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Results for “Genetic polymorphisms”

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At least 811 records · Page 45Linked to original sources
PubMed2002

[Genetic polymorphism of erythrocytic enzymes in Yakut populations].

Polymorphism of the erythrocytic enzymes PGM1, ACP1, ESD, and GLO1 was found in Yakut populations. The allelic frequencies of the polymorphic systems studied varied within the following ranges: PGM1*1+, 0.5833-0.7791; PGM1*1-, 0.0345-0.1176; PGM1*2+, 0.1250-0.2813; ACP1*A, 0.1429-0.3382; ACP1*B, 0.6548-0.8571; ESD*2, 0.1250-0.4643; and GLO1*1, 0.0116-0.2845.

Acid Phosphatase↗
PubMed2002

[Genetic polymorphisms of the renin-angiotensin system and essential hypertension].

BACKGROUND: The renin-angiotensin system (RAS) is known to regulate the blood pressure (BP). Several RAS polymorphisms have been associated with essential hypertension (EH), but there is uncertainty about this association. We examined whether the insertion/deletion (I/D) polymorphism of the angiotensin converting enzyme (ACE) gene, and the M235T polymorphism of the angiotensinogen (AGT) gene were associated with EH in a sample of Spanish hipertensive patients. PATIENTS AND METHOD: We studied 1,204 patients with EH (BP > 140/90 mmHg): 668 males, aged 50.8 (13.6) years with systolic BP 151.7 (19.1) and diastolic BP 94.3 (13) mmHg [mean (SD)] and 536 females, aged 52.4 (13.9) years with systolic BP 155.1 (19.8) and diastolic BP 94.5 (12.3) mmHg. As a control group, 367 men and 280 women with no family history of cardiovascular disease who had a normal blood pressure were included. Polymorphisms were determined by PCR amplification of genomic DNA, followed by enzyme digestion for the AGT gene polymorphism. RESULTS: The genotype distribution and allele frequencies of the two RAS polymorphisms were similar in hypertensive and control subjects. Similarly, there were no differences in BP level with regard to the genotype in male or female patients. In addition, we did not find any compound effect of the I/D ACE gene and M235T AGT gene polymorphisms on BP levels in hypertensive subjects. CONCLUSIONS: This study suggests that in the population studied, the contribution of the ACE I/D polymorphism and the AGT M235T polymorphism in the development of EH is less important than previously estimated.

Female↗
PubMed2002

Association studies of serum prostate-specific antigen levels and the genetic polymorphisms at the androgen receptor and prostate-specific antigen genes.

Testing for serum prostate-specific antigen (PSA) levels has been widely used to screen for prostate cancer. However, PSA testing has low specificity and sensitivity because PSA is not prostate cancer-specific. PSA is encoded by the APS gene, and the expression of this gene is regulated by androgens. W. Xue et al. Cancer Res., 60: 839-841, 2000 reported recently that serum PSA levels are associated with a G/A polymorphism at androgen responsive element 1 (ARE1) of APS and/or the CAG repeats in exon 1 of the androgen receptor (AR) gene. This result, if confirmed, may significantly increase the specificity and sensitivity of PSA testing by incorporating genotype-specific thresholds. In this study, we tested for the association between serum PSA levels and these single nucleotide polymorphisms (SNPs) in a large sample of 518 men. For the AR gene, we observed slightly (but not statistically significant) higher mean serum PSA levels in men with shorter CAG repeats (<or=21) or shorter GGC repeats (<or=16). For the ARE1 of the APS, we found slightly (but not statistically significant) lower PSA levels in men with the AA genotype. It is worth noting that this observation is opposite to the findings of W. Xue et al. Cancer Res., 60: 839-841, 2000. We hypothesize that the effects of ARE1 and AR genotypes on mean PSA levels may reflect the effect of other causal polymorphisms in these genes, which are in linkage disequilibrium with these polymorphisms. A systematic approach is required to identify sequence variants in these genes and other related genes, and to test for an association between these variants and PSA levels in large samples.

Adult↗
PubMed2002

[Genetic polymorphisms, function and clinical effect of HLA-G].

HLA-G is a non-classical major histocompatibility complex class I molecule that differs from the classical HLA I class molecules by (1) a limited polymorphism, (2) a tissue-restricted distribution and (3) a transcription of spliced messenger RNAs encoding for at least four membrane-bound and two soluble HLA-G isoforms. Extensive studies over the past few years have identified HLA-G as a molecule involved in immune tolerance. In this review, attempts were made to summarize the current state of knowledge of the polymorphisms, expression, function, the effects of HLA-G on immuno-associated disease, evolution of HLA-G and its utility in disease therapy.

Alleles↗
PubMed2001

Dissecting the contradictory findings of angiotensin converting enzyme genetic polymorphism with blood pressure and hypertension.

The studies on the association of deletion/insertion (D/I) polymorphism of angiotensin converting enzyme (ACE) gene with blood pressure and hypertension reported contradictory results. We review the articles that considered blood pressure or hypertension as the main outcome measure to have an overview of the situation. There is heterogeneity of allele frequencies of ACE locus among ethnic groups. In descending order of D allele frequencies, ethnic groups are: Gulf Bedouin (0.657), Black (0.597), White (0.577), Chinese (0.400), Japanese (0.377), Bangladeshi (0.374) and Indian Sikh (0.373). Multiple studies were available for the Caucasians and Japanese with relatively large sample sizes. Three out of five studies in the Caucasians found association either in males or in females with blood pressure or hypertension. None of the three Japanese studies observed an association. So, ACE locus may be considered a marker for blood pressure or hypertension in the Caucasians but not in the Japanese. This racial difference is not surprising, because heterogenecity of ACE activity according to ACE genotypes has been reported among ethnic groups, and important differences in environmental factors persist. Studies in other populations were either small or sampling procedures were not adequately described. Given that the studies varied in designs, settings, sample size, and adjustment for confounding variables, adequately powered large-scale multicentre, multi-ethnic population-based studies using same method are required to resolve this contradiction.

