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PubMed1997

CYP2D6, NAT2 and CYP2E1 genetic polymorphisms in nonagenarians.

BACKGROUND: enzymatic polymorphisms affecting the metabolic disposition of xenobiotics may modulate the rate of activation or deactivation of carcinogens and other toxic environmental chemicals. Hence, these polymorphisms may influence the risk of suffering some types of cancer and other degenerative diseases that are incompatible with extreme longevity. AIMS: to establish the distribution of three well known enzymatic polymorphisms that affect the CYP2D6, NAT-2 and CYP2E1 genes and the activity of their enzymatic gene products, involved in the disposition of many xenobiotics, in a group of nonagenarians and in much younger controls. PATIENTS: the three genotypes were determined in 41 nonagenarians (10 males, mean age 92.2 years, range 90-98) free of known malignancies or neurodegenerative diseases. The control groups comprised 217 healthy volunteers (128 males, mean age 36.3 years; SD, 12.7) for the CYP2D6 and NAT2 genotypes and 137 (116 males, mean age 32 years; SD, 18.8) for the CYP2E1 genotype. METHODS: after extraction of DNA from white blood cells, polymerase chain reaction and restriction fragment polymorphism methods were used to identify the allelic variants of the three genotypes. RESULTS: we found no qualitative or quantitative difference in the mutations underlying the three genetic polymorphisms studied, nor in the expected enzymatic phenotypes. Instead, a close parallelism exists between advanced age and younger groups. CONCLUSION: longevity does not seem to be related to any special configuration of these three polymorphic traits. Comparisons with younger controls may be adequate when studying the distribution of these polymorphisms in diseases affecting old people. No genetically determined differences in the activation of drugs metabolized by these enzymes are to be expected in very old people.

Aged↗

PubMed2002

Sex hormone-binding globulin polymorphisms in familial and sporadic breast cancer.

Ovarian steroids are one of the strongest risk factors for breast cancer. Sex hormone-binding globulin (SHBG) binds and transports sex steroids in the blood, regulating their bioavailable fraction and access to target cells. It can also inhibit the estradiol-induced proliferation of breast cancer cells through its membrane receptor. Three coding-region polymorphisms, which lead to an amino acid change, have been reported. We studied the influence of these three polymorphisms on breast cancer risk in three different populations: Polish familial breast cancer cases, 27% of them carrying a BRCA1/BRCA2 mutation, Nordic familial and sporadic breast cancer cases. The reported G to A polymorphism in exon 1 was not found in the 423 analyzed samples. Instead, we found a C to T transition causing an arg to cys amino acid change within the same codon in one Polish breast cancer patient and her daughter. Both of them were heterozygotes for the exon 8 G to A polymorphism as well. They were diagnosed for bilateral breast cancer and carried a BRCA1 mutation (5382insC). Analysis of the tumor samples showed that they had lost the wild-type allele both at exons 1 and 8 of the SHBG gene. Analysis of the other Polish samples showed no correlation of the exon 8 polymorphism to breast cancer, bilateral breast cancer, BRCA1/BRCA2 mutations or age at diagnosis. No association of the exon 8 polymorphism with breast cancer in the Nordic familial or sporadic cases was found. The C to T polymorphism located in exon 4 was rare in all the studied populations (overall allele frequency 0.011). However, in each of the study populations there was a trend for a lower variant allele frequency in cancer cases than in controls. Variant allele frequency in all the breast cancer cases was significantly lower than in all the controls (chi(2) = 5.27, P-value 0.02; odds ratio = 0.23, 95% confidence interval 0.05-0.84).

Adult↗

PubMed2005

CYP1A1 and CYP1B1 polymorphisms and risk of lung cancer among never smokers: a population-based study.

