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Genetic polymorphisms of the renin-angiotensin system and angiographic extent and severity of coronary artery disease: the CORGENE study.

Genetic polymorphisms of the renin-angiotensin system (RAS) have been associated with coronary artery disease (CAD) but no relation between these polymorphisms and coronary atherosclerosis has yet been systematically evaluated. The CORGENE study is a cross-sectional study involving 463 Caucasians who underwent standardized coronary angiography for established or suspected CAD [156 patients with a previous myocardial infarction (MI), 307 without MI]. Four angiographic scores assessing the extent and severity of the coronary lesions were obtained from a double visual analysis of each angiogram, arbitration being achieved by a quantitative measurement. Three different genotypes were analyzed: the angiotensin I-converting enzyme insertion/deletion (ACE I/D) polymorphism, the Met to Thr change at position 235 of the angiotensinogen gene (AGT M235T) and the A to C transition at position 1166 of the angiotensin II type-1 receptor gene (AT1R A1166C). No significant association was observed between these polymorphisms and the clinical characteristics of MI and non-MI subjects. While most classical risk factors were positively correlated with the angiographic scores, no significant relationship could be established with the three genotypes (r ranging from -0.08 to 0.05). Only one significant correlation was observed: between the presence of the AGT 235T allele and the extent of the coronary lesions (r = -0.19, P = 0.04) in patients with low-risk status. These overall results are not in favor of a role of these RAS genetic polymorphisms in the development of coronary atherosclerosis.

Angiotensinogen↗

Genetic polymorphism of CYP2C9 and CYP2C19 in a Bolivian population: an investigative and comparative study.

OBJECTIVE: Several reports of CYP2C genetic polymorphism demonstrate its potential clinical role in determining both inter-individual and inter-ethnic differences in drug efficacy. We estimated the distribution of CYP2C9 and CYP2C19 common variants in the Bolivian population (a South American population), and compared these data with those from Asian, African, Caucasian and Oceanian populations. METHODS: Genomic DNA was obtained from 778 unrelated healthy volunteers from Bolivia. The genotypic status of CYP2C9 and CYP2C19 was determined by means of polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Allelic and genotypic frequencies of CYP2C9 and CYP2C19 were determined for the Bolivian population, and comparison of the data with other ethnic groups revealed a lower CYP2C9*2 frequency (4.8%) than in Caucasians, but a higher frequency than in Asians; frequencies of CYP2C9*3 (3.0%) and CYP2C9 (0.4%) poor metabolizers (PMs) were similar to those seen in Asian populations. Frequencies of CYP2C19*2 (7.8%), CYP2C19*3 (0.1%), and CYP2C19 PMs (1.0%) in the Bolivian population were for the most part lower than in Caucasian, Asian, Oceanian and African populations. CONCLUSION: This is the first study to investigate a South American population for genetic polymorphism in the CYP2C subfamily. The Bolivian population differs from most other ethnic groups in the incidence of CYP2C9 and CYP2C19 common variants that might be influenced by its admixture characteristics.

Adolescent↗

Newly characterized genetic polymorphism of uropepsinogen group A (PGA) using both isoelectric focusing and immunoblotting.

Genetic polymorphism of uropepsinogen group A (PGA) was characterized in human urine using a technique involving both polyacrylamide gel isoelectric focusing and immunoblotting with an anti-PGA antibody. PGA was clearly separable into five fractions, termed I to V in order of decreasing anodal mobility. The most slowly migrating fraction V was composed of F (fast) and/or S (slow) band(s). The population frequencies of the three patterns of fraction V (F, FS, and S) and family studies indicated that PGA V is controlled by a pair of alleles, PGA V*F and PGA V*S, at a single autosomal locus, and that both are codominant. The frequencies of the genes are 0.07 for PGA V*F and 0.93 for PGA V*S.

Humans↗

Genetic polymorphism of CYP2D6 and CYP2C19 metabolism determined by phenotyping Israeli ethnic groups.

