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Find video protocols related to scientific articles indexed in Pubmed.
Fine-mapping of the HNF1B multicancer locus identifies candidate variants that mediate endometrial cancer risk.
Jodie N Painter, Tracy A O'Mara, Jyotsna Batra, Timothy Cheng, Felicity A Lose, Joe Dennis, Kyriaki Michailidou, Jonathan P Tyrer, Shahana Ahmed, Kaltin Ferguson, Catherine S Healey, Susanne Kaufmann, Kristine M Hillman, Carina Walpole, Leire Moya, Pamela Pollock, Angela Jones, Kimberley Howarth, Lynn Martin, Maggie Gorman, Shirley Hodgson, , Ma Magdalena Echeverry de Polanco, Monica Sans, Angel Carracedo, Sergi Castellvi-Bel, Augusto Rojas-Martinez, Erika Santos, Manuel R Teixeira, Luis Carvajal-Carmona, Xiao-Ou Shu, Jirong Long, Wei Zheng, Yong-Bing Xiang, Grant W Montgomery, Penelope M Webb, Rodney J Scott, Mark McEvoy, John Attia, Elizabeth Holliday, Nicholas G Martin, Dale R Nyholt, Anjali K Henders, Peter A Fasching, Alexander Hein, Matthias W Beckmann, Stefan P Renner, Thilo Dörk, Peter Hillemanns, Matthias Dürst, Ingo Runnebaum, Diether Lambrechts, Lieve Coenegrachts, Stefanie Schrauwen, Frédéric Amant, Boris Winterhoff, Sean C Dowdy, Ellen L Goode, Attila Teoman, Helga B Salvesen, Jone Trovik, Tormund S Njolstad, Henrica M J Werner, Katie Ashton, Tony Proietto, Geoffrey Otton, Gerasimos Tzortzatos, Miriam Mints, Emma Tham, Per Hall, Kamila Czene, Jianjun Liu, Jingmei Li, John L Hopper, Melissa C Southey, Arif B Ekici, Matthias Ruebner, Nicola Johnson, Julian Peto, Barbara Burwinkel, Frederik Marme, Hermann Brenner, Aida K Dieffenbach, Alfons Meindl, Hiltrud Brauch, Annika Lindblom, Jeroen Depreeuw, Matthieu Moisse, Jenny Chang-Claude, Anja Rudolph, Fergus J Couch, Janet E Olson, Graham G Giles, Fiona Bruinsma, Julie M Cunningham, Brooke L Fridley, Anne-Lise Børresen-Dale, Vessela N Kristensen, Angela Cox, Anthony J Swerdlow, Nicholas Orr, Manjeet K Bolla, Qin Wang, Rachel Palmieri Weber, Zhihua Chen, Mitul Shah, Juliet D French, Paul D P Pharoah, Alison M Dunning, Ian Tomlinson, Douglas F Easton, Stacey L Edwards, Deborah J Thompson, Amanda B Spurdle.
Hum. Mol. Genet.
PUBLISHED: 11-08-2014
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Common variants in the hepatocyte nuclear factor 1 homeobox B (HNF1B) gene are associated with the risk of type II diabetes and multiple cancers. Evidence to date indicates that cancer risk may be mediated via genetic or epigenetic effects on HNF1B gene expression. We previously found single nucleotide polymorphisms (SNPs) at the HNF1B locus to be associated with endometrial cancer, and now report extensive fine-mapping and in silico and laboratory analyses of this locus. Analysis of 1,184 genotyped and imputed SNPs in 6,608 Caucasian cases and 37,925 controls, and 895 Asian cases and 1,968 controls, revealed the best signal of association for SNP rs11263763 (P=8.4×10(-14), OR=0.86, 95% CI=0.82-0.89), located within HNF1B intron 1. Haplotype analysis and conditional analyses provide no evidence of further independent endometrial cancer risk variants at this locus. SNP rs11263763 genotype was associated with HNF1B mRNA expression but not with HNF1B methylation in endometrial tumour samples from The Cancer Genome Atlas. Genetic analyses prioritized rs11263763 and four other SNPs in high to moderate LD as the most likely causal SNPs. Three of these SNPs map to the extended HNF1B promoter based on chromatin marks extending from the minimal promoter region. Reporter assays demonstrated that this extended region reduces activity in combination with the minimal HNF1B promoter, and that the minor alleles of rs11263763 or rs8064454 are associated with decreased HNF1B promoter activity. Our findings provide evidence for a single signal associated with endometrial cancer risk at the HNF1B locus, and that risk is likely mediated via altered HNF1B gene expression.
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The molecular characterization of a depurinated trial DNA sample can be a model to understand the reliability of the results in forensic genetics.
Electrophoresis
PUBLISHED: 10-31-2014
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The role of DNA damage in PCR processivity/fidelity is a relevant topic in molecular investigation of aged/forensic samples. In order to reproduce one of the most common lesions occurring in postmortem tissues, a new protocol based on aqueous hydrolysis of the DNA was developed in vitro. Twenty-five forensic laboratories were then provided with 3.0 ?g of a trial sample (TS) exhibiting, in mean, the loss of 1 base of 20, and a molecular weight below 300 bp. Each participating laboratory could freely choose any combination of methods, leading to the quantification and to the definition of the STR profile of the TS, through the documentation of each step of the analytical approaches selected. The results of the TS quantification by qPCR showed significant differences in the amount of DNA recorded by the participating laboratories using different commercial kits. These data show that only DNA quantification "relative" to the used kit (probe) is possible, being the "absolute" amount of DNA inversely related to the length of the target region (r(2) = 0.891). In addition, our results indicate that the absence of a shared stable and certified reference quantitative standard is also likely involved. STR profiling was carried out selecting five different commercial kits and amplifying the TS for a total number of 212 multiplex PCRs, thus representing an interesting overview of the different analytical protocols used by the participating laboratories. Nine laboratories decided to characterize the TS using a single kit, with a number of amplifications varying from 2 to 12, obtaining only partial STR profiles. Most of the participants determined partial or full profiles using a combination of two or more kits, and a number of amplifications varying from 2 to 27. The performance of each laboratory was described in terms of number of correctly characterized loci, dropped-out markers, unreliable genotypes, and incorrect results. The incidence of unreliable and incorrect genotypes was found to be higher for participants carrying out a limited number of amplifications, insufficient to define the correct genotypes from damaged DNA samples such as the TS. Finally, from a dataset containing about 4500 amplicons, the frequency of PCR artifacts (allele dropout, allele drop-in, and allelic imbalance) was calculated for each kit showing that the new chemistry of the kits is not able to overcome the concern of template-related factors. The results of this collaborative exercise emphasize the advantages of using a standardized degraded DNA sample in the definition of which analytical parameters are critical for the outcome of the STR profiles.
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Replication of previous genome-wide association studies of psychiatric diseases in a large schizophrenia case-control sample from Spain.
Schizophr. Res.
PUBLISHED: 08-12-2014
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Genome wide association studies (GWAS) has allowed the discovery of some interesting risk variants for schizophrenia (SCZ). However, this high-throughput approach presents some limitations, being the most important the necessity of highly restrictive statistical corrections as well as the loss of statistical power inherent to the use of a Single Nucleotide Polymorphism (SNP) analysis approach. These problems can be partially solved through the use of a polygenic approach. We performed a genotyping study in SCZ using 86 previously associated SNPs identified by GWAS of SCZ, bipolar disorder (BPD) and autistic spectrum disorder (ASD) patients. The sample consisted of 3063 independent cases with DSM-IV-TR diagnosis of SCZ and 2847 independent controls of European origin from Spain. A polygenic score analysis was also used to test the overall effect on the SCZ status. One SNP, rs12290811, located in the ODZ4 gene reached statistical significance (p=1.7×10(-4), Allelic odds ratio=1.21), a value very near to those reported in previous GWAS of BPD patients. In addition, 4 SNPs were close to the significant threshold: rs3850333, in the NRXN1 gene; rs6932590, at MHC; rs2314398, located in an intergenic region on chromosome 2; and rs1006737, in the CACNA1C gene. We also found that 74% of the studied SNPs showed the same tendency (risk or protection alleles) previously reported in the original GWAS (p<0.001). Our data strengthen the polygenic component of susceptibility to SCZ. Our findings show ODZ4 as a risk gene for SCZ, emphasizing the existence of common vulnerability in psychosis.
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Predicting proliferative vitreoretinopathy: temporal and external validation of models based on genetic and clinical variables.
Br J Ophthalmol
PUBLISHED: 07-31-2014
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To validate three models for predicting proliferative vitreoretinopathy (PVR) based on the analysis of genotypic data and relevant clinical characteristics.
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Cuba: exploring the history of admixture and the genetic basis of pigmentation using autosomal and uniparental markers.
PLoS Genet.
PUBLISHED: 07-01-2014
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We carried out an admixture analysis of a sample comprising 1,019 individuals from all the provinces of Cuba. We used a panel of 128 autosomal Ancestry Informative Markers (AIMs) to estimate the admixture proportions. We also characterized a number of haplogroup diagnostic markers in the mtDNA and Y-chromosome in order to evaluate admixture using uniparental markers. Finally, we analyzed the association of 16 single nucleotide polymorphisms (SNPs) with quantitative estimates of skin pigmentation. In the total sample, the average European, African and Native American contributions as estimated from autosomal AIMs were 72%, 20% and 8%, respectively. The Eastern provinces of Cuba showed relatively higher African and Native American contributions than the Western provinces. In particular, the highest proportion of African ancestry was observed in the provinces of Guantánamo (40%) and Santiago de Cuba (39%), and the highest proportion of Native American ancestry in Granma (15%), Holguín (12%) and Las Tunas (12%). We found evidence of substantial population stratification in the current Cuban population, emphasizing the need to control for the effects of population stratification in association studies including individuals from Cuba. The results of the analyses of uniparental markers were concordant with those observed in the autosomes. These geographic patterns in admixture proportions are fully consistent with historical and archaeological information. Additionally, we identified a sex-biased pattern in the process of gene flow, with a substantially higher European contribution from the paternal side, and higher Native American and African contributions from the maternal side. This sex-biased contribution was particularly evident for Native American ancestry. Finally, we observed that SNPs located in the genes SLC24A5 and SLC45A2 are strongly associated with melanin levels in the sample.
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RAD51C germline mutations found in Spanish site-specific breast cancer and breast-ovarian cancer families.
Breast Cancer Res. Treat.
PUBLISHED: 06-23-2014
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BRCA1 and BRCA2 are the most well-known breast and ovarian cancer susceptibility genes. Additional genes involved in DNA repair have been identified as predisposing to breast cancer. Recently, RAD51C, a new Fanconi Anemia gene, essential for homologous recombination repair, has been reported to be a rare hereditary breast and ovarian cancer susceptibility gene. Indeed, several pathogenic mutations have been identified in BRCA1/BRCA2-negative hereditary breast and ovarian cancer families. Here, we present the results of the screening of RAD51C mutations in a large series of 516 BRCA1/BRCA2-negative Spanish patients from breast and/or ovarian cancer families, and the evaluation of these results in the context of all RAD51C carriers. RAD51C mutation screening was performed by DNA analysis for all index cases. All the genetic variants identified were analyzed in silico for splicing and protein predictions. cDNA analysis was performed for three selected variants. All previous RAD51C mutation studies on breast and/or ovarian cancer were reviewed. We identified three inactivating RAD51C mutations. Two mutations were found in breast and ovarian cancer families and one mutation in a site-specific breast cancer family. Based on the mean age of ovarian cancer diagnosis in RAD51C carriers, we would recommend prophylactic bilateral salpingo-ophorectomy in premenopausal RAD51C mutation carriers. Our results support that RAD51C is a rare breast and ovarian cancer susceptibility gene and may contribute to a small fraction of families including breast and ovarian cancer cases and families with only breast cancer. Thus, RAD51C testing should be offered to hereditary breast and/or ovarian cancer families without selecting for specific cancer origin.
