Showing papers by "David Altshuler published in 2014"
Broad Institute1, Harvard University2, Hannover Medical School3, University of Helsinki4, Minerva Foundation Institute for Medical Research5, University of Southern California6, National Institutes of Health7, National Institute for Health and Welfare8, University of Mississippi Medical Center9, University of Mississippi10, Massachusetts Institute of Technology11, University of Michigan12, University of Oxford13, King Abdulaziz University14, Danube University Krems15, Albert Einstein College of Medicine16
TL;DR: Age-related clonal hematopoiesis is a common condition that is associated with increases in the risk of hematologic cancer and in all-cause mortality, with the latter possibly due to an increased risk of cardiovascular disease.
Abstract: Background The incidence of hematologic cancers increases with age. These cancers are associated with recurrent somatic mutations in specific genes. We hypothesized that such mutations would be detectable in the blood of some persons who are not known to have hematologic disorders. Methods We analyzed whole-exome sequencing data from DNA in the peripheral-blood cells of 17,182 persons who were unselected for hematologic phenotypes. We looked for somatic mutations by identifying previously characterized single-nucleotide variants and small insertions or deletions in 160 genes that are recurrently mutated in hematologic cancers. The presence of mutations was analyzed for an association with hematologic phenotypes, survival, and cardiovascular events. Results Detectable somatic mutations were rare in persons younger than 40 years of age but rose appreciably in frequency with age. Among persons 70 to 79 years of age, 80 to 89 years of age, and 90 to 108 years of age, these clonal mutations were observed in 9.5% (219 of 2300 persons), 11.7% (37 of 317), and 18.4% (19 of 103), respectively. The majority of the variants occurred in three genes: DNMT3A, TET2, and ASXL1. The presence of a somatic mutation was associated with an increase in the risk of hematologic cancer (hazard ratio, 11.1; 95% confidence interval [CI], 3.9 to 32.6), an increase in all-cause mortality (hazard ratio, 1.4; 95% CI, 1.1 to 1.8), and increases in the risks of incident coronary heart disease (hazard ratio, 2.0; 95% CI, 1.2 to 3.4) and ischemic stroke (hazard ratio, 2.6; 95% CI, 1.4 to 4.8). Conclusions Age-related clonal hematopoiesis is a common condition that is associated with increases in the risk of hematologic cancer and in all-cause mortality, with the latter possibly due to an increased risk of cardiovascular disease. (Funded by the National Institutes of Health and others.)
3,183 citations
TL;DR: In this paper, the authors aggregated published meta-analyses of genome-wide association studies (GWAS), including 26,488 cases and 83,964 controls of European, east Asian, south Asian and Mexican and Mexican American ancestry.
Abstract: To further understanding of the genetic basis of type 2 diabetes (T2D) susceptibility, we aggregated published meta-analyses of genome-wide association studies (GWAS), including 26,488 cases and 83,964 controls of European, east Asian, south Asian and Mexican and Mexican American ancestry. We observed a significant excess in the directional consistency of T2D risk alleles across ancestry groups, even at SNPs demonstrating only weak evidence of association. By following up the strongest signals of association from the trans-ethnic meta-analysis in an additional 21,491 cases and 55,647 controls of European ancestry, we identified seven new T2D susceptibility loci. Furthermore, we observed considerable improvements in the fine-mapping resolution of common variant association signals at several T2D susceptibility loci. These observations highlight the benefits of trans-ethnic GWAS for the discovery and characterization of complex trait loci and emphasize an exciting opportunity to extend insight into the genetic architecture and pathogenesis of human diseases across populations of diverse ancestry.
954 citations
University of Texas Health Science Center at Houston1, Broad Institute2, Harvard University3, University of Wisconsin–Milwaukee4, University of Washington5, Washington University in St. Louis6, University of North Carolina at Chapel Hill7, Icahn School of Medicine at Mount Sinai8, University of Michigan9, Lund University10, University of Leicester11, Queen Mary University of London12, University of Oxford13, University of Milan14, University of Verona15, Merck & Co.16, National Institutes of Health17, Levanger Hospital18, Norwegian University of Science and Technology19, University of Ottawa20, Stanford University21, University of Iowa22, George Washington University23, Umeå University24, University of Dundee25, Cambridge University Hospitals NHS Foundation Trust26, Technische Universität München27, University of Kiel28, University of Lübeck29, University of Bonn30, Group Health Cooperative31, Baylor College of Medicine32, Houston Methodist Hospital33, Tufts University34, IMDEA35, University of Leeds36, King Abdulaziz University37, Wellcome Trust Sanger Institute38, University of Mississippi39, Fred Hutchinson Cancer Research Center40, University of Virginia41, University of Vermont42, Boston University43
TL;DR: Rare mutations that disrupt AP OC3 function were associated with lower levels of plasma triglycerides and APOC3, and carriers of these mutations were found to have a reduced risk of coronary heart disease.
