中国苗族人群中细胞色素P450 2C19基因多态性的研究

为研究细胞色素P4502C19在中国苗族人群中的基因型,采用聚合酶链式反应与限制性内切核酸酶片段长度多态性技术分析了98例无血缘关系苗族人群的基因型。结果显示50人为CYP2C19野生型纯合子（wt/wt）;39人为CYP2C19m1杂合子（wt/m1）;9人为CYP2C19m1突变型纯合子（m1/m1）。与国内外相关报道比较,本实验得出的CYP2C19m1突变频率与文献报道相符。 Abstract：In order to study the cytochrome P450 2C19 gene polymorphism in Miao population, the genotypes of ninety-eight unrelated Miao subjects were studied by polymera se chain reaction and restricted fragment length polymorphism (RFLP). The result s showed that fifty were homozygous for wild-type (wt/wt); thirty-nine wer e heterozygous for the CYP2C19m1 (wt/m1);nine were homozygou s for CYP2C19m1(m1/m1).The frequency of CYP2C19m1 was in agreement with that of other published data.     

104名藏族志愿者中细胞色素P450 2C19m1的基因多态性

细胞色素P450 2C19（CYP2C19）参与临床上许多重要药物的代谢。根据其代谢S－美芬妥英或其他CYP2C19底物的能力不同,有强代谢者（EMs）和弱代谢者（PMs）之分。PMs表型的频发率存在明显的种族差异。在本文中,我们主要报道了细胞色素P450 2C19 m1在中国藏族人群中的多态性分布。在104例无血缘关系藏族人群中,49人（47.1%）为CYP2C19野生型纯合子（wt/wt）,46人（44.2%）为CYP2C19m1杂合子（wt/m1）,9人（8.7%）为CYP2C19m1突变型纯合子（m1/m1）。CYP2C19野生型等位基因频率为0.692,CYP2C19m1等位基因频率为0.308。该结果与国内外报道的中国其余民族的CYP2C19m1等位基因频率相比具有一定可比性。 关键词：细胞色素P450 2C19;基因型;藏族;聚合酶链反应;限制性内切核酸酶片段长度多态（RFLP）Abstract: Cytochrome P 450 2C19（CYP2C19） is involved in the metabolism of a number of clinically used drugs. Individuals can be characterized as extensive metabolizers （EMs）or poor metabolizers（PMs）, according to the drugs-metabolized ability of CYP2C19 in population studies. The incidence of poor metabolizer phenotype shows marked interracial differences. In this article we report the gene polymorphism of CYP2C19 in Zang population. There were 49 wild-type homozygotes（wt/wt）, 46 were heterozygotes（wt/m1） and 9 were homozygotes（m1/m1） among 104 unrelated Zang subjects. The frequency of CYP2C19m1 allele was 0.308, which was in agreement with that in other published data.     

南京市正常人群NQO1、CYP1A1、mEH基因的多态性研究

应用PCR技术,对南京市正常人群中NQO1、CYP1A1、Meh-外显子3、Meh－外显子4基因型多态性进行了研究。88例样本中,相关基因野生型纯合子（wt/wt ）、杂合子（wt/vt）、突变型纯合子（vt/vt）三种基因型的频率分布及基因频率分别是：NQO1 29.5%（0.304）,51.1%(0.495)和19.3%(0.202);CYP1A1 35.2%(0.329)、44.3%(0.489)和20.5%(0.181);Meh－外显子3为26.1%(0.297),56.8 %(0.496),17.0%(0.207);Meh－外显子4为83.0% (0.826),15.9%(0.165),1.1%(0.00 8)。以上结果与国外的有关报道存在一定差异,在不同地区中国人群的频率分布特征基本一致,种族差异可能是造成有关基因型分布差异的重要原因。     

