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PubMed1999

UDP-glucuronosyltransferase (UGT1A1*28 and UGT1A6*2) polymorphisms in Caucasians and Asians: relationships to serum bilirubin concentrations.

Polymorphisms that alter UDP-glucuronosyltransferase (UGT) activities have been identified. Mutations in the promoter of the UGT1A1 gene (UGT1A1*28), resulting in 5, 7 or 8, instead of 6 thymine-adenine (TA) repeats, alter bilirubin conjugation. Two missense mutations on one allele of UGT1A6 (UGT1A6*2) result in T181A and R184S amino acid substitutions and reduced activity against phenolics, such as 4-nitrophenol, 4-hydroxycoumarin and butylated hydroxy anisole. We determined the frequency of these polymorphisms in 245 healthy men and women, aged 20-40 years and examined the relationship between TA repeat number and serum bilirubin concentrations in a subset of 24 Asians and 169 Caucasians. The frequencies of the UGT1A1*28 genotypes were 0.537, 0.348, 0.098, 0.008 and 0.008 for promoter TA repeats 6/6, 6/7, 7/7, 5/6 and 6/8, respectively. Both allele and genotype frequencies varied by race (P < 0.02), with 11% of the Caucasians and none of the Asians having the 7/7 genotype. Within both ethnic groups, serum bilirubin increased with increased numbers of UGT1A1 promoter TA repeats (P = 0.0001). However, a strong ethnic group-by-UGT1A1 genotype interaction suggests that additional ethnic differences in bilirubin metabolism contribute to observed bilirubin concentrations. Genotype frequencies for UGT1A6*2 were 0.478, 0.392, 0.029, 0.090, 0.012 for wild-type (wt)/wt, wt/T181A + R184S, wt/R184S, T181A + R184S/T181A + R184S and T181A + R184S/R184S, respectively. The co-occurrence of polymorphisms in UGT1A1 and UGT1A6 differed from that expected (P < 0.0001): individuals homozygous wild-type for UGT1A1 and UGT1A6 were observed at twice the expected frequency; individuals homozygous variant for both genes were ten-fold more frequent and individuals homozygous wild-type for one gene and homozygous variant for the other were ten-fold less frequent than expected. Overall, 8% were homozygous variant for both UGT1 polymorphisms and 43% had at least one variant allele for both UGT1A1*28 and UGT1A6*2. These highly prevalent polymorphisms, which result in modified expression and activity of UGTs, may influence susceptibility to cancers associated with altered metabolism of endogenous and xenobiotic compounds.

Asian People↗
PubMed2000

Practical applications of genotypic surveys for forensic STR testing.

Legitimate genotype frequency estimation for multiallelic loci relies on component allele frequencies, as population surveys represent only a fraction of possible DNA profiles. Multilocus genotypes from two ethnic human populations, African American (n=195) and U.S. Caucasian (n=200), were compiled at 13 STR loci that are used worldwide in forensic investigation (D3S1358, vWA, FGA, D16S539, TH01, TPOX, CSF1PO, D8S1179, D21S11, D18S51, D5S818, D13S317, and D7S820). Sex-specific AmpFlSTR multiplexes provided stringent PCR-based STR typing specifically optimized for multicolor fluorescence detection. Heterozygosity at each STR locus ranged from 0.57 to 0.89 and encompassed from seven (TH01) to twenty-one (D21S11) alleles. Homozygosity tests, tests based on the distinct numbers of observed homozygous and heterozygous classes, log likelihood ratio tests, and exact tests assessed that the degree of divergence from theoretical Hardy-Weinberg proportions for all 13 STRs does not have practical consequence in genotype frequency estimation. Departures from linkage equilibrium, between loci, that imposed significance to forensic calculations were not indicated by observed variance of the number of heterozygous loci or Karlin interclass correlation tests. For forensic casework, reliable multilocus profile estimates may be obtained from the product of component genotype frequencies, each calculated through application of the Hardy-Weinberg equation to population database allele frequency estimates reported here. The average probability that two randomly selected, unrelated individuals possess an identical thirteen-locus DNA profile was one in 1.8x10(15) African Americans and one in 3.8x10(14) U.S. Caucasians.