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A three-stage genome-wide association study identifies a susceptibility locus for late radiotherapy toxicity at 2q24.1.
Nat. Genet.
PUBLISHED: 06-05-2014
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There is increasing evidence supporting the role of genetic variants in the development of radiation-induced toxicity. However, previous candidate gene association studies failed to elucidate the common genetic variation underlying this phenotype, which could emerge years after the completion of treatment. We performed a genome-wide association study on a Spanish cohort of 741 individuals with prostate cancer treated with external beam radiotherapy (EBRT). The replication cohorts consisted of 633 cases from the UK and 368 cases from North America. One locus comprising TANC1 (lowest unadjusted P value for overall late toxicity=6.85×10(-9), odds ratio (OR)=6.61, 95% confidence interval (CI)=2.23-19.63) was replicated in the second stage (lowest unadjusted P value for overall late toxicity=2.08×10(-4), OR=6.17, 95% CI=2.25-16.95; Pcombined=4.16×10(-10)). The inclusion of the third cohort gave unadjusted Pcombined=4.64×10(-11). These results, together with the role of TANC1 in regenerating damaged muscle, suggest that the TANC1 locus influences the development of late radiation-induced damage.
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Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.
Dan E Arking, Sara L Pulit, Lia Crotti, Pim van der Harst, Patricia B Munroe, Tamara T Koopmann, Nona Sotoodehnia, Elizabeth J Rossin, Michael Morley, Xinchen Wang, Andrew D Johnson, Alicia Lundby, Daniel F Gudbjartsson, Peter A Noseworthy, Mark Eijgelsheim, Yuki Bradford, Kirill V Tarasov, Marcus Dörr, Martina Müller-Nurasyid, Annukka M Lahtinen, Ilja M Nolte, Albert Vernon Smith, Joshua C Bis, Aaron Isaacs, Stephen J Newhouse, Daniel S Evans, Wendy S Post, Daryl Waggott, Leo-Pekka Lyytikäinen, Andrew A Hicks, Lewin Eisele, David Ellinghaus, Caroline Hayward, Pau Navarro, Sheila Ulivi, Toshiko Tanaka, David J Tester, Stéphanie Chatel, Stefan Gustafsson, Meena Kumari, Richard W Morris, Asa T Naluai, Sandosh Padmanabhan, Alexander Kluttig, Bernhard Strohmer, Andrie G Panayiotou, Maria Torres, Michael Knoflach, Jaroslav A Hubacek, Kamil Slowikowski, Soumya Raychaudhuri, Runjun D Kumar, Tamara B Harris, Lenore J Launer, Alan R Shuldiner, Alvaro Alonso, Joel S Bader, Georg Ehret, Hailiang Huang, W H Linda Kao, James B Strait, Peter W Macfarlane, Morris Brown, Mark J Caulfield, Nilesh J Samani, Florian Kronenberg, Johann Willeit, , J Gustav Smith, Karin H Greiser, Henriette Meyer zu Schwabedissen, Karl Werdan, Massimo Carella, Leopoldo Zelante, Susan R Heckbert, Bruce M Psaty, Jerome I Rotter, Ivana Kolčić, Ozren Polašek, Alan F Wright, Maura Griffin, Mark J Daly, David O Arnar, Hilma Holm, Unnur Thorsteinsdottir, Joshua C Denny, Dan M Roden, Rebecca L Zuvich, Valur Emilsson, Andrew S Plump, Martin G Larson, Christopher J O'Donnell, Xiaoyan Yin, Marco Bobbo, Adamo P d'Adamo, AnnaMaria Iorio, Gianfranco Sinagra, Angel Carracedo, Steven R Cummings, Michael A Nalls, Antti Jula, Kimmo K Kontula, Annukka Marjamaa, Lasse Oikarinen, Markus Perola, Kimmo Porthan, Raimund Erbel, Per Hoffmann, Karl-Heinz Jöckel, Hagen Kälsch, Markus M Nöthen, Marcel den Hoed, Ruth J F Loos, Dag S Thelle, Christian Gieger, Thomas Meitinger, Siegfried Perz, Annette Peters, Hanna Prucha, Moritz F Sinner, Melanie Waldenberger, Rudolf A de Boer, Lude Franke, Pieter A van der Vleuten, Britt Maria Beckmann, Eimo Martens, Abdennasser Bardai, Nynke Hofman, Arthur A M Wilde, Elijah R Behr, Chrysoula Dalageorgou, John R Giudicessi, Argelia Medeiros-Domingo, Julien Barc, Florence Kyndt, Vincent Probst, Alice Ghidoni, Roberto Insolia, Robert M Hamilton, Stephen W Scherer, Jeffrey Brandimarto, Kenneth Margulies, Christine E Moravec, Fabiola Del Greco M, Christian Fuchsberger, Jeffrey R O'Connell, Wai K Lee, Graham C M Watt, Harry Campbell, Sarah H Wild, Nour E El Mokhtari, Norbert Frey, Folkert W Asselbergs, Irene Mateo Leach, Gerjan Navis, Maarten P van den Berg, Dirk J van Veldhuisen, Manolis Kellis, Bouwe P Krijthe, Oscar H Franco, Albert Hofman, Jan A Kors, André G Uitterlinden, Jacqueline C M Witteman, Lyudmyla Kedenko, Claudia Lamina, Ben A Oostra, Gonçalo R Abecasis, Edward G Lakatta, Antonella Mulas, Marco Orrù, David Schlessinger, Manuela Uda, Marcello R P Markus, Uwe Völker, Harold Snieder, Timothy D Spector, Johan Arnlöv, Lars Lind, Johan Sundström, Ann-Christine Syvänen, Mika Kivimäki, Mika Kähönen, Nina Mononen, Olli T Raitakari, Jorma S Viikari, Vera Adamkova, Stefan Kiechl, María Brión, Andrew N Nicolaides, Bernhard Paulweber, Johannes Haerting, Anna F Dominiczak, Fredrik Nyberg, Peter H Whincup, Aroon D Hingorani, Jean-Jacques Schott, Connie R Bezzina, Erik Ingelsson, Luigi Ferrucci, Paolo Gasparini, James F Wilson, Igor Rudan, Andre Franke, Thomas W Mühleisen, Peter P Pramstaller, Terho J Lehtimäki, Andrew D Paterson, Afshin Parsa, Yongmei Liu, Cornelia M van Duijn, David S Siscovick, Vilmundur Gudnason, Yalda Jamshidi, Veikko Salomaa, Stephan B Felix, Serena Sanna, Marylyn D Ritchie, Bruno H Stricker, Kari Stefansson, Laurie A Boyer, Thomas P Cappola, Jesper V Olsen, Kasper Lage, Peter J Schwartz, Stefan Kääb, Aravinda Chakravarti, Michael J Ackerman, Arne Pfeufer, Paul I W de Bakker, Christopher Newton-Cheh.
Nat. Genet.
PUBLISHED: 05-29-2014
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The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ?8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD.
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Identifying gene-environment interactions in schizophrenia: contemporary challenges for integrated, large-scale investigations.
, Jim van Os, Bart P Rutten, Inez Myin-Germeys, Philippe Delespaul, Wolfgang Viechtbauer, Catherine van Zelst, Richard Bruggeman, Ulrich Reininghaus, Craig Morgan, Robin M Murray, Marta Di Forti, Philip McGuire, Lucia R Valmaggia, Matthew J Kempton, Charlotte Gayer-Anderson, Kathryn Hubbard, Stephanie Beards, Simona A Stilo, Adanna Onyejiaka, François Bourque, Gemma Modinos, Stefania Tognin, Maria Calem, Michael C O'Donovan, Michael J Owen, Peter Holmans, Nigel Williams, Nicholas Craddock, Alexander Richards, Isla Humphreys, Andreas Meyer-Lindenberg, F Markus Leweke, Heike Tost, Ceren Akdeniz, Cathrin Rohleder, J Malte Bumb, Emanuel Schwarz, Koksal Alptekin, Alp Üçok, Meram Can Saka, E Cem Atbaşoğlu, Sinan Guloksuz, Güvem Gümüş-Akay, Burçin Cihan, Hasan Karadag, Haldan Soygür, Eylem Şahin Cankurtaran, Semra Ulusoy, Berna Akdede, Tolga Binbay, Ahmet Ayer, Handan Noyan, Gülşah Karadayı, Elçin Akturan, Halis Ulas, Celso Arango, Mara Parellada, Miguel Bernardo, Julio Sanjuan, Julio Bobes, Manuel Arrojo, Jose Luis Santos, Pedro Cuadrado, José Juan Rodríguez Solano, Angel Carracedo, Enrique García Bernardo, Laura Roldán, Gonzalo Lopez, Bibiana Cabrera, Sabrina Cruz, Eva Ma Díaz Mesa, María Pouso, Estela Jiménez, Teresa Sanchez, Marta Rapado, Emiliano González, Covadonga Martínez, Emilio Sanchez, Ma Soledad Olmeda, Lieuwe de Haan, Eva Velthorst, Mark van der Gaag, Jean-Paul Selten, Daniella van Dam, Elsje van der Ven, Floor van der Meer, Elles Messchaert, Tamar Kraan, Nadine Burger, Marion Leboyer, Andrei Szoke, Franck Schürhoff, Pierre-Michel Llorca, Stéphane Jamain, Andrea Tortelli, Flora Frijda, Jeanne Vilain, Anne-Marie Galliot, Grégoire Baudin, Aziz Ferchiou, Jean-Romain Richard, Ewa Bulzacka, Thomas Charpeaud, Anne-Marie Tronche, Marc De Hert, Ruud van Winkel, Jeroen Decoster, Catherine Derom, Evert Thiery, Nikos C Stefanis, Gabriele Sachs, Harald Aschauer, Iris Lasser, Bernadette Winklbaur, Monika Schlögelhofer, Anita Riecher-Rossler, Stefan Borgwardt, Anna Walter, Fabienne Harrisberger, Renata Smieskova, Charlotte Rapp, Sarah Ittig, Fabienne Soguel-dit-Piquard, Erich Studerus, Joachim Klosterkötter, Stephan Ruhrmann, Julia Paruch, Dominika Julkowski, Desiree Hilboll, Pak C Sham, Stacey S Cherny, Eric Y H Chen, Desmond D Campbell, Miaoxin Li, Carlos María Romeo-Casabona, Aitziber Emaldi Cirión, Asier Urruela Mora, Peter Jones, James Kirkbride, Mary Cannon, Dan Rujescu, Ilaria Tarricone, Domenico Berardi, Elena Bonora, Marco Seri, Thomas Marcacci, Luigi Chiri, Federico Chierzi, Viviana Storbini, Mauro Braca, Maria Gabriella Minenna, Ivonne Donegani, Angelo Fioritti, Daniele La Barbera, Caterina Erika La Cascia, Alice Mulè, Lucia Sideli, Rachele Sartorio, Laura Ferraro, Giada Tripoli, Fabio Seminerio, Anna Maria Marinaro, Patrick McGorry, Barnaby Nelson, G Paul Amminger, Christos Pantelis, Paulo R Menezes, Cristina M Del-Ben, Silvia H Gallo Tenan, Rosana Shuhama, Mirella Ruggeri, Sarah Tosato, Antonio Lasalvia, Chiara Bonetto, Elisa Ira, Merete Nordentoft, Marie-Odile Krebs, Neus Barrantes-Vidal, Paula Cristóbal, Thomas R Kwapil, Elisa Brietzke, Rodrigo A Bressan, Ary Gadelha, Nadja P Maric, Sanja Andric, Marina Mihaljevic, Tijana Mirjanic.
