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1.
Annu Rev Genomics Hum Genet ; 20: 181-200, 2019 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-30978304

RESUMO

The past decade has seen a technological revolution in human genetics that has empowered population-level investigations into genetic associations with phenotypes. Although these discoveries rely on genetic variation across individuals, association studies have overwhelmingly been performed in populations of European descent. In this review, we describe limitations faced by single-population studies and provide an overview of strategies to improve global representation in existing data sets and future human genomics research via diversity-focused, multiethnic studies. We highlight the successes of individual studies and meta-analysis consortia that have provided unique knowledge. Additionally, we outline the approach taken by the Population Architecture Using Genomics and Epidemiology (PAGE) study to develop best practices for performing genetic epidemiology in multiethnic contexts. Finally, we discuss how limiting investigations to single populations impairs findings in the clinical domain for both rare-variant identification and genetic risk prediction.

2.
Genet Med ; 21(4): 798-812, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30655598

RESUMO

Identifying genes and variants contributing to rare disease phenotypes and Mendelian conditions informs biology and medicine, yet potential phenotypic consequences for variation of >75% of the ~20,000 annotated genes in the human genome are lacking. Technical advances to assess rare variation genome-wide, particularly exome sequencing (ES), enabled establishment in the United States of the National Institutes of Health (NIH)-supported Centers for Mendelian Genomics (CMGs) and have facilitated collaborative studies resulting in novel "disease gene" discoveries. Pedigree-based genomic studies and rare variant analyses in families with suspected Mendelian conditions have led to the elucidation of hundreds of novel disease genes and highlighted the impact of de novo mutational events, somatic variation underlying nononcologic traits, incompletely penetrant alleles, phenotypes with high locus heterogeneity, and multilocus pathogenic variation. Herein, we highlight CMG collaborative discoveries that have contributed to understanding both rare and common diseases and discuss opportunities for future discovery in single-locus Mendelian disorder genomics. Phenotypic annotation of all human genes; development of bioinformatic tools and analytic methods; exploration of non-Mendelian modes of inheritance including reduced penetrance, multilocus variation, and oligogenic inheritance; construction of allelic series at a locus; enhanced data sharing worldwide; and integration with clinical genomics are explored. Realizing the full contribution of rare disease research to functional annotation of the human genome, and further illuminating human biology and health, will lay the foundation for the Precision Medicine Initiative.


Assuntos
Doenças Genéticas Inatas/genética , Heterogeneidade Genética , Genoma Humano/genética , Genômica/tendências , Bases de Dados Genéticas , Predisposição Genética para Doença , Humanos , National Institutes of Health (U.S.) , Linhagem , Estados Unidos , Sequenciamento Completo do Exoma/métodos
4.
Diabetologia ; 60(12): 2384-2398, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28905132

RESUMO

AIMS/HYPOTHESIS: Elevated levels of fasting glucose and fasting insulin in non-diabetic individuals are markers of dysregulation of glucose metabolism and are strong risk factors for type 2 diabetes. Genome-wide association studies have discovered over 50 SNPs associated with these traits. Most of these loci were discovered in European populations and have not been tested in a well-powered multi-ethnic study. We hypothesised that a large, ancestrally diverse, fine-mapping genetic study of glycaemic traits would identify novel and population-specific associations that were previously undetectable by European-centric studies. METHODS: A multiethnic study of up to 26,760 unrelated individuals without diabetes, of predominantly Hispanic/Latino and African ancestries, were genotyped using the Metabochip. Transethnic meta-analysis of racial/ethnic-specific linear regression analyses were performed for fasting glucose and fasting insulin. We attempted to replicate 39 fasting glucose and 17 fasting insulin loci. Genetic fine-mapping was performed through sequential conditional analyses in 15 regions that included both the initially reported SNP association(s) and denser coverage of SNP markers. In addition, Metabochip-wide analyses were performed to discover novel fasting glucose and fasting insulin loci. The most significant SNP associations were further examined using bioinformatic functional annotation. RESULTS: Previously reported SNP associations were significantly replicated (p ≤ 0.05) in 31/39 fasting glucose loci and 14/17 fasting insulin loci. Eleven glycaemic trait loci were refined to a smaller list of potentially causal variants through transethnic meta-analysis. Stepwise conditional analysis identified two loci with independent secondary signals (G6PC2-rs477224 and GCK-rs2908290), which had not previously been reported. Population-specific conditional analyses identified an independent signal in G6PC2 tagged by the rare variant rs77719485 in African ancestry. Further Metabochip-wide analysis uncovered one novel fasting insulin locus at SLC17A2-rs75862513. CONCLUSIONS/INTERPRETATION: These findings suggest that while glycaemic trait loci often have generalisable effects across the studied populations, transethnic genetic studies help to prioritise likely functional SNPs, identify novel associations that may be population-specific and in turn have the potential to influence screening efforts or therapeutic discoveries. DATA AVAILABILITY: The summary statistics from each of the ancestry-specific and transethnic (combined ancestry) results can be found under the PAGE study on dbGaP here: https://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?study_id=phs000356.v1.p1.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/genética , Grupo com Ancestrais do Continente Europeu , Jejum/sangue , Feminino , Estudo de Associação Genômica Ampla , Humanos , Insulina/sangue , Masculino , Polimorfismo de Nucleotídeo Único/genética
5.
Dev Biol ; 402(1): 17-31, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-25753732

