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PubMed2006

Candidate-gene association study of mothers with pre-eclampsia, and their infants, analyzing 775 SNPs in 190 genes.

Pre-eclampsia (PE) affects 5-7% of pregnancies in the US, and is a leading cause of maternal death and perinatal morbidity and mortality worldwide. To identify genes with a role in PE, we conducted a large-scale association study evaluating 775 SNPs in 190 candidate genes selected for a potential role in obstetrical complications. SNP discovery was performed by DNA sequencing, and genotyping was carried out in a high-throughput facility using the MassARRAY(TM) System. Women with PE (n = 394) and their offspring (n = 324) were compared with control women (n = 602) and their offspring (n = 631) from the same hospital-based population. Haplotypes were estimated for each gene using the EM algorithm, and empirical p values were obtained for a logistic regression-based score test, adjusted for significant covariates. An interaction model between maternal and offspring genotypes was also evaluated. The most significant findings for association with PE were COL1A1 (p = 0.0011) and IL1A (p = 0.0014) for the maternal genotype, and PLAUR (p = 0.0008) for the offspring genotype. Common candidate genes for PE, including MTHFR and NOS3, were not significantly associated with PE. For the interaction model, SNPs within IGF1 (p = 0.0035) and IL4R (p = 0.0036) gave the most significant results. This study is one of the most comprehensive genetic association studies of PE to date, including an evaluation of offspring genotypes that have rarely been considered in previous studies. Although we did not identify statistically significant evidence of association for any of the candidate loci evaluated here after adjusting for multiple testing using the false discovery rate, additional compelling evidence exists, including multiple SNPs with nominally significant p values in COL1A1 and the IL1A region, and previous reports of association for IL1A, to support continued interest in these genes as candidates for PE. Identification of the genetic regulators of PE may have broader implications, since women with PE are at increased risk of death from cardiovascular diseases later in life.

Adult↗

PubMed2005

Use of SNPs to determine the breakpoints of complex deficiencies, facilitating gene mapping in Caenorhabditis elegans.

BACKGROUND: Genetic deletions or deficiencies have been used for gene mapping and discovery in various organisms, ranging from the nematode Caenorhabditis elegans all the way to humans. One problem with large deletions is the determination of the location of their breakpoints. This is exacerbated in the case of complex deficiencies that delete a region of the genome, while retaining some of the intervening sequence. Previous methods, using genetic complementation or cytology were hampered by low marker density and were consequently not very precise at positioning the breakpoints of complex deficiencies. The identification of increasing numbers of Single Nucleotide Polymorphisms (SNPs) has resulted in the use of these as genetic markers, and consequently in their utilization for defining the breakpoints of deletions using molecular biology methods. RESULTS: Here, we show that SNPs can be used to help position the breakpoints of a complex deficiency in C. elegans. The technique uses a combination of genetic crosses and molecular biology to generate robust and highly reproducible results with strong internal controls when trying to determine the breakpoints of deficiencies. The combined use of this technique and standard genetic mapping allowed us to rapidly narrow down the region of interest in our attempts to clone a gene. CONCLUSION: Unlike previous methods used to locate deficiency breakpoints, our technique has the advantage of not being limited by the amount of starting material. It also incorporates internal controls to eliminate false positives and negatives. The technique can also easily be adapted for use in other organisms in which both genetic deficiencies and SNPs are available, thereby aiding gene discovery in these other models.

Animals↗

PubMed2004

CLC-2 single nucleotide polymorphisms (SNPs) as potential modifiers of cystic fibrosis disease severity.

