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1.  Variant in the sequence of the LINGO1 gene confers risk of essential tremor 
Nature genetics  2009;41(3):277-279.
We identified a marker in LINGO1 showing genome-wide significant association (P = 1.2 × 10−9, odds ratio = 1.55) with essential tremor. LINGO1 has potent, negative regulatory influences on neuronal survival and is also important in regulating both central-nervous-system axon regeneration and oligodendrocyte maturation. An increase in the number of fusiform swellings of Purkinje cell axons in LINGO1 knockout models highlights the potential role of LINGO1 in essential tremor pathophysiology.
doi:10.1038/ng.299
PMCID: PMC3740956  PMID: 19182806
2.  A study based on whole-genome sequencing yields a rare variant at 8q24 associated with prostate cancer 
Nature genetics  2012;44(12):1326-1329.
Western countries, prostate cancer is the most prevalent cancer of men, and one of the leading causes of cancer-related death in men. Several genome-wide association studies have yielded numerous common variants conferring risk of prostate cancer. In the present study we analyzed 32.5 million variants discovered by whole-genome sequencing 1,795 Icelanders. One variant was found to be associated with prostate cancer in European populations: rs188140481[A] (OR = 2.90, Pcomb = 6.2×10−34) located on 8q24, with an average risk allele control frequency of 0.54%. This variant is only very weakly correlated (r2 ≤ 0.06) with previously reported risk variants on 8q24, and remains significant after adjustment for all of them. Carriers of rs188140481[A] were diagnosed with prostate cancer 1.26 years younger than non-carriers (P = 0.0059). We also report results for the previously described HOXB13 mutation (rs138213197[T]), confirming it as prostate cancer risk variant in populations from all over Europe.
doi:10.1038/ng.2437
PMCID: PMC3562711  PMID: 23104005
3.  Common variants on 9q22.33 and 14q13.3 predispose to thyroid cancer in European populations 
Nature genetics  2009;41(4):460-464.
In order to search for sequence variants conferring risk of thyroid cancer we conducted a genome-wide association study in 192 and 37,196 Icelandic cases and controls, respectively, followed by a replication study in individuals of European descent. Here we show that two common variants, located on 9q22.33 and 14q13.3, are associated with the disease. Overall, the strongest association signals were observed for rs965513 on 9q22.33 (OR = 1.75; P = 1.7 × 10−27) and rs944289 on 14q13.3 (OR = 1.37; P = 2.0 × 10−9). The gene nearest to the 9q22.33 locus is FOXE1 (TTF2) and NKX2-1 (TTF1) is among the genes located at the 14q13.3 locus. Both variants contribute to an increased risk of both papillary and follicular thyroid cancer. Approximately 3.7% of individuals are homozygous for both variants, and their estimated risk of thyroid cancer is 5.7-fold greater than that of noncarriers. In a study on a large sample set from the general population, both risk alleles are associated with low concentrations of thyroid stimulating hormone (TSH), and the 9q22.33 allele is associated with low concentration of thyroxin (T4) and high concentration of triiodothyronine (T3).
doi:10.1038/ng.339
PMCID: PMC3664837  PMID: 19198613
4.  Discovery of common variants associated with low TSH levels and thyroid cancer risk 
Nature genetics  2012;44(3):319-322.
To search for sequence variants conferring risk of nonmedullary thyroid cancer, we focused our analysis on 22 SNPs with a P < 5 × 10−8 in a genome-wide association study on levels of thyroid stimulating hormone (TSH) in 27,758 Icelanders. Of those, rs965513 has previously been shown to associate with thyroid cancer. The remaining 21 SNPs were genotyped in 561 Icelandic individuals with thyroid cancer (cases) and up to 40,013 controls. Variants suggestively associated with thyroid cancer (P < 0.05) were genotyped in an additional 595 non-Icelandic cases and 2,604 controls. After combining the results, three variants were shown to associate with thyroid cancer: rs966423 on 2q35 (OR = 1.34; Pcombined = 1.3 × 10−9), rs2439302 on 8p12 (OR = 1.36; Pcombined = 2.0 × 10−9) and rs116909374 on 14q13.3 (OR = 2.09; Pcombined = 4.6 × 10−11), a region previously reported to contain an uncorrelated variant conferring risk of thyroid cancer. A strong association (P = 9.1 × 10−91) was observed between rs2439302 on 8p12 and expression of NRG1, which encodes the signaling protein neuregulin 1, in blood.
doi:10.1038/ng.1046
PMCID: PMC3655412  PMID: 22267200
5.  Common sequence variants on 2p15 and Xp11.22 confer susceptibility to prostate cancer 
Gudmundsson, Julius | Sulem, Patrick | Rafnar, Thorunn | Bergthorsson, Jon T | Manolescu, Andrei | Gudbjartsson, Daniel | Agnarsson, Bjarni A | Sigurdsson, Asgeir | Benediktsdottir, Kristrun R | Blondal, Thorarinn | Jakobsdottir, Margret | Stacey, Simon N | Kostic, Jelena | Kristinsson, Kari T | Birgisdottir, Birgitta | Ghosh, Shyamali | Magnusdottir, Droplaug N | Thorlacius, Steinunn | Thorleifsson, Gudmar | Zheng, S Lilly | Sun, Jielin | Chang, Bao-Li | Elmore, J Bradford | Breyer, Joan P | McReynolds, Kate M | Bradley, Kevin M | Yaspan, Brian L | Wiklund, Fredrik | Stattin, Par | Lindström, Sara | Adami, Hans-Olov | McDonnell, Shannon K | Schaid, Daniel J | Cunningham, Julie M | Wang, Liang | Cerhan, James R | St Sauver, Jennifer L | Isaacs, Sara D | Wiley, Kathleen E | Partin, Alan W | Walsh, Patrick C | Polo, Sonia | Ruiz-Echarri, Manuel | Navarrete, Sebastian | Fuertes, Fernando | Saez, Berta | Godino, Javier | Weijerman, Philip C | Swinkels, Dorine W | Aben, Katja K | Witjes, J Alfred | Suarez, Brian K | Helfand, Brian T | Frigge, Michael L | Kristjansson, Kristleifur | Ober, Carole | Jonsson, Eirikur | Einarsson, Gudmundur V | Xu, Jianfeng | Gronberg, Henrik | Smith, Jeffrey R | Thibodeau, Stephen N | Isaacs, William B | Catalona, William J | Mayordomo, Jose I | Kiemeney, Lambertus A | Barkardottir, Rosa B | Gulcher, Jeffrey R | Thorsteinsdottir, Unnur | Kong, Augustine | Stefansson, Kari
Nature genetics  2008;40(3):281-283.