Abstract: Background Plasma triglyceride levels are heritable and are correlated with the risk of coronary heart disease. Sequencing of the protein-coding regions of the human genome (the exome) has the potential to identify rare mutations that have a large effect on phenotype. Methods We sequenced the protein-coding regions of 18,666 genes in each of 3734 participants of European or African ancestry in the Exome Sequencing Project. We conducted tests to determine whether rare mutations in coding sequence, individually or in aggregate within a gene, were associated with plasma triglyceride levels. For mutations associated with triglyceride levels, we subsequently evaluated their association with the risk of coronary heart disease in 110,970 persons. Results An aggregate of rare mutations in the gene encoding apolipoprotein C3 (APOC3) was associated with lower plasma triglyceride levels. Among the four mutations that drove this result, three were loss-of-function mutations: a nonsense mutation (R19X) and two splice-site mutations (IVS2+1G→A and IVS3+1G→T). The fourth was a missense mutation (A43T). Approximately 1 in 150 persons in the study was a heterozygous carrier of at least one of these four mutations. Triglyceride levels in the carriers were 39% lower than levels in noncarriers (P<1×10 − 20 ), and circulating levels of APOC3 in carriers were 46% lower than levels in noncarriers (P = 8×10 − 10 ). The risk of coronary heart disease among 498 carriers of any rare APOC3 mutation was 40% lower than the risk among 110,472 noncarriers (odds ratio, 0.60; 95% confidence interval, 0.47 to 0.75; P = 4×10 − 6 ). Conclusions Rare mutations that disrupt APOC3 function were associated with lower levels of plasma triglycerides and APOC3. Carriers of these mutations were found to have a reduced risk of coronary heart disease. (Funded by the National Heart, Lung, and Blood Institute and others.)
877 citations
Broad Institute1, Harvard University2, Universidad Autónoma Metropolitana3, National Autonomous University of Mexico4, Universidad Autónoma de Nuevo León5, Massachusetts Institute of Technology6, University of Southern California7, Mexican Social Security Institute8, University of Hawaii at Manoa9, Max Planck Society10, University of Minnesota11, University of California, San Francisco12, National University of Singapore13, University of Oxford14, University of Michigan15, Yeshiva University16, Texas Biomedical Research Institute17, Wake Forest University18, National Health Service19, Imperial College London20, Hallym University21, Hebrew University of Jerusalem22, Wolfson Medical Center23, University of Texas Health Science Center at Houston24, University of Eastern Finland25, Agency for Science, Technology and Research26, University of Mississippi27, University of Texas Health Science Center at San Antonio28
TL;DR: Analysis in Mexican and Latin American individuals identified SLC16A11 as a novel candidate gene for type 2 diabetes with a possible role in triacylglycerol metabolism and an archaic genome sequence indicated that the risk haplotype introgressed into modern humans via admixture with Neanderthals.
Abstract: Performing genetic studies in multiple human populations can identify disease risk alleles that are common in one population but rare in others, with the potential to illuminate pathophysiology, health disparities, and the population genetic origins of disease alleles. Here we analysed 9.2 million single nucleotide polymorphisms (SNPs) in each of 8,214 Mexicans and other Latin Americans: 3,848 with type 2 diabetes and 4,366 non-diabetic controls. In addition to replicating previous findings, we identified a novel locus associated with type 2 diabetes at genome-wide significance spanning the solute carriers SLC16A11 and SLC16A13 (P = 3.9 × 10(-13); odds ratio (OR) = 1.29). The association was stronger in younger, leaner people with type 2 diabetes, and replicated in independent samples (P = 1.1 × 10(-4); OR = 1.20). The risk haplotype carries four amino acid substitutions, all in SLC16A11; it is present at ~50% frequency in Native American samples and ~10% in east Asian, but is rare in European and African samples. Analysis of an archaic genome sequence indicated that the risk haplotype introgressed into modern humans via admixture with Neanderthals. The SLC16A11 messenger RNA is expressed in liver, and V5-tagged SLC16A11 protein localizes to the endoplasmic reticulum. Expression of SLC16A11 in heterologous cells alters lipid metabolism, most notably causing an increase in intracellular triacylglycerol levels. Despite type 2 diabetes having been well studied by genome-wide association studies in other populations, analysis in Mexican and Latin American individuals identified SLC16A11 as a novel candidate gene for type 2 diabetes with a possible role in triacylglycerol metabolism.
