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Results for “Genetic polymorphism”

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At least 847 records · Page 47Linked to original sources
PubMed2004

[Genetic polymorphisms of alcohol-metabolizing enzymes and cytokines in patients with alcohol induced pancreatitis and alcoholic liver cirrhosis].

BACKGROUND/AIMS: Susceptibility to organ damage induced by alcohol may be related to inherited variations (polymorphisms) in alcohol-metabolizing enzymes, or polymorphisms affecting cytokines. The aim of this study was to compare the genotype and allelic frequencies of ADH2, ADH3, ALDH2, cytochrome P450-2E1, IL-1, IL-6, IL-8 and tumor necrosis factor-alpha in patients with alcoholic pancreatitis and alcoholic liver cirrhosis with those of controls. METHODS: We determined the polymorphism of genes of the above-mentioned alcohol-metabolizing enzymes and cytokines in 29 alcoholic pancreatitis patients (AP), 22 alcoholic liver cirrhosis patients (LC) and 100 healthy blood donors (control). The genotypes were characterized by restriction fragment length polymorphism after amplification of genomic DNA by polymerase chain reaction. RESULTS: The allelic frequency of CYP2E1*c2 was significantly different in three groups (AP: LC: Control=0.224: 0.136: 0.320, p<0.05). There was no significant difference in the other genotypes or allelic frequencies of the three groups. The allelic frequencies of CYP2E1*c2 and ALDH2*2 were more frequent in the control than patients with alcoholic liver cirrhosis (LC: Control=0.136: 0.320, p<0.05, LC: Control= 0.114: 0.265, p<0.05). Allelic frequencies of ADH2 was statistically different between LC and control (ADH2*1; LC: Control=0.727: 0.495, ADH2*2; 0.227: 0.360, ADH2*3; 0.046: 0.145, p<0.05). CONCLUSIONS: There was no difference in the frequencies of genotype and allele of enzymes and cytokines among the three groups. However, frequency of ADH2*1 was significantly higher and those of CYP2E1*c2 and ALDH2*2 were significantly lower than LC group than control.

Adult↗
PubMed2004

[Role of cholesteryl ester transfer protein activity and genetic polymorphism in ischemic heart disease in type 2 diabetic patients].

Cholesteryl Ester Transfer Protein (CETP) facilates the exchange of triglycerides (TG) and cholesteryl ester between lipoproteins particles. Diabetic subjects have been reported to have higher TG levels and lower high density lipoprotein-cholesterol (HDL-C) levels which contribute to the increased cardiovascular risk observed in some of these patients. The CETP activity was shown to be more important in a group of 93 non insulino-dependant diabetics with coronary artery disease than in a group of 92 healthy subjects (p = 0.033). Several polymorphisms have been reported in the CETP gene. The common Taq IB polymorphism is associated with decreased CETP activity and increased HDL-C. We have observed a frequency of 0.31 for B2 allele in deference to those reported in subjects from Caucasian population. An association between the presence of the B2B2 genotype, decreased CETP activity and increased of plasma HDL-C was observed in healthy subjects but not in diabetics with coronary artery disease.

Adult↗
PubMed2004

5, 10-Methylenetetrahydrofolate reductase (MTHFR) 677 C --> T genetic polymorphism in 228 Croatian volunteers.

5, 10-Methylenetetrahydrofolate Reductase (MTHFR) is one of the key enzymes in the metabolism of homocysteine, where it catalyses its remethylation. The autosomal recessive bp 677 C --> T mutation in the MTHFR gene leads to the substitution of valine for alanine. Individuals who are homozygous for this C677T mutation exhibit a decreased specific activity and increased thermolability of this enzyme. This leads to increased plasma levels of homocysteine, which is a known risk factor for atherosclerosis and various manifestations of the atherosclerotic disease. The aim of this study was to find out the distribution and frequency of this mutation in the general Croatian population. A group of 228 volunteers (175 males and 53 females) has been analyzed for the MTHFR polymorphism, which revealed the following distribution: 105 (46.05%) individuals were without mutation (C/C), 102 (44.74%) were heterozygous (C/T) and 21 (9.21%) homozygous (T/T). These findings are within the results of studies on other European populations.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed2003

Cyp17 genetic polymorphism in prostate cancer and benign prostatic hyperplasia.

