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At least 1,171 records · Page 65Linked to original sources
PubMed2005

Atrial fibrillation-associated minK38G/S polymorphism modulates delayed rectifier current and membrane localization.

BACKGROUND: Atrial fibrillation (AF) is a common acquired arrhythmia with multi-factorial pathogenesis. Recently, a single nucleotide polymorphism (SNP, A/G) at position 112 in the KCNE1 gene, resulting in a glycine/serine amino acid substitution at position 38 of the minK peptide, was associated with AF occurrence (AF more frequent with minK38G); however, the functional effect of this SNP is unknown. METHODS AND RESULTS: We used patch clamp recording, confocal microscopy and protein biochemistry to study the effect of this SNP on delayed-rectifier current expression and mathematical simulation to identify potential functional consequences. The density of slow delayed rectifier current (I(Ks)) resulting from co-expression with KvLQT1 was smaller with minK38G (e.g. at +10 mV: 50+/-7 pA/pF in Chinese hamster ovary (CHO) cells, 45+/-14 pA/pF for COS-7 cells) compared to minK38S (93+/-17 pA/pF, 104+/-23 pA/pF, respectively, P<0.05 for each). I(Ks) kinetics and voltage-dependence were unaffected. Currents resulting from co-expression of human ether-a-go-go-related gene (HERG) were similar for minK38G and minK38S, e.g. upon repolarization from +10 to -50 mV: tail currents 23+/-4 pA/pF versus 22+/-5 pA/pF (P=ns). KvLQT1 membrane immunofluorescence was less in CHO cells co-expressing minK38G versus minK38S, and surface expression of KvLQT1, as determined by labelling with streptavidin/biotin, was increased with minK38S co-expression. Computer simulations with a human atrial action potential model predicted that the minK38G SNP would slightly prolong the atrial action potential and reduce the frequency for alternans behaviour. In the presence of reduced repolarization reserve, these effects were enhanced and under specific conditions early afterdepolarizations occurred. CONCLUSIONS: The minK38G isoform is associated with reduced I(Ks), likely due to decreased KvLQT1 membrane expression. This study reveals a novel amino acid determinant of the minK-KvLQT1 interaction, and if the role of minK38G in AF is confirmed, would suggest mechanistic heterogeneity in genetic determinants of AF.

Animals↗
PubMed2004

Primer design and marker clustering for multiplex SNP-IT primer extension genotyping assay using statistical modeling.

MOTIVATION: The optimization of the primer design is critical for the development of high-throughput SNP genotyping methods. Recently developed statistical models of the SNP-IT primer extension genotyping reaction allow further improvement of primer quality for the assay. RESULTS: Here we describe how the statistical models can be used to improve primer design for the assay. We also show how to optimize clustering of the SNP markers into multiplex panels using statistical model for multiplex SNP-IT. The primer set failure probability calculated by a model is used as a minimization function for both primer selection and primers clustering. Three clustering algorithms for the multiplex genotyping SNP-IT assay are described and their relative performance is evaluated. We also describe the approaches to improve the speed of primer design and clustering calculations when using the statistical models. Our clustering decreases the average failure probability of the marker set by 7-25%. The experimental marker failure rate in the multiplex reaction was reduced dramatically and success rate can be achieved as high as 96%. AVAILABILITY: The primer design using statistical models is freely available from www.autoprimer.com.

Algorithms↗
PubMed2004

Single nucleotide polymorphisms of the SCN5A gene in Han Chinese and their relation with Brugada syndrome.