We conducted a genome-wide SNP association study on prostate cancer on over 23,000 Icelanders, followed by a replication study including over 15,500 individuals from Europe and the United States. Two newly identified variants were shown to be associated with prostate cancer: rs5945572 on Xp11.22 and rs721048 on 2p15 (odds ratios (OR) = 1.23 and 1.15; P = 3.9 × 10−13 and 7.7 × 10−9, respectively). The 2p15 variant shows a significantly stronger association with more aggressive, rather than less aggressive, forms of the disease.
doi:10.1038/ng.89
PMCID: PMC3598012  PMID: 18264098
6.  Genetic correction of PSA values using sequence variants associated with PSA levels 
Science translational medicine  2010;2(62):62ra92.
Measuring serum levels of the prostate specific antigen (PSA) is the most common screening method for prostate cancer. However, PSA levels are affected by a number of factors apart from neoplasia. Notably, around 40% of the variability of PSA levels in the general population is accounted for by inherited factors, suggesting that it may be possible to improve both sensitivity and specificity by adjusting test results for genetic effects. In order to search for sequence variants that associate with PSA levels, we performed a genome-wide association study and follow-up analysis using PSA information from 15,757 Icelandic and 454 British men not diagnosed with prostate cancer. Overall, we detected a genome-wide significant association between PSA levels and SNPs at six loci: 5p15.33 (rs2736098), 10q11 (rs10993994), 10q26 (rs10788160), 12q24 (rs11067228), 17q12 (rs4430796), and 19q13.33 (rs17632542 (KLK3: I179T), each with Pcombined < 3×10−10. Among 3,834 men who underwent a biopsy of the prostate, the 10q26, 12q24, and 19q13.33 alleles that associate with high PSA levels are associated with higher probability of a negative biopsy (OR between 1.15 and 1.27). Assessment of association between the 6 loci and prostate cancer risk in 5,325 cases and 41,417 controls from Iceland, the Netherlands, Spain, Romania, and the US showed that the SNPs at 10q26 and 12q24 were exclusively associated with PSA levels, whereas the other 4 loci also were associated with prostate cancer risk. We propose that a personalized PSA cutoff value, based on genotype, should be used when deciding to perform a prostate biopsy.
doi:10.1126/scitranslmed.3001513
PMCID: PMC3564581  PMID: 21160077
7.  Genome-wide association and replication studies identify four variants associated with prostate cancer susceptibility 
Nature genetics  2009;41(10):1122-1126.
We report a genome-wide association follow up study on prostate cancer. We identify four variants associated with the disease in European populations: rs10934853-A (OR = 1.12, P = 2.9×10−10) on 3q21.3, two moderately correlated (r2 = 0.07) variants on 8q24.21; rs16902094-G (OR = 1.21, P = 6.2×10−15) and rs445114-T (OR = 1.14, P = 4.7×10−10) and rs8102476-C (OR = 1.12, P = 1.6×10−11) on 19q13.2. We also refine a previous association signal on 11q13 with the SNP rs11228565-A (OR =1.23, P = 6.7 × 10−12). In a multi-variant analysis, using 22 prostate cancer risk variants typed in the Icelandic population, we estimate that carriers belonging to the top 1.3% of the risk distribution have a risk of developing the disease that is more than 2.5 times greater than the population average risk estimates.
doi:10.1038/ng.448
PMCID: PMC3562712  PMID: 19767754
8.  Strengthening the Reporting of Genetic Risk Prediction Studies (GRIPS): Explanation and Elaboration 
European journal of epidemiology  2011;26(4):313-337.
The rapid and continuing progress in gene discovery for complex diseases is fuelling interest in the potential application of genetic risk models for clinical and public health practice.The number of studies assessing the predictive ability is steadily increasing, but they vary widely in completeness of reporting and apparent quality.Transparent reporting of the strengths and weaknesses of these studies is important to facilitate the accumulation of evidence on genetic risk prediction.A multidisciplinary workshop sponsored by the Human Genome Epidemiology Network developed a checklist of 25 items recommended for strengthening the reporting of Genetic RIsk Prediction Studies (GRIPS), building on the principles established by prior reporting guidelines.These recommendations aim to enhance the transparency, quality and completeness of study reporting, and thereby to improve the synthesis and application of information from multiple studies that might differ in design, conduct or analysis.
doi:10.1007/s10654-011-9551-z
PMCID: PMC3088812  PMID: 21424820
9.  CDKN2A Mutations and Melanoma Risk in the Icelandic Population 
Journal of medical genetics  2008;45(5):284-289.
Background
Germline CDKN2A mutations have been observed in 20-40% of high-risk melanoma-prone families, however little is known about their prevalence in population-based series of melanoma cases and controls.
Methods
We resequenced the CDKN2A gene, including the p14ARF variant and promoter regions, in approximately 703 registry-ascertained melanoma cases and 691 population-based controls from Iceland, a country in which the incidence of melanoma has increased rapidly.
Results
We identified a novel germline variant, G89D that was strongly associated with increased melanoma risk and appeared to be an Icelandic founder mutation. The G89D variant was present in about 2% of Icelandic invasive cutaneous malignant melanoma cases. Relatives of affected G89D carriers were at significantly increased risk of melanoma, head & neck cancers, and pancreatic carcinoma compared to relatives of other melanoma patients. Nineteen other germline variants were identified, but none conferred an unequivocal risk of melanoma.
Conclusions
This population-based study of Icelandic melanoma cases and controls showed a frequency of disease-related CDKN2A mutant alleles ranging from 0.7% to 1.0%, thus expanding our knowledge about the frequency of CDKN2A mutations in different populations. In contrast to North America and Australia where a broad spectrum of mutations was observed at a similar frequency, in Iceland, functional CDKN2A mutations consists of only one or two different variants. Additional genetic and/or environmental factors are likely critical for explaining the high incidence rates for melanoma in Iceland. This study adds to the geographic regions for which population-based estimates of CDKN2A mutation frequencies are available.
doi:10.1136/jmg.2007.055376
PMCID: PMC3236640  PMID: 18178632
melanoma; CDKN2A; G89D; pancreatic cancer; population-based
10.  The chromosome 9p21 risk locus is associated with angiographic severity and progression of coronary artery disease 
European Heart Journal  2010;31(24):3017-3023.
Aims
We tested the hypothesis that the 9p21 risk locus promotes atherosclerosis by examining the association between rs10757278 and coronary artery disease (CAD) severity and progression determined by semi-quantitative angiographic scores.