The cytochrome P450 (CYP) superfamily of enzymes catalyse one of the first steps in the metabolism of carcinogens such as polycyclic aromatic hydrocarbons, nitroaromatics and arylamines. Polymorphisms within the CYP1A1 gene have been shown to be associated with lung cancer risk, predominantly among Asian populations. Despite functional evidence of a possible role of CYP1B1 in lung cancer susceptibility, only a few studies have evaluated polymorphisms in this gene in relation to lung cancer susceptibility. This population-based study evaluates polymorphisms in both of these CYP genes within never smokers, most of whom had environmental tobacco smoke (ETS) exposure. Cases (n = 160) were identified through the metropolitan Detroit Surveillance, Epidemiology and End Results program, and age, sex and race-matched population-based controls (n = 181) were identified using random digit dialing. Neither CYP1A1 MspI nor CYP1A1 Ile(462)Val was associated with lung cancer susceptibility among Caucasians or African-Americans. Among Caucasians, however, CYP1B1 Leu(432)Val was significantly associated with lung cancer susceptibility odds ratio (OR) for at least one valine allele = 2.87 [95% confidence interval (CI) 1.63-5.07]. Combinations of this Phase I enzyme polymorphism along with selected Phase II enzyme polymorphisms (GSTM1 null, GSTP1 Ile(105)Val and NQO1 C(609)T) were evaluated. The combination of CYP1B1 Leu(432)Val and NQO1 C(609)T appeared to be associated with the highest risk of lung cancer (OR = 4.14, 95% CI 1.60-10.74), although no combinations differed significantly from the risk associated with CYP1B1 Leu(432)Val alone. When individuals were stratified by household ETS exposure (yes/no), CYP1B1 Leu(432)Val alone and in combination with Phase II enzyme polymorphisms was more strongly associated with increased lung cancer susceptibility among those with at least some household ETS exposure. Additional studies will be required to further validate these findings among never smokers and to evaluate the effects of this polymorphism among smoking populations as well.

Adenocarcinoma↗

PubMed2005

One-carbon metabolism related gene polymorphisms interact with alcohol drinking to influence the risk of colorectal cancer in Japan.

One-carbon metabolism, in which folate plays an essential role, is involved in DNA methylation and synthesis, and is suspected of impacting on colorectal carcinogenesis. Alcohol is well recognized as a risk factor for colorectal cancer (CRC) and interactions with one-carbon metabolism have also been suggested. Therefore, functional polymorphisms in genes encoding members of this pathway, MTHFR C677T and A1298C (genes for methylenetetrahydrofolate reductase), MTR A2756G (gene for methionine synthase) and TS (gene for thymidylate synthase) tandem repeats polymorphisms, have attracted attention. We conducted a matched case-control study with 257 incident CRC cases and 771 non-cancer controls at the Aichi Cancer Center to clarify associations among folate intake and four polymorphisms with reference to CRC risk. Gene-environment interaction between polymorphisms, drinking and folate consumption was also evaluated. None of the polymorphisms showed any significant impact on CRC risk by genotype alone, but when combined with alcohol consumption the MTHFR 677CC type showed a significantly reduced risk (odds ratio (OR) = 0.45, 95% confidence interval (CI): 0.23-0.86) (P = 0.01). MTR GG showed increased risk only among drinkers (OR = 3.35, 1.40-8.05) (P = 0.047). TS polymorphism did not show statistical significance by genotype alone, while interaction with drinking was significant (P = 0.028). The association was not changed even after stratification by daily folate consumption and drinking habit. In conclusion, we found consistently significant interactions between one-carbon metabolism-related polymorphisms and alcohol drinking.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗

PubMed1987

Natural selection and Y-linked polymorphism.

Several population genetic models allowing natural selection to act on Y-linked polymorphism are examined. The first incorporates pleiotropic effects of a Y-linked locus, such that viability, segregation distortion, fecundity and sexual selection can all be determined by one locus. It is shown that no set of selection parameters can maintain a stable Y-linked polymorphism. Interaction with the X chromosome is allowed in the next model, with viabilities determined by both X- and Y-linked factors. This model allows four fixation equilibria, two equilibria with X polymorphism and a unique point with both X- and Y-linked polymorphism. Stability analysis shows that the complete polymorphism is never stable. When X- and Y-linked loci influence meiotic drive, it is possible to have all fixation equilibria simultaneously unstable, and yet there is no stable interior equilibrium. Only when viability and meiotic drive are jointly affected by both X- and Y-linked genes can a Y-linked polymorphism be maintained. Unusual dynamics, including stable limit cycles, are generated by this model. Numerical simulations show that only a very small portion of the parameter space admits Y polymorphism, a result that is relevant to the interpretation of levels of Y-DNA sequence variation in natural populations.