南京市正常人群NQO1、CYP1A1、mEH基因的多态性研究

应用PCR技术,对南京市正常人群中NQO1、CYP1A1、mEH-外显子3、mEH－外显子4基因型多态性进行了研究。88例样本中,相关基因野生型纯合子（wt/wt）、杂合子（wt/vt）、突变型纯合子（vt/vt）三种基因型的频率分布及基因频率分别是：NQO1 29.5%（0.304）,51.1%(0.495)和19.3%(0.202);CYP1A?135.2%(0.329)、44.3%(0.489)和20.5%(0.181);mEH－外显子3为26.1%(0.297),56.8%(0.496),17.0%(0.207);mEH－外显子4为83.0%(0.826),15.9%(0.165),1.1%(0.008)。以上结果与国外的有关报道存在一定差异,在不同地区中国人群的频率分布特征基本一致,种族差异可能是造成有关基因型分布差异的重要原因。 Abstract：The polymorphisms of NQO1, CYP1A1, mEH-Exon3 ,and mEH-Exon4 genes in normal Nanjing population (88 cases) were investigat ed by PCR approach. The results showed that the population frequency distributio ns of genotypes of wild-type,heterozygote, homozygous variant were respectively: NQO1? 29.5%,51.1%,19.3%;CYP 1A1 35.2%,44.3%,20.5%;mEH-exon3 26.1 %,56.8%,17.0%;mEH-exon4 83.0%,15.9%,1.1%. The frequency distributions o f genotypes in Nanjing population differ from those of other countries and do no t show marked differences compared with other different area in Chinese populati on. The ethnic difference might be an important reason which results in the diff erences of related genotypes.     

新生儿CYP2E1基因5′端RsaⅠ位点多态性和PON2基因148位点多态性与早产的关系

为探讨新生儿细胞色素P450 2E1(CYP2E1)基因多态性和对氧磷酶2(二乙基对硝基苯磷酸酯酶2)基因(PON2)148位点多态性对早产的影响,采用横断面调查方法,使用统一的调查表,由安庆市各县医院对入院分娩孕妇及其单胎、活产、早产和对照新生儿进行调查,共得到有效样本209个母亲-新生儿对。单因素分析结果显示：CYP2E1野生纯合子基因型( ／ )与突变纯合子基因型(-／-)／杂合子基因型( ／-)比较,对早产的影响不具有统计学意义。而PON2 Alal48Ala纯合子基因型与G1y148G1y纯合子基因型／Ala148 Gly杂合子基因型比较,对早产的影响具有显著的统计学意义。进一步分析CYP2E1基因5′端RsaⅠ位点多态性和PON2基因148位点多态性是否存在交互作用,结果显示：CYP2E1野生纯合子基因型和PON2 Ala148Ala纯合子基因型这一组合与参照组比较,对早产的影响有显著的统计学意义。基因CYP2E1 5′端Rsa I位点多态性与新生儿早产不相关,但基因PON2 148位点多态性与新生儿早产相关,且CPY2E1 5′端Rsa I位点多态性和PON2 148位点多态性之间对早产的影响存在交互作用。     

CYP1A1、CYP1B1、NET、DAT1单个和联合基因型与汉族人群乳腺癌易感性的研究（英文）

乳腺癌是最常见的女性癌症,其发生是遗传因素和环境因素相互作用的结果。因此,我们就CYP1A1MspⅠ(m1多态)、CYP1B1 Leu432Val、NET T-182C、DAT1-VNTR等基因多态性对新疆汉族人群乳腺癌易感性的研究进行探讨。在以144例乳腺癌患者和120例正常对照组为研究对象的病例-对照研究中,发现CYP1A1MspⅠ位点CC基因型、C等位基因(OR=3.32,95%CI:1.24~8.86;OR=1.58,95%CI:1.09~2.31)和高风险联合基因型CYP1A1 MspⅠ与CYP1B1 Leu432Val,CYP1A1 MspⅠ与DAT1-VNTR,CYP1B1 Leu432Val与DAT1-VNTR(OR=2.43,95%CI:1.23~4.78;OR=4.53,95%CI:1.26~16.27;OR=2.98,95%CI:1.10~8.06)与乳腺癌风险增加有关。CYP1B1、NET和DAT1基因多态性与乳腺癌易感性无关。这些研究结果表明,CYP1A1 MspⅠ多态性和CYP1A1、CYP1B1、DAT1高风险联合基因型能增加新疆汉族人群患乳腺癌的风险。     

