Browsing by Subject "Gene frequency"

Now showing 1 - 9 of 9

Open Access
Coagulation factor V gene mutation increases the risk of venous thrombosis in Behcet's disease
(Oxford University Press, 1996) Gül, A.; Özbek, U.; Öztürk, C.; Inanç, M.; Koniçe, M.; Özçelik, T.
We investigated the prevalence of the coagulation factor V gene G1691A mutation in 64 patients with Behcet's disease (BD) and in 107 apparently healthy individuals. The mutation was present in the heterozygous state in 37.5% of the patients with a history of deep vein thrombosis (12/32) and in 9.4% of the patients without any thrombotic event (3/32). Eleven healthy individuals were also heterozygous for the mutation (10.3%). The prevalence of the mutation in BD patients with and without thrombosis was significantly different (P = 0.0079). We conclude that the factor V gene mutation may play a major role in the development of venous thrombosis in BD.
Open Access
DNA repair gene polymorphisms and bladder cancer susceptibility in a Turkish population
(International Institute of Anticancer Research, 2006) Karahalil, B.; Kocabas, N. A.; Özçelik, T.
Background: Occupational exposure and life style preferences, such as smoking are the main known environmental susceptibility factors for bladder cancer. A growing list of chemicals has been shown to induce oxidative DNA damage. Base excision repair (BER) genes (X-ray repair cross complementing 1, XRCC1 and human 8-oxoguanine DNA glycosylase 1, OGG1) may play a key role in maintaining genome integrity and preventing cancer development. Materials and Methods: We tested whether polymorphisms in XRCC1 and OGG1 are associated with bladder cancer risk by using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) assay. In addition, the possible modifying affect of cigarette smoking was evaluated. Results: No studies, to date, have examined the association between genetic polymorphisms in DNA repair genes and bladder cancer susceptibility, in the Turkish population. We found the OGG1 Cys326Cys genotype to be more frequent among bladder cancer patients (odds ratio (OR): 2.41 (95% CI, 1.36-4.25)). However, in the case of XRCC1, there was no significant difference in susceptibility to bladder cancer development between patients with the Arg399 and these with the Gln399 allele (OR: 0.72 (95% CI, 0.41-1.26)). Conclusion: Our data showed that OGG1 genetic polymorphisms might be useful as prognostic genetic markers for bladder cancer in the clinical setting.
Open Access
Early postzygotic mutations contribute to de novo variation in a healthy monozygotic twin pair
(B M J Group, 2014) Dal, G. M.; Ergüner, B.; Saǧıroǧlu, M. S.; Yüksel, B.; Onat, O. E.; Alkan C.; Özçelik, T.
Background: Human de novo single-nucleotide variation (SNV) rate is estimated to range between 0.82-1.70×10-8 mutations per base per generation. However, contribution of early postzygotic mutations to the overall human de novo SNV rate is unknown. Methods: We performed deep whole-genome sequencing (more than 30-fold coverage per individual) of the whole-blood-derived DNA samples of a healthy monozygotic twin pair and their parents. We examined the genotypes of each individual simultaneously for each of the SNVs and discovered de novo SNVs regarding the timing of mutagenesis. Putative de novo SNVs were validated using Sanger-based capillary sequencing. Results: We conservatively characterised 23 de novo SNVs shared by the twin pair, 8 de novo SNVs specific to twin I and 1 de novo SNV specific to twin II. Based on the number of de novo SNVs validated by Sanger sequencing and the number of callable bases of each twin, we calculated the overall de novo SNV rate of 1.31×10-8 and 1.01×10-8 for twin I and twin II, respectively. Of these, rates of the early postzygotic de novo SNVs were estimated to be 0.34×10-8 for twin I and 0.04×10-8 for twin II. Conclusions: Early postzygotic mutations constitute a substantial proportion of de novo mutations in humans. Therefore, genome mosaicism resulting from early mitotic events during embryogenesis is common and could substantially contribute to the development of diseases.