Genetic polymorphism of the cytochrome P450 isoenzymes CYP2D6 and CYP2C19 was determined by phenotyping four ethnic groups of the Israeli population. The groups consisted of Ethiopian subjects, Yemenite subjects, and Russian subjects representing first-generation new immigrants and an Israeli Arab group. Dextromethorphan was used as the probe for CYP2D6 activity and mephenytoin was used for CYP2C19 activity. The two drugs were administered simultaneously and urine samples were collected over a period of 8 hours. The CYP2D6 phenotype was determined from the ratio of dextromethorphan conversion to dextrorphan and the CYP2C19 phenotype from the ratio of S-mephenytoin and R-mephenytoin. The used liquid chromatographic method was able to completely separate dextrorphan and dextromethorphan. Fluorescence detection allowed dextromethorphan quantification at 1 ng/mL. Mephenytoin enantiomers were completely separated in high-performance liquid chromatography and the respective fractions were collected and analyzed using a gas chromatography/mass spectrometry system with selective ion monitoring. The prevalence of poor metabolizer phenotype of dextromethorphan (CYP2D6) in the Yemenite (0%) and Ethiopian groups (0%) was significantly different from the prevalence in the Russian (17%) and Israeli Arab (9%) groups. A significant difference was also found in the distribution of the metabolic ratio of the extensive metabolizer phenotype between the Ethiopian group and the Russian and Yemenite groups. No significant difference was found in the prevalence of poor mephenytoin metabolizer phenotype (CYP2C19) between the Yemenite (8%), Ethiopian (6%), Russian (9%), and Israeli Arab (8%) groups. No difference was observed in the distribution of metabolic ratio within the extensive metabolizer phenotype subgroups of the four ethnic groups.

Adult↗

Distributive characteristics of Ser49Gly and Gly389Arg genetic polymorphisms of beta1-adrenoceptor in Chinese Han and Dai populations.

AIM: Genetic polymorphisms causing Ser49Gly and Gly389Arg mutants of beta(1)-adrenoceptor may result in significant changes in the function of this receptor. The aim of the present study was to investigate the frequencies of the Ser49Gly and Gly389Arg mutant alleles in healthy Chinese populations and to investigate the differences between 2 Chinese ethnic groups (Han and Dai populations) with respect to the frequencies of these alleles. METHODS: A total of 225 Han Chinese and 175 Dai Chinese unrelated healthy volunteers were recruited for this study. Genomic DNA was extracted from peripheral blood leukocytes by using a standard manual chloroform-phenol extraction. Fragments spanning the 2 polymorphisms were amplified by using polymerase chain reaction with template genomic DNA and relevant primers. The DNA products including the polymorphic loci were subjected to restriction endonuclease digestion with Eco0109I and BcgI. Digested fragments were detected with an ultraviolet detector after electrophoresis (100 V for approximately 1.5 h). RESULTS: The frequencies of the Gly49 and Arg389 alleles were, respectively, 16.2% and 76.4% in the Han population and 14.6% and 75.7% in the Dai population. CONCLUSION: The polymorphisms causing the Ser49Gly and Gly389Arg mutations of the beta(1)-adrenoceptor existed in both healthy Han and Dai Chinese populations. The frequencies of the Ser49Gly and Gly389Arg mutant alleles were not significantly different in the Han and Dai populations. However, the frequency of the Gly389 variant seems to be significantly lower in these 2 populations than in an African-American population.

Adolescent↗

Genetic polymorphism of glycine-rich beta-glycoprotein in the Italian population.

Genetic polymorphism of glycine-rich beta-glycoprotein (GBG) was studied in populations from northern and southern Italy, respectively. Gene frequencies were as follows: northern Italy (n = 431): GbS = 0.7675, GbF = 0.2049, GbS 0.7 = 0.0127, GbF1 = 0.0139; southern Italy (n = 161): GbS = 0.7050, GbF = 0.2360, GbS 0.7 = 0.0373, GbF1 = 0.0217. Comparison of these two populations with the Swiss population revealed a significant drift in gene frequencies from north to south. A new GBG phenotype, supposedly heterozygous, with a slow migrating F band and a regular S band in agarose electrophoresis was observed.

Complement Factor B↗

Genetic polymorphism of alpha-2-HS-glycoprotein in a Spanish population.