Black or African American↗
PubMed2006

HLA class II distribution in Congolese with hyperthyroidism: preliminary results.

OBJECTIVE: Incidence of the hyperthyroidism is continuously increasing, whereas our knowledge concerning the facilitating or etiologic factors of this increase are still partial. To evaluate some of these unknown factors, we started this preliminary study, in order to identify HLA genes in hyperthyroid Congolese, and to determine their susceptibilty in the appearance and development of hyperthyroidism at the Hospital Clinic of Kinshasa. MATERIALS AND METHODS: Nine Congolese women with hyperthyroidism, and thirteen healthy controls (3 women and 10 men) were examined and compared for HLA-DR and HLA-DQ genes analyses, from August 2000 to August 2002. DRB1 and DQB1 alleles were identified, using the Polymerase Chain Reaction (PCR) and immobilized sequence-specific oligonucleotide (SSO HLA-DRB1 and DQB1 test) probes assays. RESULTS: In the group with hyperthyroidism, three alleles (HLA-DR1, HLA-DR2, HLA-DR3) and an allele group (HLA-DR11,13,14) were found for DRB1 locus, while only one allele (HLA-DQB1*0602) was identified for DQB1 locus; allele group HLA-DR11,13,14 was the most frequent (allele frequency=0.50), followed by HLA-DR3 allele (allele frequency=0.222); 6 haplotypes were observed, with predominance of haplotype DR3/DR11,13,14 (genotype frequency=0.333), followed by haplotype DR11,13,14/DR11,13,14-DQB1*0602 (genotype frequency=0.222). In the group of healthy controls, three alleles (HLA-DR2, HLA-DR3, HLA-DR4) and an allele group (HLA-DR11,13,14) were identified for DRB1; HLA-DR2 allele was predominant (allele frequency=0.615), followed by allele group HLA-DR11,13,14 (allele frequency=0.231); a statistic significant difference was observed between the frequencies of DR2 allele and allele group DR11,13,14 in the healthy controls compared to those of hyperthyroid patients (p=0.02); 6 haplotypes were also detected in this group, the most frequent haplotype being HLA-DR2/DR2-DQB1*0602 (genotype frequency=0.540 versus 0.333 in the hyperthyroid group) (p=0.048). HLA-DQB1*0602 was dominant in the healthy controls group (allele frequency=0.890), versus HLA-DQB1*0302 (allele frequency=0.110). CONCLUSIONS: HLA-DR2, HLA-DQB1*0602 and DR2/DR2-DQB1*0.602 would play a protective role against the hyperthyroidism, while DR3 allele, allele group DR11,13,14 and haplotype HLA-DR3/DR11,13,14 would predispose to this disease or to Graves' exophtalmopathy. A large and profound study is needed to confirm our preliminary results.

Child↗
PubMed2003

Population genetic structure of earthworms (Lumbricus rubellus) in soils contaminated by heavy metals.

The genetic structure of earthworm (Lumbricus rubellus) populations from plots (N = 3) contaminated by sewage sludge (containing Cd, Cu, Pb, Zn) and reference plots (N = 3) was compared. Earthworms (N = 30-40 per plot) were collected during May 2000 and electrophoretic analyses were used to assess genetic variation at three polymorphic loci (GPI, LAP, PGM). Allele and genotype frequencies for GPI and PGM differed significantly between sludge and reference populations. Sludge populations were characterized by a reduced frequency of the most common genotype and allele at these loci, and the presence of alleles not found in the reference population. Allele and genotype frequencies did not differ significantly among individual plots within the sludge or the reference population. These results suggest that certain alleles and genotypes may be more sensitive to the effects of heavy metals. Multi-locus heterozygosity was significantly higher in the sludge population compared to the reference population; the proportion of individuals heterozygous at two or more loci was more than 15% higher in the sludge population. Results demonstrate that measures of population genetic structure in earthworms may represent useful biological indicators for the assessment of impacted terrestrial habitats.