Steroid hormones, especially androgens, are believed to play a key role in the etiology of prostate cancer. Therefore, polymorphisms in genes involved in the androgen metabolism may affect the risk of prostate cancer. One such gene is CYP17, which encodes the cytochrome P450c17alpha enzyme that mediates both 17alpha-hydroxylase and 17,20-lyase in the steroid biosynthesis pathway. A polymorphism in the 5'-promoter region of the CYP17 gene has been associated with increased risk for prostate cancer. The T to C transition in the risk allele creates a new recognition site for the restriction enzyme MspA1. In this study we investigated the distribution of this polymorphism in the Turkish population and its association with prostate cancer and benign prostatic hyperplasia. Genotype frequencies in the patients with prostate cancer or prostatic hyperplasia and the control group were not significantly different. Our data provide no evidence for an association between prostate cancer risk and the CYP17 gene polymorphism.

Adult↗
PubMed2002

[Genetic polymorphism of pyruvate dehydrogenase kinase 4 (PDK4), paraoxonase 2 (PON2), and fatty acid binding protein 2 (FABP2) in the NIDDM population of Senegal].

We reported a study about three candidate genes which may be involved in non-insulin dependent diabetes mellitus (NIDDM): Pyruvate Dehydrogenase Kinase 4 (PDK4), Paraoxonase 2 (PON2) and Fatty Acid Binding Protein 2 (FABP2). The reported mutation in the three candidate genes were tested for 179 black subjects from Dakar (Sénégal) by PCR-RFLP techniques. There was no significant difference between both control and NIDDM subjects. The genotype frequency in the senegalese population was quite similar as compared to reported frequency in white populations excepted for PDK4 polymorphism. These results suggest that none of these gene variants is a major NIDDM predisposing locus for the negroid population of Senegal.

Adolescent↗
PubMed2005

[Genetic polymorphism of Y-chromosome short tandem repeat in Elunchun ethnic group of China].

OBJECTIVE: To reveal the allelic frequencies and haplotype frequencies of ten Y-chromosome short tandem repeats(STR) loci (DYS392, DYS438, DYS439, DYS456, DYS459, DYS460,DYS461, DYS462, DYS389I and DYS389II systems) in an Elunchun population sample. METHODS: PCR and polyacrylamidegel electrophoresis(PAGE) followed by silver staining were performed to analyze the blood samples from 102 unrelated Elunchun male individuals. RESULTS: The allele diversity values for each locus ranged from 0.418(DYS461) to 0.727(DYS389 I). Gene diversities were higher than 0.5 except DYS462(0.479) and DYS461 (GATAA7.2)(0.418). Furthermore, 101 haplotypes from 10 Y-chromosome STRs loci were found in the sample and a high haplotype diversity 0.99 was determined. CONCLUSION: The above findings suggest that the ten Y-chromosome STR loci are valuable Y-specific markers for establishing Y-STR database, understanding human origin, paternity testing and personal identification.

China↗
PubMedDate not supplied

Genetic polymorphisms of CYP2E1 and GSTP1 in a South Indian population--comparison with North Indians, Caucasians and Chinese.

CYP2E1 and GSTP1 enzymes belong to phase I and phase II group of drug metabolizing enzymes respectively which are involved in the metabolic activation and detoxification of various potential genotoxic compounds. The functional polymorphism in these genes exhibit inter-individual variations in susceptibility towards various diseases and difference in therapeutic response. The variant sequences of these genes differ considerably between ethnic groups. Therefore, the objective of the study was to assess the prevalence of CYP2E1 & GSTP1 gene variants in healthy volunteers of Tamilnadu, a population of South India. The genotype distribution of CYP2E1*1B A2A2, A2A1 and A1A1 were 61%, 36% and 3% respectively. The distribution of CYP2E1*5B c1c1, c1c2 genotypes were 99.2%and 0.8%. CYP2E1*6 DD, DC and CC genotype frequencies were 72%, 25% and 3% respectively. The allele frequencies of CYP2E1*1B, CYP2E1*5B and CYP2E1*6 were A2- 0.79 A1- 0.21, c1-0.996 c2 - 0.004 and D- 0.84 C- 0.16 respectively. The genotypic distribution of GSTP1 (Ile/Val) were Ile/Ile - 44%, Ile/Val -47% and Val/Val- 9 % whereas, the allelic frequencies were 0.67 for Ile and 0.33 for Val allele. The molecular studies in these enzymes provide basis for further epidemiological investigations in the population where the functional mutations in the genes alter therapeutic response and acts as susceptibility markers for various clinical conditions.

