Browsing by Subject "single nucleotide polymorphism"

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  • Webb, Anne; Cottage, Amanda; Wood, Thomas; Khamassi, Khalil; Hobbs, Douglas; Gostkiewicz, Krystyna; White, Mark; Khazaei, Hamid; Ali, Mohamed; Street, Daniel; Duc, Gerard; Stoddard, Fred L.; Maalouf, Fouad; Ogbonnaya, Francis C.; Link, Wolfgang; Thomas, Jane; O'Sullivan, Donal M. (2016)
    Faba bean (Vicia faba L.) is a globally important nitrogen-fixing legume, which is widely grown in a diverse range of environments. In this work, we mine and validate a set of 845 SNPs from the aligned transcriptomes of two contrasting inbred lines. Each V. faba SNP is assigned by BLAST analysis to a single Medicago orthologue. This set of syntenically anchored polymorphisms were then validated as individual KASP assays, classified according to their informativeness and performance on a panel of 37 inbred lines, and the best performing 757 markers used to genotype six mapping populations. The six resulting linkage maps were merged into a single consensus map on which 687 SNPs were placed on six linkage groups, each presumed to correspond to one of the six V. faba chromosomes. This sequence-based consensus map was used to explore synteny with the most closely related crop species, lentil and the most closely related fully sequenced genome, Medicago. Large tracts of uninterrupted colinearity were found between faba bean and Medicago, making it relatively straightforward to predict gene content and order in mapped genetic interval. As a demonstration of this, we mapped a flower colour gene to a 2-cM interval of Vf chromosome 2 which was highly colinear with Mt3. The obvious candidate gene from 78 gene models in the collinear Medicago chromosome segment was the previously characterized MtWD40-1 gene controlling anthocyanin production in Medicago and resequencing of the Vf orthologue showed a putative causative deletion of the entire 50 end of the gene.
  • Kondelin, J.; Salokas, K.; Saarinen, L.; Ovaska, K.; Rauanheimo, H.; Plaketti, R.-M.; Hamberg, J.; Liu, X.; Yadav, L.; Gylfe, A.E.; Cajuso, T.; Hänninen, U.A.; Palin, K.; Ristolainen, H.; Katainen, R.; Kaasinen, E.; Tanskanen, T.; Aavikko, M.; Taipale, M.; Taipale, J.; Renkonen-Sinisalo, L.; Lepistö, A.; Koskensalo, S.; Böhm, J.; Mecklin, J.-P.; Ongen, H.; Dermitzakis, E.T.; Kilpivaara, O.; Vahteristo, P.; Turunen, M.; Hautaniemi, S.; Tuupanen, S.; Karhu, A.; Välimäki, N.; Varjosalo, M.; Pitkänen, E.; Aaltonen, L.A. (2018)
    Microsatellite instability (MSI) leads to accumulation of an excessive number of mutations in the genome, mostly small insertions and deletions. MSI colorectal cancers (CRCs), however, also contain more point mutations than microsatellite-stable (MSS) tumors, yet they have not been as comprehensively studied. To identify candidate driver genes affected by point mutations in MSI CRC, we ranked genes based on mutation significance while correcting for replication timing and gene expression utilizing an algorithm, MutSigCV. Somatic point mutation data from the exome kit-targeted area from 24 exome-sequenced sporadic MSI CRCs and respective normals, and 12 whole-genome-sequenced sporadic MSI CRCs and respective normals were utilized. The top 73 genes were validated in 93 additional MSI CRCs. The MutSigCV ranking identified several well-established MSI CRC driver genes and provided additional evidence for previously proposed CRC candidate genes as well as shortlisted genes that have to our knowledge not been linked to CRC before. Two genes, SMARCB1 and STK38L, were also functionally scrutinized, providing evidence of a tumorigenic role, for SMARCB1 mutations in particular. © 2018 The Authors. Published under the terms of the CC BY 4.0 license