BACKGROUND: Mutations in the cardiac sodium channel gene (SCN5A) may lead to a broad spectrum of familial arrhythmias, including long QT syndrome (LQTS), idiopathic ventricular fibrillation (IVF), and isolated cardiac conduction diseases. Recent studies have shown that polymorphisms in the SCN5A gene also play an important role in the manifestation of disorders involving cardiac excitability. In this study, we investigated the polymorphisms of the SCN5A gene in Han Chinese and its relation to Brugada syndrome (BS). METHODS: Genomic DNA was isolated from 120 unrelated healthy volunteers and 48 unrelated Brugada syndrome patients by means of standard procedures. All exons including the putative splicing sites of the SCN5A gene were amplified by PCR and sequenced directly or after subcloning using an ABI Prism 377 DNA sequencer. RESULTS: A total of 5 single nucleotide polymorphisms (SNPs) were identified in the Han Chinese population, including 3 novel ones: G87A(A29A), 4245 + 82A > G, and G6174A. The allele frequencies of each SNP in the Han Chinese population were as follows: G87A (A29A) 27.5%, A1673G (H558R) 10.4%, 4245 + 82A > G 32.8%, C5457T (D1819D) 41.3%, and G6174A 44.9%. S1102Y and 10 other SNPs identified in other ethnic populations were not detected in this study. There was no significant difference in the allele frequency of A1673G (H558R) between different ethnic populations (all P > 0.5). On the other hand, the allele frequency of C5457T (D1819D) among Han Chinese was similar to its frequency among Japanese (P > 0.5), but higher than that among Americans (P < 0.005). The allele G1673 (R558) was over-represented in BS patients compared to controls (P < 0.005), but there was no significant difference in genotype frequencies at this locus. There were also no differences in either the allele or genotype frequencies of the 4 other identified SNPs when comparing BS patients with healthy controls. CONCLUSIONS: The distribution of SCN5A SNPs may vary between different ethnicities. The polymorphism of A1673G might be associated with BS and may contribute to a susceptibility to BS in Han Chinese.

Case-Control Studies↗
PubMed2006

The ATP-binding cassette transporter ABCA2 as a mediator of intracellular trafficking.

ATP-binding cassette (ABC) transporters are a family of proteins that translocate molecules across cellular membranes. Substrates can include lipids, cholesterol and drugs. Mutations in ABC transporter genes can cause human pathologies and drug resistance phenotypes in cancer cells. ABCA2, the second member the A sub-family to be identified, was found at high levels in ovarian carcinoma cells resistant to the anti-cancer agent, estramustine (EM). In vitro models with elevated levels of ABCA2 are resistant to a variety of compounds, including estradiol, mitoxantrone and a free radical initiator, 2,2'-azobis-(2-amidinopropane) (AAPH). ABCA2 is most abundant in the central nervous system (CNS), ovary and macrophages. Enhanced expression of ABCA2 and related proteins, including ABCA1, ABCA4 and ABCA7, is found in human macrophages upon bolus cholesterol treatment. ABCA2 also plays a role in the trafficking of low-density lipoprotein (LDL)-derived free cholesterol and is coordinately expressed with genes involved in cholesterol homeostasis. Additionally, ABCA2 expression has been linked with gene cluster patterns consistent with pathologies including Alzheimer's disease (AD). A single-nucleotide polymorphism (SNP) in exon 14 of the ABCA2 gene was shown to be linked to early onset AD in humans, supporting the observation that ABCA2 expression influences levels of beta-amyloid peptide (Abeta), the primary component of senile plaques. ABCA2 may play a role in cholesterol transport and affect a cellular phenotype conducive to the pathogenesis of a variety of human diseases including AD, atherosclerosis and cancer.

ATP-Binding Cassette Transporters↗
PubMed2003

Recipient ctla-4 +49 G/G genotype is associated with reduced incidence of acute rejection after liver transplantation.