Alleles↗
PubMed2006

Genotype profiles of loci encoding DNA repair enzymes in newborn and elderly populations: no evidence of association with longevity.

The comparison of genotype frequencies between neonates and elderly populations can aid in the identification of loci, and polymorphisms within those loci, that affect longevity. Here we have compared genotype frequencies of seven polymorphisms at four loci involved in DNA repair between a cohort of newborns (n = 290) and a retired population (average age at sampling 70.02 years; n = 430) who have suffered a lifetime of DNA damage from normal, metabolic processes, and on whom selection on DNA repair gene variants may be expected to have acted. No differences in genotype frequencies at the four SNP loci were seen, indicating that there is no evidence of association with longevity in this population. Significant differences in frequency of certain repeat sizes at three microsatellite loci were detected. However, since there is no known functional consequence of these repeat lengths, the action of selection cannot yet be ascribed.

Aged↗
PubMed2002

Association between vitamin D receptor polymorphism and type 2 diabetes or metabolic syndrome in community-dwelling older adults: the Rancho Bernardo Study.

Vitamin D receptor (VDR) polymorphism influences susceptibility to type 1 diabetes, but the association with type 2 diabetes is not clear. We investigated the association between VDR polymorphism and type 2 diabetes and metabolic syndrome in a community-based study of unrelated older adults without known diabetes. Oral glucose tolerance test (75 g), plasma glucose and insulin measurement, homeostasis model assessment (HOMA), and VDR genotyping were performed. The distributions of genotype frequencies of ApaI, BsmI, and TaqI polymorphism did not differ between persons with and without diabetes, but the frequency of aa genotype of ApaI polymorphism was marginally higher in persons with type 2 diabetes (P =.058). Fasting plasma glucose (P <.05) and prevalence of glucose intolerance (P <.05) were significantly higher in nondiabetic persons with aa genotype compared with those with AA genotype. The bb genotype of BsmI polymorphism was associated with insulin resistance as assessed by HOMA after adjustment for age, sex, body mass index (BMI), and calcium and vitamin D use in persons without diabetes (P <.05). Our research suggests that ApaI polymorphism may be associated with glucose intolerance independent of defective insulin secretion and BsmI polymorphism with insulin resistance in a nondiabetic Caucasian population.

Aged↗
PubMed2006

Detection of benzimidazole resistance in Haemonchus contortus using RFLP-PCR technique.

Benzimidazole (BZ) resistance in Haemonchus contortus is linked primarily with the mutation in the beta-tubulin isotype 1 gene that substitute phenylalanine (Phe) to tyrosine (Tyr) at 200 codon of the gene. In the present study, a new restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) technique has been developed for detection of BZ resistance in the beta-tubulin isotype 1 gene of H. contortus. The technique utilizes two primers viz. AvikaF and AvikaR to amplify the region containing mutation in the beta-tubulin gene followed by restriction digestion. After digestion, the 'rr' individuals (homozygous resistant) revealed 257 and 48 bp bands, the 'rS' individuals (heterozygous) showed 305, 257 and 48 bp bands, while 'SS' individuals (homozygous susceptible) revealed uncut 305 bp band. A total of 162 adult male H. contortus collected from Avikanagar, Jaipur and Bikaner regions (54 from each region) were genotyped for analyzing BZ resistance in the beta-tubulin gene. Out of which, 130 adults were 'rr' types, 20 'rS' types and 12 'SS' types. The results showed that genotypic frequencies of different genotypes (rr, rS and SS) were highly significant difference among the three regions (P<0.001). The 'rr' individuals were higher (98%) in Jaipur followed by Avikanagar (93%) and Bikaner (50%) regions. Overall, the prevalence of BZ resistant allele (r) was higher (86%) as compared to BZ susceptible allele (S) (14%). The technique was also found suitable for genotyping of larvae of H. contortus and yielded reproducible results. The study indicated that RFLP-PCR is an easy, reproducible and less expensive than allele specific PCR. This technique will be helpful in establishing the prevalence rate of BZ resistance in H. contortus and can also be utilized for existing worm control programme.