RESUMO

The vacuolated lens (vl) mouse mutation arose on the C3H/HeSnJ background and results in lethality, neural tube defects (NTDs) and cataracts. The vl phenotypes are due to a deletion/frameshift mutation in the orphan GPCR, Gpr161. A recent study using a null allele demonstrated that Gpr161 functions in primary cilia and represses the Shh pathway. We show the hypomorphic Gpr161(vl) allele does not severely affect the Shh pathway. To identify additional pathways regulated by Gpr161 during neurulation, we took advantage of naturally occurring genetic variation in the mouse. Previously Gpr161(vl-C3H) was crossed to different inbred backgrounds including MOLF/EiJ and the Gpr161(vl) mutant phenotypes were rescued. Five modifiers were mapped (Modvl: Modifier of vl) including Modvl5(MOLF). In this study we demonstrate the Modvl5(MOLF) congenic rescues the Gpr161(vl)-associated lethality and NTDs but not cataracts. Bioinformatics determined the transcription factor, Cdx1, is the only annotated gene within the Modvl5 95% CI co-expressed with Gpr161 during neurulation and not expressed in the eye. Using Cdx1 as an entry point, we identified the retinoid acid (RA) and canonical Wnt pathways as downstream targets of Gpr161. QRT-PCR, ISH and IHC determined that expression of RA and Wnt genes are down-regulated in Gpr161(vl/vl) but rescued by the Modvl5(MOLF) congenic during neurulation. Intraperitoneal RA injection restores expression of canonical Wnt markers and rescues Gpr161(vl/vl) NTDs. These results establish the RA and canonical Wnt as pathways downstream of Gpr161 during neurulation, and suggest that Modvl5(MOLF) bypasses the Gpr161(vl) mutation by restoring the activity of these pathways.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Neurulação , Receptores Acoplados a Proteínas-G/metabolismo , Tretinoína/metabolismo , Proteínas Wnt/metabolismo , Animais , Sequência de Bases , Linhagem Celular , Genes Reporter , Variação Genética , Proteínas Hedgehog/metabolismo , Proteínas de Homeodomínio/metabolismo , Hibridização In Situ , Camundongos , Camundongos Endogâmicos C3H , Camundongos Transgênicos , Modelos Genéticos , Dados de Sequência Molecular , Mutação , Defeitos do Tubo Neural/genética , Fenótipo , Locos de Características Quantitativas , RNA Mensageiro/metabolismo , Transdução de Sinais , Fatores de Tempo , Via de Sinalização Wnt , Proteína Wnt3A/metabolismo
6.
PLoS One ; 10(3): e0120491, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25789475

RESUMO

BACKGROUND: Several regions of the genome show pleiotropic associations with multiple cancers. We sought to evaluate whether 181 single-nucleotide polymorphisms previously associated with various cancers in genome-wide association studies were also associated with melanoma risk. METHODS: We evaluated 2,131 melanoma cases and 20,353 controls from three studies in the Population Architecture using Genomics and Epidemiology (PAGE) study (EAGLE-BioVU, MEC, WHI) and two collaborating studies (HPFS, NHS). Overall and sex-stratified analyses were performed across studies. RESULTS: We observed statistically significant associations with melanoma for two lung cancer SNPs in the TERT-CLPTM1L locus (Bonferroni-corrected p<2.8x10-4), replicating known pleiotropic effects at this locus. In sex-stratified analyses, we also observed a potential male-specific association between prostate cancer risk variant rs12418451 and melanoma risk (OR=1.22, p=8.0x10-4). No other variants in our study were associated with melanoma after multiple comparisons adjustment (p>2.8e-4). CONCLUSIONS: We provide confirmatory evidence of pleiotropic associations with melanoma for two SNPs previously associated with lung cancer, and provide suggestive evidence for a male-specific association with melanoma for prostate cancer variant rs12418451. This SNP is located near TPCN2, an ion transport gene containing SNPs which have been previously associated with hair pigmentation but not melanoma risk. Previous evidence provides biological plausibility for this association, and suggests a complex interplay between ion transport, pigmentation, and melanoma risk that may vary by sex. If confirmed, these pleiotropic relationships may help elucidate shared molecular pathways between cancers and related phenotypes.