新生儿基因CYP2E1 5′端RsaⅠ和PON2311位点多态性与早产的关系

探讨新生儿基因细胞色素P450 2E1（CYP2E1）5‘端RsaI多态性和对氧磷酶2（二乙基对硝基苯磷酸酯酶2）基因311位点（PON2311）多态性对早产的影响。采用横断面调查方法,使用统一的调查表,由安庆市各县医院对入院分娩孕妇及其单胎,活产,早产和对照新生儿进行调查,共得到有效样本194个母亲－新生儿对。单因素分析结果显示：CYP2E1野生纯合子基因型（cut/cut)与突变纯合子基因型（uncut/uncut)/杂合子基因型（cut/uncut)比较,对早产的影响不具有统计学意义,而PONS2 Ser311Ser纯合子基因型与Cys311Cys纯合子基因型／Cys311Ser杂合子基因型比较,对早产的影响具有显著的统计学意义。进一步分析CYP2E15‘端RsaI位点多态性和PON2311位点多态性是否存在交互作用。结果显示：CYP2E1野生纯合子基因型和PON2 Ser311Ser纯合子基因型这一组合与参照组比较,对早产的影响具有显著的统计学意义。基因CYP2E15‘端Rsa I位点多态性与新生儿早产不相关,但基因PON2311位点多态性与新生儿早产相关,且CYP2E1 5‘端RsaI位点多态性和PON2311位点多态性之间对早产的影响存在交互作用。     

中国人LDR152/PstⅠ RFLPs及其在一个强直性肌营养不良症(DM)家系中的连锁分析

强直性肌营养不良症是一种常染色体显性遗传病,临床上以发病晚、症状表现多样为特征。本研究应用19号染色体上与DM基因紧密连锁的单拷贝片段LDR152(D19S19)在中国上海地区人群(61例)及1个DM家系中进行RFLP(Restriction Fragment Length Polymorphism)的连锁分析,结果表明:(1)等位片段19kb和11kb在人群中的分布频率分别为43.44％和56.56％,其中19kb纯合子为22.95％、11kb纯合子为36.07％,19kb和11kb杂合子为40.98％,此结果与国外报道的明显不同。(2)在我们所分析的这例DM家系中,发现DM基因与19kb等位片段相连锁,并呈孟德尔式遗传。进而,对两例无任何临床症状的DM基因携带者作出了明确的基因诊断,并对家系中患DM的危险成员进行了DM的风险估计。     

应用可视化基因芯片技术检测幽门螺杆菌感染个体化药物治疗相关基因

目的:建立一种能同时检测幽门螺杆菌克拉霉素(23S)、喹诺酮(gyrA)耐药位点和人PPI代谢相关CYP2C19的基因多态性情况的基因芯片检测方法.方法:通过分析筛选人基因组CYP4502C19 *2,CYP4502C19*3及幽门螺杆菌克拉霉素和喹诺酮类耐药位点的DNA序列,设计制备了HP感染个体化药物治疗检测基因芯片,并对其特异性、灵敏度、重复性进行了评价.结果:该芯片可以检测出不低于103 CFU/ml的幽门螺杆菌和不低于2ng/μl的人基因组DNA.196例临床标本的芯片检测结果与测序结果基本一致.结论:应用可视化基因芯片进行幽门螺杆菌感染个体化药物治疗相关基因检测具有较高的特异性和敏感性,结果准确且易判读,具有较好的应用前景,可以为临床医生提供用药指导.     

