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PubMed2001

Role of genetic polymorphism of glutathione-S-transferase T1 and microsomal epoxide hydrolase in aflatoxin-associated hepatocellular carcinoma.

Exposure to aflatoxins is a risk factor for hepatocellular carcinoma (HCC). Aflatoxins occur in peanut butter and are metabolized by genetically polymorphic enzymes such as glutathione-S-transferases encoded by glutathione-S-transferase mu 1 gene (GSTM1) and glutathione-S-transferase theta 1 gene (GSTT1) and microsomal epoxide hydrolase encoded by epoxide hydrolase gene (EPHX). The rate at which aflatoxins become activated or detoxified may depend on polymorphisms in the encoding genes. GSTM1 homozygous deletion was indeed found to modify the association between peanut butter consumption and HCC. In this study, we investigate possible roles of GSTT1 and EPHX polymorphisms in this relationship. From a Sudanese case-control study on HCC, we analyzed data of 112 incident cases and 194 controls. All participants were interviewed using a standardized questionnaire inquiring about social and demographic factors, peanut butter consumption, and other known HCC risk factors. Univariate analysis showed that GSTT1 polymorphism was not associated with HCC, whereas EPHX 113HH and 139HH genotypes increased the risk of HCC (Odds ratio, 3.10; 95% Confidence interval, 1.18-8.12). Adjustment for age and region of origin slightly attenuated this association (Odds ratio, 2.56; 95% Confidence interval, 0.83-7.95). Interestingly, unlike GSTM1, both GSTT1 and EPHX polymorphism did not modify the association between peanut butter consumption and HCC. In conclusion, these epidemiological findings do not suggest significant roles of GSTT1 and EPHX in aflatoxin metabolism, although EPHX polymorphism is possibly related to the increased risk of HCC. Further studies are needed to investigate mechanisms by which the EPHX polymorphism potentially modifies cancer risk.

Adult↗
PubMed2005

Genetic polymorphisms of eosinophil-derived neurotoxin and eosinophil cationic protein in tropical pulmonary eosinophilia.

Because eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP) are critical in the pathogenesis of tropical pulmonary eosinophilia (TPE), we analyzed genetic polymorphisms of both in 181 individuals from southern India with varying clinical manifestations of Wuchereria bancrofti infection (including 26 with TPE). Using haplotype frequency analysis, we identified four known (of nine) and two novel haplotypes for EDN (1, 2, 7, 8, 10, and 11). For ECP, five (of seven known) haplotypes (1-5) were identified. Although we found no significant association between frequencies of EDN and ECP polymorphisms and TPE development, we observed a unique pattern of EDN and ECP polymorphism distribution among this population. Genotype TT at locus 1088 of ECP in one TPE patient was not observed in any other clinical group. Although the EDN and ECP polymorphisms appear unlikely to be associated with the development of TPE, further analyses will be more definitive.

Animals↗
PubMed2004

[The genetic polymorphism of 7 Y-STR loci and haplotype in Tibetan population].

OBJECTIVE: To investigate the genetic polymorphism of 7 Y-STR loci and haplotypes in Tibetan population. METHODS: The DNA samples from 67 Tibetan men were analyzed by PCR and the denatured PAGE followed by silver staining. RESULTS: 25 alleles were identified for 6 loci including DYS393, DYS389 I, DYS19, DYS390, DYS389 II and DYS392, 22 alleles were identified for DYS385, the frequency distributions were between 0.0149-0.5075, the DP value distributions were between 0.5075-0.8991, the DP value of DYS 385 was the highest. 51 haplotypes were identified for the YH6 system which consisted of the 7 loci, the DP value of this system was 0.9887, the alleles for DYS393 and DYS389 II were few, it followed that perhaps Tibetan population had met with bottleneck event in their evolution process. CONCLUSION: The 7 STR loci above belong to loci of high discriminating ability, the haplotypes are highly polymorphic.

Alleles↗
PubMed1989

Genetic polymorphism of IgG in the mink. V. Two new genetic markers of the lambda light chains of mink immunoglobulins, L4 and L5.