Schizophr Bull
PUBLISHED: 05-24-2014
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Recent years have seen considerable progress in epidemiological and molecular genetic research into environmental and genetic factors in schizophrenia, but methodological uncertainties remain with regard to validating environmental exposures, and the population risk conferred by individual molecular genetic variants is small. There are now also a limited number of studies that have investigated molecular genetic candidate gene-environment interactions (G × E), however, so far, thorough replication of findings is rare and G × E research still faces several conceptual and methodological challenges. In this article, we aim to review these recent developments and illustrate how integrated, large-scale investigations may overcome contemporary challenges in G × E research, drawing on the example of a large, international, multi-center study into the identification and translational application of G × E in schizophrenia. While such investigations are now well underway, new challenges emerge for G × E research from late-breaking evidence that genetic variation and environmental exposures are, to a significant degree, shared across a range of psychiatric disorders, with potential overlap in phenotype.
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Synaptic, transcriptional and chromatin genes disrupted in autism.
Silvia De Rubeis, Xin He, Arthur P Goldberg, Christopher S Poultney, Kaitlin Samocha, A Ercument Cicek, Yan Kou, Li Liu, Menachem Fromer, Susan Walker, Tarjinder Singh, Lambertus Klei, Jack Kosmicki, Shih-Chen Fu, Branko Aleksic, Monica Biscaldi, Patrick F Bolton, Jessica M Brownfeld, Jinlu Cai, Nicholas G Campbell, Angel Carracedo, Maria H Chahrour, Andreas G Chiocchetti, Hilary Coon, Emily L Crawford, Lucy Crooks, Sarah R Curran, Geraldine Dawson, Eftichia Duketis, Bridget A Fernandez, Louise Gallagher, Evan Geller, Stephen J Guter, R Sean Hill, Iuliana Ionita-Laza, Patricia Jimenez Gonzalez, Helena Kilpinen, Sabine M Klauck, Alexander Kolevzon, Irene Lee, Jing Lei, Terho Lehtimäki, Chiao-Feng Lin, Avi Ma'ayan, Christian R Marshall, Alison L McInnes, Benjamin Neale, Michael J Owen, Norio Ozaki, Mara Parellada, Jeremy R Parr, Shaun Purcell, Kaija Puura, Deepthi Rajagopalan, Karola Rehnström, Abraham Reichenberg, Aniko Sabo, Michael Sachse, Stephan J Sanders, Chad Schafer, Martin Schulte-Rüther, David Skuse, Christine Stevens, Peter Szatmari, Kristiina Tammimies, Otto Valladares, Annette Voran, Li-San Wang, Lauren A Weiss, A Jeremy Willsey, Timothy W Yu, Ryan K C Yuen, , Edwin H Cook, Christine M Freitag, Michael Gill, Christina M Hultman, Thomas Lehner, Aarno Palotie, Gerard D Schellenberg, Pamela Sklar, Matthew W State, James S Sutcliffe, Christopher A Walsh, Stephen W Scherer, Michael E Zwick, Jeffrey C Barrett, David J Cutler, Kathryn Roeder, Bernie Devlin, Mark J Daly, Joseph D Buxbaum.
Nature
PUBLISHED: 05-18-2014
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The genetic architecture of autism spectrum disorder involves the interplay of common and rare variants and their impact on hundreds of genes. Using exome sequencing, here we show that analysis of rare coding variation in 3,871 autism cases and 9,937 ancestry-matched or parental controls implicates 22 autosomal genes at a false discovery rate (FDR) < 0.05, plus a set of 107 autosomal genes strongly enriched for those likely to affect risk (FDR < 0.30). These 107 genes, which show unusual evolutionary constraint against mutations, incur de novo loss-of-function mutations in over 5% of autistic subjects. Many of the genes implicated encode proteins for synaptic formation, transcriptional regulation and chromatin-remodelling pathways. These include voltage-gated ion channels regulating the propagation of action potentials, pacemaking and excitability-transcription coupling, as well as histone-modifying enzymes and chromatin remodellers-most prominently those that mediate post-translational lysine methylation/demethylation modifications of histones.
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Whole exome sequencing for the identification of a new mutation in TGFB2 involved in a familial case of non-syndromic aortic disease.
Clin. Chim. Acta
PUBLISHED: 04-25-2014
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Non-syndromic aortic disease (NSAD) is a frequently asymptomatic but potentially lethal disease characterised by familial cases of thoracic aortic aneurysms and dissections. This monogenic but genetically heterogeneous condition is primarily inherited as an autosomal dominant disorder with low penetrance and variable expression. Mutations in ACTA2, TGFBR1, TGFBR2, MYH11, SMAD3, MYLK, and FBN1 genes have been described but still, there are many unresolved familial cases.
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Brain activation of the defensive and appetitive survival systems in obsessive compulsive disorder.
Brain Imaging Behav
PUBLISHED: 04-25-2014
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Several studies have shown that basic emotions are responsible for a significant enhancement of early visual processes and increased activation in visual processing brain regions. It may be possible that the cognitive uncertainty and repeated behavioral checking evident in Obsessive Compulsive Disorder (OCD) is due to the existence of abnormalities in basic survival circuits, particularly those associated with the visual processing of the physical characteristics of emotional-laden stimuli. The objective of the present study was to test if patients with OCD show evidence of altered basic survival circuits, particularly those associated with the visual processing of the physical characteristics of emotional stimuli. Fifteen patients with OCD and 12 healthy controls underwent functional magnetic resonance imaging acquisition while being exposed to emotional pictures, with different levels of arousal, intended to trigger the defensive and appetitive basic survival circuits. Overall, the present results seem to indicate dissociation in the activity of the defense and appetitive survival systems in OCD. Results suggest that the clinical group reacts to basic threat with a strong activation of the defensive system mobilizing widespread brain networks (i.e., frontal, temporal, occipital-parietal, and subcortical nucleus) and blocking the activation of the appetitive system when facing positive emotional triggers from the initial stages of visual processing (i.e., superior occipital gyrus).
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Development of a forensic skin colour predictive test.
Forensic Sci Int Genet
PUBLISHED: 04-21-2014
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There is growing interest in skin colour prediction in the forensic field. However, a lack of consensus approaches for recording skin colour phenotype plus the complicating factors of epistatic effects, environmental influences such as exposure to the sun and unidentified genetic variants, present difficulties for the development of a forensic skin colour predictive test centred on the most strongly associated SNPs. Previous studies have analysed skin colour variation in single unadmixed population groups, including South Asians (Stokowski et al., 2007, Am. J. Hum. Genet, 81: 1119-32) and Europeans (Jacobs et al., 2013, Hum Genet. 132: 147-58). Nevertheless, a major challenge lies in the analysis of skin colour in admixed individuals, where co-ancestry proportions do not necessarily dictate any one person's skin colour. Our study sought to analyse genetic differences between African, European and admixed African-European subjects where direct spectrometric measurements and photographs of skin colour were made in parallel. We identified strong associations to skin colour variation in the subjects studied from a pigmentation SNP discovery panel of 59 markers and developed a forensic online classifier based on naïve Bayes analysis of the SNP profiles made. A skin colour predictive test is described using the ten most strongly associated SNPs in 8 genes linked to skin pigmentation variation.
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A novel stop mutation in the vascular endothelial growth factor-C gene (VEGFC) results in Milroy-like disease.
J. Med. Genet.
PUBLISHED: 04-17-2014
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Milroy and Milroy-like disease are rare disorders characterised by congenital lymphoedema caused by dysfunctional lymphatic vessel formation. Loss of extracellular response mediated by vascular endothelial growth factor receptor 3 (VEGFR-3) is associated with Milroy disease, and VEGFR-3 gene is mutated in around 70% of the cases diagnosed. The only genetic alteration known to be associated with Milroy-like disease was recently identified in a family with a frameshift mutation in vascular endothelial growth factor C (VEGFC) gene, which encodes a VEGFR3 ligand.
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Whole-exome sequencing identifies rare pathogenic variants in new predisposition genes for familial colorectal cancer.
Genet. Med.
PUBLISHED: 04-08-2014
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Purpose:Colorectal cancer is an important cause of mortality in the developed world. Hereditary forms are due to germ-line mutations in APC, MUTYH, and the mismatch repair genes, but many cases present familial aggregation but an unknown inherited cause. The hypothesis of rare high-penetrance mutations in new genes is a likely explanation for the underlying predisposition in some of these familial cases.Methods:Exome sequencing was performed in 43 patients with colorectal cancer from 29 families with strong disease aggregation without mutations in known hereditary colorectal cancer genes. Data analysis selected only very rare variants (0-0.1%), producing a putative loss of function and located in genes with a role compatible with cancer. Variants in genes previously involved in hereditary colorectal cancer or nearby previous colorectal cancer genome-wide association study hits were also chosen.Results:Twenty-eight final candidate variants were selected and validated by Sanger sequencing. Correct family segregation and somatic studies were used to categorize the most interesting variants in CDKN1B, XRCC4, EPHX1, NFKBIZ, SMARCA4, and BARD1.Conclusion:We identified new potential colorectal cancer predisposition variants in genes that have a role in cancer predisposition and are involved in DNA repair and the cell cycle, which supports their putative involvement in germ-line predisposition to this neoplasm.Genet Med advance online publication 24 July 2014Genetics in Medicine (2014); doi:10.1038/gim.2014.89.
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Investigation of gene-environment interactions between 47 newly identified breast cancer susceptibility loci and environmental risk factors.
Int. J. Cancer
PUBLISHED: 04-03-2014
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A large genotyping project within the Breast Cancer Association Consortium (BCAC) recently identified 41 associations between single nucleotide polymorphisms (SNPs) and overall breast cancer (BC) risk. We investigated whether the effects of these 41 SNPs, as well as six SNPs associated with estrogen receptor (ER) negative BC risk are modified by 13 environmental risk factors for BC. Data from 22 studies participating in BCAC were pooled, comprising up to 26,633 cases and 30,119 controls. Interactions between SNPs and environmental factors were evaluated using an empirical Bayes-type shrinkage estimator. Six SNPs showed interactions with associated p-values (pint ) <1.1 × 10(-3) . None of the observed interactions was significant after accounting for multiple testing. The Bayesian False Discovery Probability was used to rank the findings, which indicated three interactions as being noteworthy at 1% prior probability of interaction. SNP rs6828523 was associated with increased ER-negative BC risk in women ?170 cm (OR = 1.22, p = 0.017), but inversely associated with ER-negative BC risk in women <160 cm (OR = 0.83, p = 0.039, pint = 1.9 × 10(-4) ). The inverse association between rs4808801 and overall BC risk was stronger for women who had had four or more pregnancies (OR = 0.85, p = 2.0 × 10(-4) ), and absent in women who had had just one (OR = 0.96, p = 0.19, pint = 6.1 × 10(-4) ). SNP rs11242675 was inversely associated with overall BC risk in never/former smokers (OR = 0.93, p = 2.8 × 10(-5) ), but no association was observed in current smokers (OR = 1.07, p = 0.14, pint = 3.4 × 10(-4) ). In conclusion, recently identified BC susceptibility loci are not strongly modified by established risk factors and the observed potential interactions require confirmation in independent studies.