Methods and results
The rs10757278 single nucleotide polymorphism (SNP) was genotyped as the marker for the 9p21 locus in 2334 Caucasian patients undergoing cardiac catheterization (mean age 63, male 67%). Angiographic CAD was assessed using two semi-quantitative scoring systems with one estimating severity (Gensini) and the other extent (Sullivan). A subset of 308 patients who underwent two or more coronary angiograms at least 6 months apart were examined for net change in Gensini and Sullivan scores over time to determine the rate of CAD progression by genotype and were further classified as ‘progressors’ or ‘non-progressors’ based on absolute change per year in angiographic severity score. We replicated the association between the rs10757278 SNP and myocardial infarction and binary (presence/absence) angiographic classifications of CAD. Furthermore, we observed a significant additive association with this SNP, and both severity and extent of CAD using angiographic scores, after adjustment for age, gender, body mass index, traditional cardiovascular risk factors, myocardial infarction, and statin use (Gensini P = 0.016, Sullivan P = 0.005). In addition, there was a significant linear association with CAD progression before and after adjustment for covariates (Gensini P = 0.023, Sullivan P = 0.003) with homozygotes for the risk variant having three-fold greater odds of CAD progression compared with the referent group.
Conclusion
The 9p21 risk locus is associated with angiographically defined severity, extent, and progression of CAD, suggesting a role for this locus in influencing atherosclerosis and its progression.
doi:10.1093/eurheartj/ehq272
PMCID: PMC3001587  PMID: 20729229
Atherosclerosis; angiography; coronary disease; genetics; genomics; 9p21
11.  Large-scale association analyses identifies 13 new susceptibility loci for coronary artery disease 
Schunkert, Heribert | König, Inke R. | Kathiresan, Sekar | Reilly, Muredach P. | Assimes, Themistocles L. | Holm, Hilma | Preuss, Michael | Stewart, Alexandre F. R. | Barbalic, Maja | Gieger, Christian | Absher, Devin | Aherrahrou, Zouhair | Allayee, Hooman | Altshuler, David | Anand, Sonia S. | Andersen, Karl | Anderson, Jeffrey L. | Ardissino, Diego | Ball, Stephen G. | Balmforth, Anthony J. | Barnes, Timothy A. | Becker, Diane M. | Becker, Lewis C. | Berger, Klaus | Bis, Joshua C. | Boekholdt, S. Matthijs | Boerwinkle, Eric | Braund, Peter S. | Brown, Morris J. | Burnett, Mary Susan | Buysschaert, Ian | Carlquist, Cardiogenics, John F. | Chen, Li | Cichon, Sven | Codd, Veryan | Davies, Robert W. | Dedoussis, George | Dehghan, Abbas | Demissie, Serkalem | Devaney, Joseph M. | Do, Ron | Doering, Angela | Eifert, Sandra | El Mokhtari, Nour Eddine | Ellis, Stephen G. | Elosua, Roberto | Engert, James C. | Epstein, Stephen E. | Faire, Ulf de | Fischer, Marcus | Folsom, Aaron R. | Freyer, Jennifer | Gigante, Bruna | Girelli, Domenico | Gretarsdottir, Solveig | Gudnason, Vilmundur | Gulcher, Jeffrey R. | Halperin, Eran | Hammond, Naomi | Hazen, Stanley L. | Hofman, Albert | Horne, Benjamin D. | Illig, Thomas | Iribarren, Carlos | Jones, Gregory T. | Jukema, J.Wouter | Kaiser, Michael A. | Kaplan, Lee M. | Kastelein, John J.P. | Khaw, Kay-Tee | Knowles, Joshua W. | Kolovou, Genovefa | Kong, Augustine | Laaksonen, Reijo | Lambrechts, Diether | Leander, Karin | Lettre, Guillaume | Li, Mingyao | Lieb, Wolfgang | Linsel-Nitschke, Patrick | Loley, Christina | Lotery, Andrew J. | Mannucci, Pier M. | Maouche, Seraya | Martinelli, Nicola | McKeown, Pascal P. | Meisinger, Christa | Meitinger, Thomas | Melander, Olle | Merlini, Pier Angelica | Mooser, Vincent | Morgan, Thomas | Mühleisen, Thomas W. | Muhlestein, Joseph B. | Münzel, Thomas | Musunuru, Kiran | Nahrstaedt, Janja | Nelson, Christopher P. | Nöthen, Markus M. | Olivieri, Oliviero | Patel, Riyaz S. | Patterson, Chris C. | Peters, Annette | Peyvandi, Flora | Qu, Liming | Quyyumi, Arshed A. | Rader, Daniel J. | Rallidis, Loukianos S. | Rice, Catherine | Rosendaal, Frits R. | Rubin, Diana | Salomaa, Veikko | Sampietro, M. Lourdes | Sandhu, Manj S. | Schadt, Eric | Schäfer, Arne | Schillert, Arne | Schreiber, Stefan | Schrezenmeir, Jürgen | Schwartz, Stephen M. | Siscovick, David S. | Sivananthan, Mohan | Sivapalaratnam, Suthesh | Smith, Albert | Smith, Tamara B. | Snoep, Jaapjan D. | Soranzo, Nicole | Spertus, John A. | Stark, Klaus | Stirrups, Kathy | Stoll, Monika | Tang, W. H. Wilson | Tennstedt, Stephanie | Thorgeirsson, Gudmundur | Thorleifsson, Gudmar | Tomaszewski, Maciej | Uitterlinden, Andre G. | van Rij, Andre M. | Voight, Benjamin F. | Wareham, Nick J. | Wells, George A. | Wichmann, H.-Erich | Wild, Philipp S. | Willenborg, Christina | Witteman, Jaqueline C. M. | Wright, Benjamin J. | Ye, Shu | Zeller, Tanja | Ziegler, Andreas | Cambien, Francois | Goodall, Alison H. | Cupples, L. Adrienne | Quertermous, Thomas | März, Winfried | Hengstenberg, Christian | Blankenberg, Stefan | Ouwehand, Willem H. | Hall, Alistair S. | Deloukas, Panos | Thompson, John R. | Stefansson, Kari | Roberts, Robert | Thorsteinsdottir, Unnur | O’Donnell, Christopher J. | McPherson, Ruth | Erdmann, Jeanette | Samani, Nilesh J.
Nature genetics  2011;43(4):333-338.
We performed a meta-analysis of 14 genome-wide association studies of coronary artery disease (CAD) comprising 22,233 cases and 64,762 controls of European descent, followed by genotyping of top association signals in 60,738 additional individuals. This genomic analysis identified 13 novel loci harboring one or more SNPs that were associated with CAD at P<5×10−8 and confirmed the association of 10 of 12 previously reported CAD loci. The 13 novel loci displayed risk allele frequencies ranging from 0.13 to 0.91 and were associated with a 6 to 17 percent increase in the risk of CAD per allele. Notably, only three of the novel loci displayed significant association with traditional CAD risk factors, while the majority lie in gene regions not previously implicated in the pathogenesis of CAD. Finally, five of the novel CAD risk loci appear to have pleiotropic effects, showing strong association with various other human diseases or traits.