431 citations
Harvard University1, Broad Institute2, deCODE genetics3, University of Oxford4, University of Copenhagen5, University of Michigan6, Yeshiva University7, Texas Biomedical Research Institute8, Wake Forest University9, University of Southern Denmark10, Pfizer11, Ealing Hospital12, National Health Service13, Imperial College London14, Hallym University15, Lund University16, University of Helsinki17, University of Texas Health Science Center at Houston18, Norwegian University of Science and Technology19, Uppsala University20, University of Bergen21, Aalborg University22, Novo Nordisk23, University of Eastern Finland24, Technische Universität München25, University of North Carolina at Chapel Hill26, University of Liverpool27, National Institute for Health and Welfare28, National University of Singapore29, Agency for Science, Technology and Research30, University of Iceland31, King Abdulaziz University32, Danube University Krems33, University of Pennsylvania34, University of Mississippi35, Churchill Hospital36, Massachusetts Institute of Technology37
TL;DR: In this article, the authors identified 12 rare protein-truncating variants in SLC30A8, which encodes an islet zinc transporter (ZnT8) and harbors a common variant (p.Trp325Arg) associated with T2D risk and glucose and proinsulin levels.
Abstract: Loss-of-function mutations protective against human disease provide in vivo validation of therapeutic targets, but none have yet been described for type 2 diabetes (T2D). Through sequencing or genotyping of ~150,000 individuals across 5 ancestry groups, we identified 12 rare protein-truncating variants in SLC30A8, which encodes an islet zinc transporter (ZnT8) and harbors a common variant (p.Trp325Arg) associated with T2D risk and glucose and proinsulin levels. Collectively, carriers of protein-truncating variants had 65% reduced T2D risk (P = 1.7 × 10(-6)), and non-diabetic Icelandic carriers of a frameshift variant (p.Lys34Serfs*50) demonstrated reduced glucose levels (-0.17 s.d., P = 4.6 × 10(-4)). The two most common protein-truncating variants (p.Arg138* and p.Lys34Serfs*50) individually associate with T2D protection and encode unstable ZnT8 proteins. Previous functional study of SLC30A8 suggested that reduced zinc transport increases T2D risk, and phenotypic heterogeneity was observed in mouse Slc30a8 knockouts. In contrast, loss-of-function mutations in humans provide strong evidence that SLC30A8 haploinsufficiency protects against T2D, suggesting ZnT8 inhibition as a therapeutic strategy in T2D prevention.
394 citations
Washington University in St. Louis1, Broad Institute2, University of Texas Health Science Center at Houston3, University of North Carolina at Chapel Hill4, University of Oxford5, University of Lübeck6, University of Washington7, University of Wisconsin–Milwaukee8, Stanford University9, University of Pennsylvania10, University of Amsterdam11, Technische Universität München12, University of California, Los Angeles13, Cleveland Clinic14, University of Vermont15, University of Missouri–Kansas City16, Ohio State University17, Baylor College of Medicine18, University of Virginia19, Boston University20, University of Michigan21, Harvard University22, Mayo Clinic23, University of Copenhagen24, Vanderbilt University25, University of Dundee26, King Abdulaziz University27, University of Cambridge28, Pompeu Fabra University29, University of Ottawa30, University of Mississippi31
TL;DR: In this paper, the exons of the Niemann-Pick C1-like 1 (NPC1L1) protein were sequenced in 7364 patients with coronary heart disease and in 14,728 controls without such disease who were of European, African or South Asian ancestry.
Abstract: Ezetimibe lowers plasma levels of low-density lipoprotein (LDL) cholesterol by inhibiting the activity of the Niemann-Pick C1-like 1 (NPC1L1) protein. However, whether such inhibition reduces the risk of coronary heart disease is not known. Human mutations that inactivate a gene encoding a drug target can mimic the action of an inhibitory drug and thus can be used to infer potential effects of that drug.We sequenced the exons of NPC1L1 in 7364 patients with coronary heart disease and in 14,728 controls without such disease who were of European, African, or South Asian ancestry. We identified carriers of inactivating mutations (nonsense, splice-site, or frameshift mutations). In addition, we genotyped a specific inactivating mutation (p.Arg406X) in 22,590 patients with coronary heart disease and in 68,412 controls. We tested the association between the presence of an inactivating mutation and both plasma lipid levels and the risk of coronary heart disease.With sequencing, we identified 15 distinct NPC1L1 inactivating mutations; approximately 1 in every 650 persons was a heterozygous carrier for 1 of these mutations. Heterozygous carriers of NPC1L1 inactivating mutations had a mean LDL cholesterol level that was 12 mg per deciliter (0.31 mmol per liter) lower than that in noncarriers (P=0.04). Carrier status was associated with a relative reduction of 53% in the risk of coronary heart disease (odds ratio for carriers, 0.47; 95% confidence interval, 0.25 to 0.87; P=0.008). In total, only 11 of 29,954 patients with coronary heart disease had an inactivating mutation (carrier frequency, 0.04%) in contrast to 71 of 83,140 controls (carrier frequency, 0.09%).Naturally occurring mutations that disrupt NPC1L1 function were found to be associated with reduced plasma LDL cholesterol levels and a reduced risk of coronary heart disease. (Funded by the National Institutes of Health and others.).