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A candidate gene study of capecitabine-related toxicity in colorectal cancer identifies new toxicity variants at DPYD and a putative role for ENOSF1 rather than TYMS.
Gut
PUBLISHED: 03-21-2014
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Capecitabine is an oral 5-fluorouracil (5-FU) pro-drug commonly used to treat colorectal carcinoma and other tumours. About 35% of patients experience dose-limiting toxicity. The few proven genetic biomarkers of 5-FU toxicity are rare variants and polymorphisms, respectively, at candidate loci dihydropyrimidine dehydrogenase (DPYD) and thymidylate synthase (TYMS).
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Next generation sequencing challenges in the analysis of cardiac sudden death due to arrhythmogenic disorders.
Electrophoresis
PUBLISHED: 03-18-2014
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Inherited arrhythmogenic disorders is a relatively common cause of cardiac sudden death in young people. Diagnosis has been difficult so far due to the genetic heterogeneity of the disease. Next generation sequencing (NGS) is offering a new scenario for diagnosis. The purpose of our study was to validate NGS for the analysis of twenty-eight genes known to be associated with inherited arrhythmogenic disorders and therefore with sudden cardiac death. SureSelect hybridization was used to enrich DNA from 53 samples, prior to be sequenced with the SOLID™ System of Life Technologies. Depth of coverage, consistency of coverage across samples, and location of variants identified were assessed. All the samples showed a depth of coverage over 200×, except one of them discarded because of its coverage below 30×. Average percentage of target bp covered at least 20× was 96.45%. In the remaining samples, following a prioritization process 46 possible variants in 31 samples were found, of which 45 were confirmed by Sanger sequencing. After filtering variants according to their minor allele frequency in the Exome Sequencing Project 27 putative pathogenic variants in 20 samples remained. With the use of in silico tools, 13 variants in 11 samples were classified as likely pathogenic. In conclusion, NGS allowed us to accurately detect arrhythmogenic disease causing mutations in a fast and cost-efficient manner that is suitable for daily clinical and forensic practice of genetic testing of this type of disorders.
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The human early-life exposome (HELIX): project rationale and design.
Environ. Health Perspect.
PUBLISHED: 03-06-2014
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Developmental periods in early life may be particularly vulnerable to impacts of environmental exposures. Human research on this topic has generally focused on single exposure-health effect relationships. The "exposome" concept encompasses the totality of exposures from conception onward, complementing the genome.
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"New turns from old STaRs": Enhancing the capabilities of forensic short tandem repeat analysis.
Electrophoresis
PUBLISHED: 02-26-2014
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The field of research and development of forensic STR genotyping remains active, innovative, and focused on continuous improvements. A series of recent developments including the introduction of a sixth dye have brought expanded STR multiplex sizes while maintaining sensitivity to typical forensic DNA. New supplementary kits complimenting the core STRs have also helped improve analysis of challenging identification cases such as distant pairwise relationships in deficient pedigrees. This article gives an overview of several recent key developments in forensic STR analysis: availability of expanded core STR kits and supplementary STRs, short-amplicon mini-STRs offering practical options for highly degraded DNA, Y-STR enhancements made from the identification of rapidly mutating loci, and enhanced analysis of genetic ancestry by analyzing 32-STR profiles with a Bayesian forensic classifier originally developed for SNP population data. As well as providing scope for genotyping larger numbers of STRs optimized for forensic applications, the launch of compact next-generation sequencing systems provides considerable potential for genotyping the sizeable proportion of nucleotide variation existing in forensic STRs, which currently escapes detection with CE.
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Cerebral and cerebellar MRI volumes in Williams syndrome.
Res Dev Disabil
PUBLISHED: 02-14-2014
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Individuals with Williams syndrome (WS) present a set of cognitive, affective and motor symptoms that resemble those of patients with lesions to the cerebellum. Although there is some evidence for overall structural alterations in this brain region in WS, explorations on cerebellar white matter and cerebellar cortex volumes remain rather neglected. We aimed to compare absolute and relative cerebellar volumes, as well as patterns of white matter to cortex volumes in this brain region, between a group of individuals with WS and a group of healthy controls. T1-weighted magnetic resonance images were acquired in 17 individuals with WS and in 15 typically developing individuals. Our results showed that even though individuals from the clinical group had significantly smaller cerebrums (and cerebellums), cerebellar volumes relative to intracranial volumes were significantly enlarged. In addition, while gray matter was relatively spared and white matter disproportionately reduced in the cerebrum in WS, relative cerebellar cortex and white matter volumes were preserved. These findings support the hypothesis that volume alterations in the cerebellum are associated with the cognitive, affective and motor profiles in WS.
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Characterization of CYP1A2, CYP2C19, CYP3A4 and CYP3A5 polymorphisms in South Brazilians.
Mol. Biol. Rep.
PUBLISHED: 01-18-2014
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Potential causes of variability in drug response include intrinsic factors such as ethnicity and genetic differences in the expression of enzymes that metabolize drugs, such as those from Cytochrome P450 (CYPs) superfamily. Pharmacogenetic studies search for genetic differences between populations since relevant alleles occur with varying frequencies among different ethnic populations. The Brazilian population is one of the most heterogeneous in the world, resulting from multiethnic admixture of Amerindians, Europeans, and Africans across centuries. Since the knowledge of CYP allele frequency distributions is relevant to pharmacogenetic strategies and these data are scarce in the Brazilian population, this study aimed to describe genotype and allele distributions of 15 single nucleotide polymorphisms (SNPs) at CYP 1A2, 2C19, 3A4, and 3A5 genes in African and European descents from South Brazil. A sample of 179 healthy individuals of European and African ancestry was genotyped by the MassARRAY SNP genotyping system. CYP3A5*3, CYP1A2*1F, CYP3A4*1B, and CYP2C19*2 were the most frequent alleles found in our sample. Significant differences in genotype and allelic distribution between African and European descents were observed for CYP3A4 and CYP3A5 genes. CYP3A4*1B was observed in higher frequency in African descents (0.379) than in European descents (0.098), and European descents showed higher frequency of CYP3A5*3 (0.810) than African descents (0.523). Our results indicate that only a few polymorphisms would have impact in pharmacogenetic testing in South Brazilians. Further studies with larger sample sizes are required also among other Brazilian regions.
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New genes emerging for colorectal cancer predisposition.
World J. Gastroenterol.
PUBLISHED: 01-14-2014
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Colorectal cancer (CRC) is one of the most frequent neoplasms and an important cause of mortality in the developed world. This cancer is caused by both genetic and environmental factors although 35% of the variation in CRC susceptibility involves inherited genetic differences. Mendelian syndromes account for about 5% of the total burden of CRC, with Lynch syndrome and familial adenomatous polyposis the most common forms. Excluding hereditary forms, there is an important fraction of CRC cases that present familial aggregation for the disease with an unknown germline genetic cause. CRC can be also considered as a complex disease taking into account the common disease-commom variant hypothesis with a polygenic model of inheritance where the genetic components of common complex diseases correspond mostly to variants of low/moderate effect. So far, 30 common, low-penetrance susceptibility variants have been identified for CRC. Recently, new sequencing technologies including exome- and whole-genome sequencing have permitted to add a new approach to facilitate the identification of new genes responsible for human disease predisposition. By using whole-genome sequencing, germline mutations in the POLE and POLD1 genes have been found to be responsible for a new form of CRC genetic predisposition called polymerase proofreading-associated polyposis.
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A colorectal cancer susceptibility new variant at 4q26 in the Spanish population identified by genome-wide association analysis.
PLoS ONE
PUBLISHED: 01-01-2014
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Non-hereditary colorectal cancer (CRC) is a complex disorder resulting from the combination of genetic and non-genetic factors. Genome-wide association studies (GWAS) are useful for identifying such genetic susceptibility factors. However, the single loci so far associated with CRC only represent a fraction of the genetic risk for CRC development in the general population. Therefore, many other genetic risk variants alone and in combination must still remain to be discovered. The aim of this work was to search for genetic risk factors for CRC, by performing single-locus and two-locus GWAS in the Spanish population.
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The MLH1 c.1852_1853delinsGC (p.K618A) variant in colorectal cancer: genetic association study in 18,723 individuals.
PLoS ONE
PUBLISHED: 01-01-2014
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Colorectal cancer is one of the most frequent neoplasms and an important cause of mortality in the developed world. Mendelian syndromes account for about 5% of the total burden of CRC, being Lynch syndrome and familial adenomatous polyposis the most common forms. Lynch syndrome tumors develop mainly as a consequence of defective DNA mismatch repair associated with germline mutations in MLH1, MSH2, MSH6 and PMS2. A significant proportion of variants identified by screening these genes correspond to missense or noncoding changes without a clear pathogenic consequence, and they are designated as "variants of uncertain significance", being the c.1852_1853delinsGC (p.K618A) variant in the MLH1 gene a clear example. The implication of this variant as a low-penetrance risk variant for CRC was assessed in the present study by performing a case-control study within a large cohort from the COGENT consortium-COST Action BM1206 including 18,723 individuals (8,055 colorectal cancer cases and 10,668 controls) and a case-only genotype-phenotype correlation with several clinical and pathological characteristics restricted to the Epicolon cohort. Our results showed no involvement of this variant as a low-penetrance variant for colorectal cancer genetic susceptibility and no association with any clinical and pathological characteristics including family history for this neoplasm or Lynch syndrome.
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Large genomic rearrangements of BRCA1 and BRCA2 among patients referred for genetic analysis in Galicia (NW Spain): delimitation and mechanism of three novel BRCA1 rearrangements.
PLoS ONE
PUBLISHED: 01-01-2014
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In the Iberian Peninsula, which includes mainly Spain and Portugal, large genomic rearrangements (LGRs) of BRCA1 and BRCA2 have respectively been found in up to 2.33% and 8.4% of families with hereditary breast and/or ovarian cancer (HBOC) that lack point mutations and small indels. In Galicia (Northwest Spain), the spectrum and frequency of BRCA1/BRCA2 point mutations differs from the rest of the Iberian populations. However, to date there are no Galician frequency reports of BRCA1/BRCA2 LGRs. Here we used multiplex ligation-dependent probe amplification (MLPA) to screen 651 Galician index cases (out of the 830 individuals referred for genetic analysis) without point mutations or small indels. We identified three different BRCA1 LGRs in four families. Two of them have been previously classified as pathogenic LGRs: the complete deletion of BRCA1 (identified in two unrelated families) and the deletion of exons 1 to 13. We also identified the duplication of exons 1 and 2 that is a LGR with unknown pathogenicity. Determination of the breakpoints of the BRCA1 LGRs using CNV/SNP arrays and sequencing identified them as NG_005905.2:g.70536_180359del, NG_005905.2:g.90012_97270dup, and NC_000017.10:g.41230935_41399840delinsAluSx1, respectively; previous observations of BRCA1 exon1-24del, exon1-2dup, and exon1-13del LGRs have not characterized them in such detail. All the BRCA1 LGRs arose from unequal homologous recombination events involving Alu elements. We also detected, by sequencing, one BRCA2 LGR, the Portuguese founder mutation c.156_157insAluYa5. The low frequency of BRCA1 LGRs within BRCA1 mutation carriers in Galicia (2.34%, 95% CI: 0.61-7.22) seems to differ from the Spanish population (9.93%, 95% CI: 6.76-14.27, P-value?=?0.013) and from the rest of the Iberian population (9.76%, 95% CI: 6.69-13.94, P-value?=?0.014).