Assuntos
Estudo de Associação Genômica Ampla , Neoplasias Pulmonares/genética , Melanoma/genética , Neoplasias Cutâneas/genética , Idoso , Idoso de 80 Anos ou mais , Alelos , Estudos de Casos e Controles , Feminino , Pleiotropia Genética , Genótipo , Humanos , Neoplasias Pulmonares/patologia , Masculino , Melanoma/patologia , Proteínas de Membrana/genética , Metagenômica , Pessoa de Meia-Idade , Proteínas de Neoplasias/genética , Polimorfismo de Nucleotídeo Único , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Risco , Fatores Sexuais , Neoplasias Cutâneas/metabolismo , Telomerase/genética
7.
BMC Proc ; 8(Suppl 1 Genetic Analysis Workshop 18Vanessa Olmo): S81, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25519410

RESUMO

Most association studies focus on disease risk, with less attention paid to disease progression or severity. These phenotypes require longitudinal data. This paper presents a new method for analyzing longitudinal data to map genes in both population-based and family-based studies. Using simulated systolic blood pressure measurements obtained from Genetic Analysis Workshop 18, we cluster the phenotype data into trajectory subgroups. We then use the Bayesian posterior probability of being in the high subgroup as a quantitative trait in an association analysis with genotype data. This method maintains high power (>80%) in locating genes known to affect the simulated phenotype for most specified significance levels (α). We believe that this method can be useful to aid in the discovery of genes that affect severity or progression of disease.

8.
Invest Ophthalmol Vis Sci ; 55(10): 6839-50, 2014 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-25205864

RESUMO

PURPOSE: Substantial progress has been made in identifying susceptibility variants for AMD in European populations; however, few studies have been conducted to understand the role these variants play in AMD risk in diverse populations. The present study aims to examine AMD risk across diverse populations in known and suspected AMD complement factor and lipid-related loci. METHODS: Targeted genotyping was performed across study sites for AMD and lipid trait-associated single nucleotide polymorphism (SNPs). Genetic association tests were performed at individual sites and then meta-analyzed using logistic regression assuming an additive genetic model stratified by self-described race/ethnicity. Participants included cases with early or late AMD and controls with no signs of AMD as determined by fundus photography. Populations included in this study were European Americans, African Americans, Mexican Americans, and Singaporeans from the Population Architecture using Genomics and Epidemiology (PAGE) study. RESULTS: Index variants of AMD, rs1061170 (CFH) and rs10490924 (ARMS2), were associated with AMD at P=3.05×10(-8) and P=6.36×10(-6), respectively, in European Americans. In general, none of the major AMD index variants generalized to our non-European populations with the exception of rs10490924 in Mexican Americans at an uncorrected P value<0.05. Four lipid-associated SNPS (LPL rs328, TRIB1 rs6987702, CETP rs1800775, and KCTD10/MVK rs2338104) were associated with AMD in African Americans and Mexican Americans (P<0.05), but these associations did not survive strict corrections for multiple testing. CONCLUSIONS: While most associations did not generalize in the non-European populations, variants within lipid-related genes were found to be associated with AMD. This study highlights the need for larger well-powered studies in non-European populations.


Assuntos
DNA/genética , Grupos Étnicos/genética , Predisposição Genética para Doença , Degeneração Macular/genética , Polimorfismo de Nucleotídeo Único , Proteínas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Fator H do Complemento/genética , Fator H do Complemento/metabolismo , Feminino , Frequência do Gene , Genótipo , Humanos , Degeneração Macular/etnologia , Degeneração Macular/metabolismo , Masculino , Pessoa de Meia-Idade , Fenótipo , Prevalência , Estudos Prospectivos , Proteínas/metabolismo , Fatores de Risco , Estados Unidos/epidemiologia
9.
Cancer Epidemiol Biomarkers Prev ; 23(11): 2568-78, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25139936