Allele and genotype frequencies of the polymorphic cytochrome P450 genes (CYP1A1, CYP3A4, CYP3A5, CYP2C9 and CYP2C19) in the Jordanian population

Drug metabolizing enzymes participate in the neutralizing of xenobiotics and biotransformation of drugs. Human cytochrome P450, particularly CYP1A1, CYP2C9, CYP2C19, CYP3A4 and CYP3A5, play an important role in drug metabolism. The genes encoding the CYP enzymes are polymorphic, and extensive data have shown that certain alleles confer reduced enzymatic function. The goal of this study was to determine the frequencies of important allelic variants of CYP1A1, CYP2C9, CYP2C19, CYP3A4 and CYP3A5 in the Jordanian population and compare them with the frequency in other ethnic groups. Genotyping of CYP1A1(m1 and m2), CYP2C9 (*2 and *3), CYP2C19 (*2 and *3), CYP3A4*5, CYP3A5 (*3 and *6), was carried out on Jordanian subjects. Different variants allele were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). CYP1A1 allele frequencies in 290 subjects were 0.764 for CYP1A1*1, 0.165 for CYP1A1*2A and 0.071 for CYP1A1*2C. CYP2C9 allele frequencies in 263 subjects were 0.797 for CYP2C9*1, 0.135 for CYP2C9*2 and 0.068 for CYP2C9*3. For CYP2C19, the frequencies of the wild type (CYP2C19*1) and the nonfunctional (*2 and *3) alleles were 0.877, 0.123 and 0, respectively. Five subjects (3.16?%) were homozygous for *2/*2. Regarding CYP3A4*1B, only 12 subjects out of 173 subjects (6.9?%) were heterozygote with none were mutant for this polymorphism. With respect to CYP3A5, 229 were analyzed, frequencies of CYP3A5*1,*3 and *6 were 0.071, 0.925 and 0.0022, respectively. Comparing our data with that obtained in several Caucasian, African-American and Asian populations, Jordanians are most similar to Caucasians with regard to allelic frequencies of the tested variants of CYP1A1, CYP2C9, CYP2C19, CYP3A4 and CYP3A5.     

Genotype analysis of the CYP2C19 gene in HCV-seropositive patients with cirrhosis and hepatocellular carcinoma

This study was conducted to assess whether the genotypic frequency of Smephenytoin 4'-hydroxylase CYP2C19 gene differs in Japanese cirrhotic patients who developed hepatocellular carcinoma. Thirty-eight patients with cirrhosis were studied. The wild-type allele CYP2C19*1 and the two mutated alleles, CYP2C19*2 and CYP2C19*3, were identified by PCR-RFLP method. Individuals with homozygous CYP2C19*2 or CYP2C19*3 mutation and those with CYP2C19*2 and CYP2C19*3 heterozygous mutation were predicted to be the poor metabolizer (PM) phenotype. The overall frequency of PM predicted from the genotyping analysis was 29% (11 of the 38 patients), consisting of 5 patients homozygous for CYP2C19*2, two homozygous for CYP2C19*3 and four heterozygous for the two defects. Among 24 HCV-seropositive patients with cirrhosis and hepatocellular carcinoma, the frequency of PM was 41.7% and significantly higher than that observed in 186 healthy controls. We postulate that the PM phenotype caused by the mutation of CYP2C19 gene in cirrhotic patients with HCV infection is associated with a high risk for developing hepatocellular carcinoma.     

CYP17 and CYP19 genetic variants are not associated with age at natural menopause in Polish women

The aim of the study was to investigate associations between two common polymorphisms of CYP17 and CYP19, encoding key enzymes of estrogen biosynthesis, and age at menopause in Polish women. One hundred fifty women after menopause (49.5 ± 3.8 years), with no previous history of hormone replacement therapy took part in the study. The genetic control group consisted of 150 newborns from the same population. We investigated an association between the age at menopause and the single nucleotide polymorphism T → C in the 5′ untranslated region (promoter) of the CYP17 gene (c.-34T>C; rs743572 – MspA1) or the number of tetranucleotide repeats [TTTA]_n (rs60271534) including deletion/insertion (D/I) of a 3 bp sequence in intron 4 of the CYP19 gene. CYP17 polymorphism was analyzed by PCR-RFLP and CYP19 by PCR and capillary electrophoresis. In the case of CYP17 polymorphism, 28.7% and 36.7% wild homozygous (TT), 50.7% and 46.0% heterozygous (TC), as well as 20.6% and 17.3% mutated homozygous (CC) types were identified in the subjects and controls, respectively. The frequency of mutated alleles (C) was 46.0% vs. 40.3% (p = 0.19). In the case of CYP19 polymorphism, 34.0% and 32.0% of homozygotes (1_1), 50.7% and 51.3% of heterozygotes (1_2), 15.3% and 16.7% of homozygotes (2_2) were identified in the subjects and controls, respectively. No association between the studied CYP17 or CYP19 polymorphisms and age at menopause was found in Polish women.     