Biometry↗

PubMed1993

Nucleotide polymorphism in the Adh1 locus of pearl millet (Pennisetum glaucum) (Poaceae).

We investigated nucleotide polymorphism in the Adh1 locus of pearl millet (Pennisetum glaucum) (Poaceae) by determining the DNA sequence of 20 alleles from 10 individuals. The individuals were sampled from throughout pearl millet's indigenous range and represent both wild and cultivated accessions. Our results indicated that there is little nucleotide polymorphism in the Adh1 locus. Estimates of per site nucleotide polymorphism did not differ significantly between cultivated and wild millet accessions. We compared nucleotide polymorphism in pearl millet Adh1 with nucleotide polymorphism in maize (Zea mays) Adh1 and conclude that the maize Adh1 sample is more polymorphic. Increased polymorphism in maize Adh1 may be attributable, in part, to faster substitution rates in the maize lineage. Analysis suggests that substitution rates in the maize Adh1 lineage are approximately 1.7 times faster than substitution rates in the millet Adh1 lineage.

Alcohol Dehydrogenase↗

PubMed2003

Haplotype analysis of the CETP gene: not TaqIB, but the closely linked -629C-->A polymorphism and a novel promoter variant are independently associated with CETP concentration.

The TaqIB polymorphism in intron 1 of the cholesteryl ester transfer protein (CETP) gene is associated with plasma CETP concentration, high-density lipoprotein cholesterol (HDL-C) and coronary artery disease (CAD). These associations are generally thought to arise from linkage disequilibrium between TaqIB and (an)other functional polymorphism(s). To identify putative functional sites, we investigated phenotypic associations of TaqIB and four tightly linked polymorphisms (novel -2708G-->A and +784CCC-->A, and previously identified -971G-->A and -629C-->A) in 709 males with CAD (REGRESS). In addition to genotype analyses, a novel method to estimate haplotype effects was used to examine the individual and joint effects of these DNA variants on CETP concentration and HDL-C. All polymorphisms were associated with CETP concentration and HDL-C, except for -971 with HDL-C. Stepwise regression and haplotype analyses indicated that only -629 was independently associated with HDL-C. Similar analyses additionally indicated that -2708 and -629 were independently associated with CETP concentration, whereby the most frequent alleles acted in a cumulative manner. Nonetheless, detailed haplotype analysis revealed that a 3-polymorphism haplotype model consisting of -2708, -629 and -971 explained the variation in CETP concentration best. The involvement of -971 could be due to interaction effects that were observed between -971 and both -629 (P<0.001) and -2708 (P=0.047). In conclusion, the TaqIB polymorphism is not instrumental in determining CETP or HDL-C levels, but is a marker for the -629 promoter variant. Our analyses, furthermore, indicate that the -2708 and -971 polymorphisms are likely to play a role in determining CETP concentration.

Aged↗

PubMed2003

Genetic association of Alzheimer's disease with multiple polymorphisms in alpha-2-macroglobulin.

