Publications by authors named "Maggie C Y Ng"

122 Publications

Multiethnic Genome-Wide Association Study of Subclinical Atherosclerosis in Individuals With Type 2 Diabetes.

Circ Genom Precis Med 2021 Aug 9;14(4):e003258. Epub 2021 Jul 9.

Department of Epidemiology (N.F., G.H.), University of North Carolina, Chapel Hill.

Background: Coronary artery calcification (CAC) and carotid artery intima-media thickness (cIMT) are measures of subclinical atherosclerosis in asymptomatic individuals and strong risk factors for cardiovascular disease. Type 2 diabetes (T2D) is an independent cardiovascular disease risk factor that accelerates atherosclerosis.

Methods: We performed meta-analyses of genome-wide association studies in up to 2500 T2D individuals of European ancestry (EA) and 1590 T2D individuals of African ancestry with or without exclusion of prevalent cardiovascular disease, for CAC measured by cardiac computed tomography, and 3608 individuals of EA and 838 individuals of African ancestry with T2D for cIMT measured by ultrasonography within the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) Consortium.

Results: We replicated 2 loci (rs9369640 and rs9349379 near and rs10757278 near ) for CAC and one locus for cIMT (rs7412 and rs445925 near ) that were previously reported in the general EA populations. We identified one novel CAC locus (rs8000449 near at 13q13.3) at =2.0×10 in EA. No additional loci were identified with the meta-analyses of EA and African ancestry. The expression quantitative trait loci analysis with nearby expressed genes derived from arterial wall and metabolic tissues from the Genotype-Tissue Expression project pinpoints , encoding a matricellular protein involved in bone formation and bone matrix organization, as the potential candidate gene at this locus. In addition, we found significant associations (<3.1×10) for 3 previously reported coronary artery disease loci for these subclinical atherosclerotic phenotypes (rs2891168 near and rs11170820 near for CAC, and rs7412 near for cIMT).

Conclusions: Our results provide potential biological mechanisms that could link CAC and cIMT to increased cardiovascular disease risk in individuals with T2D.
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http://dx.doi.org/10.1161/CIRCGEN.120.003258DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8435075PMC
August 2021

Gene Set Enrichment Analyses Identify Pathways Involved in Genetic Risk for Diabetic Retinopathy.

Am J Ophthalmol 2021 Jun 21. Epub 2021 Jun 21.

Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA; Broad Institute of Harvard and MIT, Cambridge, MA.

Purpose: To identify functionally related genes associated with diabetic retinopathy (DR) risk using gene set enrichment analyses (GSEA) applied to genome-wide association study (GWAS) meta-analyses.

Methods: We analyzed DR GWAS meta-analyses performed on 3,246 Europeans and 2,611 African Americans with type 2 diabetes. Gene sets relevant to five key DR pathophysiology processes were investigated: tissue injury, vascular events, metabolic events and glial dysregulation, neuronal dysfunction, and inflammation. Keywords relevant to these processes were queried in four pathway and ontology databases. Two GSEA methods, Meta-Analysis Gene set Enrichment of variaNT Associations (MAGENTA) and Multi-marker Analysis of GenoMic Annotation (MAGMA) were used. Gene sets were defined to be enriched for gene associations with DR if the P value corrected for multiple testing (Pcorr) was <.05.

Results: Five gene sets were significantly enriched for multiple modest genetic associations with DR in one method (MAGENTA or MAGMA) and also at least nominally significant (uncorrected P <.05) in the other method. These pathways were regulation of the lipid catabolic process (2-fold enrichment, Pcorr=.014); nitric oxide biosynthesis (1.92-fold enrichment, Pcorr=.022); lipid digestion, mobilization and transport (1.6-fold enrichment, P=.032); apoptosis (1.53-fold enrichment, P=.041); and retinal ganglion cell degeneration (2-fold enrichment, Pcorr=.049). The interferon gamma (IFNG) gene, previously implicated in DR by protein-protein interactions in our GWAS, was among the top ranked genes in the nitric oxide pathway (best variant P=.0001).

Conclusions: These GSEA indicate that variants in genes involved in oxidative stress, lipid transport and catabolism and cell degeneration are enriched for genes associated with DR risk.
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http://dx.doi.org/10.1016/j.ajo.2021.06.014DOI Listing
June 2021

Determinants of penetrance and variable expressivity in monogenic metabolic conditions across 77,184 exomes.