Open Access
The exon 13 duplication in the BRCA1 gene is a founder mutation present in geographicaly diverse populations
(Cell Press, 2000) Mazoyer, S.; Leary, J.; Kirk, J.; Fleischmann, E.; Wagner, T.; Claes, K.; Messiaen, L.; Foulkes, W.; Desrochers, M.; Simard, J.; Phelan, C. M.; Kwan, E.; Narod, S. A.; Vahteristo, P.; Nevanlinna, H.; Durando, X.; Bignon, Y. J.; Peyrat, J. P.; Bonnardel, C.; Sinilnikova, O. M.; Puget, N.; Lenoir, G. M.; Audoynaud, C.; Goldgar, D.; Maugard, C.; Caux, V.; Gad, S.; Stoppa-Lyonnet, D.; Noguès, C.; Lidereau, R.; Machavoine, C.; Bressac-De Paillerets, B.; Kuschel, B.; Betz, B.; Niederacher, D.; Beckmann, M. W.; Hamann, U.; Ponder, B. A. P.; Robinson, M.; Taylor G. R.; Bishop, T.; Catteau, A.; Solomon, E.; Cohen, B.; Steel, M.; Collins, N.; Stratton, M.; Van Der Looij, M.; Oláh, E.; Miller, N. J.; Barton, D. E.; Sverdlov, R. S.; Friedman, E.; Radice P.; Montagna, M.; Sensi, E.; Caligo, M.; Van Eijk, R.; Devilee, P.; Van Der Luijt, R.; Heimdal, K.; Møller, P.; Borg, Å.; Diez, O.; Cortes, J.; Domenech, M.; Baiget, M.; Osorio, A.; Benítez, J.; Maillet, P.; Sappino, A. P.; Özdag, H.; Özçelik, T.; Ozturk, M.; Rohlfs, E. M.; Boyd, J.; McDermott, D.; Offit, K.; Unger, M.; Nathanson, K.; Weber, B. L.; Sellers, T. A.; Hampton, E.; Couch, F. J.; Neuhausen, S.; Gayther, S. A.
Recently, a 6-kb duplication of exon 13, which creates a frameshift in the coding sequence of the BRCA1 gene, has been described in three unrelated U.S. families of European ancestry and in one Portuguese family. Here, our goal was to estimate the frequency and geographic diversity of carriers of this duplication. To do this, a collaborative screening study was set up that involved 39 institutions from 19 countries and included 3,580 unrelated individuals with a family history of the disease and 934 early-onset breast and/or ovarian cancer cases. A total of 11 additional families carrying this mutation were identified in Australia (1), Belgium (1), Canada (1), Great Britain (6), and the United States (2). Haplotyping showed that they are likely to derive from a common ancestor, possibly of northern British origin. Our results demonstrate that it is strongly advisable, for laboratories carrying out screening either in English-speaking countries or in countries with historical links with Britain, to include within their BRCA1 screening protocols the polymerase chain reaction-based assay described in this report.
Open Access
Genetics and epigenetics of liver cancer
(Elsevier, 2013) Özen, Çiğdem; Yıldız, Gökhan; Dağcan, Alper Tunga; Çevik, Dilek; Örs, Ayşegül; Keleş, Umut; Topel, Hande; Öztürk, Mehmet
Hepatocellular carcinoma (HCC) represents a major form of primary liver cancer in adults. Chronic infections with hepatitis B (HBV) and C (HCV) viruses and alcohol abuse are the major factors leading to HCC. This deadly cancer affects more than 500,000 people worldwide and it is quite resistant to conventional chemo- and radiotherapy. Genetic and epigenetic studies on HCC may help to understand better its mechanisms and provide new tools for early diagnosis and therapy. Recent literature on whole genome analysis of HCC indicated a high number of mutated genes in addition to well-known genes such as TP53, CTNNB1, AXIN1 and CDKN2A, but their frequencies are much lower. Apart from CTNNB1 mutations, most of the other mutations appear to result in loss-of-function. Thus, HCC-associated mutations cannot be easily targeted for therapy. Epigenetic aberrations that appear to occur quite frequently may serve as new targets. Global DNA hypomethylation, promoter methylation, aberrant expression of non-coding RNAs and dysregulated expression of other epigenetic regulatory genes such as EZH2 are the best-known epigenetic abnormalities. Future research in this direction may help to identify novel biomarkers and therapeutic targets for HCC.