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Multiple sporadic colorectal cancers display a unique methylation phenotype.
PLoS ONE
PUBLISHED: 01-01-2014
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Epigenetics are thought to play a major role in the carcinogenesis of multiple sporadic colorectal cancers (CRC). Previous studies have suggested concordant DNA hypermethylation between tumor pairs. However, only a few methylation markers have been analyzed. This study was aimed at describing the epigenetic signature of multiple CRC using a genome-scale DNA methylation profiling. We analyzed 12 patients with synchronous CRC and 29 age-, sex-, and tumor location-paired patients with solitary tumors from the EPICOLON II cohort. DNA methylation profiling was performed using the Illumina Infinium HM27 DNA methylation assay. The most significant results were validated by Methylight. Tumors samples were also analyzed for the CpG Island Methylator Phenotype (CIMP); KRAS and BRAF mutations and mismatch repair deficiency status. Functional annotation clustering was performed. We identified 102 CpG sites that showed significant DNA hypermethylation in multiple tumors with respect to the solitary counterparts (difference in ? value ?0.1). Methylight assays validated the results for 4 selected genes (p?=?0.0002). Eight out of 12(66.6%) multiple tumors were classified as CIMP-high, as compared to 5 out of 29(17.2%) solitary tumors (p?=?0.004). Interestingly, 76 out of the 102 (74.5%) hypermethylated CpG sites found in multiple tumors were also seen in CIMP-high tumors. Functional analysis of hypermethylated genes found in multiple tumors showed enrichment of genes involved in different tumorigenic functions. In conclusion, multiple CRC are associated with a distinct methylation phenotype, with a close association between tumor multiplicity and CIMP-high. Our results may be important to unravel the underlying mechanism of tumor multiplicity.
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Association between CASP8 -652 6N del polymorphism (rs3834129) and colorectal cancer risk: results from a multi-centric study.
PLoS ONE
PUBLISHED: 01-01-2014
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The common -652 6N del variant in the CASP8 promoter (rs3834129) has been described as a putative low-penetrance risk factor for different cancer types. In particular, some studies suggested that the deleted allele (del) was inversely associated with CRC risk while other analyses failed to confirm this. Hence, to better understand the role of this variant in the risk of developing CRC, we performed a multi-centric case-control study. In the study, the variant -652 6N del was genotyped in a total of 6,733 CRC cases and 7,576 controls recruited by six different centers located in Spain, Italy, USA, England, Czech Republic and the Netherlands collaborating to the international consortium COGENT (COlorectal cancer GENeTics). Our analysis indicated that rs3834129 was not associated with CRC risk in the full data set. However, the del allele was under-represented in one set of cases with a family history of CRC (per allele model OR?=?0.79, 95% CI?=?0.69-0.90) suggesting this allele might be a protective factor versus familial CRC. Since this multi-centric case-control study was performed on a very large sample size, it provided robust clarification of the effect of rs3834129 on the risk of developing CRC in Caucasians.
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Impact of pharmacogenetics on CNS side effects related to efavirenz.
Pharmacogenomics
PUBLISHED: 07-18-2013
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This article evaluates which genetic factors are involved in CNS toxicity related to long-term treatment with efavirenz (EFV) standard doses and their relationship with plasma concentrations.
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Supercomplex assembly determines electron flux in the mitochondrial electron transport chain.
Science
PUBLISHED: 07-02-2013
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The textbook description of mitochondrial respiratory complexes (RCs) views them as free-moving entities linked by the mobile carriers coenzyme Q (CoQ) and cytochrome c (cyt c). This model (known as the fluid model) is challenged by the proposal that all RCs except complex II can associate in supercomplexes (SCs). The proposed SCs are the respirasome (complexes I, III, and IV), complexes I and III, and complexes III and IV. The role of SCs is unclear, and their existence is debated. By genetic modulation of interactions between complexes I and III and III and IV, we show that these associations define dedicated CoQ and cyt c pools and that SC assembly is dynamic and organizes electron flux to optimize the use of available substrates.
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Involvement of LCA5 in Leber Congenital Amaurosis and Retinitis Pigmentosa in the Spanish Population.
Ophthalmology
PUBLISHED: 06-10-2013
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We aimed to identify novel genetic defects in the LCA5 gene underlying Leber congenital amaurosis (LCA) in the Spanish population and to describe the associated phenotype.
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A genetic case-control study confirms the implication of SMAD7 and TNF locus in the development of proliferative vitreoretinopathy.
Invest. Ophthalmol. Vis. Sci.
PUBLISHED: 05-28-2013
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Proliferative vitreoretinopathy (PVR) is still the major cause of failure of retinal detachment (RD) surgery and although the risk for developing this complication is associated with some clinical characteristics, the correlation is far from absolute, raising the possibility of genetic susceptibility. The objective of this study was to analyze the genetic contribution to PVR in patients undergoing RD surgery, the Retina 4 Project.
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Genetic susceptibility variants associated with colorectal cancer prognosis.
Carcinogenesis
PUBLISHED: 05-27-2013
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Colorectal cancer (CRC) is the second leading cause of cancer-related death among men and women in Western countries. Once a tumour develops, a differentiated prognosis could be determined by lifestyle habits or inherited and somatic genetic factors. Finding such prognostic factors will be helpful in order to identify cases with a shorter survival or at a higher risk of recurrence that may benefit from more intensive treatment and follow-up surveillance. Sixteen CRC genetic susceptibility variants were directly genotyped in a cohort of 1235 CRC patients recruited by the EPICOLON Spanish consortium. Univariate Cox and multivariate regression analyses were performed taking as primary outcomes overall survival (OS), disease-free survival and recurrence-free interval. Genetic variants rs9929218 at 16q22.1 and rs10795668 at 10p14 may have an effect on OS. The G allele of rs9929218 was linked with a better OS [GG genotype, genotypic model: hazard ratio (HR) = 0.65, 95% confidence interval (CI) 0.45-0.93, P = 0.0179; GG/GA genotypes, dominant model: HR = 0.66, 95% CI 0.47-0.94, P = 0.0202]. Likewise, the G allele of rs10795668 was associated with better clinical outcome (GG genotype, genotypic model: HR = 0.73, 95% CI 0.53-1.01, P = 0.0570; GA genotype, genotypic model: HR = 0.66, 95% CI 0.47-0.92, P = 0.0137; GG/GA genotypes, dominant model: HR = 0.68, 95% CI 0.50-0.94, P = 0.0194). In conclusion, CRC susceptibility variants rs9929218 and rs10795668 may exert some influence in modulating patients survival and they deserve to be further tested in additional CRC cohorts in order to confirm their potential as prognosis or predictive biomarkers.
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Ancestry analysis reveals a predominant Native American component with moderate European admixture in Bolivians.
Forensic Sci Int Genet
PUBLISHED: 05-10-2013
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We have genotyped 46 Ancestry Informative Markers (AIMs) in two of the most populated areas in Bolivia, namely, La Paz (Andean region; n=105), and Chuquisaca (Sub-Andean region; n=73). Using different analytical tools, we inferred admixture proportions of these two American communities by comparing the genetic profiles with those publicly available from the CEPH (Centre dEtude du Polymorphisme Humain) panel representing three main continental groups (Africa, Europe, and America). By way of simulations, we first evaluated the minimum sample size needed in order to obtain accurate estimates of ancestry proportions. The results indicated that sample sizes above 30 individuals could be large enough to estimate main continental ancestry proportions using the 46 AIMs panel. With the exception of a few individuals, the results also indicated that Bolivians showed a predominantly Native American ancestry with variable levels of European admixture. The proportions of ancestry were statistically different in La Paz and Chuquisaca: the Native American component was 86% and 77% (Mann-Whitney U-test: un-adjusted P-value=2.1×10(-5)), while the European ancestry was 13% and 21% (Mann-Whitney U-test: un-adjusted P-value=3.6×10(-5)), respectively. The African ancestry in Bolivians captured by the AIMs analyzed in the present study was below 2%. The inferred ancestry of Bolivians fits well with previous studies undertaken on haplotype data, indicating a major proportion of Native American lineages. The genetic differences observed in these two groups suggest that forensic genetic analysis should be better performed based on local databases built in the main Bolivian areas.
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Genome-wide association study identifies multiple risk loci for chronic lymphocytic leukemia.
Sonja I Berndt, Christine F Skibola, Vijai Joseph, Nicola J Camp, Alexandra Nieters, Zhaoming Wang, Wendy Cozen, Alain Monnereau, Sophia S Wang, Rachel S Kelly, Qing Lan, Lauren R Teras, Nilanjan Chatterjee, Charles C Chung, Meredith Yeager, Angela R Brooks-Wilson, Patricia Hartge, Mark P Purdue, Brenda M Birmann, Bruce K Armstrong, Pierluigi Cocco, Yawei Zhang, Gianluca Severi, Anne Zeleniuch-Jacquotte, Charles Lawrence, Laurie Burdette, Jeffrey Yuenger, Amy Hutchinson, Kevin B Jacobs, Timothy G Call, Tait D Shanafelt, Anne J Novak, Neil E Kay, Mark Liebow, Alice H Wang, Karin E Smedby, Hans-Olov Adami, Mads Melbye, Bengt Glimelius, Ellen T Chang, Martha Glenn, Karen Curtin, Lisa A Cannon-Albright, Brandt Jones, W Ryan Diver, Brian K Link, George J Weiner, Lucia Conde, Paige M Bracci, Jacques Riby, Elizabeth A Holly, Martyn T Smith, Rebecca D Jackson, Lesley F Tinker, Yolanda Benavente, Nikolaus Becker, Paolo Boffetta, Paul Brennan, Lenka Foretova, Marc Maynadié, James McKay, Anthony Staines, Kari G Rabe, Sara J Achenbach, Celine M Vachon, Lynn R Goldin, Sara S Strom, Mark C Lanasa, Logan G Spector, Jose F Leis, Julie M Cunningham, J Brice Weinberg, Vicki A Morrison, Neil E Caporaso, Aaron D Norman, Martha S Linet, Anneclaire J De Roos, Lindsay M Morton, Richard K Severson, Elio Riboli, Paolo Vineis, Rudolph Kaaks, Dimitrios Trichopoulos, Giovanna Masala, Elisabete Weiderpass, Maria-Dolores Chirlaque, Roel C H Vermeulen, Ruth C Travis, Graham G Giles, Demetrius Albanes, Jarmo Virtamo, Stephanie Weinstein, Jacqueline Clavel, Tongzhang Zheng, Theodore R Holford, Kenneth Offit, Andrew Zelenetz, Robert J Klein, John J Spinelli, Kimberly A Bertrand, Francine Laden, Edward Giovannucci, Peter Kraft, Anne Kricker, Jenny Turner, Claire M Vajdic, Maria Grazia Ennas, Giovanni M Ferri, Lucia Miligi, Liming Liang, Joshua Sampson, Simon Crouch, Ju-Hyun Park, Kari E North, Angela Cox, John A Snowden, Josh Wright, Angel Carracedo, Carlos Lopez-Otin, Sílvia Beà, Itziar Salaverria, David Martín-Garcia, Elias Campo, Joseph F Fraumeni, Silvia de Sanjosé, Henrik Hjalgrim, James R Cerhan, Stephen J Chanock, Nathaniel Rothman, Susan L Slager.