The genetic polymorphism of alpha-2-HS-glycoprotein (AHSG) was analyzed in 489 unrelated individuals living in Madrid (central Spain), by isoelectric focusing in miniaturized polyacrylamide gels followed by immunoblotting. The allele frequencies were estimated to be 0.7147 and 0.2771 for AHSG*1 and AHSG*2, respectively. In addition to the common alleles, 3 rare variants (AHSG*3, AHSG*10 and AHSG*11) have been found in this study.

Alleles↗

Lack of association between Caucasian lung cancer risk and O6-methylguanine-DNA methyltransferase-codon 178 genetic polymorphism.

The formation of DNA adducts is thought to be a critical step for the induction of chemically induced cancer. O(6)-Methylguanine-DNA methyltransferase (MGMT) is a ubiquitously expressed enzyme that repairs DNA adducts formed by alkylating carcinogens. Thus, genetic polymorphisms of the MGMT that could result in differences in MGMT activity are potential risk factors for cancer. In the present study, we established a convenient and reliable genotyping method for the MGMT codon 178 polymorphism, a Lys (AAG) to Arg (AGG) substitution, using restriction fragment length polymorphism (RFLP), and studied differences in the distribution of this polymorphism in 92 Caucasian lung cancer patients and 85 controls. Frequencies of the "A" and "G" alleles (MGMT codon 178, AAG and AGG, respectively) were 0.91 and 0.09, respectively. The genetic polymorphism of the MGMT codon 178 was linked with that of the MGMT codon 143 (P < 0.05). The distribution of the MGMT codon 178 genetic polymorphism was not significantly different between lung cancer patients and controls. Thus, our study suggests that the MGMT codon 178 (and possibly 143) polymorphisms do not appear to markedly affect lung cancer risk for this population. In addition, we found an apparent 10bp-deletion in the intron before exon 5 by DNA sequencing. Because this "deletion" was observed in all sequenced samples (N = 20), the previously reported human (Caucasian) MGMT gene sequence should be revised to exclude this 10bp segment.

Codon↗

The association of endometriosis risk and genetic polymorphisms involving dioxin detoxification enzymes: a systematic review.

Genetic polymorphisms involving genes encoding for dioxin detoxification enzymes have been implicated as a risk factor for endometriosis, but individual studies have been equivocal and controversial. We therefore performed a systematic review of 10 studies on association of endometriosis and various genes involved in dioxin detoxification process excluding GSTM1/GSTT1. We found that almost all genetic variants involving CYP1A1, CYP2E1, EPHX1, AHR, ARNT, AHRR, and NAT1 that have been investigated by single studies show no association with endometriosis. Two genetic variants were reported to be associated with endometriosis, with each variant only investigated by a single study and there has been no independent confirmation so far. For CYP1A1 MspI polymorphisms, women with +/- and +/+ genotype have about 40% of increased risk of endometriosis as compared with women of -/- genotype. However, there is no strong indication that CYP1A1 MspI polymorphism is consistently associated with endometriosis. For NAT2 polymorphisms, there is no evidence that it is associated with endometriosis.

Aryl Hydrocarbon Receptor Nuclear Translocator↗

Human CYP4F12 genetic polymorphism: identification and functional characterization of seven variant allozymes.

The human cytochrome CYP4F12 has been shown to be metabolically active toward inflammatory mediators and exogenous compounds such as antihistaminic drugs. We recently identified a genetic polymorphism within the promoter region, associated with a decreased level of enzyme expression. In the present study, we report the further identification of single nucleotide polymorphisms in the coding sequence of the CYP4F12 gene. A polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis of DNA samples from 53 unrelated French Caucasians, allowed the identification of ten mutations, comprising seven missense mutations, 31C>T (Leu11Phe), 38C>T (Pro13Leu), 47C>T (Met16Thr), 4759G>A (Asp76Asn), 4801G>A (Val90Leu), 8896C>T (Arg188Cys) and 23545G>A (Gly522Ser). Their functional impact toward ebastine hydroxylation was evaluated using heterologous expression in Saccharomyces cerevisiae cells of site-directed mutated cDNA variants. Five out seven variants did not exhibit any significant difference in CYP4F12 catalytic activity, whereas two variants, Val90Ile and Arg188Cys, displayed significant changes in their Michaelis-Menten (Km, Vm) parameters. These data on CYP4F12 genetic polymorphism provide tools for further studies of association with pathological processes involving an inflammatory component and with variations in anti-histaminic drug response.

