广东人群CYP3A4基因rs28371759(20070T>C)位点多态性调查

目的:探讨广东人群CYP3A4基因rs28371759(20070T>C)位点的分布特点,为广东患者使用CYP3A4底物药提供理论参考依据。方法:以200名广东志愿者的口腔拭子DNA为模板,PCR扩增包含rs28371759多态位点的DNA片断,用限制性内切酶MspI消化PCR产物,通过聚丙烯酰胺凝胶电泳-银染获得样品的限制性酶切图谱用于判别基因型。结果:在受检的200例样品中,检出杂合子3例,余者皆为野生型纯合子。野生型纯合子、杂合子、突变型纯合子的频率分别为0.985、0.015、0,突变等位基因20070C即CYP3A4*18A的频率为0.007 5。结论:本研究得到了广东人群CYP3A4基因rs28371759位点的多态性分布情况,为研究CYP3A4基因多态性与临床药物效应的相互关系奠定了基础。     

新生儿先天性肾上腺皮质增生症双重杂合突变的检出

先天性肾上腺皮质增生症的最常见病因是21-羟化酶的缺乏,目前已经发现多个21-羟化酶基因CYP21的突变类型.本文报道1例新生儿先天性肾上腺皮质增生症患儿的双重杂合突变.     

新生儿先天性肾上腺皮质增生症双重杂合突变的检出

先天性肾上腺皮质增生症的最常见病因是21-羟化酶的缺乏,目前已经发现多个21-羟化酶基因CYP21的突变类型.本文报道1例新生儿先天性肾上腺皮质增生症患儿的双重杂合突变.     

11β-羟化酶缺陷症研究进展

1991年首次报道CYP11B1基因突变引起11β-羟化酶缺陷症(11β-hydroxylase deficiency,11β-OHD)以来,最新研究表明11β-OHD 占先天性肾上腺皮质增生症(congennital adrenal hyperplasia,CAH) 的0.2%~8.0%,在普通人群中发病率为1/9 000 000,而在从摩洛哥移民到以色列的犹太人群中,该病在新生儿中的发病率高达1/7 000~ 1/5 000,不同的地区及种群发病率不同, 其在中东和北非等地区发病率最高     

脂蛋白脂肪酶基因突变的研究

目的：筛查国人脂蛋白脂肪酶(LPL)基因的突变，并探讨其与高甘油三酯血症的关系。方法：对高甘油三酯血症组(48例)和正常甘油三酯对照组(121例)的各扩增片段进行分析，电泳图谱异常者进行PCR产物测序。对于频率较高的多态性位点，引入限制性核酸内切酶位点利用PCR-RFLP进行鉴定。结果：在高甘油三酯血症人群中，检出2例内含子3受位剪接点上游6bp的C→T转换的突变杂合子，1例外显子5Pm^207→Leu突变杂合子，在全部样品中检出1例Ser^447→stop突变纯合子，50例Ser^447→stop杂合子。结论：天津地区人群中存在着LPL基因突变，除Ser^447→stop外，内含子3和外显子5的突变多与高甘油三酯血症相关，可能是高甘油三酯血症的遗传易感因子。     

CYP3A4基因多态性与汉族小儿耐药性癫痫的关系

目的探讨耐药性癫痫的汉族儿童CYP3A4*18A、CYP3A4*1G与癫痫耐药的相关性。方法应用聚合酶链反应-限制性片段长度多态性技术,共检测西南地区238例儿童的CYP3A4*18A、CYP3A4*1G基因型频率和等位基因频率,其中耐药性癫痫(耐药组)83例、抗癫痫药物治疗有效(有效组)87例、健康儿童(正常组)68例。结果 CYP3A4*1G野生纯合子频率在耐药组、有效组、正常组分别为47%、45%、50%,突变杂合子频率分别为46%、49%、43%,突变纯合子频率为7%、6%、7%;等位基因野生型频率分别为70%、70%、71%,突变型频率分别为30%、30%、29%。3组基因型频率及等位基因频率差异均无显著意义(P>0.05)。CYP3A4*18A在耐药组中分布野生纯合子93%、突变杂合子7%,等位基因野生型96%、突变型4%;有效组、正常组野生纯合子100%,未发现突变。耐药组CYP3A4*18A多态性的突变杂合子基因型频率及突变型等位基因频率高于有效组,差异有显著意义(P<0.05),耐药组与正常组基因型频率及等位基因频率比较,差异无显著意义(P>0.05)。结论西南地区汉族儿童CYP3A4*18A基因多态性可能与癫痫耐药存在相关性,CYP3A4*1G基因多态性与癫痫耐药可能无相关性。检测CYP3A4*18A基因型也许是选择有效抗癫痫药物的方法之一。     