Two new allotypes of the light (L) chains IgG, L4 and L5, were identified in the mink with dispecific antiserum produced by immunization with allogenic IgG. By means of hybrid IgG molecules and proteolytic fragments, L4 and L5 were localized on the C region of the L chain. L4 and L5 occurred frequently in the three mink populations studied and L4 and L5 are inherited independently of the known mink C gamma allotypes. L4 and L5 are encoded by closely linked genes. The antigenic specificities of L4 and L5 were not identified in the closely related Mustelidae and in the other mammalian representatives. Consequently, L4 and L5 are species specific to mink. Determination of the phenotype combinations of the five allotypes on the L chains (including the new L4 and L5) demonstrated the existence of seven combinations only with a predominance of L1,2,3; L4,5, and L1,2,3,4,5 phenotypes. Based on the results obtained, it is concluded that the mink C lambda locus has a complex organization. A model for the mink C lambda locus with at least three or possibly five linked genes is suggested.

Animals↗
PubMed1991

Genetic polymorphism of inter-alpha-trypsin-inhibitor (ITI): formal genetic and linkage analyses.

The polymorphism of inter-alpha-trypsin-inhibitor, ITI, was demonstrated by isoelectric focusing in agarose gels (pH 5-8) followed by protein blotting and immunoassay. Segregation in 239 families with 677 children is consistent with the formal hypothesis that there are two common codominant alleles, ITI*1, ITI*2, and one rare codominant allele, ITI*3, at an autosomal locus ITI. Allele frequencies were calculated as ITI*1 = 0.600, ITI*2 = 0.393, ITI*3 = 0.007. Linkage analysis with 36 markers is presented. Slightly positive lod scores were obtained for PGM3 (zeta = 1.35, theta = 0.10) and AK1 (zeta = 1.34, theta = 0.10).

Alleles↗
PubMed1992

Genetic polymorphism of plasminogen and vitamin D binding protein in red deer (Cervus elaphus L.).

Genetic polymorphism was detected in the red deer (Cervus elaphus L.), plasma proteins, plasminogen (PLG) and vitamin D binding protein (GC) using antiserum to human proteins. The affinity of the antisera to deer plasma was less than 10% that of a human standard but they bound specifically to proteins of molecular weight expected for GC and PLG. Three codominant alleles of GC and five of PLG were observed. In a set 124 farmed deer calves and their parents, six calves had genotypes which were not consistent with the expectations of inheritance. Further inconsistencies were found when variation in isocitrate dehydrogenase (IDH) and transferrin (TRF) was examined. Using genetic models which included pedigree error parameters the data were shown to be consistent with genetic inheritance of all loci in a data set containing approximately 4.8% (SE 1.4%) parent-progeny pedigree mismatches. In samples from four deer populations representative of the red deer introduced to New Zealand the GC and PLG polymorphisms provided a probability of paternity exclusion (PE) of between 0.34 and 0.54 and when IDH and TRF were also included the PE was between 0.46 and 0.66. The four populations differed significantly in allele frequency, which supports historical evidence that they originate from separate introductions of small numbers of European red deer.

Animals↗
PubMed1999

Cytochrome P4502E1 genetic polymorphisms and lung cancer in a Taiwanese population.

Cytochrome P4502E1 (CYP2E1) is involved in metabolic activation of carcinogenic nitrosamines, benzene and low molecular weight halogenated hydrocarbons. In this study, we assessed the association between CYP2E1 RsaI and DraI genetic polymorphisms and lung cancer in a Taiwanese population. The RsaI genotype distribution was significantly different between 119 lung cancer patients and 231 non-cancer controls. The homozygote variants of RsaI genotypes were more common in controls (6.9%) than in lung cancer patients (0.8%). The estimated odds ratio (OR) was 0.11 (95% confidence interval (CI), 0.01-0.87). After adjusting for age, sex, and smoking status, the OR was 0.12 (95%, CI, 0.02-0.95). This is the first observation of a positive association between this locus and lung cancer in an Asian population. No significant differences in CYP2E1 DraI genotype distributions were found between cases and controls. The results of this study indicate that CYP2E1 RsaI polymorphism, but not DraI polymorphism, may contribute to the development of lung cancer in Taiwan.