Open Access
A global reference for human genetic variation
(Nature Publishing Group, 2015) Auton, A.; Abecasis, G. R.; Altshuler, D. M.; Durbin, R. M.; Bentley, D. R.; Chakravarti, A.; Clark, A. G.; Donnelly, P.; Eichler, E. E.; Flicek, P.; Gabriel, S. B.; Gibbs, R. A.; Green, E. D.; Hurles, M. E.; Knoppers, B. M.; Korbel, J. O.; Lander, E. S.; Lee, C.; Lehrach, H.; Mardis, E. R.; Marth, G. T.; McVean, G. A.; Nickerson, D. A.; Schmidt, J. P.; Sherry, S. T.; Wang, J.; Wilson, R. K.; Boerwinkle, E.; Doddapaneni, H.; Han, Y.; Korchina, V.; Kovar, C.; Lee, S.; Muzny, D.; Reid, J. G.; Zhu, Y.; Chang, Y.; Feng, Q.; Fang, X.; Guo, X.; Jian, M.; Jiang, H.; Jin, X.; Lan, T.; Li, G.; Li, J.; Li, Y.; Liu, S.; Liu, X.; Lu, Y.; Ma, X.; Tang, M.; Wang, B.; Wang, G.; Wu, H.; Wu, R.; Xu, X.; Yin, Y.; Zhang, D.; Zhang, W.; Zhao, J.; Zhao, M.; Zheng, X.; Gupta, N.; Gharani, N.; Toji, L. H.; Gerry, N. P.; Resch, A. M.; Barker, J.; Clarke, L.; Gil, L.; Hunt, S. E.; Kelman, G.; Kulesha, E.; Leinonen, R.; McLaren, W. M.; Radhakrishnan, R.; Roa, A.; Smirnov, D.; Smith, R. E.; Streeter, I.; Thormann, A.; Toneva, I.; Vaughan, B.; Zheng-Bradley, X.; Grocock, R.; Humphray, S.; James, T.; Kingsbury, Z.; Sudbrak, R.; Albrecht, M. W.; Amstislavskiy, V. S.; Borodina, T. A.; Lienhard, M.; Mertes, F.; Sultan, M.; Timmermann, B.; Yaspo, Marie-Laure; Fulton, L.; Ananiev, V.; Belaia, Z.; Beloslyudtsev, D.; Bouk, N.; Chen, C.; Church, D.; Cohen, R.; Cook, C.; Garner, J.; Hefferon, T.; Kimelman, M.; Liu, C.; Lopez, J.; Meric, P.; O'Sullivan, C.; Ostapchuk, Y.; Phan, L.; Ponomarov, S.; Schneider, V.; Shekhtman, E.; Sirotkin, K.; Slotta, D.; Zhang, H.; Balasubramaniam, S.; Burton, J.; Danecek, P.; Keane, T. M.; Kolb-Kokocinski, A.; McCarthy, S.; Stalker, J.; Quail, M.; Davies, C. J.; Gollub, J.; Webster, T.; Wong, B.; Zhan, Y.; Campbell, C. L.; Kong, Y.; Marcketta, A.; Yu, F.; Antunes, L.; Bainbridge, M.; Sabo, A.; Huang, Z.; Coin, L. J. M.; Fang, L.; Li, Q.; Li, Z.; Lin, H.; Liu, B.; Luo, R.; Shao, H.; Xie, Y.; Ye, C.; Yu, C.; Zhang, F.; Zheng, H.; Zhu, H.; Alkan, C.; Dal, E.; Kahveci, F.; Garrison, E. P.; Kural, D.; Lee, W. P.; Leong, W. F.; Stromberg, M.; Ward, A. N.; Wu, J.; Zhang, M.; Daly, M. J.; DePristo, M. A.; Handsaker, R. E.; Banks, E.; Bhatia, G.; Del Angel, G.; Genovese, G.; Li, H.; Kashin, S.; McCarroll, S. A.; Nemesh, J. C.; Poplin, R. E.; Yoon, S. C.; Lihm, J.; Makarov, V.; Gottipati, S.; Keinan, A.; Rodriguez-Flores, J. L.; Rausch, T.; Fritz, M. H.; Stütz, A. M.; Beal, K.; Datta, A.; Herrero, J.; Ritchie, G. R. S.; Zerbino, D.; Sabeti, P. C.; Shlyakhter, I.; Schaffner, S. F.; Vitti, J.; Cooper, D. N.; Ball, E. V.; Stenson, P. D.; Barnes, B.; Bauer, M.; Cheetham, R. K.; Cox, A.; Eberle, M.; Kahn, S.; Murray, L.; Peden, J.; Shaw, R.; Kenny, E. E.; Batzer, M. A.; Konkel, M. K.; Walker, J. A.; MacArthur, D. G.; Lek, M.; Herwig, R.; Ding, L.; Koboldt, D. C.; Larson, D.; Ye, K.; Gravel, S.; Swaroop, A.; Chew, E.; Lappalainen, T.; Erlich, Y.; Gymrek, M.; Willems, T. F.; Simpson, J. T.; Shriver, M. D.; Rosenfeld, J. A.; Bustamante, C. D.; Montgomery, S. B.; De