  • Venhoranta, Heli; Pausch, Hubert; Wysocki, Michal; Szczerbal, Izabela; Hänninen, Reetta; Taponen, Juhani; Uimari, Pekka; Flisikowski, Krzysztof; Lohi, Hannes; Fries, Ruedi; Switonski, Marek; Andersson, Magnus (2013)
  • Kuchenbaecker, K.B.; McGuffog, L.; Barrowdale, D.; Lee, Andrew; Soucy, P.; Dennis, J.; Domchek, S.M.; Robson, M.; Spurdle, A.B.; Ramus, S.J.; Mavaddat, N.; Terry, M.B.; Neuhausen, S.L.; Schmutzler, R.K.; Simard, J.; Pharoah, P.D.P.; Offit, K.; Couch, F.J.; Chenevix-Trench, G.; Easton, D.F.; Antoniou, A.C.; Healey, S.; Lush, M.; Hamann, U.; Southey, M.; John, E.M.; Chung, W.K.; Daly, M. B.; Buys, S.S.; Goldgar, D.E.; Dorfling, C.M.; van Rensburg, E.J.; Ding, Y.C.; Ejlertsen, B.; Gerdes, A.-M.; Hansen, T.V.O.; Slager, S.; Hallberg, E.; Benitez, J.; Osorio, A.; Cohen, N.; Lawler, W.; Weitzel, J.N.; Peterlongo, P.; Pensotti, V.; Dolcetti, R.; Barile, M.; Aittomäki, K.; Nevanlinna, H.; Rantala, J. (2017)
    Background: Genome-wide association studies (GWAS) have identified 94 common single-nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk and 18 associated with ovarian cancer (OC) risk. Several of these are also associated with risk of BC or OC for women who carry a pathogenic mutation in the high-risk BC and OC genes BRCA1 or BRCA2. The combined effects of these variants on BC or OC risk for BRCA1 and BRCA2 mutation carriers have not yet been assessed while their clinical management could benefit from improved personalized risk estimates. Methods: We constructed polygenic risk scores (PRS) using BC and OC susceptibility SNPs identified through population-based GWAS: for BC (overall, estrogen receptor [ER]-positive, and ER-negative) and for OC. Using data from 15 252 female BRCA1 and 8211 BRCA2 carriers, the association of each PRS with BC or OC risk was evaluated using a weighted cohort approach, with time to diagnosis as the outcome and estimation of the hazard ratios (HRs) per standard deviation increase in the PRS. Results: The PRS for ER-negative BC displayed the strongest association with BC risk in BRCA1 carriers (HR = 1.27, 95% confidence interval [CI] = 1.23 to 1.31, P = 8.2 × 10-53). InBRCA2 carriers, the strongest association with BC risk was seen for the overall BCPRS (HR = 1.22, 95% CI = 1.17 to 1.28, P = 7.2 × 10-20). The OC PRS was strongly associated with OC risk for both BRCA1 and BRCA2 carriers. These translate to differences in absolute risks (more than 10% in each case) between the top and bottom deciles of the PRS distribution; for example, the OC risk was 6% by age 80 years for BRCA2 carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS. Conclusions: BC and OC PRS are predictive of cancer risk in BRCA1 and BRCA2 carriers. Incorporation of the PRS into risk prediction models has promise to better inform decisions on cancer risk management. © The Author 2017.
  • Savarese, M.; Qureshi, T.; Torella, A.; Laine, P.; Giugliano, T.; Jonson, P.H.; Johari, M.; Paulin, L.; Piluso, G.; Auvinen, P.; Nigro, V.; Udd, Bjarne; Hackman, P. (2020)
    Although DNA-sequencing is the most effective procedure to achieve a molecular diagnosis in genetic diseases, complementary RNA analyses are often required. Reverse-Transcription polymerase chain reaction (RT-PCR) is still a valuable option when the clinical phenotype and/or available DNA-test results address the diagnosis toward a gene of interest or when the splicing effect of a single variant needs to be assessed. We use Single-Molecule Real-Time sequencing to detect and characterize splicing defects and single nucleotide variants in well-known disease genes (DMD, NF1, TTN). After proper optimization, the procedure could be used in the diagnostic setting, simplifying the workflow of cDNA analysis. © 2020 - IOS Press and the authors. All rights reserved.