RESUMO

BACKGROUND: Multiple primary cancers account for approximately 16% of all incident cancers in the United States. Although genome-wide association studies (GWAS) have identified many common genetic variants associated with various cancer sites, no study has examined the association of these genetic variants with risk of multiple primary cancers (MPC). METHODS: As part of the National Human Genome Research Institute (NHGRI) Population Architecture using Genomics and Epidemiology (PAGE) study, we used data from the Multiethnic Cohort (MEC) and Women's Health Initiative (WHI). Incident MPC (IMPC) cases (n = 1,385) were defined as participants diagnosed with more than one incident cancer after cohort entry. Participants diagnosed with only one incident cancer after cohort entry with follow-up equal to or longer than IMPC cases served as controls (single-index cancer controls; n = 9,626). Fixed-effects meta-analyses of unconditional logistic regression analyses were used to evaluate the associations between 188 cancer risk variants and IMPC risk. To account for multiple comparisons, we used the false-positive report probability (FPRP) to determine statistical significance. RESULTS: A nicotine dependence-associated and lung cancer variant, CHRNA3 rs578776 [OR, 1.16; 95% confidence interval (CI), 1.05-1.26; P = 0.004], and two breast cancer variants, EMBP1 rs11249433 and TOX3 rs3803662 (OR, 1.16; 95% CI, 1.04-1.28; P = 0.005 and OR, 1.13; 95% CI, 1.03-1.23; P = 0.006), were significantly associated with risk of IMPC. The associations for rs578776 and rs11249433 remained (P < 0.05) after removing subjects who had lung or breast cancers, respectively (P ≤ 0.046). These associations did not show significant heterogeneity by smoking status (Pheterogeneity ≥ 0.53). CONCLUSIONS: Our study has identified rs578776 and rs11249433 as risk variants for IMPC. IMPACT: These findings may help to identify genetic regions associated with IMPC risk.


Assuntos
Suscetibilidade a Doenças , Neoplasias/etiologia , Idoso , Estudos Epidemiológicos , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Genômica , Genótipo , Humanos , Masculino , Polimorfismo de Nucleotídeo Único
10.
PLoS One ; 9(3): e89791, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24598796

RESUMO

BACKGROUND: Risk of non-Hodgkin lymphoma (NHL) is higher among individuals with a family history or a prior diagnosis of other cancers. Genome-wide association studies (GWAS) have suggested that some genetic susceptibility variants are associated with multiple complex traits (pleiotropy). OBJECTIVE: We investigated whether common risk variants identified in cancer GWAS may also increase the risk of developing NHL as the first primary cancer. METHODS: As part of the Population Architecture using Genomics and Epidemiology (PAGE) consortium, 113 cancer risk variants were analyzed in 1,441 NHL cases and 24,183 controls from three studies (BioVU, Multiethnic Cohort Study, Women's Health Initiative) for their association with the risk of overall NHL and common subtypes [diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL)] using an additive genetic model adjusted for age, sex and ethnicity. Study-specific results for each variant were meta-analyzed across studies. RESULTS: The analysis of NHL subtype-specific GWAS SNPs and overall NHL suggested a shared genetic susceptibility between FL and DLBCL, particularly involving variants in the major histocompatibility complex region (rs6457327 in 6p21.33: FL OR=1.29, p=0.013; DLBCL OR=1.23, p=0.013; NHL OR=1.22, p=5.9 × E-05). In the pleiotropy analysis, six risk variants for other cancers were associated with NHL risk, including variants for lung (rs401681 in TERT: OR per C allele=0.89, p=3.7 × E-03; rs4975616 in TERT: OR per A allele=0.90, p=0.01; rs3131379 in MSH5: OR per T allele=1.16, p=0.03), prostate (rs7679673 in TET2: OR per C allele=0.89, p=5.7 × E-03; rs10993994 in MSMB: OR per T allele=1.09, p=0.04), and breast (rs3817198 in LSP1: OR per C allele=1.12, p=0.01) cancers, but none of these associations remained significant after multiple test correction. CONCLUSION: This study does not support strong pleiotropic effects of non-NHL cancer risk variants in NHL etiology; however, larger studies are warranted.


Assuntos
Pleiotropia Genética , Linfoma não Hodgkin/genética , Estudos de Casos e Controles , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Polimorfismo de Nucleotídeo Único , Risco
11.
Am J Hum Genet ; 93(4): 661-71, 2013 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-24094743

RESUMO

Genome-wide association studies (GWASs) primarily performed in European-ancestry (EA) populations have identified numerous loci associated with body mass index (BMI). However, it is still unclear whether these GWAS loci can be generalized to other ethnic groups, such as African Americans (AAs). Furthermore, the putative functional variant or variants in these loci mostly remain under investigation. The overall lower linkage disequilibrium in AA compared to EA populations provides the opportunity to narrow in or fine-map these BMI-related loci. Therefore, we used the Metabochip to densely genotype and evaluate 21 BMI GWAS loci identified in EA studies in 29,151 AAs from the Population Architecture using Genomics and Epidemiology (PAGE) study. Eight of the 21 loci (SEC16B, TMEM18, ETV5, GNPDA2, TFAP2B, BDNF, FTO, and MC4R) were found to be associated with BMI in AAs at 5.8 × 10(-5). Within seven out of these eight loci, we found that, on average, a substantially smaller number of variants was correlated (r(2) > 0.5) with the most significant SNP in AA than in EA populations (16 versus 55). Conditional analyses revealed GNPDA2 harboring a potential additional independent signal. Moreover, Metabochip-wide discovery analyses revealed two BMI-related loci, BRE (rs116612809, p = 3.6 × 10(-8)) and DHX34 (rs4802349, p = 1.2 × 10(-7)), which were significant when adjustment was made for the total number of SNPs tested across the chip. These results demonstrate that fine mapping in AAs is a powerful approach for both narrowing in on the underlying causal variants in known loci and discovering BMI-related loci.