La Vega, F. M.; Byrnes, J. K.; Carroll, A. W.; DeGorter, M. K.; Lacroute, P.; Maples, B. K.; Martin, A. R.; Moreno-Estrada, A.; Shringarpure, S. S.; Zakharia, F.; Halperin, E.; Baran, Y.; Cerveira, E.; Hwang, J.; Malhotra, A.; Plewczynski, D.; Radew, K.; Romanovitch, M.; Zhang, C.; Hyland, F. C. L.; Craig, D. W.; Christoforides, A.; Homer, N.; Izatt, T.; Kurdoglu, A. A.; Sinari, S. A.; Squire, K.; Xiao, C.; Sebat, J.; Antaki, D.; Gujral, M.; Noor, A.; Ye, K.; Burchard, E. G.; Hernandez, R. D.; Gignoux, C. R.; Haussler, D.; Katzman, S. J.; Kent, W. J.; Howie, B.; Ruiz-Linares, A.; Dermitzakis, E. T.; Devine, S. E.; Kang, H. M.; Kidd, J. M.; Blackwell, T.; Caron, S.; Chen, W.; Emery, S.; Fritsche, L.; Fuchsberger, C.; Jun, G.; Li, B.; Lyons, R.; Scheller, C.; Sidore, C.; Song, S.; Sliwerska, E.; Taliun, D.; Tan, A.; Welch, R.; Wing, M. K.; Zhan, X.; Awadalla, P.; Hodgkinson, A.; Li, Y.; Shi, X.; Quitadamo, A.; Lunter, G.; Marchini, J. L.; Myers, S.; Churchhouse, C.; Delaneau, O.; Gupta-Hinch, A.; Kretzschmar, W.; Iqbal, Z.; Mathieson, I.; Menelaou, A.; Rimmer, A.; Xifara, D. K.; Oleksyk, T. K.; Fu, Y.; Liu, X.; Xiong, M.; Jorde, L.; Witherspoon, D.; Xing, J.; Browning, B. L.; Browning, S. R.; Hormozdiari, F.; Sudmant, P. H.; Khurana, E.; Tyler-Smith, C.; Albers, C. A.; Ayub, Q.; Chen, Y.; Colonna, V.; Jostins, L.; Walter, K.; Xue, Y.; Gerstein, M. B.; Abyzov, A.; Balasubramanian, S.; Chen, J.; Clarke, D.; Fu, Y.; Harmanci, A. O.; Jin, M.; Lee, D.; Liu, J.; Mu, X. J.; Zhang, J.; Zhang, Y.; Hartl, C.; Shakir, K.; Degenhardt, J.; Meiers, S.; Raeder, B.; Casale, F. P.; Stegle, O.; Lameijer, E. W.; Hall, I.; Bafna, V.; Michaelson, J.; Gardner, E. J.; Mills, R. E.; Dayama, G.; Chen, K.; Fan, X.; Chong, Z.; Chen, T.; Chaisson, M. J.; Huddleston, J.; Malig, M.; Nelson, B. J.; Parrish, N. F.; Blackburne, B.; Lindsay, S. J.; Ning, Z.; Zhang, Y.; Lam, H.; Sisu, C.; Challis, D.; Evani, U. S.; Lu, J.; Nagaswamy, U.; Yu, J.; Li, W.; Habegger, L.; Yu, H.; Cunningham, F.; Dunham, I.; Lage, K.; Jespersen, J. B.; Horn, H.; Kim, D.; Desalle, R.; Narechania, A.; Sayres, M. A. W.; Mendez, F. L.; Poznik, G. D.; Underhill, P. A.; Mittelman, D.; Banerjee, R.; Cerezo, M.; Fitzgerald, T. W.; Louzada, S.; Massaia, A.; Yang, F.; Kalra, D.; Hale, W.; Dan, X.; Barnes, K. C.; Beiswanger, C.; Cai, H.; Cao, H.; Henn, B.; Jones, D.; Kaye, J. S.; Kent, A.; Kerasidou, A.; Mathias, R.; Ossorio, P. N.; Parker, M.; Rotimi, C. N.; Royal, C. D.; Sandoval, K.; Su, Y.; Tian, Z.; Tishkoff, S.; Via, M.; Wang, Y.; Yang, H.; Yang, L.; Zhu, J.; Bodmer, W.; Bedoya, G.; Cai, Z.; Gao, Y.; Chu, J.; Peltonen, L.; Garcia-Montero, A.; Orfao, A.; Dutil, J.; Martinez-Cruzado, J. C.; Mathias, R. A.; Hennis, A.; Watson, H.; McKenzie, C.; Qadri, F.; LaRocque, R.; Deng, X.; Asogun, D.; Folarin, O.; Happi, C.; Omoniwa, O.; Stremlau, M.; Tariyal, R.; Jallow, M.; Joof, F. S.; Corrah, T.; Rockett, K.; Kwiatkowski, D.; Kooner, J.; Hien, T. T.; Dunstan, S. J.; ThuyHang, N.; Fonnie, R.; Garry, R.; Kanneh, L.; Moses, L.; Schieffelin, J.; Grant, D. S.; Gallo, C.; Poletti, G.; Saleheen, D.; Rasheed, A.; Brooks, L. D.; Felsenfeld, A. L.; McEwen, J. E.; Vaydylevich, Y.; Duncanson, A.; Dunn, M.; Schloss, J. A.
The 1000 Genomes Project set out to provide a comprehensive description of common human genetic variation by applying whole-genome sequencing to a diverse set of individuals from multiple populations. Here we report completion of the project, having reconstructed the genomes of 2,504 individuals from 26 populations using a combination of low-coverage whole-genome sequencing, deep exome sequencing, and dense microarray genotyping. We characterized a broad spectrum of genetic variation, in total over 88 million variants (84.7 million single nucleotide polymorphisms (SNPs), 3.6 million short insertions/deletions (indels), and 60,000 structural variants), all phased onto high-quality haplotypes. This resource includes >99% of SNP variants with a frequency of >1% for a variety of ancestries. We describe the distribution of genetic variation across the global sample, and discuss the implications for common disease studies. © 2015 Macmillan Publishers Limited. All rights reserved.
Open Access
Increased frequency of extremely skewed X chromosome inactivation in juvenile idiopathic arthritis
(John Wiley & Sons, Inc., 2009) Uz, E.; Mustafa, C.; Topaloglu, R.; Bilginer, Y.; Dursun, A.; Kasapcopur, O.; Ozen, S.; Bakkaloglu, A.; Ozcelik, T.
Objective. Juvenile idiopathic arthritis (JIA) is a childhood rheumatic disease of unknown etiology. Two subgroups of JIA, i.e., oligoarticular and polyarticular, are thought to have an autoimmune component, and show a higher female:male ratio. Skewed X chromosome inactivation (XCI) has previously been shown to be associated with scleroderma and autoimmune thyroiditis, 2 autoimmune disorders occurring predominantly in females. This study was undertaken to extend the analysis to the pediatric age group and to determine the XCI profiles of patients with JIA.