doi:10.1038/ng.784
PMCID: PMC3119261  PMID: 21378990
12.  Strengthening the reporting of genetic risk prediction studies (GRIPS): explanation and elaboration 
The rapid and continuing progress in gene discovery for complex diseases is fueling interest in the potential application of genetic risk models for clinical and public health practice. The number of studies assessing the predictive ability is steadily increasing, but they vary widely in completeness of reporting and apparent quality. Transparent reporting of the strengths and weaknesses of these studies is important to facilitate the accumulation of evidence on genetic risk prediction. A multidisciplinary workshop sponsored by the Human Genome Epidemiology Network developed a checklist of 25 items recommended for strengthening the reporting of Genetic RIsk Prediction Studies (GRIPS), building on the principles established by previous reporting guidelines. These recommendations aim to enhance the transparency, quality and completeness of study reporting, and thereby to improve the synthesis and application of information from multiple studies that might differ in design, conduct or analysis.
doi:10.1038/ejhg.2011.27
PMCID: PMC3083630  PMID: 21407270
13.  Sequence variants at CHRNB3-CHRNA6 and CYP2A6 affect smoking behavior 
Thorgeirsson, Thorgeir E. | Gudbjartsson, Daniel F. | Surakka, Ida | Vink, Jacqueline M. | Amin, Najaf | Geller, Frank | Sulem, Patrick | Rafnar, Thorunn | Esko, Tõnu | Walter, Stefan | Gieger, Christian | Rawal, Rajesh | Mangino, Massimo | Prokopenko, Inga | Mägi, Reedik | Keskitalo, Kaisu | Gudjonsdottir, Iris H. | Gretarsdottir, Solveig | Stefansson, Hreinn | Thompson, John R. | Aulchenko, Yurii S. | Nelis, Mari | Aben, Katja K. | den Heijer, Martin | Dirksen, Asger | Ashraf, Haseem | Soranzo, Nicole | Valdes, Ana M | Steves, Claire | Uitterlinden, André G | Hofman, Albert | Tönjes, Anke | Kovacs, Peter | Hottenga, Jouke Jan | Willemsen, Gonneke | Vogelzangs, Nicole | Döring, Angela | Dahmen, Norbert | Nitz, Barbara | Pergadia, Michele L. | Saez, Berta | De Diego, Veronica | Lezcano, Victoria | Garcia-Prats, Maria D. | Ripatti, Samuli | Perola, Markus | Kettunen, Johannes | Hartikainen, Anna-Liisa | Pouta, Anneli | Laitinen, Jaana | Isohanni, Matti | Huei-Yi, Shen | Allen, Maxine | Krestyaninova, Maria | Hall, Alistair S | Jones, Gregory T. | van Rij, Andre M. | Mueller, Thomas | Dieplinger, Benjamin | Haltmayer, Meinhard | Jonsson, Steinn | Matthiasson, Stefan E. | Oskarsson, Hogni | Tyrfingsson, Thorarinn | Kiemeney, Lambertus A. | Mayordomo, Jose I. | Lindholt, Jes S | Pedersen, Jesper Holst | Franklin, Wilbur A. | Wolf, Holly | Montgomery, Grant W. | Heath, Andrew C. | Martin, Nicholas G. | Madden, Pamela A.F. | Giegling, Ina | Rujescu, Dan | Järvelin, Marjo-Riitta | Salomaa, Veikko | Stumvoll, Michael | Spector, Tim D | Wichmann, H-Erich | Metspalu, Andres | Samani, Nilesh J. | Penninx, Brenda W. | Oostra, Ben A. | Boomsma, Dorret I. | Tiemeier, Henning | van Duijn, Cornelia M. | Kaprio, Jaakko | Gulcher, Jeffrey R. | McCarthy, Mark I. | Peltonen, Leena | Thorsteinsdottir, Unnur | Stefansson, Kari
Nature genetics  2010;42(5):448-453.
Smoking is a risk factor for most of the diseases leading in mortality1. We conducted genome-wide association (GWA) meta-analyses of smoking data within the ENGAGE consortium to search for common alleles associating with the number of cigarettes smoked per day (CPD) in smokers (N=31,266) and smoking initiation (N=46,481). We tested selected SNPs in a second stage (N=45,691 smokers), and assessed some in a third sample (N=9,040). Variants in three genomic regions associated with CPD (P< 5·10−8), including previously identified SNPs at 15q25 represented by rs1051730-A (0.80 CPD,P=2.4·10−69), and SNPs at 19q13 and 8p11, represented by rs4105144-C (0.39 CPD, P=2.2·10−12) and rs6474412-T (0.29 CPD,P= 1.4·10−8), respectively. Among the genes at the two novel loci, are genes encoding nicotine-metabolizing enzymes (CYP2A6 and CYP2B6), and nicotinic acetylcholine receptor subunits (CHRNB3 and CHRNA6) highlighted in previous studies of nicotine dependence2-3. Nominal associations with lung cancer were observed at both 8p11 (rs6474412-T,OR=1.09,P=0.04) and 19q13 (rs4105144-C,OR=1.12,P=0.0006).
doi:10.1038/ng.573
PMCID: PMC3080600  PMID: 20418888
14.  Common variants conferring risk of schizophrenia 
Stefansson, Hreinn | Ophoff, Roel A. | Steinberg, Stacy | Andreassen, Ole A. | Cichon, Sven | Rujescu, Dan | Werge, Thomas | Pietiläinen, Olli P. H. | Mors, Ole | Mortensen, Preben B. | Sigurdsson, Engilbert | Gustafsson, Omar | Nyegaard, Mette | Tuulio-Henriksson, Annamari | Ingason, Andres | Hansen, Thomas | Suvisaari, Jaana | Lonnqvist, Jouko | Paunio, Tiina | Børglum, Anders D. | Hartmann, Annette | Fink-Jensen, Anders | Nordentoft, Merete | Hougaard, David | Norgaard-Pedersen, Bent | Böttcher, Yvonne | Olesen, Jes | Breuer, René | Möller, Hans-Jürgen | Giegling, Ina | Rasmussen, Henrik B. | Timm, Sally | Mattheisen, Manuel | Bitter, István | Réthelyi, János M. | Magnusdottir, Brynja B. | Sigmundsson, Thordur | Olason, Pall | Masson, Gisli | Gulcher, Jeffrey R. | Haraldsson, Magnus | Fossdal, Ragnheidur | Thorgeirsson, Thorgeir E. | Thorsteinsdottir, Unnur | Ruggeri, Mirella | Tosato, Sarah | Franke, Barbara | Strengman, Eric | Kiemeney, Lambertus A. | Melle, Ingrid | Djurovic, Srdjan | Abramova, Lilia | Kaleda, Vasily | Sanjuan, Julio | de Frutos, Rosa | Bramon, Elvira | Vassos, Evangelos | Fraser, Gillian | Ettinger, Ulrich | Picchioni, Marco | Walker, Nicholas | Toulopoulou, Timi | Need, Anna C. | Ge, Dongliang | Yoon, Joeng Lim | Shianna, Kevin V. | Freimer, Nelson B. | Cantor, Rita M. | Murray, Robin | Kong, Augustine | Golimbet, Vera | Carracedo, Angel | Arango, Celso | Costas, Javier | Jönsson, Erik G. | Terenius, Lars | Agartz, Ingrid | Petursson, Hannes | Nöthen, Markus M. | Rietschel, Marcella | Matthews, Paul M. | Muglia, Pierandrea | Peltonen, Leena | St Clair, David | Goldstein, David B. | Stefansson, Kari | Collier, David A.