Cytochrome P-450 CYP2E1↗
PubMed2005

Cytochrome P450 1B1 and catechol-O-methyltransferase genetic polymorphisms and breast cancer risk in Chinese women: results from the shanghai breast cancer study and a meta-analysis.

Cytochrome P450 1B1 (CYP1B1) and catechol-O-methyltransferase (COMT) are important estrogen-metabolizing enzymes and, thus, genetic polymorphisms of these enzymes may affect breast cancer risk. A population-based case-control study was conducted to assess the association of breast cancer risk with CYP1B1 and COMT polymorphisms. A meta-analysis was done to summarize the findings from this and previous studies. Included in this study were 1,135 incident breast cancer cases diagnosed from August 1996 through March 1998 among female residents of Shanghai and 1,235 randomly selected, age frequency-matched controls from the same general population. The common alleles of the CYP1B1 gene were Arg (79.97%) in codon 48, Ala (80.53%) in codon 119, and Leu (86.57%) in codon 432. The Val allele accounted for 72.46% of the total alleles identified in codon 108/158 of the COMT gene. No overall associations of breast cancer risk were found with any of the single nucleotide polymorphisms described above. This finding was supported by a meta-analysis of all previous published studies. No gene-gene interactions were observed between CYP1B1 and COMT genotypes. The associations of breast cancer risk with factors related to endogenous estrogen exposure, such as years of menstruation and body mass index, were not significantly modified by the CYP1B1 and COMT genotypes. We observed, however, that women who carried one copy of the variant allele in CYP1B1 codons 48 or 119 were less likely to have estrogen receptor-positive breast cancer than those who carried two copies of the corresponding wild-type alleles. The results from this study were consistent with those from most previous studies, indicating no major associations of breast cancer risk with CYP1B1 and COMT polymorphisms.

Adult↗
PubMed2006

[Activity of esterases and effect of genetic polymorphism in workers exposed to organophosphorus pesticides].

OBJECTIVE: To study the activity of esterases, including butyrylcholinesterase (BchE), carboxylesterase (CarbE), paraoxonase (PonE) and acetylcholinesterase (AChE), and to explore the effect of genetic polymorphism on the activity of esterase for workers exposed to organophosphorus pesticides (OPs). METHODS: Two hundred and forty-one long term OPs directly exposed workers and 151 indirectly exposed workers in the same factory were taken as study group. One hundred and sixty unexposed persons were taken as control group. The activity of serum enzymes was measured and the polymorphic distribution was detected using 7900 genotype detecting system and CMOS Chip technique. The effect of long-term exposure to organophosphorus pesticides was analyzed. RESULTS: The activities of BchE, CarbE and PonE were independent on the gender or age in control group. Average values of Carb and BchE activities of directly and indirectly exposed workers were lower than those in control group respectively. PonE activity in directly exposed group was lower than that in control group. AChE activity in directly exposed group was lower than that in indirectly exposed group. All the differences were significant (P < 0.01). In the direct exposure group, the frequency of three variants of butyrylcholinesterase gene K (BCHE-K) polymorphism was 74.3%, 24.1% and 1.6% for UU, UK and KK respectively. Frequency of allele U and K was 0.863 and 0.137 respectively in the same group. Frequency of three variants of PON192 polymorphism was 15.0%, 45.5% and 39.5% for AA, AB and BB respectively in direct exposure group. Gene frequency of low activity (PON*A) and high activity (PON*B) was 0.378 and 0.622 respectively. Frequency of three variants of PON55 polymorphism was 96.2%, 3.8% and 0% for MM, LM and LL respectively in direct exposure group. Frequency of allele M and L was 0.981 and 0.019 respectively in the same group. The activity of PON was different in various genotypes of PON192 and PON55. CONCLUSION: The long-term exposure to OPs could inhibit the activities of CarbE, BchE, PonE and ACh E in different level. The genetic polymorphisms of PON192 and PON55 affect the activity of PonE, which is related to the detoxification of OPs and health impact.