  • Tikkanen, Alli (Helsingfors universitet, 2019)
    Organic Anion Transporting Polypeptide 2B1 (OATP2B1) is an influx transporter expressed widely throughout the body in tissues such as intestine, liver, brain, placenta and skeletal muscle. Since many clinically used drugs are transported by OATP2B1, changes in the function of the transporter due to genetic polymorphism could lead to altered pharmacokinetics or -dynamics of OATP2B1 substrate drugs. The aim of this Master’s thesis was to create and optimize a cellular uptake assay to study the function of OATP2B1. Furthermore, the aim was to study the effects of six naturally occurring nonsynonymous single nucleotide variants on OATP2B1 transport function in vitro. With site-directed mutagenesis, single nucleotide changes were introduced into the gene coding for OATP2B1. OATP2B1 variants were expressed in human derived HEK293 cell line using baculovirus expression system. A cellular uptake assay with estrone-3-sulfate and a fluorescent probe 4’, 5’-dibromofluorescein (DBF) as substrates was set up and optimized. With the assay, OATP2B1-mediated uptake of variants was compared to the transport activity of OATP2B1 wild type. Amino acid changes Ser486Phe and Cys520Ser impaired OATP2B1 transport function severely. In addition, variant Thr318Ile transported DBF and estrone-3-sulfate less efficiently compared to OATP2B1 wild type, but Arg312Gln, Thr392Ile and Ser532Arg transport function was not affected. A method to study OATP2B1 function was created successfully. According to the results, single amino acid changes in OATP2B1 can impair OATP2B1 function. The results and method can be utilized to understand findings from pharmacogenetic studies in vivo, and to predict consequences of especially rare variants, which can be difficult to detect in small sample populations in clinical studies. However, further studies on the expression level and cellular localization of OATP2B1 variants are needed to fully characterize the impact of the variants studied.
  • Savarese, Marco; Välipakka, Salla; Johari, Mridul; Hackman, Peter; Udd, Bjarne (2020)
    Human genes have a variable length. Those having a coding sequence of extraordinary length and a high number of exons were almost impossible to sequence using the traditional Sanger-based gene-by-gene approach. High-throughput sequencing has partly overcome the size-related technical issues, enabling a straightforward, rapid and relatively inexpensive analysis of large genes. Several large genes (e.g. TTN, NEB, RYR1, DMD) are recognized as disease-causing in patients with skeletal muscle diseases. However, because of their sheer size, the clinical interpretation of variants in these genes is probably the most challenging aspect of the high-throughput genetic investigation in the field of skeletal muscle diseases. The main aim of this review is to discuss the technical and interpretative issues related to the diagnostic investigation of large genes and to reflect upon the current state of the art and the future advancements in the field. © 2020 - IOS Press and the authors. All rights reserved.
  • Waldenström macroglobulinemia Group (2018)
    Waldenström macroglobulinemia (WM)/lymphoplasmacytic lymphoma (LPL) is a rare, chronic B-cell lymphoma with high heritability. We conduct a two-stage genome-wide association study of WM/LPL in 530 unrelated cases and 4362 controls of European ancestry and identify two high-risk loci associated with WM/LPL at 6p25.3 (rs116446171, near EXOC2 and IRF4; OR = 21.14, 95% CI: 14.40–31.03, P = 1.36 × 10 −54 ) and 14q32.13 (rs117410836, near TCL1; OR = 4.90, 95% CI: 3.45–6.96, P = 8.75 × 10 −19 ). Both risk alleles are observed at a low frequency among controls (~2–3%) and occur in excess in affected cases within families. In silico data suggest that rs116446171 may have functional importance, and in functional studies, we demonstrate increased reporter transcription and proliferation in cells transduced with the 6p25.3 risk allele. Although further studies are needed to fully elucidate underlying biological mechanisms, together these loci explain 4% of the familial risk and provide insights into genetic susceptibility to this malignancy. © 2018, The Author(s).
  • Ziermans, T.; Dumontheil, I.; Roggeman, C.; Peyrard-Janvid, M.; Matsson, H.; Kere, J.; Klingberg, T. (2012)