Open Access
Mutations in RAD21 disrupt regulation of apob in patients with chronic intestinal pseudo-obstruction
(W.B. Saunders, 2015) Bonora, E.; Bianco, F.; Cordeddu, L.; Bamshad, M.; Francescatto, L.; Dowless, D.; Stanghellini, V.; Cogliandro, R. F.; Lindberg, G.; Mungan, Z.; Cefle, K.; Ozcelik, T.; Palanduz, S.; Ozturk, S.; Gedikbasi, A.; Gori, A.; Pippucci, T.; Graziano, C.; Volta, U.; Caio, G.; Barbara, G.; D'Amato, M.; Seri, M.; Katsanis, N.; Romeo, G.; De Giorgio, R.
Background Aims Chronic intestinal pseudo-obstruction (CIPO) is characterized by severe intestinal dysmotility that mimics a mechanical subocclusion with no evidence of gut obstruction. We searched for genetic variants associated with CIPO to increase our understanding of its pathogenesis and to identify potential biomarkers. Methods We performed whole-exome sequencing of genomic DNA from patients with familial CIPO syndrome. Blood and lymphoblastoid cells were collected from patients and controls (individuals without CIPO); levels of messenger RNA (mRNA) and proteins were analyzed by quantitative reverse-transcription polymerase chain reaction, immunoblot, and mobility shift assays. Complementary DNAs were transfected into HEK293 cells. Expression of rad21 was suppressed in zebrafish embryos using a splice-blocking morpholino (rad21a). Gut tissues were collected and analyzed. Results We identified a homozygous mutation (p.622, encodes Ala>Thr) in RAD21 in patients from a consanguineous family with CIPO. Expression of RUNX1, a target of RAD21, was reduced in cells from patients with CIPO compared with controls. In zebrafish, suppression of rad21a reduced expression of runx1; this phenotype was corrected by injection of human RAD21 mRNA, but not with the mRNA from the mutated p.622 allele. rad21a Morpholino zebrafish had delayed intestinal transit and greatly reduced numbers of enteric neurons, similar to patients with CIPO. This defect was greater in zebrafish with suppressed expression of ret and rad21, indicating their interaction in the regulation of gut neurogenesis. The promoter region of APOB bound RAD21 but not RAD21 p.622 Ala>Thr; expression of wild-type RAD21 in HEK293 cells repressed expression of APOB, compared with control vector. The gut-specific isoform of APOB (APOB48) is overexpressed in sera from patients with CIPO who carry the RAD21 mutation. APOB48 also is overexpressed in sporadic CIPO in sera and gut biopsy specimens. Conclusions Some patients with CIPO carry mutations in RAD21 that disrupt the ability of its product to regulate genes such as RUNX1 and APOB. Reduced expression of rad21 in zebrafish, and dysregulation of these target genes, disrupts intestinal transit and the development of enteric neurons.
Open Access
p53 codon 72 polymorphism in bladder cancer-No evidence of association with increased risk or invasiveness
(Springer, 2001) Törüner, G. A.; Uçar, A.; Tez, M.; Çetinkaya, M.; Özen, H.; Özçelik, T.
We studied the effect of the p53 gene Arg72Pro polymorphism on bladder cancer susceptibility in a case control study of 121 bladder cancer patients and 114 age-sex matched controls to determine whether this polymorphism is a biomarker for the risk and how aggressive the disease is. Genomic DNA was obtained from venous blood samples for genotype determination by PCR and restriction digestion. The genotype frequencies in the patient group were Arg/Arg: 0.3553, Arg/Pro: 0.4711, Pro/Pro: 0.1736, and in the control group Arg/Arg: 0.3684, Arg/Pro: 0.4825, Pro/Pro: 0.1491. The distribution of genotypes between the two groups was not statistically different (χ2 = 0.260, df: 2, P = 0.878). The patient group was subdivided into two groups as superficial bladder cancer (n = 88) and invasive bladder cancer (n = 33), according to the presence of muscle invasion. The distribution of genotypes in the superficial group was Arg/Arg: 0.3409, Arg/Pro: 0.5114, Pro/Pro: 0.1477 and in the invasive group Arg/Arg: 0.3940, Arg/Pro: 0.3636, Pro/Pro: 0.2424. No association was observed with the invasiveness of the tumor (χ2 = 2.542, df: 2, P = 0.281). Stratification of the data by tobacco exposure did not result in a significant difference in genotype frequencies. These data do not support an association between the p53 Arg72Pro polymorphism and bladder cancer.