基因检测对华法林和硫酸氢氯吡格雷个体化用药的临床指导价值

<正>华法林具有治疗窗窄、患者个体差异大等因素导致临床用药剂量难以评估。研究发现~([1]),维生素K环氧化物还原酶复合体1(VKORC1)和细胞色素P450(CYP) 2C9基因与华法林体内代谢密切相关,在亚洲人群中,CYP2C9基因的突变型主要存在于CYP2C9*3(包括野生AA型、杂合突变AC型和纯合突变CC型),而VKORC1的突变型主要是VKO-RC1-1639 (包括野生GG型、杂合突变GA型和纯合突变AA型)。硫酸氢氯吡格雷在体内主要依赖CYP2C19酶活化后转化为活性产物而发挥抗血小板作用,CYP2C19酶存在多种突变等位基因,CYP2C19×2和CYP2C19×3两种类型是中国人群主要变异类型,且CYP2C19×2出现频率     

中国汉族癫痫患者CYP2C19和CYP2C9基因多态性对苯妥英钠血药浓度的影响

目的 研究中国汉族癫痫患者细胞色素P450(CYP450)2C19和2C9基因多态性对苯妥英钠血药浓度的影响.方法 用PCR-RFLP方法,分析82例患者的CYP2C19*2,*3及CYP2C9*3这3个单碱基突变位点,用荧光偏振免疫法(FPIA)测定苯妥英钠血药浓度.结果 CYP2C9*3*、CYP2C19*2及CYP2C19*3等位基因频率分别为7.3%,33.5%和3.7%.强、中间、弱代谢组间的标准化血药浓度差别显著(P=0.000).苯妥英钠血药浓度的多元线性回归中,CYP2C19*2、CYP2C19*3、CYP2C9*3这3个基因突变位点beta值分别为5.71,6.65,6.95.结论 基因突变导致苯妥英钠血药浓度升高,且与突变位点的数量有关.     

葡萄糖脑苷脂酶基因多态性与帕金森病的相关性

目的 研究贵州人群帕金森病(PD)患者的葡萄糖脑苷脂酶(GBA)基因N370S、V394L和IA44P突变位点多态性,探讨GBA基因突变与PD的相关性.方法 选取50例PD患者和50例正常对照组的基因组DNA,通过PCR扩增GBA基因的外显子8-11 DNA片段,再以纯化的PCR产物作模板,通过PCR分别扩增GBA基因外显子9和外显子10 DNA片段,纯化后测序.结果 PD患者和正常对照组的GBA基因外显子9和外显子10核苷酸序列完全一致,未发现突变点.结论 在中国贵州人群中,GBA基因N370S、V394L和LA44P突变位点无多态性,提示GBA基因N370S、V394L和L444P突变与中国贵州人群的PD不具有相关性.     

CYP2C19基因多态性与肝癌易感性关系的研究

目的 研究内蒙古地区汉族人群CYP2C19基因多态性与肝癌易感性的关系.方法 采用等位基因特异性扩增(ASA)技术对内蒙古地区254例汉族健康人和68例汉族肝癌患者进行CYP2C19基因型分布频率的研究,分析CYP2C19基因多态性与肝癌易感性的关系.结果 CYP2C19ml 3种多态基因型在内蒙古地区汉族人群肝癌组与对照组的分布频率分别为:wt/wt 50％、wt/ml 33.8％、ml/ml 16.2％和wt/wt 40.6％、wt/ml 50.3％、ml/ml9.1％.结果 显示携带CYP2C19ml突变杂合型(wt/ml)的个体患肝癌的风险度比野生型纯合子(wt/wt)升高1.8倍,经统计学检验差异有显著性(P＜0.05).CYP2C19m2基因型在内蒙古地区汉族人群肝癌组与对照组的分布频率分别为wt/wt 85.3％、wt/m2 14.7％和wt/wt 91.3％、wt/m2 8.7％,两者之间比较差异无统计学意义(P＞0.05).对照组中CYP2C19快代谢者占87％,慢代谢者占13％;肝癌组中快代谢者占72.1％,慢代谢者占27.9％,经统计学检验差异有显著性(P＜0.05).慢代谢型患肝癌的危险是快代谢型的2.6倍.结论 携带突变杂合型CYP2C19ml基因型者肝癌的易感性增加,CYP2C19慢代谢型与肝癌的风险有关.     

Single nucleotide polymorphisms of the human cyp2a13 gene: evidence for a null allele.