BACKGROUND: Cystic fibrosis (CF) lung disease manifest by impaired chloride secretion leads to eventual respiratory failure. Candidate genes that may modify CF lung disease severity include alternative chloride channels. The objectives of this study are to identify single nucleotide polymorphisms (SNPs) in the airway epithelial chloride channel, CLC-2, and correlate these polymorphisms with CF lung disease. METHODS: The CLC-2 promoter, intron 1 and exon 20 were examined for SNPs in adult CF dF508/dF508 homozygotes with mild and severe lung disease (forced expiratory volume at one second (FEV1) > 70% and < 40%). RESULTS: PCR amplification of genomic CLC-2 and sequence analysis revealed 1 polymorphism in the hClC -2 promoter, 4 in intron 1, and none in exon 20. Fisher's analysis within this data set, did not demonstrate a significant relationship between the severity of lung disease and SNPs in the CLC-2 gene. CONCLUSIONS: CLC-2 is not a key modifier gene of CF lung phenotype. Further studies evaluating other phenotypes associated with CF may be useful in the future to assess the ability of CLC-2 to modify CF disease severity.

Adult↗

PubMed2025

Association of CYP19 gene SNPs (rs7176005 and rs6493497) with polycystic ovary syndrome susceptibility in Northern Chinese women.

PURPOSE: The objective of this study was to elucidate the relationship between two single nucleotide polymorphisms (SNPs) rs7176005 and rs6493497 in CYP19 gene and the risk of polycystic ovary syndrome (PCOS) in Northern Chinese women. METHODS: In this case-control study, a total of 340 women with PCOS and 340 matched healthy controls were recruited. Polymerase chain reaction ligase detection reaction (PCR-LDR) method was used to investigate two SNPs (rs7176005 and rs6493497) in the 5'-flanking region of CYP19 gene exon 1. RESULTS: We observed a significant association of rs7176005 and rs6493497 with reduced risk of PCOS. Compared with CC genotype, a significant association of CT genotype (p = 0.019), TT genotype (p < 0.001) and combined CT + TT genotype (p < 0.001) with reduced risk of PCOS was observed. The result of linkage disequilibrium analysis showed that these two SNPs are in complete linkage disequilibrium (r2 = 1). For rs7176005 SNP, compared with CC genotype, CT, TT and CT + TT genotypes reduced the risk of PCOS. The age, BMI-adjusted OR were 0.650 (95% CI = 0.460-0.917), 0.158 (95% CI = 0.066-0.376) and 0.545(95% CI = 0.391-0.759), respectively. CONCLUSIONS: These findings highlight a significant association between CYP19 gene polymorphisms and PCOS susceptibility, implying potential protective effects of T and A alleles. Of course, the major limitation of this study is the sample size of the case-control study. Larger cohort studies are needed to confirm these findings and investigate the underlying causes.

Adult↗

PubMed2006

Detection of SNPs in the plasma of pregnant women and in the urine of kidney transplant recipients by mass spectrometry.

Recently, it has been discovered that cell-free fetal DNA is smaller than corresponding maternal DNA. Therefore, circulating fetal DNA can be enriched by size-fractionation. Such a selection improves the non-invasive prenatal diagnosis of paternally inherited single gene mutations. Recent studies showed that MALDI-TOF mass spectrometry (MS) can be used to reliably detect fetal-specific single-nucleotide polymorphisms (SNPs) in maternal plasma. In this study, we looked at whether the size-fractionation approach could improve the detection of paternally inherited SNPs by MS assay. Our results indicated that the size-fractionation approach improved the analysis of paternally inherited SNP alleles. Our previous studies showed that donor-derived STR sequences could be detected in the urine of kidney transplant recipients. Here, we also examined whether donor-specific SNPs could be detected in recipient's urine by MS.

DNA↗

PubMed2005

Multiple SNPs in intron 7 of thyrotropin receptor are associated with Graves' disease.

Our previous studies using microsatellite markers near or in the TSH receptor (TSHR) gene revealed significant association between autoimmune thyroid disease (AITD) in Japanese patients and TSHR microsatellite alleles. In the present study, we performed a case-control analysis of AITD using single-nucleotide polymorphisms (SNPs) spaced 3-50 kb apart spanning the TSHR gene. We observed significant associations between AITD/Graves' disease (GD)/Hashimoto's thyroiditis and multiple SNPs. Specifically, the SNP JST022302 and several adjacent SNPs in intron 7 of the TSHR gene were significantly associated with GD (P = 0.039-0.0004) but not Hashimoto's thyroiditis. Furthermore, we identified three haplotype blocks around intron 7 by linkage disequilibrium analysis. A single SNP haplotype [AATG(CT)6(TT)AG] in the haplotype block including JST022302 showed significant association with GD in haplotype case-control analysis (P = 0.0058). These findings suggest that alleles of intron 7 of the TSHR gene contribute to GD susceptibility.