Aryl Hydrocarbon Hydroxylases↗

Genetic polymorphism of IgG in mink. II. A genetic analysis of allotypes.

Population distribution and inheritance pattern were analyzed in mink IgG allotypes: L1 (L chains), H2, H3, H4, H6, H7, and H8 (the constant region of the H chains, i.e. C gamma-allotypes) and conformational allotype 5 with unknown chain localization. Contrary to expectation, neither allelism, nor close linkage were demonstrated for these allotypes. The major feature of the inheritance of H2, H3, and H4 C gamma-allotypes, as well as allotype 5, was significant excess of negative (without these allotypes) progeny in the F1 generation from monohybrid cross. The explanation offered for this departure of the C gamma-allotypes from normal Mendelian genetics suggests widespread latencies of their expression in mink.

Animals↗

Genetic polymorphism of interleukin-8 (IL-8) is associated with Helicobacter pylori-induced duodenal ulcer.

BACKGROUND AND AIMS: Helicobacter pylori infection almost invariably causes chronic gastritis, but only a proportion of the infected subjects develop peptic ulcers. The local inflammation associated with H. pylori infection is characterized by an increased production of the proinflammatory cytokines IL-1-B, IL-6, IL-8 and TNF-alpha. Since such cytokine production is often determined by the genetic polymorphism of regions regulating cytokine gene expression, we investigated the relationship between TNF-alpha and IL-8 polymorphisms and the development of duodenal ulcer disease. We also sought a correlation between the promoter polymorphism of the lipopolysaccharide (LPS) receptor CD14 and the formation of peptic ulcer, because CD14 plays a crucial role in the initiation of the cytokine cascade. METHODS: Genomic DNA extracted from the peripheral blood of 69 patients with H. pylori-positive duodenal ulcer disease and 47 H. pylori-positive healthy controls was analyzed for TNF-alpha -308 promoter polymorphism by RFLP, and for IL-8 -251 polymorphism by ARMS. Genetic polymorphism within the promoter of the CD14 gene was identified using the LightCycler instrument via melting point analysis. RESULTS: No significant correlation could be revealed between the TNF-alpha and CD14 promoter polymorphisms and the clinical outcome of H. pylori infection. The IL-8 A/T heterozygote mutant variant was detected with a significantly higher frequency (65.22%) among the ulcer patients than among the healthy, H. pylori-positive blood donors (36.17%), while the frequency of the normal allelic genotype (TT) was significantly higher in the control group (44.6% vs 15.9%). CONCLUSION: Analysis of the genetic predisposition to enhanced cytokine production revealed a significant association only for the IL-8 polymorphism. This observation draws attention to the possible importance of IL-8 polymorphism as a genetic predisposing factor in the pathomechanism of H. pylori-induced duodenal ulcer disease, and to the relative protection from duodenal ulcer disease that is associated with the TT genotype.

Adult↗

Association of CYP1A2 genetic polymorphisms with hepatocellular carcinoma susceptibility: a case-control study in a high-risk region of China.

OBJECTIVES: Aflatoxin B1 exposure is one of the major risk factors for hepatocellular carcinoma (HCC). CYP1A2 is a cytochrome P450 isoenzyme that plays an important role in the bioactivation of AFB1 to its carcinogenic metabolite. The study was designed to assess whether genetic polymorphisms in CYP1A2 are associated with HCC susceptibility in a high-risk region. METHODS: A case-control study of 431 HCC cases and 550 cancer-free controls recruited from an HCC endemic region in China was carried out. Three single nucleotide polymorphisms, namely -3860G > A (CYP1A2*1C), -3113G > A, and 5347T > C (CYP1A2*1B) were genotyped by polymerase chain reaction-restriction fragment length polymorphism methods. RESULTS: Homozygous carriers of the major haplotype -3860G/-3113G/5347C were associated with increased HCC susceptibility in the overall population (odds ratio [OR] = 1.65, 95% confidence interval [CI]: 1.11-2.46, P = 0.014), in HBsAg seronegative individuals (OR = 2.69, 95% CI: 1.43-5.06, P = 0.002), and in heavy smokers (OR = 2.14, 95% CI: 1.21-3.80, P=0.009). In addition, individuals carrying at least one CYP1A2*1C allele showed significantly decreased HCC risk (OR = 0.49, 95% CI: Q0.27-0.86, P = 0.013) in the HBsAg seronegative subpopulation. Furthermore, as compared with HBsAg seropositive patients, wild-type homozygotes of the CYP1A2*1C polymorphism were significantly over-represented in HBsAg seronegative patients (P = 0.024). No significant association between CYP1A2 genetic polymorphisms and HCC risk was observed in either HBsAg seropositive individuals or non-smokers. CONCLUSIONS: CYP1A2 genetic polymorphisms are associated with HCC susceptibility in smokers and HBsAg seronegative individuals in the Fusui endemic region.