Alpha-2-Macroglobulin (A2M) is a highly plausible candidate gene for Alzheimer's disease (AD) in a region of chromosome 12 that has numerous independent reports of genetic linkage. We previously reported that a 5 bp deletion in A2M was associated with AD in a subset of the National Institute of Health (NIMH) Genetics Initiative AD family sample. Efforts to replicate this association finding in case - control samples have been largely negative, while those in family samples have been more positive. We hypothesized that variable findings regarding this deletion, along with variable reports of association with V1000I, another polymorphism in the gene, result from linkage disequilibrium in the area as well as ascertainment differences between family-based and case-control studies. Thus, we resequenced the A2M locus to identify novel polymorphisms to test for genetic association with AD. We identified seven novel polymorphisms and tested them in the full NIMH sample of 1439 individuals in 437 families. We found significant genetic association of the 5 bp deletion and two novel polymorphisms with AD. Substantial linkage disequilibrium was detected across the gene as a whole, and haplotype analysis also showed significant association between AD and groups of A2M polymorphisms. Several of these polymorphisms and haplotypes remain significantly associated with AD even after correction for multiple testing. Taken together, these findings, and the positive reports in other family-based studies, continue to support a potential role for A2M or a nearby gene in AD. However, the negative case - control studies suggest that any underlying pathogenic polymorphisms have a modest effect, and may operate primarily among individuals with a family history of AD.

Aged↗

PubMed2005

Polymorphisms in the FCN2 gene determine serum variation and function of Ficolin-2.

The ficolin 1, 2 and 3 (derived from the FCN1, 2 and 3 genes, respectively) are homologous soluble pattern recognition molecules of importance for innate immunity, comprising collagen-like and fibrinogen-like domains, binding to sugar groups on different types of microorganisms. Serum concentration of Ficolin-2 varies considerably in healthy individuals. Thus, we speculated whether this could be due to variations in the FCN2 gene. We sequenced the promoter region and the exons and intron-exon boundaries of FCN2 in Danish Caucasians. For comparison, FCN1 and FCN3 were also investigated. Ficolin-2 concentrations were measured in serum and the functional relevance of amino acid substituting polymorphisms in FCN2 was investigated by binding to and recovery from N-acetylglucosamine (GlcNAc). Both FCN1 and FCN2 contained polymorphisms in the promoters and structural parts of the genes, but only polymorphisms in FCN2 resulted in amino acid exchanges. FCN2 promoter polymorphisms were associated with marked changes in the Ficolin-2 serum concentration, whereas two polymorphisms clustered in the exon encoding the fibrinogen-like domain were associated with increased and decreased GlcNAc binding, respectively. In FCN3, only a single frame-shift deletion in exon 5 was detected. These results show that the FCN genes are polymorphic and that particularly FCN2 harbors functional polymorphic sites that regulate both the expression as well as the function of Ficolin-2, which may have pathophysiological implications for innate immunity.

Acetylglucosamine↗

PubMed2006

Phosphodiesterase 4D polymorphisms and the risk of cerebral infarction in a biracial population: the Stroke Prevention in Young Women Study.

An association between polymorphisms within the phosphodiesterase 4D gene (PDE4D) and ischemic stroke was initially reported in older adults from Iceland and has been supported by studies in several other primarily elderly populations. In the present study, we examined the association between PDE4D polymorphisms and early-onset ischemic stroke in a biracial female population. A systematic search for polymorphisms in the highly evolutionary conserved regions of PDE4D was performed on 48 African-American and 48 Caucasian participants. Novel and known polymorphisms were then prioritized and genotyped in the entire study population of 224 cases of first ischemic stroke among women aged 15-49 and 211 age- and ethnicity-balanced control subjects. Forty novel and previously reported polymorphisms with a minor allele frequency greater than 0.05 were determined, with 23 polymorphisms selected for analysis in the full case-control sample. Single nucleotide polymorphism (SNP), linkage disequilibrium and haplotype analyses were performed. SNP rs918592, found in an intron near the 5' end of the gene, was significantly associated with stroke (age- and race-adjusted odds ratio (OR=1.5, P=0.007), with four other SNPs showing significant, albeit less strong, associations. The magnitude of association was similar across African-Americans and Caucasians and across multiple stroke subtypes (e.g. atherosclerotic, lacunar and non-lacunar of undetermined etiology). The association of rs918592 with stroke was confined exclusively to current smokers (OR=3.2, P=0.00014), with no association observed among never-smokers (OR=0.9, P=0.75) or former smokers (OR=1.2, P=0.66), demonstrating a gene-environment interaction (P=0.03). A strong dose-response relationship was also seen among current smokers. No specific risk haplotypes were identified.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2005

Estrogen-metabolizing gene polymorphisms and age at natural menopause in Caucasian women.