Nat. Genet.
PUBLISHED: 05-02-2013
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Genome-wide association studies (GWAS) have previously identified 13 loci associated with risk of chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL). To identify additional CLL susceptibility loci, we conducted the largest meta-analysis for CLL thus far, including four GWAS with a total of 3,100 individuals with CLL (cases) and 7,667 controls. In the meta-analysis, we identified ten independent associated SNPs in nine new loci at 10q23.31 (ACTA2 or FAS (ACTA2/FAS), P=1.22×10(-14)), 18q21.33 (BCL2, P=7.76×10(-11)), 11p15.5 (C11orf21, P=2.15×10(-10)), 4q25 (LEF1, P=4.24×10(-10)), 2q33.1 (CASP10 or CASP8 (CASP10/CASP8), P=2.50×10(-9)), 9p21.3 (CDKN2B-AS1, P=1.27×10(-8)), 18q21.32 (PMAIP1, P=2.51×10(-8)), 15q15.1 (BMF, P=2.71×10(-10)) and 2p22.2 (QPCT, P=1.68×10(-8)), as well as an independent signal at an established locus (2q13, ACOXL, P=2.08×10(-18)). We also found evidence for two additional promising loci below genome-wide significance at 8q22.3 (ODF1, P=5.40×10(-8)) and 5p15.33 (TERT, P=1.92×10(-7)). Although further studies are required, the proximity of several of these loci to genes involved in apoptosis suggests a plausible underlying biological mechanism.
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New genetic associations in thiopurine-related bone marrow toxicity among inflammatory bowel disease patients.
Pharmacogenomics
PUBLISHED: 04-11-2013
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The toxicity related to thiopurine drug therapy for inflammatory bowel disease (IBD) varies widely among patients. Almost 15-30% of patients with IBD develop side effects during treatment, often bone marrow suppression. Several factors have been implicated in determining this toxicity, mainly individual genetic variation related to formation of active thiopurine metabolites. The aim was to identify genes involved in thiopurine-related myelosuppression.
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Mutations in the gene encoding PDGF-B cause brain calcifications in humans and mice.
Nat. Genet.
PUBLISHED: 04-05-2013
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Calcifications in the basal ganglia are a common incidental finding and are sometimes inherited as an autosomal dominant trait (idiopathic basal ganglia calcification (IBGC)). Recently, mutations in the PDGFRB gene coding for the platelet-derived growth factor receptor ? (PDGF-R?) were linked to IBGC. Here we identify six families of different ancestry with nonsense and missense mutations in the gene encoding PDGF-B, the main ligand for PDGF-R?. We also show that mice carrying hypomorphic Pdgfb alleles develop brain calcifications that show age-related expansion. The occurrence of these calcium depositions depends on the loss of endothelial PDGF-B and correlates with the degree of pericyte and blood-brain barrier deficiency. Thus, our data present a clear link between Pdgfb mutations and brain calcifications in mice, as well as between PDGFB mutations and IBGC in humans.
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Development of a novel forensic STR multiplex for ancestry analysis and extended identity testing.
Electrophoresis
PUBLISHED: 03-18-2013
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There is growing interest in developing additional DNA typing techniques to provide better investigative leads in forensic analysis. These include inference of genetic ancestry and prediction of common physical characteristics of DNA donors. To date, forensic ancestry analysis has centered on population-divergent SNPs but these binary loci cannot reliably detect DNA mixtures, common in forensic samples. Furthermore, STR genotypes, forming the principal DNA profiling system, are not routinely combined with forensic SNPs to strengthen frequency data available for ancestry inference. We report development of a 12-STR multiplex composed of ancestry informative marker STRs (AIM-STRs) selected from 434 tetranucleotide repeat loci. We adapted our online Bayesian classifier for AIM-SNPs: Snipper, to handle multiallele STR data using frequency-based training sets. We assessed the ability of the 12-plex AIM-STRs to differentiate CEPH Human Genome Diversity Panel populations, plus their informativeness combined with established forensic STRs and AIM-SNPs. We found combining STRs and SNPs improves the success rate of ancestry assignments while providing a reliable mixture detection system lacking from SNP analysis alone. As the 12 STRs generally show a broad range of alleles in all populations, they provide highly informative supplementary STRs for extended relationship testing and identification of missing persons with incomplete reference pedigrees. Lastly, mixed marker approaches (combining STRs with binary loci) for simple ancestry inference tests beyond forensic analysis bring advantages and we discuss the genotyping options available.
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Comparison of the genetic background of different Colombian populations using the SNPforID 52plex identification panel.
Int. J. Legal Med.
PUBLISHED: 03-10-2013
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Various strategies for analysing SNP markers and genotyping have been published with the goal of obtaining informative profiles from biological samples that contain only small amounts of template and/or degraded DNA. In this study, a multiplex assay of 52 autosomal single-nucleotide polymorphisms (SNPs) was used to analyse 438 individuals from urban populations from different regions of Colombia, as well as a sample of 50 Native American individuals of the Pastos ethnic group from Nariño. To determine if significant differences in these 52 SNPs exist between the distinct regions of Colombia, genetic distance and admixture analyses were performed based on the available data for 17 different Colombian population groups and for population groups from Africa, Europe and America. The results demonstrate significant differences between the populations from the Southwest Andean, Central-West Andean, Central-East Andean, Orinoquian and northern Colombian Pacific Coast regions. Most of the regions exhibited a European and Native American admixture. One exception is the population from the region of Chocó (on the northern Pacific Coast), which exhibits a high proportion of African admixture (54 %). From the observed genetic backgrounds, it is possible to conclude that a single reference database for the entire country would not be suitable for forensic purposes. The allele frequencies and the forensically relevant parameters were calculated for all of the markers in each Colombian region with significant values for the combined matching probability (power of discrimination ?0.99999999999999990) and the combined probability of exclusion (?0.9990) in trios that were obtained from all of the population groups.
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Pharmacogenomics of anti-platelet therapy focused on peripheral blood cells of coronary arterial disease patients.
Clin. Chim. Acta
PUBLISHED: 02-27-2013
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To investigate genes differentially expressed in peripheral blood cells (PBCs) from patients with coronary arterial disease (CAD) under double anti-platelet therapy.
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Genetic variations in SMAD7 are associated with colorectal cancer risk in the colon cancer family registry.
PLoS ONE
PUBLISHED: 02-26-2013
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Recent genome-wide studies identified a risk locus for colorectal cancer at 18q21, which maps to the SMAD7 gene. Our objective was to confirm the association between SMAD7 SNPs and colorectal cancer risk in the multi-center Colon Cancer Family Registry.
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Novel genes detected by transcriptional profiling from whole-blood cells in patients with early onset of acute coronary syndrome.
Clin. Chim. Acta
PUBLISHED: 02-17-2013
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Genome-wide expression analysis using microarrays has been used as a research strategy to discovery new biomarkers and candidate genes for a number of diseases. We aim to find new biomarkers for the prediction of acute coronary syndrome (ACS) with a differentially expressed mRNA profiling approach using whole genomic expression analysis in a peripheral blood cell model from patients with early ACS.
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The genetic legacy of the pre-colonial period in contemporary Bolivians.
PLoS ONE
PUBLISHED: 02-12-2013
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Only a few genetic studies have been carried out to date in Bolivia. However, some of the most important (pre)historical enclaves of South America were located in these territories. Thus, the (sub)-Andean region of Bolivia was part of the Inca Empire, the largest state in Pre-Columbian America. We have genotyped the first hypervariable region (HVS-I) of 720 samples representing the main regions in Bolivia, and these data have been analyzed in the context of other pan-American samples (>19,000 HVS-I mtDNAs). Entire mtDNA genome sequencing was also undertaken on selected Native American lineages. Additionally, a panel of 46 Ancestry Informative Markers (AIMs) was genotyped in a sub-set of samples. The vast majority of the Bolivian mtDNAs (98.4%) were found to belong to the main Native American haplogroups (A: 14.3%, B: 52.6%, C: 21.9%, D: 9.6%), with little indication of sub-Saharan and/or European lineages; however, marked patterns of haplogroup frequencies between main regions exist (e.g. haplogroup B: Andean [71%], Sub-Andean [61%], Llanos [32%]). Analysis of entire genomes unraveled the phylogenetic characteristics of three Native haplogroups: the pan-American haplogroup B2b (originated ?21.4 thousand years ago [kya]), A2ah (?5.2 kya), and B2o (?2.6 kya). The data suggest that B2b could have arisen in North California (an origin even in the north most region of the American continent cannot be disregarded), moved southward following the Pacific coastline and crossed Meso-America. Then, it most likely spread into South America following two routes: the Pacific path towards Peru and Bolivia (arriving here at about ?15.2 kya), and the Amazonian route of Venezuela and Brazil southwards. In contrast to the mtDNA, Ancestry Informative Markers (AIMs) reveal a higher (although geographically variable) European introgression in Bolivians (25%). Bolivia shows a decreasing autosomal molecular diversity pattern along the longitudinal axis, from the Altiplano to the lowlands. Both autosomes and mtDNA revealed a low impact (1-2%) of a sub-Saharan component in Bolivians.
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Transcriptome and genome sequencing uncovers functional variation in humans.
Nature
PUBLISHED: 02-07-2013
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Genome sequencing projects are discovering millions of genetic variants in humans, and interpretation of their functional effects is essential for understanding the genetic basis of variation in human traits. Here we report sequencing and deep analysis of messenger RNA and microRNA from lymphoblastoid cell lines of 462 individuals from the 1000 Genomes Project--the first uniformly processed high-throughput RNA-sequencing data from multiple human populations with high-quality genome sequences. We discover extremely widespread genetic variation affecting the regulation of most genes, with transcript structure and expression level variation being equally common but genetically largely independent. Our characterization of causal regulatory variation sheds light on the cellular mechanisms of regulatory and loss-of-function variation, and allows us to infer putative causal variants for dozens of disease-associated loci. Altogether, this study provides a deep understanding of the cellular mechanisms of transcriptome variation and of the landscape of functional variants in the human genome.
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The CYP1A2 -163C>A polymorphism is associated with clozapine-induced generalized tonic-clonic seizures in Brazilian schizophrenia patients.
Psychiatry Res
PUBLISHED: 02-04-2013
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We evaluated two polymorphisms at CYP1A2 (*1C and *1F) in a sample of 108 European-derived patients with schizophrenia and their influence on the pro-convulsive effect of clozapine. We found the *1F/*1F genotype to be significantly associated with seizures, and no relationship was observed with combinations of *1F and *1C alleles.
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Enhanced localization of genetic samples through linkage-disequilibrium correction.
Am. J. Hum. Genet.