Assuntos
Afro-Americanos/genética , Índice de Massa Corporal , Genoma Humano , Estudo de Associação Genômica Ampla/métodos , Obesidade/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Loci Gênicos , Predisposição Genética para Doença , Genótipo , Humanos , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Obesidade/etnologia , Polimorfismo de Nucleotídeo Único , Adulto Jovem
12.
PLoS Biol ; 11(9): e1001661, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24068893

RESUMO

The vast majority of genome-wide association study (GWAS) findings reported to date are from populations with European Ancestry (EA), and it is not yet clear how broadly the genetic associations described will generalize to populations of diverse ancestry. The Population Architecture Using Genomics and Epidemiology (PAGE) study is a consortium of multi-ancestry, population-based studies formed with the objective of refining our understanding of the genetic architecture of common traits emerging from GWAS. In the present analysis of five common diseases and traits, including body mass index, type 2 diabetes, and lipid levels, we compare direction and magnitude of effects for GWAS-identified variants in multiple non-EA populations against EA findings. We demonstrate that, in all populations analyzed, a significant majority of GWAS-identified variants have allelic associations in the same direction as in EA, with none showing a statistically significant effect in the opposite direction, after adjustment for multiple testing. However, 25% of tagSNPs identified in EA GWAS have significantly different effect sizes in at least one non-EA population, and these differential effects were most frequent in African Americans where all differential effects were diluted toward the null. We demonstrate that differential LD between tagSNPs and functional variants within populations contributes significantly to dilute effect sizes in this population. Although most variants identified from GWAS in EA populations generalize to all non-EA populations assessed, genetic models derived from GWAS findings in EA may generate spurious results in non-EA populations due to differential effect sizes. Regardless of the origin of the differential effects, caution should be exercised in applying any genetic risk prediction model based on tagSNPs outside of the ancestry group in which it was derived. Models based directly on functional variation may generalize more robustly, but the identification of functional variants remains challenging.


Assuntos
Predisposição Genética para Doença , Estudo de Associação Genômica Ampla/métodos , Metagenômica/métodos , Polimorfismo de Nucleotídeo Único/genética , Afro-Americanos/genética , Americanos Asiáticos/genética , Índice de Massa Corporal , Diabetes Mellitus Tipo 2/genética , Grupo com Ancestrais do Continente Europeu/genética , Frequência do Gene , Variação Genética , Hispano-Americanos/genética , Humanos , Índios Norte-Americanos/genética , Lipídeos/sangue , Lipídeos/genética , Grupo com Ancestrais Oceânicos/genética
13.
Bioinformatics ; 29(21): 2744-9, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-23956302

RESUMO

SUMMARY: Although the 1000 Genomes haplotypes are the most commonly used reference panel for imputation, medical sequencing projects are generating large alternate sets of sequenced samples. Imputation in African Americans using 3384 haplotypes from the Exome Sequencing Project, compared with 2184 haplotypes from 1000 Genomes Project, increased effective sample size by 8.3-11.4% for coding variants with minor allele frequency <1%. No loss of imputation quality was observed using a panel built from phenotypic extremes. We recommend using haplotypes from Exome Sequencing Project alone or concatenation of the two panels over quality score-based post-imputation selection or IMPUTE2's two-panel combination. CONTACT: yunli@med.unc.edu. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Afro-Americanos/genética , Exoma , Variação Genética , Análise de Sequência de DNA/métodos , Frequência do Gene , Genoma Humano , Estudo de Associação Genômica Ampla , Haplótipos , Humanos , Fenótipo , Polimorfismo de Nucleotídeo Único
14.
Obesity (Silver Spring) ; 21(4): 835-46, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23712987

RESUMO

OBJECTIVE: Several genome-wide association studies (GWAS) have demonstrated that common genetic variants contribute to obesity. However, studies of this complex trait have focused on ancestrally European populations, despite the high prevalence of obesity in some minority groups. DESIGN AND METHODS: As part of the "Population Architecture using Genomics and Epidemiology (PAGE)" Consortium, we investigated the association between 13 GWAS-identified single-nucleotide polymorphisms (SNPs) and BMI and obesity in 69,775 subjects, including 6,149 American Indians, 15,415 African-Americans, 2,438 East Asians, 7,346 Hispanics, 604 Pacific Islanders, and 37,823 European Americans. For the BMI-increasing allele of each SNP, we calculated ß coefficients using linear regression (for BMI) and risk estimates using logistic regression (for obesity defined as BMI ≥ 30) followed by fixed-effects meta-analysis to combine results across PAGE sites. Analyses stratified by racial/ethnic group assumed an additive genetic model and were adjusted for age, sex, and current smoking. We defined "replicating SNPs" (in European Americans) and "generalizing SNPs" (in other racial/ethnic groups) as those associated with an allele frequency-specific increase in BMI. RESULTS: By this definition, we replicated 9/13 SNP associations (5 out of 8 loci) in European Americans. We also generalized 8/13 SNP associations (5/8 loci) in East Asians, 7/13 (5/8 loci) in African Americans, 6/13 (4/8 loci) in Hispanics, 5/8 in Pacific Islanders (5/8 loci), and 5/9 (4/8 loci) in American Indians. CONCLUSION: Linkage disequilibrium patterns suggest that tagSNPs selected for European Americans may not adequately tag causal variants in other ancestry groups. Accordingly, fine-mapping in large samples is needed to comprehensively explore these loci in diverse populations.