The aim of this pilot study was to investigate whether acute rejection after liver transplantation is associated with known single-nucleotide polymorphisms (SNPs) in the CD86- and CTLA-4 genes of liver-transplant donors and recipients. Single nucleotide polymorphisms were determined in 135 liver transplant recipients and in 73 donors. Acute rejection was not associated with CD86 + 1057 G/A genotype distributions in donors and in recipients. In univariate analysis recipient CTLA-4 -318 G/T and + 49 A/G genotype distributions were both weakly associated with acute rejection. Multivariate analysis revealed that the CTLA-4 + 49 SNP, but not the -318 SNP, was independently of other risk factors associated with acute rejection. Only one out of 13 CTLA-4 + 49 G-homozygotes (8%) experienced acute rejection(s) compared with 40% of A/A or A/G recipients. The CTLA-4 + 49 A/G SNP, which results in an amino acid substitution in the signal peptide of the protein, did not, however, affect intracellular expression or trafficking of CTLA-4 in T cells, nor soluble serum CTLA-4 concentrations of the liver transplant recipients. In conclusion, this pilot study suggests that liver transplant recipients homozygous for CTLA-4 + 49 G have a reduced risk of acute rejection.

Adult↗
PubMed2001

Novel and previously reported single-nucleotide polymorphisms in the human 5-HT(1B) receptor gene: no association with cocaine or alcohol abuse or dependence.

Evidence from animal self-administration and human genetics studies suggests that the serotonin(1B) (5-HT(1B)) receptor may be involved in modulating responses to cocaine or alcohol. We hypothesize that polymorphisms, including single-nucleotide polymorphisms (SNPs), in the human 5-HT(1B) receptor gene, may be associated with individual differences in vulnerability to cocaine or alcohol abuse or dependence. A total of 210 subjects were studied, including individuals with a primary diagnosis (DSM-IV criteria) of cocaine abuse or dependence, alcohol abuse or dependence, and controls with no history of previous or current illicit drug or alcohol abuse or dependence. Genomic DNA samples were isolated from each individual. For 157 of the subjects, polymerase chain reaction (PCR) was used to amplify the entire coding region of the 5-HT(1B) receptor gene as well as parts of the 5' and 3' untranslated regions. PCR products were sequenced in forward and reverse directions on an automated sequencer. Amplified DNA from an additional 53 subjects was sequenced in the 5' untranslated region to gain additional data on the frequency of one identified SNP. Seven polymorphisms were identified: one novel SNP in the 5' untranslated region (UTR) of the gene (A-161T); one SNP not reported in any published scientific communication (but found to be recorded in GenBank) in the 3' UTR (A1180G); two novel dinucleotide deletions at positions - 184/- 183 and - 182/- 181; and three previously identified SNPs (T-261G, C129T, G861C). Data were stratified by ethnicity and pooled Relative Risk was calculated for combined alcohol abuse and dependence cases and controls, and also for combined cocaine abuse and dependence cases and controls. No significant differences between cases and controls were found.

Alcoholism↗
PubMed2005

Human galanin (GAL) and galanin 1 receptor (GALR1) variations are not involved in fat intake and early onset obesity.

The neuropeptide galanin (GAL) is involved in food intake and in fat ingestion. Presumably, these effects are conveyed via the galanin 1 receptor (GALR1). We screened the coding region of GAL (including 444 bp of its promoter region) and GALR1 for mutations using single-strand conformation polymorphism analysis and denaturing HPLC in up to 191 obese children and adolescents and 106 healthy underweight young adults (students). In GAL, we identified 3 novel single nucleotide polymorphisms (SNPs; silent: g.-419T-->C, g.-244G-->A; missense: g.47C-->T: Ala16Val) and one infrequent missense variation (c.253A-->G: Asn85Asp), and in GALR1 2 novel SNPs (silent: c.150C-->T, missense: c.793A-->T: Ile265Phe). To test for an association with obesity, we genotyped 7 SNPs (GAL: g.-244G-->A, g.47C-->T, rs7101947, rs1042577, rs3136540; GALR1: c.150C-->T, c.793A-->T) in up to 322 obese children and adolescents compared with up to 277 healthy underweight and normal weight young adults. Furthermore, we analyzed these SNPs with respect to potential effects on the percentage of energy consumed as fat in obese children and adolescents. Allele and genotype frequencies did not differ among the groups tested. In addition, we performed a pedigree transmission disequilibrium test (PDT) for one SNP (GAL: g.-244G-->A) in 610 (518 independent) obesity-trios (obese child or adolescent and both of its parents). However, the PDT for SNP GAL g.-244G-->A revealed no transmission disequilibrium. We conclude that the analyzed SNPs in GAL and GALR1 do not play a major role in early onset obesity or dietary fat intake in the obese children and adolescents of our study groups.