PUBLISHED: 01-29-2013
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Characterizing the spatial patterns of genetic diversity in human populations has a wide range of applications, from detecting genetic mutations associated with disease to inferring human history. Current approaches, including the widely used principal-component analysis, are not suited for the analysis of linked markers, and local and long-range linkage disequilibrium (LD) can dramatically reduce the accuracy of spatial localization when unaccounted for. To overcome this, we have introduced an approach that performs spatial localization of individuals on the basis of their genetic data and explicitly models LD among markers by using a multivariate normal distribution. By leveraging external reference panels, we derive closed-form solutions to the optimization procedure to achieve a computationally efficient method that can handle large data sets. We validate the method on empirical data from a large sample of European individuals from the POPRES data set, as well as on a large sample of individuals of Spanish ancestry. First, we show that by modeling LD, we achieve accuracy superior to that of existing methods. Importantly, whereas other methods show decreased performance when dense marker panels are used in the inference, our approach improves in accuracy as more markers become available. Second, we show that accurate localization of genetic data can be achieved with only a part of the genome, and this could potentially enable the spatial localization of admixed samples that have a fraction of their genome originating from a given continent. Finally, we demonstrate that our approach is resistant to distortions resulting from long-range LD regions; such distortions can dramatically bias the results when unaccounted for.
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A colorectal cancer genome-wide association study in a Spanish cohort identifies two variants associated with colorectal cancer risk at 1p33 and 8p12.
BMC Genomics
PUBLISHED: 01-23-2013
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Colorectal cancer (CRC) is a disease of complex aetiology, with much of the expected inherited risk being due to several common low risk variants. Genome-Wide Association Studies (GWAS) have identified 20 CRC risk variants. Nevertheless, these have only been able to explain part of the missing heritability. Moreover, these signals have only been inspected in populations of Northern European origin.
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Human spermatogenic failure purges deleterious mutation load from the autosomes and both sex chromosomes, including the gene DMRT1.
PLoS Genet.
PUBLISHED: 01-17-2013
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Gonadal failure, along with early pregnancy loss and perinatal death, may be an important filter that limits the propagation of harmful mutations in the human population. We hypothesized that men with spermatogenic impairment, a disease with unknown genetic architecture and a common cause of male infertility, are enriched for rare deleterious mutations compared to men with normal spermatogenesis. After assaying genomewide SNPs and CNVs in 323 Caucasian men with idiopathic spermatogenic impairment and more than 1,100 controls, we estimate that each rare autosomal deletion detected in our study multiplicatively changes a mans risk of disease by 10% (OR 1.10 [1.04-1.16], p<2 × 10(-3)), rare X-linked CNVs by 29%, (OR 1.29 [1.11-1.50], p<1 × 10(-3)), and rare Y-linked duplications by 88% (OR 1.88 [1.13-3.13], p<0.03). By contrasting the properties of our case-specific CNVs with those of CNV callsets from cases of autism, schizophrenia, bipolar disorder, and intellectual disability, we propose that the CNV burden in spermatogenic impairment is distinct from the burden of large, dominant mutations described for neurodevelopmental disorders. We identified two patients with deletions of DMRT1, a gene on chromosome 9p24.3 orthologous to the putative sex determination locus of the avian ZW chromosome system. In an independent sample of Han Chinese men, we identified 3 more DMRT1 deletions in 979 cases of idiopathic azoospermia and none in 1,734 controls, and found none in an additional 4,519 controls from public databases. The combined results indicate that DMRT1 loss-of-function mutations are a risk factor and potential genetic cause of human spermatogenic failure (frequency of 0.38% in 1306 cases and 0% in 7,754 controls, p = 6.2 × 10(-5)). Our study identifies other recurrent CNVs as potential causes of idiopathic azoospermia and generates hypotheses for directing future studies on the genetic basis of male infertility and IVF outcomes.
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Risk of cancer in cases of suspected lynch syndrome without germline mutation.
Gastroenterology
PUBLISHED: 01-17-2013
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Colorectal cancers (CRCs) with microsatellite instability (MSI) and a mismatch repair (MMR) immunohistochemical deficit without hypermethylation of the MLH1 promoter are likely to be caused by Lynch syndrome. Some patients with these cancers have not been found to have pathogenic germline mutations and are considered to have Lynch-like syndrome (LLS). The aim of this study was to determine the risk of cancer in families of patients with LLS.
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Population genetics of 17 Y-STR markers in West Libya (Tripoli region).
Forensic Sci Int Genet
PUBLISHED: 01-04-2013
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Seventeen Y-chromosomal Short Tandem Repeats (Y-STR) included in the AmpFlSTR Y-filer PCR Amplification kit (Applied Biosystems) (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385ab, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635 and GATA H4) were genotyped in a population sample of 176 unrelated males from western Libya (Tripoli region). A total of 142 different haplotypes were found, 124 being unique. Haplotype diversity was 0.9950. Both R(ST) pairwise analyses and multidimensional scaling plot show a close genetic relationship between Tripoli and North African populations.
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Meta-analysis of mismatch repair polymorphisms within the cogent consortium for colorectal cancer susceptibility.
PLoS ONE
PUBLISHED: 01-01-2013
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In the last four years, Genome-Wide Association Studies (GWAS) have identified sixteen low-penetrance polymorphisms on fourteen different loci associated with colorectal cancer (CRC). Due to the low risks conferred by known common variants, most of the 35% broad-sense heritability estimated by twin studies remains unexplained. Recently our group performed a case-control study for eight Single Nucleotide Polymorphisms (SNPs) in 4 CRC genes. The present investigation is a follow-up of that study. We have genotyped six SNPs that showed a positive association and carried out a meta-analysis based on eight additional studies comprising in total more than 8000 cases and 6000 controls. The estimated recessive odds ratio for one of the SNPs, rs3219489 (MUTYH Q338H), decreased from 1.52 in the original Swedish study, to 1.18 in the Swedish replication, and to 1.08 in the initial meta-analysis. Since the corresponding summary probability value was 0.06, we decided to retrieve additional information for this polymorphism. The incorporation of six further studies resulted in around 13000 cases and 13000 controls. The newly updated OR was 1.03. The results from the present large, multicenter study illustrate the possibility of decreasing effect sizes with increasing samples sizes. Phenotypic heterogeneity, differential environmental exposures, and population specific linkage disequilibrium patterns may explain the observed difference of genetic effects between Sweden and the other investigated cohorts.
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Analysis of PALB2 gene in BRCA1/BRCA2 negative Spanish hereditary breast/ovarian cancer families with pancreatic cancer cases.
PLoS ONE
PUBLISHED: 01-01-2013
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The PALB2 gene, also known as FANCN, forms a bond and co-localizes with BRCA2 in DNA repair. Germline mutations in PALB2 have been identified in approximately 1% of familial breast cancer and 3-4% of familial pancreatic cancer. The goal of this study was to determine the prevalence of PALB2 mutations in a population of BRCA1/BRCA2 negative breast cancer patients selected from either a personal or family history of pancreatic cancer.
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An overview of STRUCTURE: applications, parameter settings, and supporting software.
Front Genet
PUBLISHED: 01-01-2013
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Objectives: We present an up-to-date review of STRUCTURE software: one of the most widely used population analysis tools that allows researchers to assess patterns of genetic structure in a set of samples. STRUCTURE can identify subsets of the whole sample by detecting allele frequency differences within the data and can assign individuals to those sub-populations based on analysis of likelihoods. The review covers STRUCTUREs most commonly used ancestry and frequency models, plus an overview of the main applications of the software in human genetics including case-control association studies (CCAS), population genetics, and forensic analysis. The review is accompanied by supplementary material providing a step-by-step guide to running STRUCTURE. Methods: With reference to a worked example, we explore the effects of changing the principal analysis parameters on STRUCTURE results when analyzing a uniform set of human genetic data. Use of the supporting software: CLUMPP and distruct is detailed and we provide an overview and worked example of STRAT software, applicable to CCAS. Conclusion: The guide offers a simplified view of how STRUCTURE, CLUMPP, distruct, and STRAT can be applied to provide researchers with an informed choice of parameter settings and supporting software when analyzing their own genetic data.
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Refinement of the associations between risk of colorectal cancer and polymorphisms on chromosomes 1q41 and 12q13.13.
Hum. Mol. Genet.
PUBLISHED: 11-10-2011
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In genome-wide association studies (GWASs) of colorectal cancer, we have identified two genomic regions in which pairs of tagging-single nucleotide polymorphisms (tagSNPs) are associated with disease; these comprise chromosomes 1q41 (rs6691170, rs6687758) and 12q13.13 (rs7163702, rs11169552). We investigated these regions further, aiming to determine whether they contain more than one independent association signal and/or to identify the SNPs most strongly associated with disease. Genotyping of additional sample sets at the original tagSNPs showed that, for both regions, the two tagSNPs were unlikely to identify a single haplotype on which the functional variation lay. Conversely, one of the pair of SNPs did not fully capture the association signal in each region. We therefore undertook more detailed analyses, using imputation, logistic regression, genealogical analysis using the GENECLUSTER program and haplotype analysis. In the 1q41 region, the SNP rs11118883 emerged as a strong candidate based on all these analyses, sufficient to account for the signals at both rs6691170 and rs6687758. rs11118883 lies within a region with strong evidence of transcriptional regulatory activity and has been associated with expression of PDGFRB mRNA. For 12q13.13, a complex situation was found: SNP rs7972465 showed stronger association than either rs11169552 or rs7136702, and GENECLUSTER found no good evidence for a two-SNP model. However, logistic regression and haplotype analyses supported a two-SNP model, in which a signal at the SNP rs706793 was added to that at rs11169552. Post-GWAS fine-mapping studies are challenging, but the use of multiple tools can assist in identifying candidate functional variants in at least some cases.
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A pharmacogenetics study of TPMT and ITPA genes detects a relationship with side effects and clinical response in patients with inflammatory bowel disease receiving Azathioprine.
J Gastrointestin Liver Dis
PUBLISHED: 10-01-2011
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Pharmacogenetic studies in inflammatory bowel diseases (IBD) are mainly focused on genes involved in the metabolism of Azathioprine (AZA). Use of AZA is limited by its toxicity, which occurs in 20-30% of patients. Variants in the Thiopurine S-methyltransferase (TPMT) and Inosine triphosphate pyrophosphatase (ITPA) genes have been associated with AZA toxicity, but also can contribute to the lack of response. The aims of this study were to determine the contribution of TPMT and ITPA variants in the development of AZA-related toxicity and response.
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Genome-wide study links MTMR7 gene to variant Creutzfeldt-Jakob risk.
Neurobiol. Aging
PUBLISHED: 09-22-2011
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The aim of our study was to discover genomic variations related to variant Creutzfeldt-Jakob disease (vCJD) susceptibility. A genome-wide association analysis with most vCJD samples available in the world was performed. A series of 93 vCJD UK patients and 1504 UK controls were included in the discovery stage. Our best findings were replicated in an independent population of 22 UK and 20 French vCJD cases. Post hoc analysis to assess our main results included 5711 French controls, 445 Dutch controls, and 446 sporadic Creutzfeldt-Jakob disease (CJD) cases. We found 2 genome wide significant variants tagging PRNP: rs6107516 (p = 2.6 × 10(-18)) and rs2065706 (p = 8.8 × 10(-14)). Two other single nucleotide polymorphisms (SNPs) (rs4921542 and rs7565981) were successfully replicated in independent samples and reached genome-wide significance after pooling discovery and replication populations. Rs4921542 (p = 1.6 × 10(-8)) is an intronic variant in the myotubularin related protein 7 gene (MTMR7), which is specifically expressed in the central nervous system (CNS) and dephosphorylates phosphatidylinositol 3-phosphate and inositol 1,3-bisphosphate. Rs7565981 (p = 4.2 × 10(-8)) is in an intergenic region upstream of the neuronal PAS (per-ARNT-sim) domain-containing protein 2 gene (NPAS2), a regulatory gene belonging to a family of transcription factors that has been implicated in memory, seasonal affective disorder, and the molecular clock in the mammalian forebrain. A proxy of rs7565981 (rs17024792; r(2) = 1.0) has been found to regulate the phospholipase C-delta-3 gene (PLCD3) in trans. This enzyme catalyzes the hydrolysis of phosphatidylinositol 4,5-bisphosphate. Our study reveals 2 new genome-wide significant markers for vCJD outside PRNP and provides evidence supporting a role of the phosphatidylinositol pathway in vCJD susceptibility.