Adult↗
PubMed2005

[Effects of oxidative DNA damage induced by polycyclic aromatic hydrocarbons and genetic polymorphism of the paraoxonase-1 (PON1) gene on lung cancer].

OBJECTIVES: Polycyclic aromatic hydrocarbons (PAHs), which are risk factors for lung cancer, have been reported to induce oxidative DNA damage. The paraoxonase (PON) plays a significant role in the detoxification of a variety of organophosphorous compounds, with paraoxonase-1 (PON1) being one of the endogenous free-radical scavenging systems in the human body. The aim of this case-control study was to investigate the effects of PAH exposure, oxidative stress and the Q192R polymorphism of PON1 genes, and their interactions in the carcinogenesis of lung cancer. METHODS: One hundred and seventy seven lung cancer patients and 177 age- and sex-matched controls were enrolled in this study. Each subject was asked to complete a questionnaire concerning their smoking habits and environmental exposure to PAHs. The Q192R genotypes of the PON1 gene was examined, and the concentrations of urinary 1-hydroxypyrene (1-OHP), 2-naphthol and 8-hydroxydeoxyguanosine (8-OH-dG) measured. RESULTS: Cigarette smoking was found to be a significant risk factor for lung cancer. The urinary 8-OH-dG level was higher in the patients, whereas the urinary 1-OHP and 2-naphthol levels were higher in the controls. There was a significant correlation between the urinary levels of 8-OH-dG and 1-OHP in both the cases and controls. The PON1 polymorphism was associated with an increased risk of lung cancer. Individuals carrying the Q/Q genotype of the PON1 gene were found to be at higher risk of developing lung cancer. There was a significant correlation between the urinary levels of 8-OH-dG and 1-OHP in those with the PON1 Q/Q genotype. CONCLUSIONS: These results lead to the conclusion that PAHs would induce oxidative DNA damage, especially in individuals with the PON1 Q/Q genotype. Therefore, people with the PON1 Q/Q genotype would be more susceptible to lung cancer than those with the R/R or Q/R genotypes of the PON1 gene.

Aryldialkylphosphatase↗
PubMedDate not supplied

[Protease and reverse transcriptase genetic polymorphism in HIV type 1 subtype A variants predominating in cis countries].

To define frequencies of drug resistance mutations among HIV-1 variants circulating within the territory of Russia, subtype A HIV-1 nucleotide sequences encoding protease and reverse transcriptase were analyzed. The analysis was carried out in 141 antiretroviral-naive individuals. Low frequency (less than 1%) of primary drug resistance mutations was shown. However, high frequencies of secondary mutations V77I in protease and A62V in RT (67% H 63%, respectively) linked to each other in most cases were observed. The HIV-1 isolates bearing both substitutions (MutV77I/A62V) were also characterized by the presence of several synonymous mutations, suggesting common origin for these viruses. HIV Biochip Hybridization microarray and/or Restriction fragment-length polymorphism analyses were performed to characterize gene pol polymorphism in additional 178 subtype A HIV-1 isolates. Among total 319 samples studied, Mutv77IA62V variant accounted for 56%, and was found to predominate in Russia in terms of both its geographical distribution and number of cases caused. Moreover, these viruses were prevalent in the regions known to have highest incidence of HIV-1 infection (Irkutsk, Samara, and Moscow regions). In addition, three other variants were found: viruses not containing the substitutions V77I or A62V, and variants bearing only one of them. Evolutional relationships between all four HIV-1 variants, as well as potential impact of the gene pol polymorphism on HIV-1 replicative fitness and drug resistance development are discussed.