374 citations
28 Aug 2014
TL;DR: Loss-of-function mutations in humans provide strong evidence that SLC30A8 haploinsufficiency protects against type 2 diabetes, suggesting ZnT8 inhibition as a therapeutic strategy in T2D prevention.
Abstract: Loss-of-function mutations protective against human disease provide in vivo validation of therapeutic targets, but none have yet been described for type 2 diabetes (T2D). Through sequencing or genotyping of ∼150,000 individuals across 5 ancestry groups, we identified 12 rare protein-truncating variants in SLC30A8, which encodes an islet zinc transporter (ZnT8) and harbors a common variant (p.Trp325Arg) associated with T2D risk and glucose and proinsulin levels. Collectively, carriers of protein-truncating variants had 65% reduced T2D risk (P = 1.7 × 10−6), and non-diabetic Icelandic carriers of a frameshift variant (p.Lys34Serfs*50) demonstrated reduced glucose levels (−0.17 s.d., P = 4.6 × 10−4). The two most common protein-truncating variants (p.Arg138* and p.Lys34Serfs*50) individually associate with T2D protection and encode unstable ZnT8 proteins. Previous functional study of SLC30A8 suggested that reduced zinc transport increases T2D risk, and phenotypic heterogeneity was observed in mouse Slc30a8 knockouts. In contrast, loss-of-function mutations in humans provide strong evidence that SLC30A8 haploinsufficiency protects against T2D, suggesting ZnT8 inhibition as a therapeutic strategy in T2D prevention.
370 citations
University of Helsinki1, University of Oulu2, National Institutes of Health3, Wellcome Trust Sanger Institute4, Broad Institute5, Harvard University6, University of Tartu7, University of Melbourne8, Stanford University9, Boston Children's Hospital10, University of Michigan11, Lund University12, University of Turku13, Duke University14, Intermountain Medical Center15, University of Ottawa16, University of Pennsylvania17, Wellcome Trust Centre for Human Genetics18, University of Verona19, University of Washington20, Washington University in St. Louis21, University of Tampere22, University of Eastern Finland23, University of Oxford24, Churchill Hospital25, Semel Institute for Neuroscience and Human Behavior26, Turku University Hospital27
TL;DR: In this paper, the authors compared exome sequence data on 3,000 Finns to the same number of non-Finnish Europeans and discovered that the average Finn has more low-frequency loss-of-function variants and complete gene knockouts.
Abstract: Exome sequencing studies in complex diseases are challenged by the allelic heterogeneity, large number and modest effect sizes of associated variants on disease risk and the presence of large numbers of neutral variants, even in phenotypically relevant genes. Isolated populations with recent bottlenecks offer advantages for studying rare variants in complex diseases as they have deleterious variants that are present at higher frequencies as well as a substantial reduction in rare neutral variation. To explore the potential of the Finnish founder population for studying low-frequency (0.5-5%) variants in complex diseases, we compared exome sequence data on 3,000 Finns to the same number of non-Finnish Europeans and discovered that, despite having fewer variable sites overall, the average Finn has more low-frequency loss-of-function variants and complete gene knockouts. We then used several well-characterized Finnish population cohorts to study the phenotypic effects of 83 enriched loss-of-function variants across 60 phenotypes in 36,262 Finns. Using a deep set of quantitative traits collected on these cohorts, we show 5 associations (p<5×10⁻⁸) including splice variants in LPA that lowered plasma lipoprotein(a) levels (P = 1.5×10⁻¹¹⁷). Through accessing the national medical records of these participants, we evaluate the LPA finding via Mendelian randomization and confirm that these splice variants confer protection from cardiovascular disease (OR = 0.84, P = 3×10⁻⁴), demonstrating for the first time the correlation between very low levels of LPA in humans with potential therapeutic implications for cardiovascular diseases. More generally, this study articulates substantial advantages for studying the role of rare variation in complex phenotypes in founder populations like the Finns and by combining a unique population genetic history with data from large population cohorts and centralized research access to National Health Registers.
367 citations
Broad Institute1, Harvard University2, University of Bergen3, National Autonomous University of Mexico4, Universidad Autónoma Metropolitana5, Mexican Social Security Institute6, University of Southern California7, University of Hawaii8, University of Texas Health Science Center at Houston9, University of Texas Health Science Center at San Antonio10, University of Michigan11, Haukeland University Hospital12
TL;DR: A single low-frequency variant in the MODY3-causing gene HNF1A that is associated with type 2 diabetes in Latino populations and may affect protein function is identified and may have implications for screening and therapeutic modification in this population.