BACKGROUND: Lifestyle parameters, personal history and genetic factors are thought to affect the timing of natural menopause in humans. Based on their biological function, estrogen-metabolizing gene polymorphisms have been regarded as candidate genes for early menopause. METHODS: In the present cross-sectional, multi-centre study, we analysed nine single nucleotide polymorphisms of six estrogen-metabolizing genes [three estrogen-synthesizing genes, i.e. 17-beta-hydroxysteroid dehydrogenase type 1 (17-beta HSD), cytochrome P-450 (CYP) 17 and CYP19; and three estrogen-inactivating genes, i.e. catechol-O-methyltransferase (COMT), CYP1A1 and CYP1B1] by sequencing-on-chip-technology in 1360 Caucasian women with natural menopause. Women's lifestyle parameters, reproductive and personal histories were ascertained. RESULTS: Carriage of at least one mutant allele of the CYP1B1-4 Asn453Ser A--> G polymorphism (P = 0.004) and the number of full-term pregnancies (P < 0.001) were found to be independently associated with age at natural menopause. Women with at least one polymorphic allele of CYP1B1-4 experienced natural menopause earlier than non-carriers of the polymorphism [mean (SD) 48.6 (5.0) versus 49.4 (4.3) years]. Women with no, one, two and three or more full-term pregnancies experienced natural menopause at 48.5 (5.0), 48.8 (4.8), 49.5 (4.2) and 49.6 (4.6) years, respectively. CONCLUSION: We present the most comprehensive data on estrogen-metabolizing gene polymorphisms and timing of natural menopause to date. The number of full-term pregnancies and the CYP1B1-4 polymorphism are significant predictors of timing of natural menopause in Caucasian women.

Adult↗

PubMed2004

Prediction of bone mineral density from vitamin D receptor polymorphisms is uncertain in representative samples of Japanese Women. The Japanese Population-based Osteoporosis (JPOS) Study.

BACKGROUND: Vitamin D receptor (VDR) gene polymorphisms have been inconsistently associated with bone mineral density (BMD). To precisely evaluate the associations between three VDR gene polymorphisms and BMD, we performed a large-scale representative study of the Japanese female population. METHODS: Fifty women were randomly selected from each of the 5-year age stratified populations (15-79 years) in each of the three municipalities examined, as a part of the Japanese population-based osteoporosis (JPOS) baseline study in 1996. In the study, BMD at the lumbar spine, hip, and distal forearm were measured using dual energy X-ray absorptiometry (DXA). Two polymorphisms were determined in the VDR gene locus identified by the restriction endonucleases ApaI and TaqI through a novel allele discrimination method using two different allele-specific fluorescence probes. The other VDR gene polymorphism was identified by the restriction endonuclease FokI using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Changes in BMD were determined in a follow-up study 3 years after the baseline study. RESULTS: After the exclusion of women who had any medical or menstrual history affecting BMD, 1434 women were analysed. The annual per cent changes in BMD at the lumbar spine over 3 years in subjects with tt genotype in the TaqI polymorphism were different from other genotypes, both in the women who were premenopausal at the follow-up survey (F-premenopausal women) and in the women who were postmenopausal at the baseline survey (B-postmenopausal women). However, the effects of tt genotype on change in BMD were opposite in the two groups. In addition, these associations or tendencies were not observed at the different skeletal sites. CONCLUSIONS: This study revealed that none of the individual VDR gene polymorphisms displayed consistent association with baseline BMD or BMD change. Therefore, the effect of the VDR genotype on bone mass is negligible in Japanese women.

Adolescent↗

PubMed2002

Association between glutathione S-transferase P1, T1, and M1 genetic polymorphism and survival of patients with metastatic colorectal cancer.