Nature  2009;460(7256):744-747.
Schizophrenia is a complex disorder, caused by both genetic and environmental factors and their interactions. Research on pathogenesis has traditionally focused on neurotransmitter systems in the brain, particularly those involving dopamine. Schizophrenia has been considered a separate disease for over a century, but in the absence of clear biological markers, diagnosis has historically been based on signs and symptoms. A fundamental message emerging from genome-wide association studies of copy number variations (CNVs) associated with the disease is that its genetic basis does not necessarily conform to classical nosological disease boundaries. Certain CNVs confer not only high relative risk of schizophrenia but also of other psychiatric disorders1–3. The structural variations associated with schizophrenia can involve several genes and the phenotypic syndromes, or the ‘genomic disorders’, have not yet been characterized4. Single nucleotide polymorphism (SNP)-based genome-wide association studies with the potential to implicate individual genes in complex diseases may reveal underlying biological pathways. Here we combined SNP data from several large genome-wide scans and followed up the most significant association signals. We found significant association with several markers spanning the major histocompatibility complex (MHC) region on chromosome 6p21.3-22.1, a marker located upstream of the neurogranin gene (NRGN) on 11q24.2 and a marker in intron four of transcription factor 4 (TCF4) on 18q21.2. Our findings implicating the MHC region are consistent with an immune component to schizophrenia risk, whereas the association with NRGN and TCF4 points to perturbation of pathways involved in brain development, memory and cognition.
doi:10.1038/nature08186
PMCID: PMC3077530  PMID: 19571808
15.  Strengthening the reporting of genetic risk prediction studies (GRIPS): explanation and elaboration 
European Journal of Epidemiology  2011;26(4):313-337.
The rapid and continuing progress in gene discovery for complex diseases is fuelling interest in the potential application of genetic risk models for clinical and public health practice. The number of studies assessing the predictive ability is steadily increasing, but they vary widely in completeness of reporting and apparent quality. Transparent reporting of the strengths and weaknesses of these studies is important to facilitate the accumulation of evidence on genetic risk prediction. A multidisciplinary workshop sponsored by the Human Genome Epidemiology Network developed a checklist of 25 items recommended for strengthening the reporting of Genetic RIsk Prediction Studies (GRIPS), building on the principles established by prior reporting guidelines. These recommendations aim to enhance the transparency, quality and completeness of study reporting, and thereby to improve the synthesis and application of information from multiple studies that might differ in design, conduct or analysis.
doi:10.1007/s10654-011-9551-z
PMCID: PMC3088812  PMID: 21424820
Genetic; Risk prediction; Methodology; Guidelines; Reporting
16.  New common variants affecting susceptibility to basal cell carcinoma 
Nature genetics  2009;41(8):909-914.
In a follow-up to our previously reported genome-wide association study of cutaneous basal cell carcinoma (BCC)1, we describe here several new susceptibility variants. SNP rs11170164, encoding a G138E substitution in the keratin 5 (KRT5) gene, affects risk of BCC (OR = 1.35, P = 2.1 × 10−9). A variant at 9p21 near CDKN2A and CDKN2B also confers susceptibility to BCC (rs2151280[C]; OR = 1.19, P = 6.9 × 10−9), as does rs157935[T] at 7q32 near the imprinted gene KLF14 (OR = 1.23, P = 5.7 × 10−10). The effect of rs157935[T] is dependent on the parental origin of the risk allele. None of these variants were found to be associated with melanoma or fair-pigmentation traits. A melanoma- and pigmentation-associated variant in the SLC45A2 gene, L374F, is associated with risk of both BCC and squamous cell carcinoma. Finally, we report conclusive evidence that rs401681[C] in the TERT-CLPTM1L locus confers susceptibility to BCC but protects against melanoma.
doi:10.1038/ng.412
PMCID: PMC2973331  PMID: 19578363
17.  The Scientific Foundation for Personal Genomics: Recommendations from a National Institutes of Health–Centers for Disease Control and Prevention Multidisciplinary Workshop 
The increasing availability of personal genomic tests has led to discussions about the validity and utility of such tests and the balance of benefits and harms. A multidisciplinary workshop was convened by the National Institutes of Health and the Centers for Disease Control and Prevention to review the scientific foundation for using personal genomics in risk assessment and disease prevention and to develop recommendations for targeted research. The clinical validity and utility of personal genomics is a moving target with rapidly developing discoveries but little translation research to close the gap between discoveries and health impact. Workshop participants made recommendations in five domains: (1) developing and applying scientific standards for assessing personal genomic tests; (2) developing and applying a multidisciplinary research agenda, including observational studies and clinical trials to fill knowledge gaps in clinical validity and utility; (3) enhancing credible knowledge synthesis and information dissemination to clinicians and consumers; (4) linking scientific findings to evidence-based recommendations for use of personal genomics; and (5) assessing how the concept of personal utility can affect health benefits, costs, and risks by developing appropriate metrics for evaluation. To fulfill the promise of personal genomics, a rigorous multidisciplinary research agenda is needed.
doi:10.1097/GIM.0b013e3181b13a6c
PMCID: PMC2936269  PMID: 19617843
behavioral sciences; epidemiologic methods; evidence-based medicine; genetics; genetic testing; genomics; medicine; public health
18.  Ancestry-Shift Refinement Mapping of the C6orf97-ESR1 Breast Cancer Susceptibility Locus 
PLoS Genetics  2010;6(7):e1001029.
We used an approach that we term ancestry-shift refinement mapping to investigate an association, originally discovered in a GWAS of a Chinese population, between rs2046210[T] and breast cancer susceptibility. The locus is on 6q25.1 in proximity to the C6orf97 and estrogen receptor α (ESR1) genes. We identified a panel of SNPs that are correlated with rs2046210 in Chinese, but not necessarily so in other ancestral populations, and genotyped them in breast cancer case∶control samples of Asian, European, and African origin, a total of 10,176 cases and 13,286 controls. We found that rs2046210[T] does not confer substantial risk of breast cancer in Europeans and Africans (OR = 1.04, P = 0.099, and OR = 0.98, P = 0.77, respectively). Rather, in those ancestries, an association signal arises from a group of less common SNPs typified by rs9397435. The rs9397435[G] allele was found to confer risk of breast cancer in European (OR = 1.15, P = 1.2×10−3), African (OR = 1.35, P = 0.014), and Asian (OR = 1.23, P = 2.9×10−4) population samples. Combined over all ancestries, the OR was 1.19 (P = 3.9×10−7), was without significant heterogeneity between ancestries (Phet = 0.36) and the SNP fully accounted for the association signal in each ancestry. Haplotypes bearing rs9397435[G] are well tagged by rs2046210[T] only in Asians. The rs9397435[G] allele showed associations with both estrogen receptor positive and estrogen receptor negative breast cancer. Using early-draft data from the 1,000 Genomes project, we found that the risk allele of a novel SNP (rs77275268), which is closely correlated with rs9397435, disrupts a partially methylated CpG sequence within a known CTCF binding site. These studies demonstrate that shifting the analysis among ancestral populations can provide valuable resolution in association mapping.