Abstract: Importance Latino populations have one of the highest prevalences of type 2 diabetes worldwide. Objectives To investigate the association between rare protein-coding genetic variants and prevalence of type 2 diabetes in a large Latino population and to explore potential molecular and physiological mechanisms for the observed relationships. Design, Setting, and Participants Whole-exome sequencing was performed on DNA samples from 3756 Mexican and US Latino individuals (1794 with type 2 diabetes and 1962 without diabetes) recruited from 1993 to 2013. One variant was further tested for allele frequency and association with type 2 diabetes in large multiethnic data sets of 14 276 participants and characterized in experimental assays. Main Outcome and Measures Prevalence of type 2 diabetes. Secondary outcomes included age of onset, body mass index, and effect on protein function. Results A single rare missense variant (c.1522G>A [p.E508K]) was associated with type 2 diabetes prevalence (odds ratio [OR], 5.48; 95% CI, 2.83-10.61; P = 4.4 × 10 −7 ) in hepatocyte nuclear factor 1-α ( HNF1A ), the gene responsible for maturity onset diabetes of the young type 3 (MODY3). This variant was observed in 0.36% of participants without type 2 diabetes and 2.1% of participants with it. In multiethnic replication data sets, the p.E508K variant was seen only in Latino patients (n = 1443 with type 2 diabetes and 1673 without it) and was associated with type 2 diabetes (OR, 4.16; 95% CI, 1.75-9.92; P = .0013). In experimental assays, HNF-1A protein encoding the p.E508K mutant demonstrated reduced transactivation activity of its target promoter compared with a wild-type protein. In our data, carriers and noncarriers of the p.E508K mutation with type 2 diabetes had no significant differences in compared clinical characteristics, including age at onset. The mean (SD) age for carriers was 45.3 years (11.2) vs 47.5 years (11.5) for noncarriers ( P = .49) and the mean (SD) BMI for carriers was 28.2 (5.5) vs 29.3 (5.3) for noncarriers ( P = .19). Conclusions and Relevance Using whole-exome sequencing, we identified a single low-frequency variant in the MODY3-causing gene HNF1A that is associated with type 2 diabetes in Latino populations and may affect protein function. This finding may have implications for screening and therapeutic modification in this population, but additional studies are required.
217 citations
University of North Carolina at Chapel Hill1, University of Michigan2, Renaissance Computing Institute3, University of Washington4, Broad Institute5, University of Wisconsin–Milwaukee6, Harvard University7, University of Oxford8, Norwegian University of Science and Technology9, Icahn School of Medicine at Mount Sinai10, University of Vermont11, Fred Hutchinson Cancer Research Center12, Erasmus University Rotterdam13, University of Mississippi14, University of Iceland15, University of Minnesota16, Washington University in St. Louis17, University of Edinburgh18, University of Texas Health Science Center at Houston19, University of Pittsburgh20, George Washington University21, University of Iowa22, Stanford University23, University of Auckland24, Ohio State University25, Boston University26, University of California, Los Angeles27, Jackson State University28, University of Copenhagen29, Technische Universität München30, Baylor College of Medicine31, Johns Hopkins University32, Group Health Cooperative33, University of Virginia34
TL;DR: This large whole-exome-sequencing study for LDL-C identified a gene not known to be implicated in LDL- C and provides unique insight into the design and analysis of similar experiments.
Abstract: Elevated low-density lipoprotein cholesterol (LDL-C) is a treatable, heritable risk factor for cardiovascular disease. Genome-wide association studies (GWASs) have identified 157 variants associated with lipid levels but are not well suited to assess the impact of rare and low-frequency variants. To determine whether rare or low-frequency coding variants are associated with LDL-C, we exome sequenced 2,005 individuals, including 554 individuals selected for extreme LDL-C (>98(th) or <2(nd) percentile). Follow-up analyses included sequencing of 1,302 additional individuals and genotype-based analysis of 52,221 individuals. We observed significant evidence of association between LDL-C and the burden of rare or low-frequency variants in PNPLA5, encoding a phospholipase-domain-containing protein, and both known and previously unidentified variants in PCSK9, LDLR and APOB, three known lipid-related genes. The effect sizes for the burden of rare variants for each associated gene were substantially higher than those observed for individual SNPs identified from GWASs. We replicated the PNPLA5 signal in an independent large-scale sequencing study of 2,084 individuals. In conclusion, this large whole-exome-sequencing study for LDL-C identified a gene not known to be implicated in LDL-C and provides unique insight into the design and analysis of similar experiments.
201 citations
TL;DR: The combination of large-scale DNA sequencing and functional testing in the laboratory reveals that approximately 1 in 1,000 individuals carries a variant in PPARG that reduces function in a human adipocyte differentiation assay and is associated with a substantial risk of T2D.