Assuntos
Índice de Massa Corporal , Grupos Étnicos/genética , Metagenômica/métodos , Obesidade/epidemiologia , Obesidade/genética , Alelos , Frequência do Gene , Loci Gênicos , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Desequilíbrio de Ligação , Fenótipo , Polimorfismo de Nucleotídeo Único , Fatores de Risco
15.
Atherosclerosis ; 228(2): 390-9, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23587283

RESUMO

BACKGROUND: A number of genetic variants have been discovered by recent genome-wide association studies for their associations with clinical coronary heart disease (CHD). However, it is unclear whether these variants are also associated with the development of CHD as measured by subclinical atherosclerosis phenotypes, ankle brachial index (ABI), carotid artery intima-media thickness (cIMT) and carotid plaque. METHODS: Ten CHD risk single nucleotide polymorphisms (SNPs) were genotyped in individuals of European American (EA), African American (AA), American Indian (AI), and Mexican American (MA) ancestry in the Population Architecture using Genomics and Epidemiology (PAGE) study. In each individual study, we performed linear or logistic regression to examine population-specific associations between SNPs and ABI, common and internal cIMT, and plaque. The results from individual studies were meta-analyzed using a fixed effect inverse variance weighted model. RESULTS: None of the ten SNPs was significantly associated with ABI and common or internal cIMT, after Bonferroni correction. In the sample of 13,337 EA, 3809 AA, and 5353 AI individuals with carotid plaque measurement, the GCKR SNP rs780094 was significantly associated with the presence of plaque in AI only (OR = 1.32, 95% confidence interval: 1.17, 1.49, P = 1.08 × 10(-5)), but not in the other populations (P = 0.90 in EA and P = 0.99 in AA). A 9p21 region SNP, rs1333049, was nominally associated with plaque in EA (OR = 1.07, P = 0.02) and in AI (OR = 1.10, P = 0.05). CONCLUSIONS: We identified a significant association between rs780094 and plaque in AI populations, which needs to be replicated in future studies. There was little evidence that the index CHD risk variants identified through genome-wide association studies in EA influence the development of CHD through subclinical atherosclerosis as assessed by cIMT and ABI across ancestries.


Assuntos
Doenças das Artérias Carótidas/epidemiologia , Doenças das Artérias Carótidas/genética , Doença das Coronárias/epidemiologia , Doença das Coronárias/genética , Polimorfismo de Nucleotídeo Único , Afro-Americanos/genética , Idoso , Índice Tornozelo-Braço , Doenças Assintomáticas , Doenças das Artérias Carótidas/diagnóstico , Doenças das Artérias Carótidas/etnologia , Espessura Intima-Media Carotídea , Doença das Coronárias/diagnóstico , Doença das Coronárias/etnologia , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Índios Norte-Americanos/genética , Modelos Lineares , Modelos Logísticos , Masculino , Americanos Mexicanos/genética , Pessoa de Meia-Idade , Razão de Chances , Fenótipo , Valor Preditivo dos Testes , Medição de Risco , Fatores de Risco , Estados Unidos/epidemiologia
16.
Am J Epidemiol ; 177(9): 923-32, 2013 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-23552988