Amino Acid Substitution↗
PubMed2005

[The relationship between methylenetetrahydrofolate reductase gene polymorphism and microsatellite instability in gastric cancer].

OBJECTIVE: To explore the relationship between methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and microsatellite instability (MSI) in patients with gastric cancer. METHODS: MTHFR gene C677T and A1298C polymorphism were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and MSI was examined with PCR. RESULTS: MTHFR gene C677T and A1298C polymorphisms were analyzed on 122 gastric cancers and 110 normal controls The genotype frequencies of MTHFR 677CC, 677CT and 677TT were 47.5%, 39.3% and 13.1% on patients with gastric cancer, and 48.5%, 42.6%, 8.9% in the controls respectively. There was no significant difference of genotype frequency between the two groups (P > 0.05). The individuals with 677CT genotype, 677TT genotype and 677CT + TT genotype exhibited significantly reduced risk (OR = 0.38,95% CI: 0.15-0.98; OR = 0.26,95% CI: 0.03-2.18 and OR = 0.36,95% CI: 0.07-0.98) of developing gastric cardia cancer compared with those harboring the wild-type(677CC). The individuals with 677TT genotype having a 3.03-fold (95% CI: 1.07-8.65) increased risk of developing gastric corpus cancer. The genotype frequency of MTHFR 1298AA, 1298AC and 1298CC were 59.8%, 36.1% and 4.1% in gastric cancer patients, and 57.4%, 7.6%, 5.0% in the controls, respectively. The distribution of MTHFR A1298C genotype was not significantly different between gastric cancer and controls (P > 0.05). The individuals with 1298CC genotype had a reduced risk of developing gastric antrum cancer (OR = 0.41- fold, 95% CI: 0.03-2.18, 0.05-3.72) when comparing with those having 1298AA genotype. Patients with MSI+ gastric cancer had an increased frequency of the MTHFR 677TT genotype when comparing with those suffering from MSI- gastric cancer (P = 0.009) and with controlled subjects (P = 0.008). There was no significant association found between MTHFR A1298C polymorphism and MSI (P>0.05). CONCLUSION: Polymorphism of MTHFR C677T was associated with increased risk on gastric corpus cancer and reduced risk on gastric cardia cancer. The polymorphism of MTHFR A1298C was associated with reduced risk for gastric antrum cancer while MSI pathway was possibly involved in the development of gastric cancer with MTHFR 677TT genotype.

Adult↗
PubMed2006

Prevalent genotypes of methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) in spontaneously aborted embryos.

OBJECTIVE: To assess prevalent 5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms in spontaneously aborted embryos. DESIGN: A retrospectively analyzed, prospectively obtained database. SETTING: Bundang CHA General Hospital and Kangnam CHA Hospital. PATIENT(S): Ninety-four spontaneously aborted embryos at <20 weeks of gestational age. INTERVENTION(S): None. MAIN OUTCOME MEASURE: Genotype frequency of MTHFR C677T and A1298C polymorphisms in spontaneously aborted embryos. RESULT(S): The aborted embryos exhibited both a significantly high frequency of the MTHFR 677CC genotype and a low frequency of the MTHFR 677CT genotype, compared to both the child and the adult control groups, respectively, whereas no significant change in the fetal MTHFR A1298C genotype frequency was observed. The combinative genotype of MTHFR 677CC/1298AC from the abortus had a high prevalence compared to the child controls. Further, the chromosomal integrity of the abortus did not affect the frequency of the MTHFR 677CC and 1298AC genotypes. CONCLUSION: Spontaneously aborted embryos have a unique distribution of MTHFR C677T and A1289C polymorphisms, regardless of their chromosomal integrity.