Abstract: Peroxisome proliferator-activated receptor gamma (PPARG) is a master transcriptional regulator of adipocyte differentiation and a canonical target of antidiabetic thiazolidinedione medications. In rare families, loss-of-function (LOF) mutations in PPARG are known to cosegregate with lipodystrophy and insulin resistance; in the general population, the common P12A variant is associated with a decreased risk of type 2 diabetes (T2D). Whether and how rare variants in PPARG and defects in adipocyte differentiation influence risk of T2D in the general population remains undetermined. By sequencing PPARG in 19,752 T2D cases and controls drawn from multiple studies and ethnic groups, we identified 49 previously unidentified, nonsynonymous PPARG variants (MAF < 0.5%). Considered in aggregate (with or without computational prediction of functional consequence), these rare variants showed no association with T2D (OR = 1.35; P = 0.17). The function of the 49 variants was experimentally tested in a novel high-throughput human adipocyte differentiation assay, and nine were found to have reduced activity in the assay. Carrying any of these nine LOF variants was associated with a substantial increase in risk of T2D (OR = 7.22; P = 0.005). The combination of large-scale DNA sequencing and functional testing in the laboratory reveals that approximately 1 in 1,000 individuals carries a variant in PPARG that reduces function in a human adipocyte differentiation assay and is associated with a substantial risk of T2D.
TL;DR: The increased risk for CVD conferred by APOL1 alleles was robust to correction for both traditional CVD risk factors and chronic kidney disease, indicating a genetic component to cardiovascular health disparities in individuals of African ancestry.
Abstract: Rationale:Two distinct alleles in the gene encoding apolipoprotein L1 (APOL1), a major component of high-density lipoprotein, confer protection against Trypanosoma brucei rhodesiense infection and also increase risk for chronic kidney disease. Approximately 14% of Americans with African ancestry carry 2 APOL1 risk alleles, accounting for the high chronic kidney disease burden in this population. Objective:We tested whether APOL1 risk alleles significantly increase risk for atherosclerotic cardiovascular disease (CVD) in African Americans. Methods and Results:We sequenced APOL1 in 1959 randomly selected African American participants in the Jackson Heart Study (JHS) and evaluated associations between APOL1 genotypes and renal and cardiovascular phenotypes. Previously identified association between APOL1 genotypes and chronic kidney disease was confirmed (P=2.4×10−6). Among JHS participants with 2 APOL1 risk alleles, we observed increased risk for CVD (50/763 events among participants without versus 37/280 e...
TL;DR: A spectrum of kinase genes whose overexpression can overcome NSCLC cells’ reliance on EGFR are identified and their convergence on the PI3K-AKT and MEK-ERK signaling axes in sustaining EGFR-independent survival is underscored.
Abstract: Lung adenocarcinomas harboring activating mutations in the epidermal growth factor receptor (EGFR) represent a common molecular subset of non-small cell lung cancer (NSCLC) cases. EGFR mutations predict sensitivity to EGFR tyrosine kinase inhibitors (TKIs) and thus represent a dependency in NSCLCs harboring these alterations, but the genetic basis of EGFR dependence is not fully understood. Here, we applied an unbiased, ORF-based screen to identify genetic modifiers of EGFR dependence in EGFR-mutant NSCLC cells. This approach identified 18 kinase and kinase-related genes whose overexpression can substitute for EGFR in EGFR-dependent PC9 cells, and these genes include seven of nine Src family kinase genes, FGFR1, FGFR2, ITK, NTRK1, NTRK2, MOS, MST1R, and RAF1. A subset of these genes can complement loss of EGFR activity across multiple EGFR-dependent models. Unbiased gene-expression profiling of cells overexpressing EGFR bypass genes, together with targeted validation studies, reveals EGFR-independent activation of the MEK-ERK and phosphoinositide 3-kinase (PI3K)-AKT pathways. Combined inhibition of PI3K-mTOR and MEK restores EGFR dependence in cells expressing each of the 18 EGFR bypass genes. Together, these data uncover a broad spectrum of kinases capable of overcoming dependence on EGFR and underscore their convergence on the PI3K-AKT and MEK-ERK signaling axes in sustaining EGFR-independent survival.
TL;DR: Improved survival for patients over time as well as significant differences among survivor groups are demonstrated as demonstrated in this retrospective analysis of overall survival.
TL;DR: It is demonstrated that power of rare-variant association tests is higher in the Finnish population, especially when variants' phenotypic effects are tightly coupled with fitness effects and therefore reflect a greater contribution of rarer variants.