Acetylcholinesterase↗
PubMed1999

Ethnic susceptibility to lung cancer: differences in CYP2E1, CYP1A1 and GSTM1 genetic polymorphisms between French Caucasian and Chilean populations.

Many investigators have reported an association between genetic polymorphisms of cytochromes P-450 CYP2E1, CYP1A1 or glutathione S-transferase Mu (GSTM1) and susceptibility to lung cancer. However, pronounced interethnic variations have been described in the frequencies of these polymorphisms, especially between Asians and Caucasians. The present study was set up to establish CYP2E1 (c1, c2 and C, D), CYP1A1 (m1, m2 and Ile, Val) and GSTM1 (null) allelic frequencies in Chileans (n = 96) who are an admixture of Native Americans and Caucasians (Spaniards). The rare allele frequencies were found to be 0.15 (c2), 0.21 (C), 0.23 (m2), 0.32 (Val) and 0.21 ('null' genotype). These values are significantly higher than those of Caucasians except for the GSTM1 'null' genotype and suggest differences in susceptibility to lung cancer between both populations.

Adult↗
PubMed1979

Genetic polymorphism of vitamin B12 binding (R) proteins of human saliva detected by isoelectric focusing.

Genetic polymorphism of the vitamin B12 binding (R) proteins of parotid saliva is determined by autosomal inheritance of codominant alleles. This hypothesis is supported by studies in 43 families including 152 children. For randomly collected salivas from 143 whites, 104 blacks, and 75 Chinese, gene frequencies are as follows: for whites, Rs1=0.88, Rs2=0.12; for blacks, Rs1=0.94, Rs2=0.06; for Chinese, Rs1=1.00. This genetic marker is also shared by R proteins of milk, tears, and leukocytes. In the Rs 1--2 salivary type there is less labeling of the protein products of Rs2 v. Rs1 with 57Co B12 as assessed by the intensity of the bands on the autoradiogram. There is no evidence for close linkage (theta less than 0.01) between Rs and TC II (transcobalamin II) or between Rs and salivary protein locus Pr, Db, Gl, or Ps.

Carrier Proteins↗
PubMed2004

Genetic polymorphism in the manganese superoxide dismutase gene, antioxidant intake, and breast cancer risk: results from the Shanghai Breast Cancer Study.

INTRODUCTION: It has been suggested that oxidative stress and mitochondrial DNA damage play important roles in breast cancer carcinogenesis. Manganese superoxide dismutase (MnSOD) is a major enzyme that is responsible for the detoxification of reactive oxygen species in the mitochondria. A T --> C substitution in the MnSOD gene results in a Val --> Ala change at the -9 position of the mitochondrial targeting sequence (Val-9Ala), which alters the protein secondary structure and thus affects transport of MnSOD into the mitochondria. METHODS: We evaluated this genetic polymorphism in association with breast cancer risk using data from the Shanghai Breast Cancer Study, a population-based case-control study conducted in urban Shanghai from 1996 to 1998. The MnSOD Val-9Ala polymorphism was examined in 1125 breast cancer cases and 1197 age-frequency-matched control individual. RESULTS: Breast cancer risk was slightly elevated in women with Ala/Ala genotype (odds ratio [OR] 1.3, 95% confidence interval [CI] 0.7-2.3), particularly among premenopausal women (OR 1.8, 95% CI 0.9-3.7), as compared with those with Val/Val genotype. The increased risk with the Ala/Ala genotype was stronger among premenopausal women with a higher body mass index (OR 2.5, 95% CI 0.9-7.0) and more years of menstruation (OR 2.6, 95% CI 0.8-8.0). The risk among premenopausal women was further increased twofold to threefold among those with a low intake of fruits, vegetables, vitamin supplements, selenium, or antioxidant vitamins, including carotenes and vitamins A, C, and E. However, the frequency of the Ala allele was low (14%) in the study population, and most of the ORs provided above were not statistically significant. CONCLUSION: The present study provides some evidence that genetic polymorphism in the MnSOD gene may be associated with increased risk of breast cancer among Chinese women with high levels of oxidative stress or low intake of antioxidants. Studies with a larger sample size are needed to confirm the findings.