Abortion, Spontaneous↗
PubMed2005

CTLA-4 gene 49A/G polymorphism in Turkish patients with Behçet's disease.

Genetic factors predisposing individuals to Behçet's disease (BD) are considered to play important roles in the development of the disease. Patients with BD exhibit elevated levels of pro-inflammatory cytokines, and affected organs show a significant neutrophil and lymphocyte infiltration. Current evidence suggests that the activated lymphocytes contribute to neutrophil and endothelial cell activation in these patients. The cytotoxic T lymphocyte-associated antigen (CTLA)-4 molecule plays an important role in immune regulation by downregulating T-cell activation, and the CTLA-4 49A/G polymorphism in the exon 1 has been shown to be associated with a number of autoimmune diseases. In an attempt to demonstrate whether there is an association of the CTLA-4 49A/G polymorphism with BD in the Turkish population, we genotyped 59 Turkish patients and 99 healthy individuals for single-nucleotide polymorphisms. For this purpose, genomic DNA was obtained from the peripheral blood of individuals and the region of interest was amplified using PCR. Genotyping was performed using the BbvI restriction endonuclease. It was shown that the distribution of the CTLA-4 exon 1 49A/G allele and genotype frequencies did not differ between patients with BD and healthy controls. However, allele and genotype frequencies of CTLA-4 49 A and A/A were significantly higher in patients with ocular involvement compared with patients without these symptoms (90.6% vs. 65.1%, odds ratio (OR) = 9.67, P = 0.011; and 81.25% vs. 39.5%, OR = 9.56, P = 0.015, respectively). A statistically significant difference in the A allele frequency was observed in patients with erythema nodosum-like lesions (86.1% vs. 65.8%, OR = 6.24, P = 0.04). There was also an increase in A/A genotype frequency, but the difference was not statistically significant (72.2% vs. 41.5%, OR = 6.5, P = 0.068). Our data suggest that BD patients with ocular involvement and erythema nodosum-like lesions have a higher frequency of both the A allele and the A/A genotype at position 49 of exon 1 of CTLA-4. These results may also indicate that CTLA-4 is a disease-modifying rather than a susceptibility gene for BD.

Adult↗
PubMed1995

Susceptibility to astrocytoma and meningioma: influence of allelism at glutathione S-transferase (GSTT1 and GSTM1) and cytochrome P-450 (CYP2D6) loci.

We describe a case-control study to identify associations between polymorphism at the cytochrome P-450 (CYP2D6) and glutathione S-transferase (GSTT1 and GSTM1) loci and susceptibility to astrocytoma and meningioma. Accordingly, genotype frequencies in 112 astrocytoma and 50 meningioma patients were compared with frequencies in 577 controls. GSTM1 genotype frequencies in these groups were not different. Logistic regression analysis showed GSTT1 null and CYP2D6 poor metabolizer were risk factors in astrocytoma (odds ratio = 2.67 P = 0.0005 and odds ratio = 4.17 P = 0.0043, respectively) and meningioma (odds ratio = 4.52, P = 0.0001 and odds ratio = 4.90, P = 0.0132, respectively) when corrected for the other variables. No interactive effects between genotypes were identified. The data suggest polymorphism at loci encoding carcinogen-metabolizing enzymes influences susceptibility to astrocytoma and meningioma, possibly by determining effectiveness in the detoxification of environmental carcinogens.

Adult↗
PubMed1993

Genetic risk and carcinogen exposure: a common inherited defect of the carcinogen-metabolism gene glutathione S-transferase M1 (GSTM1) that increases susceptibility to bladder cancer.