Author Summary
In genome-wide association studies of disease susceptibility, there is no particular expectation that a genotyped SNP showing an association is itself a pathogenic variant. Rather, it is more likely that a SNP giving a signal does so because it is in linkage disequilibrium (LD) with a pathogenic variant. When the analysis is shifted to a population of another ancestry, the tagging relationship between the genotyped SNP and the pathogenic variant may be disrupted, due to differing patterns of LD between populations. Thus, it is not straightforward to determine whether a susceptibility locus identified in one ancestral population is also associated with risk in another. Moreover, the differing patterns of LD between ancestral populations can be used to gain resolution in genetic mapping. We refer to this approach as ancestry-shift refinement mapping. Here, we apply it to a breast cancer risk variant near the estrogen receptor α gene that was initially described in a Chinese population. We show that the tagging relationship between the originally described SNP rs2046210 and the pathogenic variant(s) is not maintained in Europeans and Africans. We identify a SNP, rs9397435, that is associated with breast cancer risk in populations of Asian, European, and African ancestry.
doi:10.1371/journal.pgen.1001029
PMCID: PMC2908678  PMID: 20661439
19.  A sequence variant in ZFHX3 on 16q22 associates with atrial fibrillation and ischemic stroke 
Nature genetics  2009;41(8):876-878.
We performed a genome-wide scan for sequence variants associating with atrial fibrillation in Iceland and followed up the most significant associations in samples from Iceland, Norway and USA. A sequence variant, rs7193343-T, in the ZFHX3 gene on chromosome 16q22 associated significantly with atrial fibrillation (combined OR=1.21, P=1.4·10-10). This variant also associates with ischemic stroke (OR=1.11, P=0.00054) and cardioembolic stroke (OR=1.22, P=0.00021) in a combined analysis of five stroke sample sets.
doi:10.1038/ng.417
PMCID: PMC2740741  PMID: 19597491
20.  Large recurrent microdeletions associated with schizophrenia 
Stefansson, Hreinn | Rujescu, Dan | Cichon, Sven | Pietiläinen, Olli P. H. | Ingason, Andres | Steinberg, Stacy | Fossdal, Ragnheidur | Sigurdsson, Engilbert | Sigmundsson, Thordur | Buizer-Voskamp, Jacobine E. | Hansen, Thomas | Jakobsen, Klaus D. | Muglia, Pierandrea | Francks, Clyde | Matthews, Paul M. | Gylfason, Arnaldur | Halldorsson, Bjarni V. | Gudbjartsson, Daniel | Thorgeirsson, Thorgeir E. | Sigurdsson, Asgeir | Jonasdottir, Adalbjorg | Jonasdottir, Aslaug | Bjornsson, Asgeir | Mattiasdottir, Sigurborg | Blondal, Thorarinn | Haraldsson, Magnus | Magnusdottir, Brynja B. | Giegling, Ina | Möller, Hans-Jürgen | Hartmann, Annette | Shianna, Kevin V. | Ge, Dongliang | Need, Anna C. | Crombie, Caroline | Fraser, Gillian | Walker, Nicholas | Lonnqvist, Jouko | Suvisaari, Jaana | Tuulio-Henriksson, Annamarie | Paunio, Tiina | Toulopoulou, Timi | Bramon, Elvira | Di Forti, Marta | Murray, Robin | Ruggeri, Mirella | Vassos, Evangelos | Tosato, Sarah | Walshe, Muriel | Li, Tao | Vasilescu, Catalina | Mühleisen, Thomas W. | Wang, August G. | Ullum, Henrik | Djurovic, Srdjan | Melle, Ingrid | Olesen, Jes | Kiemeney, Lambertus A. | Franke, Barbara | Kahn, René S. | Linszen, Don H. | van Os, Jim | Wiersma, Durk | Bruggeman, Richard | Cahn, Wiepke | de Haan, Lieuwe | Krabbendam, Lydia | Myin-Germeys, Inez | Sabatti, Chiara | Freimer, Nelson B. | Gulcher, Jeffrey R. | Thorsteinsdottir, Unnur | Kong, Augustine | Andreassen, Ole A. | Ophoff, Roel A. | Georgi, Alexander | Rietschel, Marcella | Werge, Thomas | Petursson, Hannes | Goldstein, David B. | Nöthen, Markus M. | Peltonen, Leena | Collier, David A. | Clair, David St | Stefansson, Kari
Nature  2008;455(7210):232-236.
Reduced fecundity, associated with severe mental disorders1, places negative selection pressure on risk alleles and may explain, in part, why common variants have not been found that confer risk of disorders such as autism2 schizophrenia3 and mental retardation4. Thus, rare variants may account for a larger fraction of the overall genetic risk than previously assumed. In contrast to rare single nucleotide mutations, rare copy number variations (CNVs) can be detected using genome-wide single nucleotide polymorphism arrays. This has led to the identification of CNVs associated with mental retardation4,5 and autism2. In a genome-wide search for CNVs associating with schizophrenia, we used a population-based sample to identify de novo CNVs by analysing 9,878 transmissions from parents to offspring. The 66 de novo CNVs identified were tested for association in a sample of 1,433 schizophrenia cases and 33,250 controls. Three deletions at 1q21.1, 15q11.2 and 15q13.3 showing nominal association with schizophrenia in the first sample (phase I) were followed up in a second sample of 3,285 cases and 7,951 controls (phase II). All three deletions significantly associate with schizophrenia and related psychoses in the combined sample. The identification of these rare, recurrent risk variants, having occurred independently in multiple founders and being subject to negative selection, is important in itself. CNV analysis may also point the way to the identification of additional and more prevalent risk variants in genes and pathways involved in schizophrenia.
doi:10.1038/nature07229
PMCID: PMC2687075  PMID: 18668039
21.  The Association of a SNP Upstream of INSIG2 with Body Mass Index is Reproduced in Several but Not All Cohorts 
PLoS Genetics  2007;3(4):e61.