Adult↗
PubMed2002

Genetic polymorphism of CYP2A6 gene and tobacco-induced lung cancer risk in male smokers.

Cytochrome P450 2A6 (CYP2A6) is the principal enzyme involved in the metabolic activation of tobacco-specific nitrosamines to their ultimate carcinogenic forms and metabolism of nicotine. We investigated the effects of the CYP2A6*4, an entire CYP2A6 gene deletion-type polymorphism, on lung cancer risk and daily cigarette consumption in Japanese male smokers via a hospital-based case control study. The frequency of the CYP2A6*4 variant was compared in 370 lung cancer patients and 380 control smokers. A markedly reduced adjusted odds ratio for lung cancer risk, 0.23 [95% confidence interval, 0.08-0.67], was seen in the group with homozygous deletion (*4/*4) when the odds ratio for a group with homozygous wild (*1A/*1A) was defined to be 1.00 by logistic regression. The subjects with lung cancer were additionally divided into three groups according to the histological classification of the cancer and examined for an association with the CYP2A6 polymorphism. The *4/*4 genotype was not found in patients with squamous cell carcinoma (0 of 105) or small cell carcinoma (0 of 44), indicating that subjects with the *4/*4 genotype have low risk for lung cancers, particularly those caused by tobacco smoke. Furthermore, a significant reduction of daily cigarette consumption was observed in smokers with the *4/*4 genotype, suggesting a possibility that complete lack of CYP2A6 appeared to affect the smoking behavior. These data suggest that male smokers possessing the *1A/*1A genotype have higher risk for tobacco-induced lung cancers.

Adult↗
PubMed2002

Red meat intake, CYP2E1 genetic polymorphisms, and colorectal cancer risk.

N-Nitroso compounds are suspected colorectal cancer (CRC) carcinogens to which individuals on a diet high in red meat (RM) may be particularly exposed. Many of these compounds undergo alpha-hydroxylation by CYP2E1 to form DNA adducts. The gene coding for this enzyme is polymorphic and thus may constitute a susceptibility factor for CRC. We conducted a population-based case-control study in Hawaii to test the association of two functional polymorphisms in CYP2E1 (the G1259C RsaI substitution and a 5' 96-bp insertion variant) with CRC, as well as their modifying effects on the association of RM and processed meat (PM) with this cancer. We obtained interviews and blood samples for 521 patients with CRC (165 with rectal cancer) and 639 controls of Japanese, Caucasian, or Hawaiian origin. Genotyping was performed by PCR. After adjustment for CRC risk factors, subjects with the 5' insert variant were found to be at a 60% increased risk (95% confidence interval, 1.1-2.5) for rectal cancer. Subjects who carry the insert and who were predicted to have been exposed to increased levels of nitrosamines, based on their high intake of RM or PM, were at a markedly greater increased risk (2- and 3-fold for RM and PM, respectively) for rectal cancer. No clear association was found for colon cancer. A similar increase in rectal cancer risk was found for CYP2E1 insert carriers who consumed salted/dried fish or Oriental pickled vegetables. These data provide additional support for the hypothesis that nitrosamines are carcinogenic to the rectum in humans and that RM and, in particular, PMs are significant sources of exposure for these compounds.

Case-Control Studies↗
PubMedDate not supplied

[One carbon metabolism and trisomy 21: analysis of the genetic polymorphism].

Trisomy 21 is the most common chromosome abnormality characterized by the presence of three copies of chromosome 21 in the genome. The clinical disorder attributed to trisomy 21 is Down syndrome. Patients with Down syndrome are heterogeneous in their phenotypic expression. Due to the location of the cystathionine b-synthase gene on chromosome 21, and its involvement in one carbon metabolism, homocysteine levels have been found to be decreased in children with Down syndrome. The study of the regulation of one carbon metabolism in Down syndrome becomes important in light of possible normalization of the metabolic imbalance and the detection of increased sensitivity to therapeutic interventions. Thus, the importance of evaluating single nucleotide polymorphisms in genes involved in one carbon metabolism need to be addressed in individuals with trisomy 21. This review offers an analysis of the impact of these polymorphisms in Down syndrome and their possible implications for phenotypic heterogeneity.

Carbon↗
PubMed2003

[Review of relationship between tumor necrosis factor genetic polymorphism and hematological malignancies].

Patients with malignant tumor including hematological malignancies have high plasma levels of tumor necrosis factor (TNF) and excessive production of TNF is associated with polymorphic variation of TNF locus. TNF polymorphism affects TNF expression by affecting transcriptional regulation. The aim of this paper was to review the correlation between TNF polymorphism and hematological malignancies such as lymphoma, chronic lymphocytic leukemia, hairy cell leukemia, acute lymphocytic leukemia and multiple myeloma and to make preparation for further research of their relationship.

Hematologic Neoplasms↗