Adult↗

Absence of CYP3A genetic polymorphism assessed by urinary excretion of 6 beta-hydroxycortisol in 102 healthy subjects on rifampicin.

A previous study has demonstrated that the urinary level of 6 beta-hydroxycortisol is a marker of liver CYP3A content after induction by rifampicin. To put in evidence an eventual genetic polymorphism for this cytochrome, the frequency distribution of 6 beta-hydroxycortisol excretion was investigated in 102 healthy Caucasians before and after 6 days of oral rifampicin administration (600 mg daily). After rifampicin treatment, a wide interindividual distribution was observed but no clear bimodality. Moreover the mean 6 beta-hydroxycortisol level was higher in women (n = 38) than in men (n = 64). These observations do not favour the existence of a CYP3A genetic polymorphism based on 6 beta-hydroxycortisol excretion but evoke a sexual dimorphism. However, CYP3A is composed of at least four enzymes and as the enzyme(s) responsible for cortisol 6 beta-hydroxylation is (are) not perfectly known, it can not be excluded that a genetic polymorphism does exist for one enzyme of this family.

17-Hydroxycorticosteroids↗

[XRCC1 and XPD genetic polymorphisms predict clinical responses to platinum-based chemotherapy in advanced non-small cell lung cancer].

OBJECTIVE: DNA repair system plays an important role in tumor sensitivity to platinum-based chemotherapy. The purpose of this study was to examine the association between polymorphisms in XRCC1 and XPD, which are involved in DNA repair, and clinical responses to platinum-based chemotherapy in advanced non-small cell lung cancer (NSCLC). METHODS: XRCC1 Arg194Trp and XPD Lys751Gln were genotyped by PCR-RFLP method in 200 patients with advanced NSCLC who received platinum-based chemotherapy. Unconditional logistic regression model was used to analyze the association between genetic polymorphisms and clinical responses. RESULTS: The overall response rate (CR + PR) was 36.0%, including 1 CR, 72 PR, 94 SD and 34 PD. The XRCC1 194Trp allele carriers had higher response rate than the subjects with the Arg/Arg genotype (adjusted OR, 2.48; 95% CI, 1.36 - 4.51, P = 0.003). However, the XPD Lys751Gln polymorphism was not found to be associated with the platinum-based chemotherapy. These two genetic polymorphisms may have some interaction in the drug sensitivity, the P value for the trend was significant (P = 0.004). CONCLUSION: Those results suggest that the XRCC1 Arg194Trp and XPD Lys751Gln genetic polymorphisms may be associated with clinical responses to platinum-based chemotherapy in advanced non-small cell lung cancer.

Adult↗

Decreased coumarin 7-hydroxylase activities and CYP2A6 expression levels in humans caused by genetic polymorphism in CYP2A6 promoter region (CYP2A6*9).