BACKGROUND: Numerous studies have associated bladder cancer with exposure to carcinogens present in tobacco smoke and other environmental or occupational exposures. Approximately 50% of all humans inherit two deleted copies of the GSTM1 gene which encodes for the carcinogen-detoxification enzyme glutathione S-transferase M1. Recent findings suggest that the GSTM1 gene may modulate the internal dose of environmental carcinogens and thereby affect the risk of developing bladder cancer. PURPOSE: We investigated whether the absence of the GSTM1 gene affects bladder cancer risk and whether there are racial differences in GSTM1 genotype frequency. METHODS: Using a polymerase chain reaction (PCR)-based method, we examined the frequency of the homozygous deleted genotype (GSTM1 0/0) in 229 patients with transitional cell carcinoma of the bladder and 211 control subjects who were enrolled from the Urology Clinics at Duke University Medical Center and the University of North Carolina Hospitals. Control subjects were urology clinic patients who primarily presented with benign prostatic hypertrophy or impotence, who had no history of any cancer other than nonmelanoma skin cancer, and who were frequency matched to case patients on race, sex, and age (10-year age intervals). In order to explore racial differences in GSTM1 gene frequency, genotype was also determined in a community-based sample of 466 paid, healthy, unrelated volunteers from Durham and Chapel Hill, N.C. The presence or absence of the GSTM1 gene locus was determined by using a differential PCR, a semiquantitative technique in which multiple genes are coamplified. RESULTS: Overall, the GSTM1 0/0 genotype conferred a 70% increased risk of bladder cancer (odds ratio [OR] = 1.7; 95% confidence interval [CI] = 1.2-2.5; P = .004). Absence of the GSTM1 gene encoding the glutathione S-transferase M1 enzyme significantly increased risk to persons with exposure to the carcinogens in tobacco smoke (OR = 1.8; 95% CI = 1.2-3.0; P = .01) but poses little increased risk to persons without such exposure. Persons with smoking exposure of more than 50 pack-years who had the GSTM1 0/0 genotype had a sixfold greater risk relative to persons in the lowest risk group (i.e., nonsmokers who were GSTM1 +/+ or +/0). In the pooled clinic control and community sample groups (677 individuals), the GSTM1 0/0 genotype occurred less frequently among Blacks (35%) than among Whites (49%, P < .001). CONCLUSIONS: These findings support a protective role for the GSTM1 gene in bladder cancer. From these findings, it is estimated that 25% of all bladder cancer may be attributable to the at-risk GSTM1 0/0 genotype.

Base Sequence↗
PubMed2003

The Taq IA and Ser311 Cys polymorphisms in the dopamine D2 receptor gene and obesity.

Dopamine D2 receptors (DRD2) in the central nervous system are involved in the regulation of feeding. It remains to be elucidated if mutations in the DRD2 gene contribute to the development of obesity. The aim of the present study was to investigate whether the Taq IA and Ser311Cys polymorphisms in the DRD2 gene are associated with obesity in Nauruan and Australian subjects. Subjects were selected based on extremes of the body mass index (BMI) distribution. Two groups of Australian women were selected. The leanest group had a mean BMI of 22.5 kg/m2 (range: 20.3-24.3) and the heaviest group had a mean of 36.1 kg/m2 (32.5-44.1). Four groups of Nauruan subjects were selected. Leanest men had a mean BMI of 33.0 kg/m2 (28.4-36.9), heaviest men had a mean of 52.8 kg/m2 (46.5-69.2), leanest women had a mean of 34.8 kg/m2 (28.2-41.8) and heaviest women had a mean of 55.1 kg/m2 (49.3-73.8). Subjects were genotyped for the Taq IA and Ser311Cys polymorphisms using polymerase chain reaction (PCR) restriction fragment length polymorphism analysis and allelic discrimination Taqman PCR respectively. Leanest and heaviest groups were examined for differences in genotype frequency. Taq IA and Ser311Cys genotype frequencies did not differ significantly between leanest and heaviest Nauruan groups, or between leanest and heaviest Australians. Haplotype frequencies of these polymorphisms did not differ between leanest and heaviest groups. The Taq IA and Ser311Cys polymorphisms in the DRD2 gene are unlikely to be common causes of obesity in these populations.