Lymphocytes,DNA adducts and genetic polymorphism for metabolic enzymes in low dose cigarette smokers

The aim of this study was to investigate the relationship between genetic polymorphism of metabolic enzymes and DNA adduct levels in lymphocytes of low dose cigarette smokers (less than 20 cigarettes per day). We previously reported the effects of cytochrome P4501A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) on lymphocyte DNA adducts. This time we considered not only CYP1A1 and GSTM1 but also cytochrome P4502E1 (CYP2E1) and glutathione S-transferase T1 (GSTT1). DNA adducts in lymphocytes obtained from low dose cigarette smokers (n = 41) and nonsmokers (n = 56) were measured by the 32P-postlabelling method. The adduct levels were compared regarding smoking status and polymorphic genotypes of these four enzymes. The mean SD of DNA adduct levels in all low dose cigarette smokers and non-smokers was 1 05 0 83 per 108 nucleotidesand 0 85 0 35 per 108 nucleotides, respectively. In low dose cigarette smokers, adduct levels were higher in the rare homozygous (MM) for CYP1A1-exon 7 polymorphism compared with the other types such as common homozygous (WW) and heterozygous (WM). CYP1A1-WM, MM in combination with GSTM1 null showed highest adduct levelamong low smokers. The low smokers with rare homozygous for CYP2E1 Dra1 polymorphism tended to have lower adduct levels than wild types. Low dose cigarette smokers with combined GSTM1 null and T1 null had a higher tendency for adduct levels than others. However none of the differences reached statistical significance.     

Cytochrome P450c17α 5′-untranslated region *T/C polymorphism in endometriosis

Estrogen plays a role in the pathogenesis of endometriosis. The CYP17 gene codes for the cytochrome P450c17α enzyme that is involved in the estrogen biosynthesis. We aimed to investigate if CYP17 polymorphism could be used as marker to predict the susceptibility of endometriosis. Women were divided into two groups: (1) severe endometriosis (n=119); (2) non-endometriosis groups (n=128). A 169-bp fragment encompassing the T/C polymorphic site in 5′-untranslated promoter region (5′-UTR) of the CYP17 was amplified by the polymerase chain reaction, treated with restriction enzyme MspA1I, and electrophoresis. The polymorphism was divided into restriction-enzyme indigestible (T homozygote), T/C heterozygote, and digestible (C homozygote). Genotypes and allelic frequencies for this polymorphism in both groups were compared. We observed a higher but non-significant percentage of T homozygote in the endometriosis women compared with the non-endometriosis women. Proportions of T homozygote/heterozygote/C homozygote for CYP17 in both groups were: (1) 26.1/46.2/27.7% and (2) 17.2/45.3/37.5% (p-value=0.131). T allele was related with higher susceptibility of endometriosis. T and C allele frequencies in both groups were: (1) 49.2/50.8%; (2) 39.8/60.2% (p-value=0.046). Despite the CYP17* T allele appearing to be asscoiatd with a trend of increased risk of endometriosis, CYP17 5′-UTR gene polymorphism might not be a useful marker for prediction of endometriosis susceptibility.     