Human CYP2A13 is believed to be important in the metabolic activation of tobacco-specific nitrosamines in the respiratory tract; therefore, genetic polymorphisms of the CYP2A13 gene may be associated with interindividual differences in the risks of tobacco-related tumorigenesis. Our earlier studies identified a frequent single nucleotide polymorphism in CYP2A13 exon 5, Arg257Cys, which led to an approximate 50% decrease in metabolic activities. In the present study, three additional coding region mutations (Arg25Gln, Arg101Stop, and Asp158Glu) and several mutations in the introns and flanking regions were identified in a Chinese patient population. Of particular interest is the Arg101Stop mutation, which was due to a C > T change in exon 2. Thus, individuals homozygous for this nonsense mutation would not have a functional CYP2A13 protein and, therefore, might have reduced sensitivity to xenobiotic toxicity resulting from CYP2A13-mediated metabolic activation in the respiratory tract. The frequencies of the coding region mutations were further examined using random samples of white, black, Hispanic, and Asian newborns from New York. The frequency of the Arg25Gln mutation in Asian newborns (9.6%) was very similar to that found in the Chinese population (10.9%). On the other hand, the Arg101Stop mutation was not detected in 136 newborn samples examined (23 white, 21 black, 19 Hispanic, and 73 Asian), suggesting that this mutation may be unique for the Chinese patient population. Haplotype analysis indicated that the Arg25Gln and Arg257Cys mutations are parts of a common haplotype. However, an additional haplotype that consists of the 25Gln but not the 257Cys allele was also identified.     

CYP1A2 F21L and F186L polymorphisms in an Italian population sample

P450 cytochromes (CYPs) enzymes play a major role in variability of drug response and cancer susceptibility. In particular, up to 60-fold interindividual variation has been detected in the activity of CYP1A2, which is involved in the metabolism of caffeine, several drugs and various toxic and carcinogenic compounds. Aim of this study is to assess the frequency of CYP1A2 F21L and F186L polymorphisms (formerly CYP1A2(*)2 and (*)11 alleles), up to now found in Asiatic populations only. These variants were absent in 500 Italian healthy subjects. Therefore it can be suggested that the variation of CYP1A2-dependent metabolism in the Caucasian population is not related to these two CYP1A2 polymorphisms. Thus, this study supports the view that ethnicity is a relevant factor to be carefully considered in pharmacogenetic studies.     

Genetic predisposition to Parkinson's disease: CYP2D6 and HFE in the Faroe Islands

OBJECTIVE: To investigate whether the genetic variants of CYP2D6 and HFE are more frequent in Parkinson's disease (PD) patients compared with controls in a population where the prevalence of these variants and PD are increased. METHODS: Blood samples were collected from 79 PD patients and 154 controls in the Faroe Islands. Genotyping for the 'CYP2D6*3, *4, *6 and *9' alleles and for the C282Y and H63D mutations were performed by real-time polymerase chain reaction before Taqman assessment. RESULTS: The frequency of CYP2D6 poor metabolizers among the patients was not higher compared with the frequency found in the control group (chi2 test, P=0.86). The odds ratio was 0.92 (95% confidence interval: 0.44-1.90). Neither was a difference in HFE genotype or allele frequencies found between the patients and the controls, and the C282Y and H63D mutation carrier frequencies did not reveal any difference (chi2 test, P=0.50 and 0.60, respectively). CONCLUSION: This study does not support an association between PD and mutations of the CYP2D6 and HFE genes, although a weak association cannot be excluded. The high frequency of PD in the Faroes is most likely the result of interactions between multiple genetic and environmental factors, still to be identified.     

Genetic polymorphisms of the drug-metabolizing enzyme cytochrome P450 3A5 in a Uyghur Chinese population

1. Detection of CYP3A5 variant alleles, and knowledge about their allelic frequency in Uyghur ethnic groups, is important to establish the clinical relevance of screening for these polymorphisms to optimize pharmacotherapy.

2.?We used DNA sequencing to investigate the promoter, exons and surrounding introns, and 3′-untranslated region of the CYP3A5 gene in 96 unrelated healthy Uyghur individuals. We also used SIFT and PolyPhen-2 to predict the protein function of the novel non-synonymous mutation in CYP3A5 coding regions.