RESUMO

A loss-of-function mutation (Q141K, rs2231142) in the ATP-binding cassette, subfamily G, member 2 gene (ABCG2) has been shown to be associated with serum uric acid levels and gout in Asians, Europeans, and European and African Americans; however, less is known about these associations in other populations. Rs2231142 was genotyped in 22,734 European Americans, 9,720 African Americans, 3,849 Mexican Americans, and 3,550 American Indians in the Population Architecture using Genomics and Epidemiology (PAGE) Study (2008-2012). Rs2231142 was significantly associated with serum uric acid levels (P = 2.37 × 10(-67), P = 3.98 × 10(-5), P = 6.97 × 10(-9), and P = 5.33 × 10(-4) in European Americans, African Americans, Mexican Americans, and American Indians, respectively) and gout (P = 2.83 × 10(-10), P = 0.01, and P = 0.01 in European Americans, African Americans, and Mexican Americans, respectively). Overall, the T allele was associated with a 0.24-mg/dL increase in serum uric acid level (P = 1.37 × 10(-80)) and a 1.75-fold increase in the odds of gout (P = 1.09 × 10(-12)). The association between rs2231142 and serum uric acid was significantly stronger in men, postmenopausal women, and hormone therapy users compared with their counterparts. The association with gout was also significantly stronger in men than in women. These results highlight a possible role of sex hormones in the regulation of ABCG2 urate transporter and its potential implications for the prevention, diagnosis, and treatment of hyperuricemia and gout.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Predisposição Genética para Doença , Genética Populacional , Estudo de Associação Genômica Ampla , Gota/genética , Proteínas de Neoplasias/genética , Ácido Úrico/sangue , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Adulto , Afro-Americanos/genética , Distribuição por Idade , Comorbidade , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Gota/sangue , Gota/etnologia , Terapia de Reposição Hormonal/estatística & dados numéricos , Humanos , Índios Norte-Americanos/genética , Masculino , Americanos Mexicanos/genética , Pessoa de Meia-Idade , Polimorfismo Genético , Pós-Menopausa , Distribuição por Sexo , Estados Unidos
17.
Stat Appl Genet Mol Biol ; 12(2): 241-61, 2013 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-23502345

RESUMO

Knowledge of genes influencing longitudinal patterns may offer information about predicting disease progression. We developed a systematic procedure for testing association between SNP genotypes and longitudinal phenotypes. We evaluated false positive rates and statistical power to localize genes for disease progression. We used genome-wide SNP data from the Framingham Heart Study. With longitudinal data from two real studies unrelated to Framingham, we estimated three trajectory curves from each study. We performed simulations by randomly selecting 500 individuals. In each simulation replicate, we assigned each individual to one of the three trajectory groups based on the underlying hypothesis (null or alternative), and generated corresponding longitudinal data. Individual Bayesian posterior probabilities (BPPs) for belonging to a specific trajectory curve were estimated. These BPPs were treated as a quantitative trait and tested (using the Wald test) for genome-wide association. Empirical false positive rates and power were calculated. Our method maintained the expected false positive rate for all simulation models. Also, our method achieved high empirical power for most simulations. Our work presents a method for disease progression gene mapping. This method is potentially clinically significant as it may allow doctors to predict disease progression based on genotype and determine treatment accordingly.


Assuntos
Estudo de Associação Genômica Ampla , Genótipo , Modelos Genéticos , Modelos Estatísticos , Fenótipo , Algoritmos , Animais , Mapeamento Cromossômico/métodos , Simulação por Computador , Humanos , Masculino , Camundongos , Penetrância , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas
18.
PLoS One ; 8(2): e55258, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23424626

RESUMO

Age at menarche (AM) and age at natural menopause (ANM) define the boundaries of the reproductive lifespan in women. Their timing is associated with various diseases, including cancer and cardiovascular disease. Genome-wide association studies have identified several genetic variants associated with either AM or ANM in populations of largely European or Asian descent women. The extent to which these associations generalize to diverse populations remains unknown. Therefore, we sought to replicate previously reported AM and ANM findings and to identify novel AM and ANM variants using the Metabochip (n = 161,098 SNPs) in 4,159 and 1,860 African American women, respectively, in the Women's Health Initiative (WHI) and Atherosclerosis Risk in Communities (ARIC) studies, as part of the Population Architecture using Genomics and Epidemiology (PAGE) Study. We replicated or generalized one previously identified variant for AM, rs1361108/CENPW, and two variants for ANM, rs897798/BRSK1 and rs769450/APOE, to our African American cohort. Overall, generalization of the majority of previously-identified variants for AM and ANM, including LIN28B and MCM8, was not observed in this African American sample. We identified three novel loci associated with ANM that reached significance after multiple testing correction (LDLR rs189596789, p = 5×10⁻°8; KCNQ1 rs79972789, p = 1.9×10⁻°7; COL4A3BP rs181686584, p = 2.9×10⁻°7). Our most significant AM association was upstream of RSF1, a gene implicated in ovarian and breast cancers (rs11604207, p = 1.6×10⁻°6). While most associations were identified in either AM or ANM, we did identify genes suggestively associated with both: PHACTR1 and ARHGAP42. The lack of generalization coupled with the potentially novel associations identified here emphasize the need for additional genetic discovery efforts for AM and ANM in diverse populations.