Adult↗
PubMed2005

Association analysis of the dopamine transporter (DAT1)-67A/T polymorphism in bipolar disorder.

An imbalance in the dopaminergic system in humans has been hypothesized to contribute to the pathogenesis of a number of psychiatric illnesses, including bipolar disorder, schizophrenia, and attention deficit hyperactivity disorder. We performed a case/control study on the DAT1 (HUGO approved symbol SL6A3) gene core promoter polymorphism -67A/T to analyze the possible association of either allele of this polymorphism with bipolar disorder. The allele and genotype frequencies of the polymorphism were studied in 136 patients and 163 controls, which were matched on the basis of sex, age, and ethnicity. The genotype frequencies in the patients group were as follows: AA 30.9%; AT 55.1%; TT 14% versus the genotype frequencies in the control group: AA 49%; AT 41.8%; TT 9.2% [chi2 = 10.3, df = 2, OR = 2.15 (95% CI 1.34-3.47, P < or = 0.006]. The T-allele of the -67A/T polymorphism revealed a approximately 1.4-fold excess in the patients group comparing with the controls (P < or = 0.003). For the first time, these findings provide tentative evidence of the contribution of the DAT1 gene core promoter polymorphism to the etiopathophysiology of bipolar disorder at least in the Iranian population that we have studied. Interestingly, no allelic or genotype association was observed in the female patients (P < or = 0.6 and P < or = 0.7, respectively). Replication studies of independent samples and family-based association studies are necessary to further evaluate the significance of our findings.

Alleles↗
PubMed2002

Interleukin-13 gene polymorphism G4257A is associated with atopic dermatitis in Japanese patients.

Interleukin (IL)-13 plays an important role in the induction of immunoglobulin E (IgE) and in the pathogenesis of atopic dermatitis (AD). We investigated the allele and genotype frequencies of three IL-13 single nucleotide polymorphisms (SNPs) (A704C and C1103T in the promoter region and G4257A in exon 4) in Japanese patients with AD. For A704C and C1103T SNPs, there were no significant differences in allele or genotype frequencies between AD patients and controls. For G4257A SNP, A allele was significantly increased in AD patients (39.5%) compared with controls (29.4%) (P = 0.016). The same proportion of each genotype and allele was observed in the patient subgroup with and without asthma. Serum IgE levels and peripheral eosinophil counts were not significantly different among genotypes in G4257A SNP. There was also no significant difference in allele or genotype frequencies between AD patients with mild disease and those with severe disease, between those with family history of AD and those without it, or between those with family history of atopic disorders and those without it. This result suggests that 4257A allele is associated with susceptibility to AD and that it may function in the pathogenesis of AD itself, presumably by other mechanisms than inducing IgE production.

Adolescent↗
PubMed2002

Renin-angiotensin gene polymorphism in children with uremia and essential hypertension.