Adolescent↗
PubMed2004

Molecular characterization of porcine hyaluronidase genes 1, 2, and 3 clustered on SSC13q21.

Hyaluronidase genes (HYAL) encode hyaluronidase enzymes required for hyaluronan degradation. Both in humans and in mouse, clustered hyaluronidase genes have been identified. Here, the porcine hyaluronidase cluster consisting of genes HYAL1, HYAL2 and HYAL3 was characterized. The porcine cDNA sequences and proteins share homologies to human orthologs of 85 and 81% for HYAL1, 87 and 89% for HYAL2 and 86 and 83% for HYAL3, respectively. The porcine hyaluronidase proteins approximately share a 40% homology with each other. Furthermore, genes FUS1 and FUS2 were found within this cluster, which was assigned to SSC13q21. A total of seven SNPs were detected in the genes (four in HYAL1, two in HYAL2 and one in HYAL3). Three of the four SNPs in HYAL1 led to amino acid exchanges (C622G --> Asp24 to Glu; C633T --> Pro28 to Leu, and G1298T --> Ala250 to Ser). The amino acid replacements induce putative changes in the extended strand at Asp24, in the extended strand and the random coil at Pro28, and finally in the random coil and the alpha helix at Ala250. Frequency estimations for four SNPs located in genes HYAL1 and HYAL3 using animals (n = 295) of nine European and six Chinese pig breeds indicated several significant deviations. For example, there were no significant differences in allele frequencies between pigs representing breeds Hampshire and Jiangquhai at SNP C633T (HYAL1), but between Hampshire respectively Jiangquhai animals and Rongchang pigs. Analysis of the same breeds at SNP C588T (HYAL3) indicates significant differences between Hampshire and Jiangquhai respectively Rongchang, but not between Jiangquhai and Rongchang. The breed Göttingen Minipig displayed significant differences concerning two SNPs with respect to the other European pig breeds tested. For all three hyaluronidase genes, N-glycosylation sites are typical. For HYAL2 the lysosomal character was proven. The catalytic site responsible for HAase activity is conserved in the three enzymes. Expression of hyaluronidases was determined by RT-PCR and quantitative PCR. Broad gene expression was observed in different tissues for the three genes, respectively.

Amino Acid Sequence↗
PubMed2002

Suggestive evidence for association of two potassium channel genes with different idiopathic generalised epilepsy syndromes.

Several potassium channel genes have been implicated in epilepsy. We have investigated three such genes, KCNJ3, KCNJ6 and KCNQ2, by association studies using a broad sample of idiopathic generalised epilepsy (IGE) unselected by syndrome. One of the two single nucleotide polymorphisms (SNPs) examined in one of the inward rectifying potassium channel genes, KCNJ3, was associated with IGE by genotype (P=0.0097), while its association by allele was of borderline significance (P=0.051). Analysis of the different clinical subgroups within the IGE sample showed more significant association with the presence of absence seizures (P=0.0041) and which is still significant after correction for multiple testing. Neither SNP in the other rectifying potassium channel gene, KCNJ6, was associated with IGE or any subgroup. None of the three SNPs in the voltage-gated potassium channel gene, KCNQ2, was associated with IGE. However, one SNP was associated with epilepsy with generalised tonic clonic seizures only (P=0.016), as was an SNP approximately 56 kb distant in the closely linked nicotinic acetylcholine gene CHRNA4 (P=0.014). These two SNPs were not in linkage disequilibrium with each other, suggesting that if they are not true associations they have independently occurred by chance. Neither association remains significant after correcting for multiple testing.

3' Untranslated Regions↗
PubMed2006

Effects on production traits of haplotypes among casein genes in Norwegian goats and evidence for a site of preferential recombination.