Amino Acid Substitution↗
PubMed1992

Genetic polymorphism of IgG in the mink. VIII. A quantitative study of the expression of C gamma-allotypes (H3, H4, H6, H8) in sera.

The results of a quantitative study of the expression of mink C gamma-allotypes (H3, H4, H6, and H8) in sera are presented. H6 and H8 were found to be stably expressed, and the individual concentrations of the allotypes varied within one order of magnitude. Gene dosage effects were observed for H6 and H8: average sera allotype concentrations in homozygotes were twice those in heterozygotes. In contrast, the serum concentrations of H3 and H4 varied by three orders of magnitude, ranging from minor (2-200 micrograms/ml) to high (1-10 mg/ml). No gene dosage effects were observed for the expression of H3 and H4. Histograms for the population of H3 concentrations showed three peaks, sharply differing from those of H4, H6, and H8. There was no association between the minor expression of H3 and H4. The data obtained indicate that the expression of mink C gamma-allotypes is regulated by different allotype-specific mechanisms.

Animals↗
PubMed1992

Apolipoprotein A-IV genetic polymorphism and its impact on quantitative traits in normoglycemic and non-insulin-dependent diabetic Hispanics from the San Luis Valley, Colorado.

Apolipoprotein A-IV exhibits a common two-allele polymorphism in several human populations studied to date. Using isoelectric focusing and immunoblotting, we have analyzed plasmas from 188 non-insulin-dependent diabetic and 238 normoglycemic Hispanic individuals from the San Luis Valley, Colorado, to determine APOA4 genotype frequencies and to estimate the impact of the genotypes on quantitative traits. The frequencies of the two common alleles, APOA4*1 and APOA4*2, were 0.929 and 0.069, respectively, in normal subjects and 0.901 and 0.096, respectively, in diabetics. The third rare allele, APOA4*3, was detected sporadically in both groups. We studied the impact of APOA4 polymorphism on the levels of total plasma cholesterol, HDL cholesterol and its subfractions (HDL3 and HDL2), LDL cholesterol, triglycerides, glucose, and insulin. We observed no significant effect of the APOA4 polymorphism on any trait in diabetics. However, we did note a significant sex-specific effect in normoglycemic females on the level of total HDL cholesterol (p = 0.001) and its subfractions HDL2 (p = 0.043) and HDL3 (p = 0.001). The effect of the APOA4*2 allele in normal Hispanic females was to lower the total HDL, HDL2, and HDL3 cholesterol by 8.75 mg/dl, 2.37 mg/dl, and 5.36 mg/dl, respectively, compared to the common APOA4*1 allele.

Adult↗
PubMedDate not supplied

SV40, genetic polymorphism and mesothelioma. pathological and epidemiological evidence.

BACKGROUND: Asbestos exposure is the only cause of epidemiological relevance for pleural malignant mesothelioma (MM), but the mechanism of action is not entirely understood. A causal role was suggested for SV40 since viral DNA and proteins were detected in pleural MM and SV40 caused MM in hamsters. SV40 proteins (Tag) interact with oncogenes P53 and Rb. OBJECTIVES: To review evidence on the association of SV40 with MM, bearing in mind laboratory and epidemiological studies. METHODS: The review on SV40 was based on scientific papers published since 1990 on association of SV40 with human cancer. RESULTS: Studies researching SV40 DNA in MM tissue observed a wide range of prevalences (0% to 70%); causes of variability were not convincingly identified. An association of MM with SV40 was suggested but confounding factors and biases were not considered. Cohort studies on humans inoculated with contaminated vaccines did not show an increased incidence but their statistical power was limited. Diffusion of SV40 in humans is linked to polio vaccines produced in 1955-63 from SV40-infected monkeys. A 11-12% prevalence of SV40 in adults were reported in the USA, 2-6% in Europe and Africa. The age pattern of MM does not suggest a cohort effect related to contaminated vaccines. DISCUSSION: Association of SV40 with human MM is suggested from laboratory observations but still lacks confirmation in well designed epidemiological studies. Other putative co-factors in MM occurrence are mutations in genes involved in repair of damage caused by asbestos, notably DNA-repair genes. Preliminary observations are available but epidemiological studies are needed to test this hypothesis.

Africa↗