BACKGROUND: Members of the glutathione S-transferase (GST) superfamily are important in cellular defense mechanisms. These enzymes attach reduced glutathione to electrophilic groups in a wide variety of toxic compounds, including chemotherapeutic agents. Certain polymorphisms in GSTs are associated with changes in enzyme activity, sensitivity to chemotherapy, and overall patient survival. In a retrospective study, we investigated associations between common polymorphisms in genes for several GST subclasses (GSTP1, GSTT1, GSTM1) and survival of patients with metastatic colorectal cancer receiving 5-fluorouracil (5-FU)/oxaliplatin chemotherapy. METHODS: During 1998-2000, 107 previously treated patients with advanced colorectal cancer received 5-FU/oxaliplatin combination chemotherapy. Associations between deletion polymorphisms in GSTM1 and GSTT1 genes and between a polymorphism in the GSTP1 gene that generates an Ile(105)Val in the GSTP1 protein and survival were evaluated using relative risks (RRs) of dying and the log-rank test. All statistical tests were two-sided. RESULTS: Patients heterozygous for the GSTP1 polymorphism had an RR = 0.47 (95% confidence interval [CI] = 0.27 to 0.81) compared with patients homozygous for the GSTP1 (105)Ile allele. Patients homozygous for the mutant polymorphism had an RR = 0.16 (95% CI = 0.04 to 0.63). After adjustment for performance status and tumor site, the stratified RRs were 0.28 (95% CI = 0.07 to 1.10) for patients with two (105)Val alleles and 0.64 (95% CI = 0.36 to 1.16) for those with one (105)Val allele (P =.042). Patients with the (105)Val/(105)Val genotype survived a median of 24.9 months, those with the (105)Ile/(105)Ile genotype a median of 7.9 months, and those with the (105)Ile/(105)Val genotype a median of 13.3 months (P<.001). The GSTM1 and GSTT1 genotypes were not associated with survival or clinical response. CONCLUSIONS: The GSTP1 Ile(105)Val polymorphism is associated in a dose-dependent fashion with increased survival of patients with advanced colorectal cancer receiving 5-FU/oxaliplatin chemotherapy.

Adult↗

PubMed2004

Polymorphisms of death pathway genes FAS and FASL in esophageal squamous-cell carcinoma.

BACKGROUND: The FAS receptor-ligand system is a key regulator of apoptotic cell death, and loss of FAS expression and gain of FAS ligand (FASL) expression play important roles in the development and progression of cancer. Single-nucleotide polymorphisms in the promoter region of the FAS (G or A at position -1377 [FAS -1377G/A] and A or G at position -670 [FAS -670A/G]) and FASL (T or C at position -844 [FASL -844T/C]) genes alter the transcriptional activity of these genes. We examined the association between these polymorphisms and risk of the development and metastasis of esophageal squamous-cell carcinoma. METHODS: Genotypes of 588 case patients with esophageal squamous-cell carcinoma and 648 control subjects were determined by polymerase chain reaction-based restriction fragment length polymorphism. Associations with the risk of esophageal squamous-cell carcinoma were estimated by logistic regression. All statistical tests were two-sided. RESULTS: We observed a statistically significantly increased risk of esophageal squamous-cell carcinoma associated with the FAS -1377AA (odds ratio [OR] = 1.79, 95% confidence interval [CI] = 1.29 to 2.48; P<.001) or FAS -670GG (OR = 1.72, 95% CI = 1.26 to 2.34; P<.001) genotype, which are in strong linkage disequilibrium compared with the FAS -1377GA or GG or the FAS -670AG or AA genotype, respectively. An increased risk of esophageal squamous-cell carcinoma was also associated with the FASL -844CC genotype (OR = 2.06, 95% CI = 1.64 to 2.59; P<.001) compared with the FASL -844CT or TT genotype. Gene-gene interactions of FAS and FASL polymorphisms increased the risk of esophageal squamous-cell carcinoma in a multiplicative manner (OR for the presence of both FAS -1377AA and FASL -844CC genotypes = 4.55, 95% CI = 2.75 to 7.48; P =.001, test for homogeneity). Statistically significant interactions were found between these polymorphisms in FAS and FASL and tobacco smoking. None of the polymorphisms was associated with risk of differentiation or metastasis of esophageal squamous-cell carcinoma at diagnosis. CONCLUSION: Genetic polymorphisms in the death pathway genes FAS and FASL appear to be associated with an increased risk of developing esophageal squamous-cell carcinoma.