In goat milk the most abundant proteins are the casein genes, CSN1S1, CSN2, CSN1S2, and CSN3. Mutations have been identified within these genes affecting the level of gene expression, and effects on milk production traits have been reported. The aim of this study was to detect polymorphisms (SNPs) in the casein genes of Norwegian goats, resolve haplotype structures within the loci, and assess the effect of these haplotypes on milk production traits. Four hundred thirty-six Norwegian bucks were genotyped for 39 polymorphic sites across the four loci. The numbers of unique haplotypes present in each locus were 10, 6, 4, and 8 for CSN1S1, CSN2, CSN1S2, and CSN3, respectively. The effects of the CSN1S1 haplotypes on protein percentage and fat kilograms were significant, as were the effects of CSN3 haplotypes on fat percentage and protein percentage. A deletion in exon 12 of CSN1S1, unique to the Norwegian goat population, explained the effects of CSN1S1 haplotypes on fat kilograms, but not protein percentage. Investigation of linkage disequilibrium between all possible pairs of SNPs revealed higher levels of linkage disequilbrium for SNP pairs within casein loci than for SNP pairs between casein loci, likely reflecting low levels of intragenic recombination. Further, there was evidence for a site of preferential recombination between CSN2 and CSN1S2. The value of the haplotypes for haplotype-assisted selection (HAS) is discussed.

Animals↗
PubMed2002

The effects of the human MDR1 genotype on the expression of duodenal P-glycoprotein and disposition of the probe drug talinolol.

BACKGROUND AND OBJECTIVES: A single-nucleotide polymorphism (SNP) of the human multidrug-resistance gene in wobble position of exon 26 reportedly predicts expression and function of P-glycoprotein in human enterocytes and lymphocytes. Several other allelic variants of MDR1 have been identified, some of which lead to amino acid exchange with as yet unknown functional relevance. METHODS: In healthy white volunteers, we investigated the influence of the hereditary variants C3435T in exon 26 and G2677T/A (Ala893Ser/Thr) in exon 21 and the influence of 7 frequent or putative functional SNPs on duodenal MDR1 messenger ribonucleic acid (n = 32) and immunoreactive P-glycoprotein (n = 37) expression. Moreover, the disposition of the probe drug talinolol was evaluated in 55 subjects after oral administration (100 mg) and in 23 subjects after intravenous administration(30 mg). RESULTS: Duodenal MDR1 messenger ribonucleic acid and P-glycoprotein, as assessed by real-time polymerase chain reaction (TaqMan) and immunostaining, were not influenced by any MDR1 polymorphism studied. Talinolol disposition was not affected by the exon 26 mutation C3435T. In carriers of the TT/TA variants of G2677T/A, the area under the serum concentration-time curve values of oral talinolol were slightly but significantly elevated compared with those in carriers of at least 1 wild-type allele (P <.05, Kruskal-Wallis test; P =.014, Mann-Whitney U test). However, multiple comparisons with combinations of putative functional SNPs did not confirm a significant influence of the MDR1 genotype on talinolol disposition. CONCLUSIONS: We did not identify any influence of MDR1 genotypes on duodenal expression of P-glycoprotein and disposition of talinolol in humans.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Genomewide-linkage and haplotype-association studies map intracranial aneurysm to chromosome 7q11.

Rupture of intracranial aneurysms (IAs) causes subarachnoid hemorrhage, a devastating condition with high morbidity and mortality. Angiographic and autopsy studies show that IA is a common disorder, with a prevalence of 3%-6%. Although IA has a substantial genetic component, little attention has been given to the genetic determinants. We report here a genomewide linkage study of IA in 104 Japanese affected sib pairs in which positive evidence of linkage on chromosomes 5q22-31 (maximum LOD score [MLS] 2.24), 7q11 (MLS 3.22), and 14q22 (MLS 2.31) were found. The best evidence of linkage is detected at D7S2472, in the vicinity of the elastin gene (ELN), a candidate gene for IA. Fourteen distinct single-nucleotide polymorphisms (SNPs) were identified in ELN, and no obvious allelic association between IA and each SNP was observed. The haplotype between the intron-20/intron-23 polymorphism of ELN is strongly associated with IA (P=3.81x10-6), and homozygous patients are at high risk (P=.002), with an odds ratio of 4.39. These findings suggest that a genetic locus for IA lies within or close to the ELN locus on chromosome 7.