Case-Control Studies↗

PubMed2001

High-throughput identification, database storage and analysis of SNPs in EST sequences.

Single nucleotide polymorphisms (SNPs) are the most frequent form of DNA variation and disease-causing mutations in many genes. Due to their abundance and slow mutation rate within generations, they are thought to be the next generation of genetic markers that can be used in a myriad of important biological, genetic, pharmacological, and medical applications. There are several strategies both experimental, and in-silico for SNP discovery and mapping. Experimental SNP discovery consists of a number of labourious steps that make this process complex and expensive. In-silico discovery has been proposed as an alternative discovery method that makes use and takes advantage of large data sets with potential SNP information that have been generated with other purposes and have not been used as a SNP information source yet. However, in order to successfully apply the in-silico method to large data sets, the following challenges need to be addressed: First it is necessary to build an integrated SNP pipeline that handles data processing steps smoothly from the beginning (collecting sequence information) to end (SNPs in the database). Also, SNP detection tool parameters have to be optimized to satisfy specific goals of the project. Finally, SNP data could not be fully used until the in-silico method is validated experimentally. In this paper we present a design and implementation of an in-silico SNP detection software pipeline that exploits the existence of large EST (expressed sequence tag) data sets and effectively addresses the above challenges. First, the pipeline allows for smooth data transition between its different components by implementing data interfaces that translate the data formats of the different tools in the different stages. Second, we optimized PolyBayes parameters for SNP detection in maize EST. Finally, we implemented a user interface that along with the database structure created allows the scientist to perform preliminary analysis of the data and to perform basic statistics on the SNP data prior to experimental validation. The pipeline works with two different types of sequence assemblers (PHRAP (http://www.phrap.org/) and CAT from DoubleTwist (http://www.doubletwist.com/). It uses a Bayesian engine for SNP detection (PolyBayes), selects relevant polymorphism information which is then uploaded into a database. We detected 2439 SNPs and 822 insertion deletions (INDELs) with a PolyBayes probability higher than 0.99 on the public set of 68,000 maize ESTs. The user interface allowed us analyzing the polymorphism information right after discovery in several ways that allowed us to gain insight into the distribution and significance of the newly acquired data.

Animals↗

PubMed2003

[The SNPs analysis of encoding sequence of interacting factor gene in Chinese population].

OBJECTIVE: To screen the variations of TG interacting factor(TGIF) gene in encoding sequence in Chinese high myopia patients and normal controls and to analyze the SNPs of TGIF gene encoding sequence in Chinese population. METHODS: Genomic DNA was collected from 204 probands with high myopia and 112 unrelated persons without high myopia. The coding sequences of TGIF gene in 316 subjects were analyzed by using exon-by-exon PCR heteroduplex-SSCP analysis and sequencing. RESULTS: There were 3 types of SNP and one single nucleotide mutation in the coding sequence of TGIF gene: IVS-2 nt350 G --> T(36/204), codon140 CCA --> CCG; Pro140Pro codon163 CCG --> CTG;Pro163Leu and codon126 GTG --> GCG; Val126Ala(1/204). The SNPs of codon140 CCA --> CCG and codon163 CCG --> CTG were composed of 3 alleles and 5 genotypes in Chinese population which abide by Hardy-Weinberg law. CONCLUSION: There was no evidence to prove that mutations in the TGIF gene are responsible for the high myopia in Chinese. Three SNPs of coding sequence TGIF gene in Chinese population abide by Hardy-Weinberg law.

China↗

PubMed2005

[Rapidly screening SNPs and estimating allelic frequencies by DNA pooling and sequencing].