A SNP upstream of the INSIG2 gene, rs7566605, was recently found to be associated with obesity as measured by body mass index (BMI) by Herbert and colleagues. The association between increased BMI and homozygosity for the minor allele was first observed in data from a genome-wide association scan of 86,604 SNPs in 923 related individuals from the Framingham Heart Study offspring cohort. The association was reproduced in four additional cohorts, but was not seen in a fifth cohort. To further assess the general reproducibility of this association, we genotyped rs7566605 in nine large cohorts from eight populations across multiple ethnicities (total n = 16,969). We tested this variant for association with BMI in each sample under a recessive model using family-based, population-based, and case-control designs. We observed a significant (p < 0.05) association in five cohorts but saw no association in three other cohorts. There was variability in the strength of association evidence across examination cycles in longitudinal data from unrelated individuals in the Framingham Heart Study Offspring cohort. A combined analysis revealed significant independent validation of this association in both unrelated (p = 0.046) and family-based (p = 0.004) samples. The estimated risk conferred by this allele is small, and could easily be masked by small sample size, population stratification, or other confounders. These validation studies suggest that the original association is less likely to be spurious, but the failure to observe an association in every data set suggests that the effect of SNP rs7566605 on BMI may be heterogeneous across population samples.
Author Summary
Obesity is an epidemic in the United States of America and developing world, portending an epidemic of related diseases such as diabetes and heart disease. While diet and lifestyle contribute to obesity, half of the population variation in body mass index, a common measure of obesity, is determined by inherited factors. Many studies have reported that common sequence variants in genes are associated with an increased risk for obesity, yet most of these are not reproducible in other study cohorts, suggesting that some are false. Recently, Herbert et al. reported a slightly increased risk of obesity for people carrying two copies of the minor allele at a common variant near INSIG2. We present our attempts to further evaluate this potential association with obesity in additional populations. We find evidence of increased risk of obesity for people carrying two copies of the minor allele in five out of nine cohorts tested, using both family- and population-based testing. We indicate possible reasons for the varied results, with the hope of encouraging a combined analysis across study cohorts to more precisely define the effect of this INSIG2 gene variant.
doi:10.1371/journal.pgen.0030061
PMCID: PMC1857727  PMID: 17465681
22.  The BARD1 Cys557Ser Variant and Breast Cancer Risk in Iceland 
PLoS Medicine  2006;3(7):e217.
Background
Most, if not all, of the cellular functions of the BRCA1 protein are mediated through heterodimeric complexes composed of BRCA1 and a related protein, BARD1. Some breast-cancer-associated BRCA1 missense mutations disrupt the function of the BRCA1/BARD1 complex. It is therefore pertinent to determine whether variants of BARD1 confer susceptibility to breast cancer. Recently, a missense BARD1 variant, Cys557Ser, was reported to be at increased frequencies in breast cancer families. We investigated the role of the BARD1 Cys557Ser variant in a population-based cohort of 1,090 Icelandic patients with invasive breast cancer and 703 controls. We then used a computerized genealogy of the Icelandic population to study the relationships between the Cys557Ser variant and familial clustering of breast cancer.
Methods and Findings
The Cys557Ser allele was present at a frequency of 0.028 in patients with invasive breast cancer and 0.016 in controls (odds ratio [OR] = 1.82, 95% confidence interval [CI] 1.11–3.01, p = 0.014). The alleleic frequency was 0.037 in a high-predisposition group of cases defined by having a family history of breast cancer, early onset of breast cancer, or multiple primary breast cancers (OR = 2.41, 95% CI 1.22–4.75, p = 0.015). Carriers of the common Icelandic BRCA2 999del5 mutation were found to have their risk of breast cancer further increased if they also carried the BARD1 variant: the frequency of the BARD1 variant allele was 0.047 (OR = 3.11, 95% CI 1.16–8.40, p = 0.046) in 999del5 carriers with breast cancer. This suggests that the lifetime probability of a BARD1 Cys557Ser/BRCA2 999del5 double carrier developing breast cancer could approach certainty. Cys557Ser carriers, with or without the BRCA2 mutation, had an increased risk of subsequent primary breast tumors after the first breast cancer diagnosis compared to non-carriers. Lobular and medullary breast carcinomas were overrepresented amongst Cys557Ser carriers. We found that an excess of ancestors of contemporary carriers lived in a single county in the southeast of Iceland and that all carriers shared a SNP haplotype, which is suggestive of a founder event. Cys557Ser was found on the same SNP haplotype background in the HapMap Project CEPH sample of Utah residents.
Conclusions
Our findings suggest that BARD1 Cys557Ser is an ancient variant that confers risk of single and multiple primary breast cancers, and this risk extends to carriers of the BRCA2 999del5 mutation.
Editors' Summary
Background.
About 13% of women (one in eight women) will develop breast cancer during their lifetime, but many factors affect the likelihood of any individual woman developing this disease, for example, whether she has had children and at what age, when she started and stopped her periods, and her exposure to certain chemicals or radiation. She may also have inherited a defective gene that affects her risk of developing breast cancer. Some 5%–10% of all breast cancers are familial, or inherited. In 20% of these cases, the gene that is defective is BRCA1 or BRCA2. Inheriting a defective copy of one of these genes greatly increases a woman's risk of developing breast cancer, while researchers think that the other inherited genes that predispose to breast cancer—most of which have not been identified yet—have a much weaker effect. These are described as low-penetrance genes. Inheriting one such gene only slightly increases breast cancer risk; a woman has to inherit several to increase her lifetime risk of cancer significantly.
Why Was This Study Done?
It is important to identify these additional predisposing gene variants because they might provide insights into why breast cancer develops, how to prevent it, and how to treat it. To find low-penetrance genes, researchers do case–control association studies. They find a large group of women with breast cancer (cases) and a similar group of women without cancer (controls), and examine how often a specific gene variant occurs in the two groups. If the variant is found more often in the cases than in the controls, it might be a variant that increases a woman's risk of developing breast cancer.
What Did the Researchers Do and Find?
The researchers involved in this study recruited Icelandic women who had had breast cancer and unaffected women, and looked for a specific variant—the Cys557Ser allele—of a gene called BARD1. They chose BARD1 because the protein it encodes interacts with the protein encoded by BRCA1. Because defects in BRCA1 increase the risk of breast cancer, defects in an interacting protein might have a similar effect. In addition, the Cys557Ser allele has been implicated in breast cancer in other studies. The researchers found that the Cys557Ser allele was nearly twice as common in women with breast cancer as in control women. It was also more common (but not by much) in women who had a family history of breast cancer or who had developed breast cancer more than once. And having the Cys557Ser allele seemed to increase the already high risk of breast cancer in women who had a BRCA2 variant (known as BRCA2 999del5) that accounts for 40% of inherited breast cancer risk in Iceland.
What Do These Findings Mean?