Assuntos
Afro-Americanos/genética , Afro-Americanos/estatística & dados numéricos , Estudos Epidemiológicos , Variação Genética , Genômica , Reprodução/genética , Adolescente , Feminino , Humanos , Menarca/etnologia , Menarca/genética , Menarca/fisiologia , Menopausa/etnologia , Menopausa/genética , Menopausa/fisiologia , Pessoa de Meia-Idade
19.
PLoS Genet ; 9(1): e1003087, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23382687

RESUMO

Using a phenome-wide association study (PheWAS) approach, we comprehensively tested genetic variants for association with phenotypes available for 70,061 study participants in the Population Architecture using Genomics and Epidemiology (PAGE) network. Our aim was to better characterize the genetic architecture of complex traits and identify novel pleiotropic relationships. This PheWAS drew on five population-based studies representing four major racial/ethnic groups (European Americans (EA), African Americans (AA), Hispanics/Mexican-Americans, and Asian/Pacific Islanders) in PAGE, each site with measurements for multiple traits, associated laboratory measures, and intermediate biomarkers. A total of 83 single nucleotide polymorphisms (SNPs) identified by genome-wide association studies (GWAS) were genotyped across two or more PAGE study sites. Comprehensive tests of association, stratified by race/ethnicity, were performed, encompassing 4,706 phenotypes mapped to 105 phenotype-classes, and association results were compared across study sites. A total of 111 PheWAS results had significant associations for two or more PAGE study sites with consistent direction of effect with a significance threshold of p<0.01 for the same racial/ethnic group, SNP, and phenotype-class. Among results identified for SNPs previously associated with phenotypes such as lipid traits, type 2 diabetes, and body mass index, 52 replicated previously published genotype-phenotype associations, 26 represented phenotypes closely related to previously known genotype-phenotype associations, and 33 represented potentially novel genotype-phenotype associations with pleiotropic effects. The majority of the potentially novel results were for single PheWAS phenotype-classes, for example, for CDKN2A/B rs1333049 (previously associated with type 2 diabetes in EA) a PheWAS association was identified for hemoglobin levels in AA. Of note, however, GALNT2 rs2144300 (previously associated with high-density lipoprotein cholesterol levels in EA) had multiple potentially novel PheWAS associations, with hypertension related phenotypes in AA and with serum calcium levels and coronary artery disease phenotypes in EA. PheWAS identifies associations for hypothesis generation and exploration of the genetic architecture of complex traits.


Assuntos
Estudos de Associação Genética , Pleiotropia Genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Cálcio/sangue , Doença da Artéria Coronariana/genética , Inibidor p16 de Quinase Dependente de Ciclina/genética , Grupos Étnicos/genética , Redes Reguladoras de Genes , Genômica , Hemoglobinas/genética , Humanos , Hipertensão/genética , N-Acetilgalactosaminiltransferases , Fenótipo , Polimorfismo de Nucleotídeo Único/genética
20.
PLoS Genet ; 9(1): e1003171, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23341774

RESUMO

Genetic variants in intron 1 of the fat mass- and obesity-associated (FTO) gene have been consistently associated with body mass index (BMI) in Europeans. However, follow-up studies in African Americans (AA) have shown no support for some of the most consistently BMI-associated FTO index single nucleotide polymorphisms (SNPs). This is most likely explained by different race-specific linkage disequilibrium (LD) patterns and lower correlation overall in AA, which provides the opportunity to fine-map this region and narrow in on the functional variant. To comprehensively explore the 16q12.2/FTO locus and to search for second independent signals in the broader region, we fine-mapped a 646-kb region, encompassing the large FTO gene and the flanking gene RPGRIP1L by investigating a total of 3,756 variants (1,529 genotyped and 2,227 imputed variants) in 20,488 AAs across five studies. We observed associations between BMI and variants in the known FTO intron 1 locus: the SNP with the most significant p-value, rs56137030 (8.3 × 10(-6)) had not been highlighted in previous studies. While rs56137030was correlated at r(2)>0.5 with 103 SNPs in Europeans (including the GWAS index SNPs), this number was reduced to 28 SNPs in AA. Among rs56137030 and the 28 correlated SNPs, six were located within candidate intronic regulatory elements, including rs1421085, for which we predicted allele-specific binding affinity for the transcription factor CUX1, which has recently been implicated in the regulation of FTO. We did not find strong evidence for a second independent signal in the broader region. In summary, this large fine-mapping study in AA has substantially reduced the number of common alleles that are likely to be functional candidates of the known FTO locus. Importantly our study demonstrated that comprehensive fine-mapping in AA provides a powerful approach to narrow in on the functional candidate(s) underlying the initial GWAS findings in European populations.


Assuntos
Afro-Americanos/genética , Índice de Massa Corporal , Obesidade/genética , Proteínas/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Dioxigenase FTO Dependente de alfa-Cetoglutarato , Mapeamento Cromossômico , Grupos de Populações Continentais/genética , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Desequilíbrio de Ligação , Masculino , Metagenômica , Pessoa de Meia-Idade
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