3' Untranslated Regions↗
PubMed2002

Human non-synonymous SNPs: server and survey.

Human single nucleotide polymorphisms (SNPs) represent the most frequent type of human population DNA variation. One of the main goals of SNP research is to understand the genetics of the human phenotype variation and especially the genetic basis of human complex diseases. Non-synonymous coding SNPs (nsSNPs) comprise a group of SNPs that, together with SNPs in regulatory regions, are believed to have the highest impact on phenotype. Here we present a World Wide Web server to predict the effect of an nsSNP on protein structure and function. The prediction method enabled analysis of the publicly available SNP database HGVbase, which gave rise to a dataset of nsSNPs with predicted functionality. The dataset was further used to compare the effect of various structural and functional characteristics of amino acid substitutions responsible for phenotypic display of nsSNPs. We also studied the dependence of selective pressure on the structural and functional properties of proteins. We found that in our dataset the selection pressure against deleterious SNPs depends on the molecular function of the protein, although it is insensitive to several other protein features considered. The strongest selective pressure was detected for proteins involved in transcription regulation.

Databases, Genetic↗
PubMed2005

[Polymorphisms and bioinformatics analysis of chicken prolactin gene].

Four chicken breeds (White Leghorn, Yangshan, Taihe Silkies, White Recessive Rocks) with different reproduction were applied to screen potential SNPs related to laying performance in the 5' flanking region, exon region and partial intron region of chicken prolactin (cPRL) gene. Totally almost 4500 bp were screened rapidly based on DNA pooling and sequencing, and thirteen single nucleotide polymorphisms (SNPs) and two indels (24 bp and 15 bp) were found, including nine SNPs and two indels in the 5' flanking region, one SNP in Exon 2, two SNPs in Exon 5 and one SNP in Intron 2 respectively. Furthermore, 5' flanking region of cPRL gene was analyzed by the website of http://motif.genome.ad.jp/. A possible Evi-1 binding site (score 93) was found in White Leghorn cPRL gene because of the 24 bp insertion, another possible C/EBPbeta binding site (score 94) was found in Yangshan cPRL gene because of the variation of C-2402T. Further studies need to be carried out to verify their effects on the expression of cPRL gene, the broodiness and laying performance of chickens.

5' Flanking Region↗
PubMed2000

Loss-of-heterozygosity analysis of small-cell lung carcinomas using single-nucleotide polymorphism arrays.

Human cancers arise by a combination of discrete mutations and chromosomal alterations. Loss of heterozygosity (LOH) of chromosomal regions bearing mutated tumor suppressor genes is a key event in the evolution of epithelial and mesenchymal tumors. Global patterns of LOH can be understood through allelotyping of tumors with polymorphic genetic markers. Simple sequence length polymorphisms (SSLPs, or microsatellites) are reliable genetic markers for studying LOH, but only a modest number of SSLPs are used in LOH studies because the genotyping procedure is rather tedious. Here, we report the use of a highly parallel approach to genotype large numbers of single-nucleotide polymorphisms (SNPs) for LOH, in which samples are genotyped for nearly 1,500 loci by performing 24 polymerase chain reactions (PCR), pooling the resulting amplification products and hybridizing the mixture to a high-density oligonucleotide array. We characterize the results of LOH analyses on human small-cell lung cancer (SCLC) and control DNA samples by hybridization. We show that the patterns of LOH are consistent with those obtained by analysis with both SSLPs and comparative genomic hybridization (CGH), whereas amplifications rarely are detected by the SNP array. The results validate the use of SNP array hybridization for tumor studies.