Adult↗
PubMed1989

Genetic polymorphisms of orosomucoid ORM1 and ORM2 in a Japanese population: occurrence of new ORM1 alleles.

Genetic polymorphisms of orosomucoid ORM1 and ORM2 in a Japanese population from northern Japan were investigated using isoelectric focusing (IEF) in ultrathin layer polyacrylamide gels containing Triton X-100 and immunofixation. Nine ORM1 phenotypes which are determined by four common and one rare alleles were observed. Two of the identified alleles at this locus were considered to be new. The ORM2 pattern was classified into 14 phenotypes as products of one common and two variant alleles. The estimated allele frequencies were ORM1*1 = 0.668, ORM1*2 = 0.170, ORM1*2.1 = 0.136, ORM1*5.2 = 0.022 and ORM1*7 = 0.004; ORM2*1 = 0.972, ORM2*3 = 0.006 and ORM2*6 = 0.022.

Alleles↗
PubMed2005

Adaptation to past malarial endemia and susceptibility to common diseases in modern populations: a study of adenosine deaminase and MN blood group genetic polymorphisms.

We carried out a study of adenosine deaminase (ADA) and MN blood group genetic polymorphisms in relation to past malarial morbidity in Sardinia and in relation to susceptibility to allergic asthma (a Th2 disorder) and Crohn's disease (a Th1 disorder) in the population of Rome. Eight hundred and eight schoolchildren, aged 7--14 years from 14 Sardinian villages located in the central area of the island, were considered. One hundred and twenty-two children with allergic asthma and 39 adult patients with Crohn's disease from the population of Rome were also studied. The data suggest an interaction between the two systems concerning resistance/susceptibility, both to malaria and to the diseases considered. In Sardinia, the frequency of the *L(M)/ADA*2 gametic type is negatively correlated with past malarial endemia, suggesting an increased susceptibility to malaria leading to its decrease in areas with high malarial endemia. In Rome, this gametic type is correlated negatively to allergic asthma and positively to Crohn's disease, suggesting a protective effect against allergic asthma and increased susceptibility to Crohn's disease.

Adaptation, Physiological↗
PubMed1990

Genetic polymorphism of delta-aminolaevulinic acid dehydratase (E.C. 4.2.1.24, ALAD) in the domestic rabbit.

A genetic polymorphism of delta-aminolaevulinic acid dehydratase (ALAD) in the domestic rabbit, Oryctolagus cuniculus, was detected by starch gel electrophoresis. Family data (15 matings with 49 offspring) support the genetic model of two common codominant alleles at an autosomal locus. Gene frequencies were calculated in a random sample of 55 mixed breed, unrelated domestic rabbits: ALAD1 = 0.31 and ALAD2 = 0.69.

Animals↗
PubMed2006

[Association between genetic polymorphisms in folate metabolic enzyme genes and colorectal cancer: a nested case-control study].

OBJECTIVE: To investigate the interrelationship of genetic polymorphisms in folate metabolic enzymes (MTHFRC677T, MTHFRA1298C, MTRA2756G and MTRRA66G) and their combinative effects with colorectal cancer (CRC). METHODS: A nested case-control study was designed and carried out. 140 CRC patients and 343 control subjects were included in this study. Polymorphisms of folate metabolic enzyme genes were genotyped by PCR-restriction fragment length polymorphism method. Risk of CRC was estimated by unconditional logistic model, and P value for interaction was calculated by likelihood test. RESULTS: The allele of MTR2756G showed a positive association with CRC (OR = 2.04, 95% CI = 1.22 - 3.40). Those with MTHFR1298AA and MTR 2756AG/GG genotypes had an elevated risk with CRC (OR = 2.57, 95% CI, 1.42 -4.65), and their combinative effect showed a significant association with CRC (P = 0.04). CONCLUSION: MTR2756G allele may be a risk factor of CRC, and interaction may exsit between polymorphisms of MTHFRA1298C and MTRA2756G. Further studies with larger sample and in different ethnic groups are needed.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed2002

Genetic polymorphisms in CYP3A5, CYP3A4 and NQO1 in children who developed therapy-related myeloid malignancies.