One of seven poor metabolizers of coumarin found in Thai subjects was previously genotyped as heterozygote for the CYP2A6*4 (whole deletion) and CYP2A6*9. Thus, we aimed to investigate the relationship between the genetic polymorphism in the TATA box of the CYP2A6 gene (CYP2A6*9), expression levels of CYP2A6 mRNA and coumarin 7-hydroxylase activities in human livers. Levels of CYP2A6 mRNA were quantified by real-time quantitative reverse transcriptase-polymerase chain reaction. The mean expression levels of CYP2A6 mRNA in individuals with CYP2A6*1/*4, CYP2A6*1/*9 and CYP2A6*4/*9 were 58%, 71% and 21% of the individuals genotyped as CYP2A6*1/*1, respectively. The mean in-vitro coumarin 7-hydroxylase activities in subjects carrying CYP2A6*1/*4, CYP2A6*1/*9 and CYP2A6*4/*9 were 41%, 71% and 12%, respectively, compared to those of the subjects judged as wild-type. Vmax values for coumarin 7-hydroxylation in the liver microsomes from human subjects with genotypes of CYP2A6*1/*1, CYP2A6*1/*4, CYP2A6*1/*9 and CYP2A6*4/*9 were 0.58, 0.26, 0.44 and 0.13 nmol/min/nmol total P450, respectively. CYP2A6 protein levels in human liver microsomes with the CYP2A6*4 and the CYP2A6*9 alleles were markedly decreased. These results suggest that the genetic polymorphism in the promoter region of the CYP2A6 gene (CYP2A6*9) reduced the expression levels of CYP2A6 mRNA and protein in human livers, resulting in the decrease of coumarin 7-hydroxylase activities. Individuals judged as CYP2A6*4/*9 were expected to be poor metabolizers, having extremely low activity of CYP2A6.

Adult↗

Effect of genetic polymorphisms of MnSOD and MPO on the relationship between PAH exposure and oxidative DNA damage.

To investigate the effect of genetic polymorphisms on the oxidative damage caused by PAH exposure, we measured urinary 1-hydroxypyrene (1-OHP) and 8-hydroxydeoxyguanosine (8-OHdG) levels to determine exposure and oxidative injury in university students. After examining myeloperoxidase (MPO) and manganese superoxide dismutase (MnSOD) genotypes by PCR and RFLP, we evaluated the effects of these polymorphisms on the relationship between the urinary levels of 1-OHP and 8-OHdG. No significant relation was observed between log 1-OHP and 8-OHdG concentrations in the whole study group (p=0.182), or between urinary 8-OHdG levels and polymorphisms of MnSOD or MPO (p=0.539 and 0.993, respectively). However, significant differences of regression coefficient were found for the relation between urinary log 1-OHP and urinary 8-OHdG concentrations in the presence of different MnSOD or MPO genotypes by multiple regression after controlling for age, sex, body mass index, cotinine, and smoking. In those with the MnSOD Val/Ala or Ala/Ala genotypes this regression coefficient was 1.480 (p=0.040), whereas for the MnSOD Val/Val genotype it was 0.088 (p=0.859). The higher regression coefficient was obtained for the subject group with the MnSOD Val/Ala or Ala/Ala genotype in combination with the MPO G/G genotype (p=0.012). We suggest that the oxidative injury caused by PAH exposure is modulated by genetic polymorphisms such as MnSOD and MPO.

Base Sequence↗

Genetic polymorphisms of cytochrome P4502E1 related to the development of alcoholic liver disease.

BACKGROUND/AIMS: Because heavy drinkers do not always develop alcoholic liver disease (ALD), genetic factors may be involved. Cytochrome P4502E1 is the main enzyme that oxidizes ethanol in the non-alcohol dehydrogenase pathway. Recently, the presence of genetic polymorphisms of this enzyme was confirmed. In the present study, the genotypes of P4502E1 were analyzed in patients with or without ALD. METHODS: After extraction of DNA from white blood cells, genotypes of P4502E1 were determined by restriction fragment length polymorphisms using two endonucleases. The genotypes were separated into three types: type A, type C (homozygous for the c1 or c2 gene), and type B (heterozygous for both genes). RESULTS: In 50 patients with ALD, the prevalence of type A was 16% and that of the c2 gene was 84%. The genotypes in 10 heavy drinkers without ALD were all type A. In 34 patients with non-alcoholic liver disease and in 88 patients without hepatobiliary disease, the prevalence of type A was 65% and 71%, respectively, indicating a significantly higher prevalence of the c2 gene in ALD. In healthy nonalcoholics, the prevalence of type A was 62%-68%. CONCLUSIONS: These results suggest that polymorphisms of P4502E1 may be related to the development of ALD.

Acetaminophen↗