The M235T polymorphism of the angiotensinogen (ANG) gene, the I/D polymorphism of the angiotensin converting enzyme (ACE) gene, and the A1166C polymorphism of the angiotensin II type 1 receptor (AT1R) gene were identified in 70 patients with end-stage renal disease [20 pediatric ESRD, aged 14.9+/-3.1, years blood pressure (BP) 139+/-14/91+/-13 mmHg, 50 adult ESRD, aged 48.7+/-18.7 years, BP 149.1+/-24/96.9+/-12 mmHg], 35 with juvenile essential hypertension (JEHT, aged 14.4+/-2.7 years, 24-h mean BP 135.37+/-7.37/72.4+/-7.68 mmHg), 130 adult healthy normotensive controls (aged 34.9+/-8.1 years, BP 117.8+/-8.7/78.7+/-8.5 mmHg), and 20 pediatric controls (aged 13.2+/-1.2 years, BP 109+/-6.5/71+/-5.9 mmHg). The ACE gene polymorphism was determined by polymerase chain reaction and the ANG and AT1R gene polymorphisms by single-step LightCycler technology. The ACE gene distribution of the Hungarian controls did not differ from the results of the other Caucasian populations. In JEHT and pediatric ESRD patients, the MT genotype of ANG was more frequent than in controls (JEHT 80%, pediatric ESRD 74% versus controls 50%, P<0.02). The DD genotype of ACE was over-represented in pediatric ESRD compared with controls (ESRD 45% versus controls 22%, P<0.05). There was a non-significant increase in the CC genotype frequency of AT1R in adult patients with ESRD compared with controls. In conclusion, there was an increased frequency of the ACE DD genotype in pediatric ESRD, which could be a genetic risk factor for the development of ESRD. Furthermore, there was a significant increase in MT genotype frequency of ANG M235T polymorphism in pediatric ESRD and JEHT. The role of AT1R gene polymorphism needs further investigation.

Adolescent↗
PubMed1996

Population differentiation and evolution in the common guillemot Uria aalge.

Common (Uria aalge) and Brünnich's guillemots (U. lomvia) are colonial seabirds that nest in temperate to arctic oceans throughout the Northern hemisphere. They are very similar in the characteristics of ecology, demography and life history that are thought to determine the extent of differentiation among populations, yet geographic variation in morphology is notably greater in common guillemots. Despite evidence of strong natal philopatry, previous analyses of allozymes and the mitochondrial cytochrome b gene revealed little genetic differentiation among North Atlantic colonies of Brünnich's guillemots. To determine if the more extensive morphological variability in common guillemots reflects greater genetic variability, we sequenced part of the cytochrome b gene for 160 common guillemots from 10 colonies distributed throughout the Northern hemisphere. Genotype frequencies and phylogenetic relationships among genotypes both indicated that Atlantic and Pacific populations are genetically distinct. Genetic divergence among genotypes suggested that differentiation of these populations has resulted from separation by Pleistocene glaciers and the Bering Landbridge, as well as by currently unsuitable breeding habitat in the Arctic Ocean. Cytochrome b genotype frequencies also differed among Atlantic colonies, and appeared to define a cline similar to that described for morphological characters. Analyses of sequence variation suggested that this variation probably results from secondary contact between two refugial populations from the Pleistocene glaciations, rather than from isolation by distance or selection. In contrast, the Atlantic population of Brünnich's guillemots appears to have arisen through recent expansion of a single homogeneous refugial population.

Animals↗
PubMedDate not supplied

[The C677T polymorphism in the methylene tetrahydrofolate reductase gene among Tunisian population].

The 5,10 methylene tetrahydrofolate reductase (MTHFR) is an enzyme that catalyzes the irreversible reduction of 5,10 methylene tetrahydrofolate into 5 methyl tetrahydrofolate. It is coded by a gene where several polymorphisms have been identified. The most common is the C677T polymorphism described as presenting an heterogeneous worldwide distribution and associated with different disorders such as cardiovascular and cancerous diseases. The aim of this work was to determine the allelic and genotypic frequencies of the C677T polymorphism among a Tunisian healthy population. The study concerned 185 subjects apparently healthy. It was carried out by the PCR/RFLP method, using the restriction enzyme Hinf I. The results has showed an allelic frequency of 17.8% with a genotype frequency of 5.4%. These values are intermediate between those observed in Africa and those observed in Western countries. They must be considered in the evaluation of the clinic significance of a predisposition to diseases.

Adult↗