Therapy-related acute myeloid leukemia and myelodysplastic syndrome (t-ML) are serious complications that affect some patients after acute lymphoblastic leukemia (ALL) treatment. Genetic polymorphisms in the promoter of CYP3A4 (CYP3A4*1B) and in NAD(P)H:quinone oxidoreductase (NQO1609C-->T substitution) have been associated with the risk of t-ML. A polymorphism in CYP3A5 (CYP3A5*3) affects CYP3A activity and the wild-type allele (CYP3A5*1) is in partial linkage with the CYP3A4*1B allele. We compared the genotype frequencies for the CYP3A5*3, the CYP3A4*1B and the NQO1609C-->T substitution in 224 children with ALL who did not develop t-ML (controls) and in 53 children with ALL who did develop the complication. The allele frequencies differed significantly among whites, blacks and Hispanics (P < 0.001 for CYP3A5*3, P < 0.001 for CYP3A4*1B and P = 0.004 for NQO1609), thus we performed the comparisons between ALL controls and t-ML patients after accounting for race. We found no differences in the CYP3A4*1B allele distribution between ALL controls and t-ML patients in whites (P = 0.339, 6.6% vs. 9.8%), blacks (P = 0.498, 93.8% vs. 87.5%) or Hispanics (P = 0.523, 39.1% vs. 25.0%). The frequencies for the NQO1609C-->T allele did not differ between control and t-ML groups in whites (P = 0.191, 35.0% vs. 44.9%), blacks (P = 0.664, 37.5% vs. 37.5%) or Hispanics (P = 0.447, 65.2% vs. 50.0%). We found no differences between the control and t-ML group in the incidence of homozygous CYP3A5*3 genotypes: 82.0% vs. 85.4% in whites (P = 0.403), 6.5% vs. 12.5% in blacks (P = 0.508), and 69.6% vs. 75.0% in Hispanics (P= 0.663). Our data do not support an association between common CYP3A4, NQO1 or CYP3A5 polymorphisms and the risk of t-ML in children treated for ALL.

Acute Disease↗
PubMed1998

Genetic polymorphism in MDR-1: a tool for examining allelic expression in normal cells, unselected and drug-selected cell lines, and human tumors.

By using RNase protection analysis, residues 2677 and 2995 of MDR-1 were identified as sites of genetic polymorphism. Through use of oligonucleotide hybridization, the genomic content and expression of individual MDR-1 alleles were examined in normal tissues, unselected and drug selected cell lines, and malignant lymphomas. In normal tissues, unselected cell lines, and untreated malignant lymphoma samples, expression of MDR-1 from both alleles was similar. In contrast, in drug selected cell lines, and in relapsed malignant lymphoma samples, expression of one allele was found in a large percentage of samples. To understand how expression of one allele occurs, two multidrug resistant sublines were isolated by exposing a Burkitt lymphoma cell line to increasing concentrations of vincristine. The resistant sublines expressed only one allele and had a hybrid MDR-1 gene composed of non-MDR-1 sequences proximal to MDR-1. Previous studies showing hybrid MDR-1 genes after rearrangements provided a potential explanation for activation and expression of one MDR-1 allele. We conclude that oligonucleotide hybridization can be used as a sensitive tool to examine relative allelic expression of MDR-1, and can identify abnormal expression from a single allele. Acquired drug resistance in vitro and in patients is often associated with expression of a single MDR-1 allele, and this can be a marker of a hybrid MDR-1 gene.

Alleles↗