Alleles↗
PubMed2006

A tool for selecting SNPs for association studies based on observed linkage disequilibrium patterns.

The design of genetic association studies using single-nucleotide polymorphisms (SNPs) requires the selection of subsets of the variants providing high statistical power at a reasonable cost. SNPs must be selected to maximize the probability that a causative mutation is in linkage disequilibrium (LD) with at least one marker genotyped in the study. The HapMap project performed a genome-wide survey of genetic variation with about a million SNPs typed in four populations, providing a rich resource to inform the design of association studies. A number of strategies have been proposed for the selection of SNPs based on observed LD, including construction of metric LD maps and the selection of haplotype tagging SNPs. Power calculations are important at the study design stage to ensure successful results. Integrating these methods and annotations can be challenging: the algorithms required to implement these methods are complex to deploy, and all the necessary data and annotations are deposited in disparate databases. Here, we present the SNPbrowser Software, a freely available tool to assist in the LD-based selection of markers for association studies. This stand-alone application provides fast query capabilities and swift visualization of SNPs, gene annotations, power, haplotype blocks, and LD map coordinates. Wizards implement several common SNP selection workflows including the selection of optimal subsets of SNPs (e.g. tagging SNPs). Selected SNPs are screened for their conversion potential to either TaqMan SNP Genotyping Assays or the SNPlex Genotyping System, two commercially available genotyping platforms, expediting the set-up of genetic studies with an increased probability of success.

Computational Biology↗
PubMed2007

Influence of polymorphisms at loci encoding DNA repair proteins on cancer susceptibility and G2 chromosomal radiosensitivity.

Sixteen candidate polymorphisms (13 SNPs and 3 microsatellites) in nine genes from four DNA repair pathways were examined in 83 subjects, comprising 23 survivors of childhood cancer, their 23 partners, and 37 offspring, all of whom had previously been studied for G(2) chromosomal radiosensitivity. Genotype at the Asp148Glu SNP site in the APEX gene of the base excision repair (BER) pathway was associated with childhood cancer in survivors (P = 0.001, significant even after multiple test adjustment), due to the enhanced frequency of the APEX Asp148 allele among survivors in comparison to that of their partners. Analysis of variance (ANOVA) of G(2) radiosensitivity in the pooled sample, as well as family-based association test (FBAT) of the family-wise data, showed sporadic suggestions of associations between G(2) radiosensitivity and polymorphisms at two sites (the Thr241Met SNP site in the XRCC3 gene of the homologous recombinational pathway by ANOVA, and the Ser326Cys site in the hOGG1 gene of the BER pathway by FBAT analysis), but neither of these remained significant after multiple-test adjustment. This pilot study provides an intriguing indication that DNA repair gene polymorphisms may underlie cancer susceptibility and variation in radiosensitivity.

Adolescent↗
PubMed2005

Revealing the role of glutathione S-transferase omega in age-at-onset of Alzheimer and Parkinson diseases.

We previously reported a linkage region on chromosome 10q for age-at-onset (AAO) of Alzheimer (AD) and Parkinson (PD) diseases. Glutathione S-transferase, omega-1 (GSTO1) and the adjacent gene GSTO2, located in this linkage region, were then reported to associate with AAO of AD and PD. To examine whether GSTO1 and GSTO2 (hereafter referred to as GSTO1h) are responsible for the linkage evidence, we identified 39 families in AD that lead to our previous linkage and association findings. The evidence of linkage and association was markedly diminished after removing these 39 families from the analyses, thus providing support that GSTO1h drives the original linkage results. The maximum average AAO delayed by GSTO1h SNP 7-1 (rs4825, A nucleotide) was 6.8 (+/-4.41) years for AD and 8.6(+/-5.71) for PD, respectively. This is comparable to the magnitude of AAO difference by APOE-4 in these same AD and PD families. These findings suggest the presence of genetic heterogeneity for GSTO1h's effect on AAO, and support GSTO1h's role in modifying AAO in these two disorders.

Age of Onset↗