Four breeds of chickens (White Leghorn, Yangshan, Taihe Silkies, White Recessive Rocks) with different egg production were applied to screen potential single nucleotide polymorphisms (SNPs) related to reproduction trait in distal part region of prolactin gene based on DNA pooling and sequencing. Eight SNPs (C2402T, T-2192C, C-2161G, C-2134G, C-2062G, G-2040A, A-1944G and C-1884A) were found successfully in the fragment of 1 028 bp at the distal part of 5'flanking region. Moreover,a simple and rapid method to estimate allelic frequencies of SNPs in each breed by calculating the ratio of allele peak heights was introduced here. The accuracies of estimation for the allelic frequencies of C-2402T, C-2161G, C-1884A, C-2062G and G-2040A were verified by comparing with the results of PCR-RFLP or PCR-SSCP.

5' Flanking Region↗

PubMed2005

[SNaPshot technique for detection of single-nucleotide polymorphisms (SNPs) in HBV polymerase gene region of HBV gene].

OBJECTIVE: To establish a rapid specific method to identify the single-nucleotide polymorphisms (SNPs) of HBV polymerase gene region which are the methionine residue of the conserved YMDD motif. METHODS: Two specific primers were designed to amplify interested gene region involved in SNPs which were also used as HBV DNA identification. Specific primers of SNaPshot were designed to detect 741A-G (YVDD), 743G-T (YIDD). The different fluorescent dye labeled ddNTP was used to further extend the strand of PCR product and was detected by ABI PRISM 310 Genetic Analyzer. Sera from 13 patients with chronic hepatitis B after lamivudine treatment were analyzed. RESULTS: Aside from mutation of YMDD, there were mutations of 514C-A, 523C-A, 562T-A, 667C-A. The 13 samples were simultaneously tested with SNaPshot and DNA sequencing, the same results were obtained. The method of SNaPshot showed high specificity. CONCLUSION: Mutation of YMDD results in the changes of ATG codon, and there are new ATG codon in the upper strand of YMDD. SNaPshot technique is rapid, specific and accurate for the SNPs monitoring of HBV DNA mutation during lamivudine therapy. Two samples were determined by SnaPshot technique, identifying the co-existence of the mixed wild type and mutant type HBV infection.

Antiviral Agents↗

PubMed2005

Medicare advantage SNPs: a new opportunity for integrated care?

Medicare Advantage special needs plans (SNPs) are a new type of coordinated care plan established by the Medicare Prescription Drug, Improvement and Modernization Act. SNPs were created to encourage greater access to Medicare managed care for certain special needs populations: the institutionalized, persons dually eligible for Medicare and Medicaid, and the chronically ill. Some view SNPs as a new opportunity to integrate acute and long-term care services as well as Medicare and Medicaid financing. Others, however, question the degree to which full integration will become a widespread reality. This issue brief examines the SNP option and the promises and challenges it presents for better coordinated care.

Chronic Disease↗

PubMedDate not supplied

Association study of six activity SNPS in adrenal steroid hormone metabolism and IBM related genes with precocious puberty in Chinese girls.

OBJECTIVES: In order to investigate whether the variances in the candidate genes (Insulin receptor substrate IRS-1, beta3-adrenergic receptor ADRB3, 3 beta-hydro-xysteroid dehydrogenase HSD3B2, glucocorticoid receptor GRL and 21-hydroxylase CYP21) which affect the metabolism of adrenal steroids hormone and body composition, are associated with precocious puberty in Chinese girls. METHODS: PCR-RFLP analysis method was applied in the typing of six activity SNPs in five genes in two groups: 176 precocious puberty girls as case and 192 healthy girls as control. RESULTS: The typing results showed that the frequencies of the allele CYP21 L282 polymorphism were 32.7% and 32.6% in case and control groups (P=0.518), respectively. For IRS-1 R972, they were 0.6% in cases and 2.3% in controls (P=0.043), for ADRB3 R64, 13.6% in cases and 12% in controls (P=0. 378), and for GRL S363, 7.4% in cases and 5.73% in controls (P=0.335). No sample in the two groups carries the variation of CYP21 I172N and HSD3B2 L236S. CONCLUSION: Among these six activity SNPs in five candidate genes, IRS-1 972R was statistically associated with the onset time of puberty in Chinese girls. In order to confirm whether the candidate genes have any other activity SNPs that are associated with the onset time of puberty in Chinese girls, resequencing of these candidate genes is needed in following time.