These results indicate that inheriting the BARD1 Cys557Ser allele increases a woman's breast cancer risk but that she is unlikely to have a family history of the disease. Because carrying the Cys557Ser allele only slightly increases a woman's risk of breast cancer, for most women there is no clinical reason to test for this variant. Eventually, when all the low-penetrance genes that contribute to breast cancer risk have been identified, it might be helpful to screen women for the full set to determine whether they are at high risk of developing breast cancer. This will not happen for many years, however, since there might be tens or hundreds of these genes. For women who carry BRCA2 999del5, the situation might be different. It might be worth testing these women for the BARD1 Cys557Ser allele, the researchers explain, because the lifetime probability of developing breast cancer in women carrying both variants might approach 100%. This finding has clinical implications in terms of counseling and monitoring, as does the observation that Cys557Ser carriers have an increased risk of a second, independent breast cancer compared to non-carriers. However, all these findings need to be confirmed in other groups of patients before anyone is routinely tested for the BARD1 Cys557Ser allele.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030217.
• MedlinePlus pages about breast cancer
• Information on breast cancer from the United States National Cancer Institute
• Information on inherited breast cancer from the United States National Human Genome Research Institute
• United States National Cancer Institute information on genetic testing for BRCA1 and BRCA2 variants
• GeneTests pages on the involvement of BRCA1 and BRCA2 in hereditary breast and ovarian cancer
• Cancer Research UK's page on breast cancer statistics
In a population-based cohort of 1090 Icelandic patients, a Cys557Ser missense variant of the BARD1 gene, which interacts with BRCA1, increased the risk of single and multiple primary breast cancers.
doi:10.1371/journal.pmed.0030217
PMCID: PMC1479388  PMID: 16768547
23.  CFH Y402H Confers Similar Risk of Soft Drusen and Both Forms of Advanced AMD 
PLoS Medicine  2005;3(1):e5.
Background
Age-related macular degeneration (AMD) is the most common cause of irreversible visual impairment in the developed world. The two forms of advanced AMD, geographic atrophy and neovascular AMD, represent different pathological processes in the macula that lead to loss of central vision. Soft drusen, characterized by deposits in the macula without visual loss, are considered to be a precursor of advanced AMD. Recently, it has been proposed that a common missense variant, Y402H, in the Complement Factor H (CFH) gene increases the risk for advanced AMD. However, its impact on soft drusen, GA, or neovascular AMD—or the relationship between them—is unclear.
Methods and Findings
We genotyped 581 Icelandic patients with advanced AMD (278 neovascular AMD, 203 GA, and 100 with mixed neovascular AMD/GA), and 435 with early AMD (of whom 220 had soft drusen). A second cohort of 431 US patients from Utah, 322 with advanced AMD (244 neovascular AMD and 78 GA) and 109 early-AMD cases with soft drusen, were analyzed. We confirmed that the CFH Y402H variant shows significant association to advanced AMD, with odds ratio of 2.39 in Icelandic patients (p = 5.9 × 10−12) and odds ratio of 2.14 in US patients from Utah (p = 2.0 × 10−9) with advanced AMD. Furthermore, we show that the Y402H variant confers similar risk of soft drusen and both forms of advanced AMD (GA or neovascular AMD).
Conclusion
Soft drusen occur prior to progression to advanced AMD and represent a histological feature shared by neovascular AMD and GA. Our results suggest that CFH is a major risk factor of soft drusen, and additional genetic factors and/or environmental factors may be required for progression to advanced AMD.
A common missense variant, Y402H, in the Complement Factor H gene is associated strongly with soft drusen, a precursor of advanced age-related macular degeneration
doi:10.1371/journal.pmed.0030005
PMCID: PMC1288033  PMID: 16300415
24.  Cancer as a Complex Phenotype: Pattern of Cancer Distribution within and beyond the Nuclear Family 
PLoS Medicine  2004;1(3):e65.
Background
The contribution of low-penetrant susceptibility variants to cancer is not clear. With the aim of searching for genetic factors that contribute to cancer at one or more sites in the body, we have analyzed familial aggregation of cancer in extended families based on all cancer cases diagnosed in Iceland over almost half a century.
Methods and Findings
We have estimated risk ratios (RRs) of cancer for first- and up to fifth-degree relatives both within and between all types of cancers diagnosed in Iceland from 1955 to 2002 by linking patient information from the Icelandic Cancer Registry to an extensive genealogical database, containing all living Icelanders and most of their ancestors since the settlement of Iceland.
We evaluated the significance of the familial clustering for each relationship separately, all relationships combined (first- to fifth-degree relatives) and for close (first- and second-degree) and distant (third- to fifth-degree) relatives. Most cancer sites demonstrate a significantly increased RR for the same cancer, beyond the nuclear family. Significantly increased familial clustering between different cancer sites is also documented in both close and distant relatives. Some of these associations have been suggested previously but others not.
Conclusion
We conclude that genetic factors are involved in the etiology of many cancers and that these factors are in some cases shared by different cancer sites. However, a significantly increased RR conferred upon mates of patients with cancer at some sites indicates that shared environment or nonrandom mating for certain risk factors also play a role in the familial clustering of cancer. Our results indicate that cancer is a complex, often non-site-specific disease for which increased risk extends beyond the nuclear family.
It's not often that an entire nation's genealogy and cancer records are available. But they are in Iceland, and have been used to determine how often cancers occur in families
doi:10.1371/journal.pmed.0010065
PMCID: PMC539051  PMID: 15630470
25.  Linkage of Osteoporosis to Chromosome 20p12 and Association to BMP2 
PLoS Biology  2003;1(3):e69.
Osteoporotic fractures are a major cause of morbidity and mortality in ageing populations. Osteoporosis, defined as low bone mineral density (BMD) and associated fractures, have significant genetic components that are largely unknown. Linkage analysis in a large number of extended osteoporosis families in Iceland, using a phenotype that combines osteoporotic fractures and BMD measurements, showed linkage to Chromosome 20p12.3 (multipoint allele-sharing LOD, 5.10; p value, 6.3 × 10−7), results that are statistically significant after adjusting for the number of phenotypes tested and the genome-wide search. A follow-up association analysis using closely spaced polymorphic markers was performed. Three variants in the bone morphogenetic protein 2 (BMP2) gene, a missense polymorphism and two anonymous single nucleotide polymorphism haplotypes, were determined to be associated with osteoporosis in the Icelandic patients. The association is seen with many definitions of an osteoporotic phenotype, including osteoporotic fractures as well as low BMD, both before and after menopause. A replication study with a Danish cohort of postmenopausal women was conducted to confirm the contribution of the three identified variants. In conclusion, we find that a region on the short arm of Chromosome 20 contains a gene or genes that appear to be a major risk factor for osteoporosis and osteoporotic fractures, and our evidence supports the view that BMP2 is at least one of these genes.
Genetic analysis of Icelandic families and a replication study in a Danish population provide evidence that variation in the gene BMP2 might contribute to osteoporosis
doi:10.1371/journal.pbio.0000069
PMCID: PMC270020  PMID: 14691541

Results 1-25 (25)