Abstract: Finnish samples have been extensively utilized in studying single-gene disorders, where the founder effect has clearly aided in discovery, and more recently in genome-wide association studies of complex traits, where the founder effect has had less obvious impacts. As the field starts to explore rare variants' contribution to polygenic traits, it is of great importance to characterize and confirm the Finnish founder effect in sequencing data and to assess its implications for rare-variant association studies. Here, we employ forward simulation, guided by empirical deep resequencing data, to model the genetic architecture of quantitative polygenic traits in both the general European and the Finnish populations simultaneously. We demonstrate that power of rare-variant association tests is higher in the Finnish population, especially when variants' phenotypic effects are tightly coupled with fitness effects and therefore reflect a greater contribution of rarer variants. SKAT-O, variable-threshold tests, and single-variant tests are more powerful than other rare-variant methods in the Finnish population across a range of genetic models. We also compare the relative power and efficiency of exome array genotyping to those of high-coverage exome sequencing. At a fixed cost, less expensive genotyping strategies have far greater power than sequencing; in a fixed number of samples, however, genotyping arrays miss a substantial portion of genetic signals detected in sequencing, even in the Finnish founder population. As genetic studies probe sequence variation at greater depth in more diverse populations, our simulation approach provides a framework for evaluating various study designs for gene discovery.
TL;DR: RAFT (recessive-allele-frequency-based test) outperforms existing approaches when the variant influences disease risk in a recessive manner on simulated data, and suggests that RAFT can effectively reveal rare recessive contributions to complex diseases overlooked by conventional association tests.
Abstract: Rare-variant association studies in common, complex diseases are customarily conducted under an additive risk model in both single-variant and burden testing. Here, we describe a method to improve detection of rare recessive variants in complex diseases termed RAFT (recessive-allele-frequency-based test). We found that RAFT outperforms existing approaches when the variant influences disease risk in a recessive manner on simulated data. We then applied our method to 1,791 Finnish individuals with type 2 diabetes (T2D) and 2,657 matched control subjects. In BBS10, we discovered a rare variant (c.1189A>G [p.Ile397Val]; rs202042386) that confers risk of T2D in a recessive state (p = 1.38 × 10−6) and would be missed by conventional methods. Testing of this variant in an established in vivo zebrafish model confirmed the variant to be pathogenic. Taken together, these data suggest that RAFT can effectively reveal rare recessive contributions to complex diseases overlooked by conventional association tests.
TL;DR: In patients with medulloblastoma the presence of enhancement on MRI may correlate with increased vascularity and angiogenesis, but does not correlate with worse patient prognosis in the short or long term.
Abstract: Object Vascular endothelial growth factor (VEGF) is the major proangiogenic factor in many solid tumors Vascular endothelial growth factor receptor (VEGFR) is expressed in abundance in pediatric patients with medulloblastoma and is associated with tumor metastasis, poor prognosis, and proliferation Gadolinium enhancement on MRI has been suggested to have prognostic significance for some tumors The association of VEGF/VEGFR and Gd enhancement in medulloblastoma has never been closely examined The authors therefore sought to evaluate whether Gd-enhancing medulloblastomas have higher levels of VEGFR and CD31 Outcomes and survival in patients with enhancing and nonenhancing tumors were also compared Methods A retrospective analysis of patients with enhancing, nonenhancing, and partially enhancing medulloblastomas was performed Primary end points included risk stratification, extent of resection, and perioperative complications A cohort of 3 enhancing and 3 nonenhancing tumors was selected for VEGFR an
TL;DR: This study indicated no significant differences in clinical skills in students who volunteer at the SRFC, a first step in attempting to measure clinical skill development outside of the structured medical school setting.
Abstract: At Wayne State University School of Medicine (WSU SOM), the Robert R. Frank Student Run Free Clinic (SRFC) is one place preclinical students can gain clinical experience. There have been no published studies to date measuring the impact of student-run free clinic (SRFC) volunteerism on clinical skills development in preclinical medical students. Surveys were given to first year medical students at WSU SOM at the beginning and end of Year 1 to assess perception of clinical skills, including self-confidence, self-reflection, and professionalism. Scores of the Year 1 Objective Structured Clinical Exam (OSCE) were compared between SRFC volunteers and non-volunteers. There were a total of 206 (68.2%) and 80 (26.5%) survey responses at the beginning and end of Year 1, respectively. Of the 80 students, 31 (38.7%) volunteered at SRFC during Year 1. Statistically significant differences were found between time points in self-confidence (p < 0.001) in both groups. When looking at self-confidence in skills pertaining to SRFC, the difference between groups was statistically significant (p = 0.032) at both time points. A total of 302 students participated in the Year 1 OSCE, 27 (9%) of which were SRFC volunteers. No statistically significant differences were found between groups for mean score (p = 0.888) and established level of rapport (p = 0.394). While this study indicated no significant differences in clinical skills in students who volunteer at the SRFC, it is a first step in attempting to measure clinical skill development outside of the structured medical school setting. The findings lend themselves to development of research designs, clinical surveys, and future studies to measure the impact of clinical volunteer opportunities on clinical skills development in future physicians.