3.?We found 24 different CYP3A5 polymorphisms in the Uyghur population, three of which were novel: the synonymous mutation 43C?>?T in exon 1, two mutations 32120C?>?G and 32245T?>?C in 3′-untranslated region, and we detected the allele frequencies of CYP3A5*1 and *3 as 64.58% and 35.42%, respectively. While no subjects with CYP3A5*6 were identified. Other identified genotypes included the heterozygous genotype 1A/3A (59.38%) and 1A/3E (11.46%), which lead to decreased enzyme activity. In addition, the frequency of haplotype “TTAGGT” was the most prevalent with 0.781.

4.?Our data provide new information regarding CYP3A5 genetic polymorphisms in Uyghur individuals, which may help to improve individualization of drug therapy and offer a preliminary basis for more rational use of drugs.     

CYP1A1 and CYP1B1 genotypes, haplotypes, and TCDD-induced gene expression in subjects from Seveso, Italy

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is highly toxic in experimental animals, and is known to induce cytochrome P450 (CYP) gene expression. We investigated the effect of CYP1A1 and CYP1B1 variant genotypes and haplotypes on CYP1A1 and CYP1B1 mRNA expression and ethoxyresorufin-O-deethylase (EROD) activity in lymphocytes from 121 subjects from the Seveso population, Italy, accidentally exposed to TCDD in 1976. The 3'UTR 3801T>C and I462V variants of CYP1A1 were present in 16% and 6% of the subjects, respectively. The frequency of CYP1B1 variants was 85.2% for L432V, 49.6% for R48G and A119S, and 28.7% for N453S. There was complete linkage disequilibrium (LD) among the CYP1B1 variant loci (D'=-1) and high LD among the CYP1A1 loci (D'=0.86). Gene expression measured by RT-PCR did not vary by CYP1B1 genotype in uncultured lymphocytes. However, when lymphocytes were treated in vitro with 10 nM TCDD, CYP1B1 and CYP1A1 mRNA expression was strongly induced and modified by CYP variant alleles. Specifically, the CYP1B1*3 haplotype (L432V) was associated with increased CYP1B1 mRNA expression (P=0.03), following an additive model; the CYP1A1 I462V polymorphism was positively, although not significantly, associated with CYP1A1 expression. The CYP1B1*3 variant may have affected CYP1B1 expression in subjects highly and acutely exposed to dioxin at the time of the accident. Although based on small number of subjects, a slight increase in eczema (P=0.05, n=8) and urticaria (P=0.02, n=2) was observed 20 years after the accident in subjects carrying the CYP1B1*3 allele. Genetic variation in cytochrome P450 induction may identify subjects with variable responsiveness to TCDD and potentially increased risk of disease.     

A missense mutation in exon 6 of the CYP2D6 gene leading to a histidine 324 to proline exchange is associated with the poor metabolizer phenotype of sparteine

The sparteine/debrisoquine polymorphism is a clinically important genetic deficiency of cytochrome P4502136-catalyzed oxidative drug metabolism. 5–10% of Caucasians designated as poor metabolizers have a severely impaired capacity to metabolize more than 30 therapeutically used drugs. Genotyping of a random Caucasian population for the known cytochrome P4502D6 mutations A, B and D which are associated with the poor metabolizer phenotype has revealed a substantial number of misclassified poor metabolizers indicating the existence of one or more unknown mutations which cannot be identified with the currently available genotyping assays. Therefore we have cloned and sequenced one nonfunctional cytochrome P4502D6 allele of a. misclassified poor metabolizer and could identify a single missense mutation designated E mutation at position 3023^(A–C) in exon 6. Direct sequencing analysis, Fokl restriction analysis and a newly developed allele-specific polymerase chain reaction assay were applied to analyze for this mutation in a population study.Three out of 97 randomly selected Caucasians were carriers of this mutation and thus the E allele has a frequency of 1.5% (confidence interval_95% = 0.33–4.54%). Since only 2 out of 4 misclassified poor metabolizers carried the E mutation, additional unknown mutant alleles must exist.Computer modelling suggests that the E mutation, which results in a histidine to proline exchange in position 324 of the protein, may cause an alteration of the 3D structure of CYP2D6 in close vicinity to the active site thereby leading to total loss of enzyme function. Correspondence to. E.-U. Griese at the above address     