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Increased clopidogrel response is associated with ABCC3 expression: a pilot study.
Clin. Chim. Acta
PUBLISHED: 08-29-2011
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The aim of this study was investigate the relationship between ABCB1 and ABCC3 gene expressions in peripheral blood cells (PBC) and the response to clopidogrel in patients with coronary arterial disease (CAD).
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Comparison between universal molecular screening for Lynch syndrome and revised Bethesda guidelines in a large population-based cohort of patients with colorectal cancer.
Gut
PUBLISHED: 08-25-2011
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The selection of patients for genetic testing to rule out Lynch syndrome is currently based on fulfilment of at least one of the revised Bethesda criteria followed by mismatch repair (MMR) status analysis. A study was undertaken to compare the present approach with universal MMR study-based strategies to detect Lynch syndrome in a large series of patients with colorectal cancer (CRC).
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Association study of nonsynonymous single nucleotide polymorphisms in schizophrenia.
Biol. Psychiatry
PUBLISHED: 08-19-2011
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Genome-wide association studies using several hundred thousand anonymous markers present limited statistical power. Alternatively, association studies restricted to common nonsynonymous single nucleotide polymorphisms (nsSNPs) have the advantage of strongly reducing the multiple testing problem, while increasing the probability of testing functional single nucleotide polymorphisms (SNPs).
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Detection of a large rearrangement in PALB2 in Spanish breast cancer families with male breast cancer.
Breast Cancer Res. Treat.
PUBLISHED: 07-30-2011
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It has been demonstrated that monoallelic PALB2 (Partner and Localizer of BRCA2) gene mutations predispose to familial breast cancer. Some of the families reported with germline PALB2 mutations presented male breast cancer as a characteristic clinical feature. Therefore, we wanted to investigate the contribution of germline PALB2 mutations in a set of 131 Spanish BRCA1/BRCA2-negative breast/ovarian cancer families with at least one male breast cancer case. The analysis included direct sequencing of all coding exons and intron/exon boundaries as well as a Multiplex Ligation-dependent Probe Amplification-based analysis of genomic rearrangements. For the first time we have identified a genomic rearrangement of PALB2 gene involving a large deletion from exon 7 to 11 in a breast cancer family. We have also identified several PALB2 variants, but no other obvious deleterious PALB2 mutation has been found. Thus, our study does not support an enrichment of PALB2 germline mutations in the subset of breast cancer families with male breast cancer cases. The identification of intronic and exonic variants indicates the necessity of assessing the implications of variants that do not lead to PALB2 truncation in the pathoghenicity of the PALB2 gene.
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Common variants at VRK2 and TCF4 conferring risk of schizophrenia.
Hum. Mol. Genet.
PUBLISHED: 07-26-2011
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Common sequence variants have recently joined rare structural polymorphisms as genetic factors with strong evidence for association with schizophrenia. Here we extend our previous genome-wide association study and meta-analysis (totalling 7 946 cases and 19 036 controls) by examining an expanded set of variants using an enlarged follow-up sample (up to 10 260 cases and 23 500 controls). In addition to previously reported alleles in the major histocompatibility complex region, near neurogranin (NRGN) and in an intron of transcription factor 4 (TCF4), we find two novel variants showing genome-wide significant association: rs2312147[C], upstream of vaccinia-related kinase 2 (VRK2) [odds ratio (OR) = 1.09, P = 1.9 × 10(-9)] and rs4309482[A], between coiled-coiled domain containing 68 (CCDC68) and TCF4, about 400 kb from the previously described risk allele, but not accounted for by its association (OR = 1.09, P = 7.8 × 10(-9)).
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A melting pot of multicontinental mtDNA lineages in admixed Venezuelans.
Am. J. Phys. Anthropol.
PUBLISHED: 05-25-2011
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The arrival of Europeans in Colonial and post-Colonial times coupled with the forced introduction of sub-Saharan Africans have dramatically changed the genetic background of Venezuela. The main aim of the present study was to evaluate, through the study of mitochondrial DNA (mtDNA) variation, the extent of admixture and the characterization of the most likely continental ancestral sources of present-day urban Venezuelans. We analyzed two admixed populations that have experienced different demographic histories, namely, Caracas (n = 131) and Pueblo Llano (n = 219). The native American component of admixed Venezuelans accounted for 80% (46% haplogroup [hg] A2, 7% hg B2, 21% hg C1, and 6% hg D1) of all mtDNAs; while the sub-Saharan and European contributions made up ?10% each, indicating that Trans-Atlantic immigrants have only partially erased the native American nature of Venezuelans. A Bayesian-based model allowed the different contributions of European countries to admixed Venezuelans to be disentangled (Spain: ?38.4%, Portugal: ?35.5%, Italy: ?27.0%), in good agreement with the documented history. Seventeen entire mtDNA genomes were sequenced, which allowed five new native American branches to be discovered. B2j and B2k, are supported by two different haplotypes and control region data, and their coalescence ages are 3.9 k.y. (95% C.I. 0-7.8) and 2.6 k.y. (95% C.I. 0.1-5.2), respectively. The other clades were exclusively observed in Pueblo Llano and they show the fingerprint of strong recent genetic drift coupled with severe historical consanguinity episodes that might explain the high prevalence of certain Mendelian and complex multi-factorial diseases in this region.
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Genetic associations in the vitamin D receptor and colorectal cancer in African Americans and Caucasians.
PLoS ONE
PUBLISHED: 05-09-2011
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Low vitamin D levels are associated with an increased incidence of colorectal cancer (CRC) and higher mortality from the disease. In the US, African Americans (AAs) have the highest CRC incidence and mortality and the lowest levels of vitamin D. Single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene have been previously associated with CRC, but few studies have included AAs. We studied 795 AA CRC cases and 985 AA controls from Chicago and North Carolina as well as 1324 Caucasian cases and 990 Caucasian controls from Chicago and Spain. We genotyped 54 tagSNPs in VDR (46586959 to 46521297 Mb) and tested for association adjusting for West African ancestry, age, gender, and multiple testing. Untyped markers were imputed using MACH1.0. We analyzed associations by gender and anatomic location in the whole study group as well as by vitamin D intake in the North Carolina AA group. In the joint analysis, none of the SNPs tested was significantly associated with CRC. For four previously tested restriction fragment length polymorphisms, only one (referred to as ApaI), tagged by the SNP rs79628898, had a nominally significant p-value in AAs; none of these polymorphisms were associated with CRC in Caucasians. In the North Carolina AAs, for whom we had vitamin D intake data, we found a significant association between an intronic SNP rs11574041 and vitamin D intake, which is evidence for a VDR gene-environment interaction in AAs. In summary, using a systematic tagSNP approach, we have not found evidence for significant associations between VDR and CRC in AAs or Caucasians.
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A method for the analysis of 32 X chromosome insertion deletion polymorphisms in a single PCR.
Int. J. Legal Med.
PUBLISHED: 04-22-2011
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Studies of human genetic variation predominantly use short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs) but Insertion deletion polymorphisms (Indels) are being increasingly explored. They combine desirable characteristics of other genetic markers, especially the possibility of being analysed using short amplicon strategies, which increases the ease of analysis, contributing to justify their interest in population and forensic genetics. After the advent of autosomal and uniparental genomes (mtDNA and Y chromosome), these fields of research are also focusing on the X chromosome, given its special transmission pattern. The X chromosome markers brought new insights into the history of modern human populations and also proved useful in forensic kinship investigations, namely in deficient relationship cases and in cases where autosomes are uninformative. This work describes an X-Indel multiplex system amplifying 32 biallelic markers in one single PCR. The multiplex includes X-Indels shown to be polymorphic in the major human population groups and follows a short amplicon strategy. The set was applied in the genetic characterization of sub-Saharan African, European and East Asian population samples and revealed high forensic efficiency, as measured by the accumulated power of discrimination (0.9999990 was the lowest value in males and 0.999999999998 was the highest in females) and mean exclusion chance varied between 0.998 and 0.9996 in duos and between 0.99997 and 0.999998 in trios. Finally, a segregation analysis was performed using trio constellations of father-mother-daughters in order to address the transmission pattern and assess mutation rates of this type of markers.
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Reassessing the role of mitochondrial DNA mutations in autism spectrum disorder.
BMC Med. Genet.
PUBLISHED: 04-06-2011
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There is increasing evidence that impairment of mitochondrial energy metabolism plays an important role in the pathophysiology of autism spectrum disorders (ASD; OMIM number: 209850). A significant proportion of ASD cases display biochemical alterations suggestive of mitochondrial dysfunction and several studies have reported that mutations in the mitochondrial DNA (mtDNA) molecule could be involved in the disease phenotype.
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Prevalence of HCM and long QT syndrome mutations in young sudden cardiac death-related cases.
Int. J. Legal Med.
PUBLISHED: 04-01-2011
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Cardiomyopathies and channelopathies are major causes of sudden cardiac death. The genetic study of these diseases is difficult because of their heterogenic nature not only in their genetic traits but also in their phenotypic expression. The purpose of the present study is the analysis of a wide spectrum of previously known genetic mutations in key genes related to hypertrophic cardiomyopathy (HCM), long QT syndrome (LQTS), and Brugada syndrome (BrS) development. The samples studied include cases of sudden cardiac death (SCD) in young adults and their relatives in order to identify the real impact of genetic screening of SCD in forensic cases. Genetic screening of described variation in 16 genes implicated in the development of HCM and three more genes implicated in LQTS and BrS was performed by using MassARRAY technology. In addition, direct sequencing of the two most prevalent genes implicated in the development of SQTL type 1 and 2 was also carried out. Genetic screening allowed us to unmask four possibly pathogenic mutation carriers in the 49 SCD cases considered; carriers of mutation represent 9% (2/23) of the probands with structural anomalies found after autopsy and 7% (1/14) of the probands with structurally normal hearts after in depth autopsy protocol. One mutation was found among 12 of the recovered SCD cases considered. In people with direct family history of sudden cardiac death, but not themselves, 11 additional mutation carriers were found. Three different mutations were found in six of the 19 LQTS patients, representing three families and two different mutations were found among six patients with previous syncope. Genetic analysis in sudden cardiac death cases could help to elucidate the cause of death, but it also can help in the prevention of future deaths in families at risk. The study presented here shows the importance and relevance of genetic screening in patients with signs of cardiac hypertrophy and in family cases with more than one relative affected.
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Use of a comprehensive panel of biomarkers to predict response to a fluorouracil-oxaliplatin regimen in patients with metastatic colorectal cancer.
Pharmacogenomics
PUBLISHED: 04-01-2011
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Polymorphisms in the metabolism, detoxification or DNA repair pathways have been proposed as potential predictors of response to 5-fluorouracil and oxaliplatin. We have studied the predictive value of a set of germline genetic polymorphisms in metastatic colorectal cancer patients treated with mFolfox-6.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.