Fred Hutchinson Cancer Research Center1, Brigham and Women's Hospital2, University of Wisconsin–Milwaukee3, Broad Institute4, University of Texas Health Science Center at Houston5, Los Angeles Biomedical Research Institute6, University of North Carolina at Chapel Hill7, The Ohio State University Wexner Medical Center8, Montreal Heart Institute9, University of Virginia10, University of Michigan11, University of Mississippi Medical Center12, Boston University13
TL;DR: It is demonstrated that whole-exome imputation of sequence variants can identify low-frequency variants and discover novel variants in non-European populations and that this search for novel associations between height and common or infrequent variants across the exome in African Americans shows success.
Abstract: Adult body height is a quantitative trait for which genome-wide association studies (GWAS) have identified numerous loci, primarily in European populations. These loci, comprising common variants, explain <10% of the phenotypic variance in height. We searched for novel associations between height and common (minor allele frequency, MAF ≥5%) or infrequent (0.5% < MAF < 5%) variants across the exome in African Americans. Using a reference panel of 1692 African Americans and 471 Europeans from the National Heart, Lung, and Blood Institute's (NHLBI) Exome Sequencing Project (ESP), we imputed whole-exome sequence data into 13 719 African Americans with existing array-based GWAS data (discovery). Variants achieving a height-association threshold of P < 5E−06 in the imputed dataset were followed up in an independent sample of 1989 African Americans with whole-exome sequence data (replication). We used P < 2.5E−07 (=0.05/196 779 variants) to define statistically significant associations in meta-analyses combining the discovery and replication sets (N = 15 708). We discovered and replicated three independent loci for association: 5p13.3/C5orf22/rs17410035 (MAF = 0.10, β = 0.64 cm, P = 8.3E−08), 13q14.2/SPRYD7/rs114089985 (MAF = 0.03, β = 1.46 cm, P = 4.8E−10) and 17q23.3/GH2/rs2006123 (MAF = 0.30; β = 0.47 cm; P = 4.7E−09). Conditional analyses suggested 5p13.3 (C5orf22/rs17410035) and 13q14.2 (SPRYD7/rs114089985) may harbor novel height alleles independent of previous GWAS-identified variants (r2 with GWAS loci <0.01); whereas 17q23.3/GH2/rs2006123 was correlated with GWAS-identified variants in European and African populations. Notably, 13q14.2/rs114089985 is infrequent in African Americans (MAF = 3%), extremely rare in European Americans (MAF = 0.03%), and monomorphic in Asian populations, suggesting it may be an African-American-specific height allele. Our findings demonstrate that whole-exome imputation of sequence variants can identify low-frequency variants and discover novel variants in non-European populations.
Harvard University1, Brigham and Women's Hospital2, Broad Institute3, University of Helsinki4, National Institutes of Health5, Lund University6, Massachusetts Institute of Technology7, University of Mississippi8, University of Michigan9, University of Southern California10, Albert Einstein College of Medicine11
TL;DR: It is concluded that clonal hematopoiesis associated with a somatic mutation in a known cancer-causing gene is a common pre-malignant condition in the elderly and is associated with increased risk of transformation to hematological malignancy, as well as increased all-cause mortality, possibly due to increased cardio-metabolic disease.
TL;DR: Looking at trends over time, publications in CNS cancer have not been as prolific and have not increased as rapidly as publications in breast and lung cancer, indicating that QOL is underrepresented in neuro-oncology research.
Abstract: Our understanding of the biology of neuro-oncologic disease has improved vastly over time, however overall patient survival remains relatively poor. Our goal as clinicians, therefore, should be to ensure that the quality of life (QOL) in that survival time is optimized. Here we review neuro-oncology QOL abstracts presented at major oncology conferences and the published literature to make a quantitative comparison to other common cancer subtypes. First, all abstracts presented at major oncology meetings from 2008 to 2012 were reviewed and filtered to find those related to QOL in CNS, breast, lung, and prostate cancer. Next, a Medline search was performed to identify all QOL papers published from 2003 to 2012 for the same cancer subtypes. The results were compared as absolute values and percentages. The average percentage of CNS QOL-related abstracts presented at ASCO and ASTRO over the last 5 years was 4.9 %, compared to 6.4 % for breast, 4.4 % for lung, and 6.1 % for prostate. There is a significant difference in total percentage of QOL abstracts over the time period when comparing CNS to breast and prostate, but not lung (p < 0.05). The Medline search revealed an average of 25.2 publications per year for CNS cancer, compared to 146.2 for breast, 39.3 for lung, and 64.2 for prostate. When looking at trends over time, publications in CNS cancer have not been as prolific and have not increased as rapidly as publications in breast and lung cancer, indicating that QOL is underrepresented in neuro-oncology research. We need to improve this by standardizing QOL measures and including them in every outcome study.
01 Jul 2014
TL;DR: Substantial advantages for studying the role of rare variation in complex phenotypes in founder populations like the Finns are articulated by combining a unique population genetic history with data from large population cohorts and centralized research access to National Health Registers.