Nat Commun 2021 06 9;12(1):3505. Epub 2021 Jun 9.

Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.

Hundreds of thousands of genetic variants have been reported to cause severe monogenic diseases, but the probability that a variant carrier develops the disease (termed penetrance) is unknown for virtually all of them. Additionally, the clinical utility of common polygenetic variation remains uncertain. Using exome sequencing from 77,184 adult individuals (38,618 multi-ancestral individuals from a type 2 diabetes case-control study and 38,566 participants from the UK Biobank, for whom genotype array data were also available), we apply clinical standard-of-care gene variant curation for eight monogenic metabolic conditions. Rare variants causing monogenic diabetes and dyslipidemias display effect sizes significantly larger than the top 1% of the corresponding polygenic scores. Nevertheless, penetrance estimates for monogenic variant carriers average 60% or lower for most conditions. We assess epidemiologic and genetic factors contributing to risk prediction in monogenic variant carriers, demonstrating that inclusion of polygenic variation significantly improves biomarker estimation for two monogenic dyslipidemias.
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http://dx.doi.org/10.1038/s41467-021-23556-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8190084PMC
June 2021

Genome-wide association study of vitamin D concentrations and bone mineral density in the African American-Diabetes Heart Study.

PLoS One 2021 20;16(5):e0251423. Epub 2021 May 20.

Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC, United States of America.

Relative to European Americans, African Americans have lower 25-hydroxyvitamin D (25OHD) and vitamin D binding protein (VDBP) concentrations, higher 1,25-dihydroxyvitamin D (1,25(OH)2D3) concentrations and bone mineral density (BMD), and paradoxically reduced burdens of calcified atherosclerotic plaque (subclinical atherosclerosis). To identify genetic factors contributing to vitamin D and BMD measures, association analysis of >14M variants was conducted in a maximum of 697 African American-Diabetes Heart Study participants with type 2 diabetes (T2D). The most significant association signals were detected for VDBP on chromosome 4; variants rs7041 (β = 0.44, SE = 0.019, P = 9.4x10-86) and rs4588 (β = 0.17, SE = 0.021, P = 3.5x10-08) in the group-specific component (vitamin D binding protein) gene (GC). These variants were found to be independently associated. In addition, rs7041 was also associated with bioavailable vitamin D (BAVD; β = 0.16, SE = 0.02, P = 3.3x10-19). Six rare variants were significantly associated with 25OHD, including a non-synonymous variant in HSPG2 (rs116788687; β = -1.07, SE = 0.17, P = 2.2x10-10) and an intronic variant in TNIK (rs143555701; β = -1.01, SE = 0.18, P = 9.0x10-10), both biologically related to bone development. Variants associated with 25OHD failed to replicate in African Americans from the Insulin Resistance Atherosclerosis Family Study (IRASFS). Evaluation of vitamin D metabolism and bone mineral density phenotypes in an African American population enriched for T2D could provide insight into ethnic specific differences in vitamin D metabolism and bone mineral density.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251423PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8136717PMC
May 2021

Discovery and fine-mapping of height loci via high-density imputation of GWASs in individuals of African ancestry.

Am J Hum Genet 2021 04 12;108(4):564-582. Epub 2021 Mar 12.

The Charles R. Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.

Although many loci have been associated with height in European ancestry populations, very few have been identified in African ancestry individuals. Furthermore, many of the known loci have yet to be generalized to and fine-mapped within a large-scale African ancestry sample. We performed sex-combined and sex-stratified meta-analyses in up to 52,764 individuals with height and genome-wide genotyping data from the African Ancestry Anthropometry Genetics Consortium (AAAGC). We additionally combined our African ancestry meta-analysis results with published European genome-wide association study (GWAS) data. In the African ancestry analyses, we identified three novel loci (SLC4A3, NCOA2, ECD/FAM149B1) in sex-combined results and two loci (CRB1, KLF6) in women only. In the African plus European sex-combined GWAS, we identified an additional three novel loci (RCCD1, G6PC3, CEP95) which were equally driven by AAAGC and European results. Among 39 genome-wide significant signals at known loci, conditioning index SNPs from European studies identified 20 secondary signals. Two of the 20 new secondary signals and none of the 8 novel loci had minor allele frequencies (MAF) < 5%. Of 802 known European height signals, 643 displayed directionally consistent associations with height, of which 205 were nominally significant (p < 0.05) in the African ancestry sex-combined sample. Furthermore, 148 of 241 loci contained ≤20 variants in the credible sets that jointly account for 99% of the posterior probability of driving the associations. In summary, trans-ethnic meta-analyses revealed novel signals and further improved fine-mapping of putative causal variants in loci shared between African and European ancestry populations.
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http://dx.doi.org/10.1016/j.ajhg.2021.02.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8059339PMC
April 2021

Development of genome-wide polygenic risk scores for lipid traits and clinical applications for dyslipidemia, subclinical atherosclerosis, and diabetes cardiovascular complications among East Asians.