3-Hydroxysteroid Dehydrogenases↗

PubMed2002

SNPs in the CpG island of NAP1L2: a possible link between DNA methylation and neural tube defects?

Deletion of the murine X-linked Nap1l2 gene causes lethality from midgestation onwards. The affected embryos exhibit neural tube defects (NTDs) closely resembling spina bifida and anencephaly in humans. X-linked familial and spontaneous cases of NTD were analyzed for sequence alterations in the human NAP1L2. No differences were found in the familial cases. However, a number of single nucleotide polymorphisms (SNPs) within the 5' region of NAP1L2 were identified both in cases of spontaneous NTD and in normal controls. Most of these SNPs lead to the replacement of guanidines or cytosines within a CpG island that is conserved between the human and the mouse promoter regions. Demethylation in vitro activates Nap1l2 transcriptional activity, suggesting the importance of the CpG island in regulating the activity of the Nap1l2/NAP1L2 genes, and the potential importance of the polymorphisms in modifying their transcriptional activity. NAP1L2/Nap1l2 expression may therefore depend on the genetic-environmental factors that are frequently associated with NTDs.

Animals↗

PubMed2006

Risks of human limb deficiency anomalies associated with 29 SNPs of genes involved in homocysteine metabolism, coagulation, cell-cell interactions, inflammatory response, and blood pressure regulation.

This study explored risks of limb deficiency anomalies associated with 29 single nucleotide polymorphisms (SNPs) of genes involved in homocysteine metabolism, coagulation, cell-cell interaction, inflammatory response, and blood pressure regulation. The authors genotyped 96 cases and 437 non-malformed controls from a California population-based case-control study (1987-1988 birth cohort). Increased risk of limb anomaly was observed for three SNPs: heterozygosity for F5 Arg506Gln, with an odds ratio (OR) of 2.5 (95% confidence interval (CI), 1.0, 6.5); heterozygosity for TNF (-376)G > A, OR 2.1 (0.7, 6.2); and homozygosity for NPPA 2238T > C, OR 4.0 (1.1, 15.4). We hypothesized that effects of variant genotypes in the presence of maternal smoking, and/or in the absence of supplement intake, may exceed effects of any of these factors alone. In particular, findings for polymorphisms in SERPINE1, ITGA2, SELE, TNF, LTA, NPPA, GNB3, and ADRB2 supported the hypotheses, both for smoking and for supplement intake. These results suggest involvement of genetic variation of biologically relevant candidate genes, and gene-environment interaction, for some limb anomalies whose pathogenesis may be related to altered vascular tone or integrity.

Blood Coagulation↗

PubMed2003

Positive association of the AMPA receptor subunit GluR4 gene (GRIA4) haplotype with schizophrenia: linkage disequilibrium mapping using SNPs evenly distributed across the gene region.

The glutamatergic dysfunction hypothesis suggests that genes involved in the glutamate neurotransmitter system are candidates for schizophrenia-susceptibility genes. We have been conducting systematic studies of the association between glutamate receptors and schizophrenia. We report on a positive association of some haplotypes of the AMPA receptor subunit GluR4 gene (GRIA4) with schizophrenia. We genotyped 100 Japanese schizophrenics and 100 controls for six single nucleotide polymorphism (SNP) markers distributed at intervals of about 50 kb in the GRIA4 region, and estimated the degree of linkage disequilibrium (LD) between the SNPs. We constructed haplotypes of the SNPs in LD using the EM algorithm to test their association with schizophrenia. Significant associations were detected for the combination of SNP4-5 (chi(2) = 12.54, df = 3, P = 0.0057, P = 0.029 with Bonferroni correction) and for the combination of SNP3-4-5 (chi(2) = 18.9, df = 7, P = 0.0085, P = 0.043 with Bonferroni correction). These results suggest that at least one susceptibility locus for schizophrenia is located within or very close to the GRIA4 region in Japanese.