核苷类药与慢性HBV感染者病毒P基因准种及变异特点的关系

目的观察核苷类药治疗不同时间段慢性HBV感染患者血清乙肝病毒聚合酶(HBV P)基因准种变化及变异特点。方法运用焦磷酸测序仪器配套的软件Assay Design SW在目的区域两端保守区域设计PCR引物及测序引物,采用套式PCR方法检测血清中HBV DNA,按照Pyro-Mark ID遗传分析系统用SNP模式进行PCR产物(HBV P基因相关位点)的焦磷酸测序和突变频率检测。108例慢性HBV感染患者中用药史明确者同期测定HBV DNA、HBV标志物、ALT。结果108例患者中,61例发生变异,变异模式以经典突变L180M、M204V/I、A181V/T、N236T突变为主,有少量V173L、S202G、T184G突变;其中40例用药史明确患者中,18例发生变异,发生变异者耐药突变型在样本中所占比例为20%-100%,HBV P基因变异可以在HBV DNA、ALT发生突变前、中、后检出。结论焦磷酸测序可以快速检测HBV P基因变异;变异株突变频率变化可初步反映HBVP基因准种异质性;HBV P基因变异模式、突变频率与核苷类药物敏感性密切相关。     

突变体富集PCR法检测非小细胞肺癌病理组织EGFR基因突变

目的：建立突变体富集PCR法检测非小细胞肺癌病理组织中的EGFR基因突变。方法：选取55例细支气管肺泡癌和59例非小细胞肺癌病理组织蜡块，提取基因组DNA，采用不同的突变体富集PCR法（PCR-PAGE和PCR-RLFP）检测EGFR基因常见的19和21外显予突变，并经过直接测序验证。结果：在59例非小细胞肺癌中共检测出EGFR基因突变22例,突变率为37．3％（22／59）。55例细支气管肺泡癌中共检测出24例基因突变，突变率为43．6％（24／55）。经直接测序验证，EGFR19外显予有3种类型缺失突变。EGFR21外显予的错义突变为L858R。结论：突变体富集PCR法准确、快速、经济，便于临床筛查非小细胞肺癌病理组织中的EGFR基因突变。     

Elucidation of the genetic basis of the common 'intermediate metabolizer' phenotype for drug oxidation by CYP2D6

A subgroup of 10-15% of Caucasians are termed phenotypical 'intermediate metabolizers' of drug substrates of CYP2D6 because they have severely impaired yet residual in-vivo function of this cytochrome P450. Genotyping based on the currently known CYP2D6 alleles does not predict this phenotype satisfactorily. A systematic sequencing strategy through 1.6 kb of the CYP2D6 5'-flanking sequence revealed six mutations of which three were exclusively associated with the functional CYP2D6*2 allele (-1496 C to G; -652 C to T; and -590 G to A), two were associated with the nonfunctional *4 and with the functional *10-alleles (-1338 C to T and -912 G to A) and one (-1147 A to G) was seen in all *2, *4 and *10-alleles investigated. The -1496 C to G mutation was found to be polymorphic within CYP2D6*2 alleles. In a family study, the wild-type CYP2D6 *2[-1496 C] and the novel variant [-1496 G] allele co-segregated with lower and higher CYP2D6 in-vivo function, respectively, as shown by phenotyping using sparteine as probe drug. In a representative population sample selected for genotypes comprising one CYP2D6*2 and one non-functional allele, the median urinary metabolic ratio (MRs) for sparteine oxidation was 4.4-fold reduced in individuals with the variant allele (*2[-1496 G], MRs = 0.53, n = 27) compared with individuals lacking the mutation (*2[-1496 C], MRs = 2.33, n = 12; P < 0.0001). The mutation -1496 C to G has an estimated frequency of approximately 20% in the general population and allows establishment of a genotype for the identification of over 60% of intermediate metabolizers in Caucasian populations.     

Determination of -3858G-->A and -164C-->A genetic polymorphisms of CYP1A2 in blood and saliva by rapid allelic discrimination: large difference in the prevalence of the -3858G-->A mutation between Caucasians and Asians

Introduction Two mutations in CYP1A2, –164CA (allele CYP1A2*F) and –3858GA (allele CYP1A2*C), affecting the inducibility of the enzyme, have been published. The aim of this study was to develop a high throughput allelic discrimination assay for these mutations in both saliva and blood and to determine their frequency in Caucasians.Methods An allelic discrimination assay, based on the fluorogenic 5-nuclease activity (TaqMan), was developed for the two mutations. Genomic DNA extracted from 17 saliva and 100 blood samples from Caucasians was analysed.Results and conclusions For the –164CA mutation, we found an allelic frequency of 68% in the Caucasian population, comparable with data published for Asians and Caucasians. For the –3858GA mutation, the allele frequency was only 2% in Caucasians, a much lower value than the ~25% reported in Asians (P<0.001). The presented allelic discrimination allows fast and accurate detection of these two mutations. Genotype calls were 100% identical for DNA from saliva and blood. Saliva is easily accessible and represents an excellent alternative to the traditionally used venous blood for genotyping.