Adaptor Proteins, Signal Transducing↗

PubMed2005

Large-scale investigation of base excision repair genetic polymorphisms and lung cancer risk in a multicenter study.

BACKGROUND: Base excision repair (BER) is a highly conserved essential mechanism for maintaining genome integrity. We examined associations among four well-characterized polymorphisms of BER genes (OGG1 Ser326Cys, XRCC1 Arg194Trp, XRCC1 Arg280His, and XRCC1 Arg399Gln) and lung cancer risk. METHODS: A total of 2188 patients with lung cancer and 2198 control subjects without lung cancer recruited at 15 centers in six Eastern European countries from February 1998 to October 2002 provided DNA samples for genotype analysis. Genetic polymorphisms were analyzed by the fluorescence 5' exonuclease and Amplifluor assays. Unconditional multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). We estimated the false-positive reporting probability (FPRP) for our results by incorporating a range of prior probabilities that specific polymorphisms are associated with lung cancer risk. All statistical tests were two-sided. RESULTS: The overall odds ratio for lung cancer among those with the OGG1 Cys/Cys genotype compared with those with the OGG1 Ser/Ser genotype was 1.34 (95% CI = 0.95 to 1.88); the association was most prominent for adenocarcinoma risk (OR = 1.66, 95% CI = 1.04 to 2.66). Overall, the XRCC1 polymorphisms were not associated with the risk of lung cancer. However, the XRCC1 Arg194Trp and Arg280His variants were each associated with a reduced risk of lung cancer among subjects in the highest quartile of pack-years of smoking compared with common allele homozygotes (ORs of 0.65 [95% CI = 0.46 to 0.93] and 0.56 [95% CI = 0.36 to 0.86], respectively). The associations between the OGG1 Cys/Cys genotype and adenocarcinoma risk and between XRCC1 Arg194Trp polymorphism and lung cancer risk among heavy smokers remained robust given prior probabilities of 25% (FPRP = 0.238) and 10% (FPRP = 0.276), respectively. CONCLUSIONS: Our results do not support a major independent role of BER gene polymorphisms in lung cancer risk. However, we cannot exclude the possibility that the OGG1 Ser326Cys and XRCC1 Arg194Trp polymorphisms play minor roles in lung carcinogenesis.

Adenocarcinoma↗

PubMed2003

Tracing the history of an enzyme polymorphism: the case of alcohol dehydrogenase-2 (Adh-2) of the olive fruit fly Bactrocera oleae.

In the olive fruit fly Bactrocera oleae, previous studies have described a one-locus three-allele electrophoretic polymorphism of the enzyme alcohol dehydrogenase and provided evidence that the polymorphism is under the influence of selection. A recent study has shown that this species carries a two-locus duplication for alcohol dehydrogenase. Here, we show that the polymorphism maps at one of the duplicated loci, Adh2, and identify the nucleotide and, therefore, the inferred amino acid differences among the three allozymes. At the amino acid level, the polymorphism is of the simplest possible form: there is no intra-allozyme variation, and interallozyme differences are restricted to one amino acid for two pairs of alleles and to two amino acids for the third pair. Consideration of the amino acid residues at the sites that segregate in B. oleae in four congeneric species and the phylogenetic trees produced from the nucleotide sequences of the Adh2 gene of these species point to the same allozyme as the ancestral form of the polymorphism. Interestingly, this allozyme comprises less than 1% of the gene pool of present-day natural populations of B. oleae, where the other two allozymes appear to form a stable polymorphism. Previous studies have shown that the frequency of the rare allozyme rises rapidly in laboratory colonies maintained on artificial diet and declines again when the artificial diet is replaced with olive fruit, the natural substrate of B. oleae. The geographical distribution of several congeneric species suggests that B. oleae originated in the Indian subcontinent, where the olive tree is practically absent. The poor performance of the ancestral allele on the olive fruit suggests the possibility that the decline of this allele and the concomitant rise of the presently common alleles might be associated with the expansion of the insect's geographical distribution to areas where the olive tree has become its main and perhaps sole host. The estimated age of the polymorphism is compatible with this hypothesis, but firmer support could be difficult to obtain.