Alleles↗

PubMed2005

DNA pooling analysis of 21 norepinephrine transporter gene SNPs with attention deficit hyperactivity disorder: no evidence for association.

The norepinephrine system is known to play a role in attentional and cognitive-energetic mechanisms and is thought to be important in attention deficit hyperactivity disorder (ADHD). Stimulant medications are known to alter the activity of norepinephrine as well as dopamine in the synapse and the highly selective norepinephrine reuptake inhibitor, atomoxetine, is an effective treatment for ADHD symptoms. This study set out to investigate whether common polymorphisms within the norepinephrine transporter gene (NET1) are associated with DSM-IV ADHD combined subtype, using a sample that has previously shown association with genes that affect the synaptic release and uptake of neurotransmitters; DAT1 and SNAP-25. We identified 21 single nucleotide polymorphisms (SNPs) from publicly available databases that had minor allele frequencies > or =5% and span the NET1 genomic region, including those analyzed in previous studies of ADHD. DNA pooling was used to screen for associations using two case pools (n = 180 cases) and four control pools (n = 334 controls). We identified three SNPs that showed suggestive evidence for association using either case-control or within family tests of association, however, none of these were significant after adjustment for the number of markers analyzed. We conclude that none of the markers show significant evidence of association with ADHD although we cannot rule out small genetic effects.

Algorithms↗

PubMed2004

Fast detection of single nucleotide polymorphisms (SNPs) by primer elongation with monitoring of supercritical-angle fluorescence.

We describe the rapid detection of single nucleotide polymorphisms (SNPs) by real-time observation of primer elongation. The enzymatic elongation of surface-bound primers is monitored by detecting the increase of surface-bound fluorescence caused by the incorporation of Cy5-labelled deoxycytidine 5'-triphosphate residues (Cy5-dCTPs) into the corresponding strand. In order to discriminate against the fluorescence from unbound Cy5-dCTPs, the detection volume was restricted to the surface by collecting supercritical-angle fluorescence. The efficiency of enzymatic double-stranded DNA synthesis is governed by the complementarity of the primer and template. An SNP in the sequence of the primer obstructs its elongation increasingly with decreased distance of the mismatch to the 3' end of the primer. By real-time fluorescence detection during primer elongation, SNPs can be detected within a few minutes, which is significantly faster than in experiments where the fluorescence is measured after completion of the reaction. We demonstrate the efficiency of the method by detecting an SNP in the ErbB2 gene that is involved in causing a higher risk of breast cancer.

Base Pair Mismatch↗

PubMed2006

Dissection of mitochondrial superhaplogroup H using coding region SNPs.

Haplogroup H (hg H) includes about 40-50% of the West Eurasian mitochondrial DNA (mtDNA) samples investigated so far. In order to enhance discrimination within this haplogroup we selected 45 coding region SNPs that allow to ascribe samples to the main phylogenetic branches of super hg HV (that embraces hg H) and, in particular, to H sublineages with a much finer resolution than previous studies. SNP selection was carried out using the most up-to-date available literature on population and forensic genetics and extended by means of phylogenetic analysis of complete or coding region genomes (<430) and control region sequences. A meticulous inspection of the H phylogeny led us to the observation of various but uncharacterized subclades of hg H. The selected SNPs were amplified in two PCR-multiplex reactions and subsequently targeted in three single-base extension multiplex reactions. A total of 2214 West Eurasian samples were screened for hg H specific loci 2706 and 7028, of which 859 fell in hg H and were further subjected to subhaplogroup typing. We observed 35 different subhaplogroups in total, 33 of which were found at frequencies below 5%. This assay can be used as a prescreening tool in forensic casework for rapid discrimination between divergent lineages (very effective for high-volume crime cases) or as discriminatory assay, when identical hg H haplotypes were obtained by control region sequencing.

Adolescent↗