Association of CYP2C19*3 gene polymorphism with breast cancer in Chinese women

Cytochrome P450 (CYP) 2C19 metabolizes arachidonic acid to biologically active epoxyeicosatrienoic acids, which significantly promote proliferation of cancer cells in vitro and in vivo. We looked for a possible association between human CYP2C19*3 gene polymorphism and breast cancer in the Chinese Han population. In a Chinese Han case-control study of breast cancer patients (N = 600) and age- and gender-matched healthy controls (N = 600), we investigated polymorphism in the CYP2C19 gene by PCR-RFLP analysis. The CYP2C19*3 AG + AA genotype was significantly more prevalent in breast cancer patients than in control subjects (6.67 vs 3.00%; P = 0.003). The odds ratio for carriers of AG + AA genotype for breast cancer was 2.31 (95% confidence interval = 1.27-4.43). Among patients, estrogen receptor, tumor size, histologic grade, presence of primary lymphonode metastases, progesterone receptor positivity, and age at diagnosis were not found to be significantly associated with CYP2C19*3 genotypes (all P > 0.05). We conclude that the CYP2C19*3 gene polymorphism is associated with breast cancer risk in Chinese Han women.     

The A-204C polymorphism in the cholesterol 7alpha-hydroxylase (CYP7A1) gene determines the cholesterolemia responsiveness to a high-fat diet

The aim of the study was to ascertain whether the A-204C polymorphism in the cholesterol 7 -hydroxylase (CYP7A1) gene plays any role in determining LDL-cholesterol (LDL-C) concentration responsiveness to a high-fat diet. The concentrations of total cholesterol and LDL-cholesterol were measured in eleven healthy men (age: 30.9+/-3.2 years; BMI: 24.9+/-2.7 kg/m(2);;) who were homozygous for either the -204A or -204C allele, after 3 weeks on a low-fat (LF) diet and 3 weeks on a high-fat (HF) diet. During both dietary regimens, the isocaloric amount of food was provided to volunteers; LF diet contained 22 % of energy as a fat and 2.2 mg of cholesterol/kg of body weight a day, HF diet 40 % of fat and 9.7 mg of cholesterol/kg of body weight a day. In six subjects homozygous for the -204C allele, the concentrations of cholesterol and LDL-cholesterol were significantly higher on HF than on LF diet (cholesterol: 4.62 vs. 4.00 mmol/l, p<0.05; LDL-C: 2.15 vs. 1.63 mmol/l, p<0.01, respectively); no significant change was observed in five subjects homozygous for the -204A allele. There were no other differences in lipid and lipoprotein-lipid concentrations. Therefore, the polymorphism in the cholesterol 7alpha-hydroxylase promotor region seems to be involved in the determination of cholesterol and LDL-C responsiveness to a dietary fat challenge.     

The effect of the CYP 2C19*2 polymorphism on stroke care

Clopidogrel is an inhibitor of platelet-aggregation used in the prevention of secondary stroke. The molecule is activated by the cytochrome P450 2C19 (CYP2C19) enzyme. The frequent CYP2C19*2 point mutation causes loss of enzyme function, a decreased (heterozygous form) or blocked (homozygous form) formation of the active molecule. Thus, for a patient harboring a mutated allele, clopidogrel does not provide effective protection against stroke. Multiple drugs inhibit the CYP2C19 enzyme and their simultaneous use with clopidogrel is especially hazardous for patients with genetically decreased enzyme activity. Frequency of the CYP2C19*2 is variable in different populations, highest rates were detected in some Asian groups. In our study the CYP2C19 genotype was determined in one Hungarian sample of 354 stroke patients and 221 healthy controls. Frequency of the minor allele was found to be 12.87% (12.85% in stroke patients, 12.89% in healthy controls). The proportion of the homozygous CYP2C19*2 variant causing total loss of gene function was 1.74%, rate of the heterozygous allele causing reduced enzyme activity was 22.26% in the total population. Our results for the allele frequencies of the CYP2C19*2 gene are similar to those found in other Caucasian populations. In conclusion, the homozygous mutation, causing ineffectiveness of clopidogrel is relatively rare. However, the heterozygous form in which interaction of CYP2C19 inhibitors causes further decrease in the genetically impaired enzyme activity is present in every fifth drug-taking patient. Based on our findings, we would like to emphasize that it is important to adjust individually antiplatelet treatment in ischemic stroke patients and to take into consideration genetic factors as well as drugs taken for comorbid conditions.