Alcohol Dehydrogenase↗

PubMed2004

Analysis of the codon 72 polymorphism of the TP53 gene in patients with endometriosis.

Endometriosis is a benign gynaecologic disease that is associated with a certain risk for malignant degeneration. The disease has a genetic background, but the locations of possible genomic aberrations are still poorly clarified. In this context, the proline form of TP53 codon 72 polymorphism has been recently associated with the risk of developing endometriosis. In this case-control study, we aimed to investigate further the potential association between endometriosis and this polymorphism in order to evaluate whether this genetic variant may influence the susceptibility to the disease. Genomic DNA was obtained from a consecutive series of 303 Italian Caucasian women of reproductive age who underwent laparoscopy for benign gynaecological pathologies. Endometriosis was defined according to the criteria of Holt and Weiss [Holt V and Weiss NS (2000) Recommendations for the design of epidemiologic studies of endometriosis. Epidemiol 11,654-659] for the definite disease. Subjects of similar age without laparoscopic evidence of the disease served as control group. Molecular analysis of TP53 codon 72 polymorphism was performed by PCR amplification. Endometriosis was documented in 151 women. We found no statistically significant difference in the distribution of TP53 codon 72 polymorphism genotypes between patients with and without endometriosis. The respective proportions of arginine homozygotes, heterozygotes and proline homozygotes were 55.6, 39.7 and 4.6% in the group with endometriosis and 59.9, 30.9 and 9.2% in the control group. Moreover, no statistically significant association was demonstrated between TP53 codon 72 polymorphism and the various clinical manifestations of the disease, although a non-significant tendency towards an increased frequency of the proline allele was observed in association with specific manifestations of the disease reflecting a more severe form. Our results suggest that the TP53 codon 72 polymorphism does not confer genetic susceptibility to endometriosis in the Italian population. However, a possible susceptibility role of this polymorphism in endometriosis development towards very severe forms cannot be ruled out.

Adult↗

PubMed2001

Polymorphisms in the promoter region and at codon 54 of the MBL2 gene are not associated with IgA nephropathy.

BACKGROUND: IgA nephropathy (IgAN) occurs sporadically in unrelated individuals. Several different polymorphic genes have been investigated in recent years in order to demonstrate their possible association with IgAN. Three recent, different studies with conflicting conclusions have discussed the role of the mannose binding lectin (MBL), a serum lectin involved in natural immunity, in the IgAN pathogenesis by examination of MBL deposits in biopsies. In the present study we investigated several polymorphisms of the MBL gene located in the promoter region and in the first exon. METHODS: MBL polymorphism detection was performed in 22 Italian patients with familial IgA nephropathy and in 138 Italian patients with the sporadic form of the disease. The polymorphisms in the MBL2 promoter region and in the exon 1 were investigated, respectively, by direct sequencing and by amplification refractory mutation system-polymerase chain reaction on genomic DNA collected from peripheral blood. Seventy-four unrelated healthy subjects matched for ethnic origin were used as controls. RESULTS: Allelic and genotypic frequencies of the polymorphisms at position -550, -328, -221 and at codon 54 did not show any differences between patients and controls. Similar frequency distributions of these polymorphisms were also found in the subgroups of IgAN patients subdivided according to the clinical manifestations and the progression of the disease. CONCLUSIONS: This study indicates that the analysed polymorphisms of the MBL gene do not appear to be primarily involved in the susceptibility and severity of IgAN.

Adolescent↗