Genome Med 2021 02 19;13(1):29. Epub 2021 Feb 19.

Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.

Background: The clinical utility of personal genomic information in identifying individuals at increased risks for dyslipidemia and cardiovascular diseases remains unclear.

Methods: We used data from Biobank Japan (n = 70,657-128,305) and developed novel East Asian-specific genome-wide polygenic risk scores (PRSs) for four lipid traits. We validated (n = 4271) and subsequently tested associations of these scores with 3-year lipid changes in adolescents (n = 620), carotid intima-media thickness (cIMT) in adult women (n = 781), dyslipidemia (n = 7723), and coronary heart disease (CHD) (n = 2374 cases and 6246 controls) in type 2 diabetes (T2D) patients.

Results: Our PRSs aggregating 84-549 genetic variants (0.251 < correlation coefficients (r) < 0.272) had comparably stronger association with lipid variations than the typical PRSs derived based on the genome-wide significant variants (0.089 < r < 0.240). Our PRSs were robustly associated with their corresponding lipid levels (7.5 × 10 < P < 1.3 × 10) and 3-year lipid changes (1.4 × 10 < P < 0.0130) which started to emerge in childhood and adolescence. With the adjustments for principal components (PCs), sex, age, and body mass index, there was an elevation of 5.3% in TC (β ± SE = 0.052 ± 0.002), 11.7% in TG (β ± SE = 0.111 ± 0.006), 5.8% in HDL-C (β ± SE = 0.057 ± 0.003), and 8.4% in LDL-C (β ± SE = 0.081 ± 0.004) per one standard deviation increase in the corresponding PRS. However, their predictive power was attenuated in T2D patients (0.183 < r < 0.231). When we included each PRS (for TC, TG, and LDL-C) in addition to the clinical factors and PCs, the AUC for dyslipidemia was significantly increased by 0.032-0.057 in the general population (7.5 × 10 < P < 0.0400) and 0.029-0.069 in T2D patients (2.1 × 10 < P < 0.0428). Moreover, the quintile of TC-related PRS was moderately associated with cIMT in adult women (β ± SE = 0.011 ± 0.005, P = 0.0182). Independent of conventional risk factors, the quintile of PRSs for TC [OR (95% CI) = 1.07 (1.03-1.11)], TG [OR (95% CI) = 1.05 (1.01-1.09)], and LDL-C [OR (95% CI) = 1.05 (1.01-1.09)] were significantly associated with increased risk of CHD in T2D patients (4.8 × 10 < P < 0.0197). Further adjustment for baseline lipid drug use notably attenuated the CHD association.

Conclusions: The PRSs derived and validated here highlight the potential for early genomic screening and personalized risk assessment for cardiovascular disease.
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http://dx.doi.org/10.1186/s13073-021-00831-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7893928PMC
February 2021

Identification of type 2 diabetes loci in 433,540 East Asian individuals.

Nature 2020 06 6;582(7811):240-245. Epub 2020 May 6.

Vanderbilt Genetics Institute, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.

Meta-analyses of genome-wide association studies (GWAS) have identified more than 240 loci that are associated with type 2 diabetes (T2D); however, most of these loci have been identified in analyses of individuals with European ancestry. Here, to examine T2D risk in East Asian individuals, we carried out a meta-analysis of GWAS data from 77,418 individuals with T2D and 356,122 healthy control individuals. In the main analysis, we identified 301 distinct association signals at 183 loci, and across T2D association models with and without consideration of body mass index and sex, we identified 61 loci that are newly implicated in predisposition to T2D. Common variants associated with T2D in both East Asian and European populations exhibited strongly correlated effect sizes. Previously undescribed associations include signals in or near GDAP1, PTF1A, SIX3, ALDH2, a microRNA cluster, and genes that affect the differentiation of muscle and adipose cells. At another locus, expression quantitative trait loci at two overlapping T2D signals affect two genes-NKX6-3 and ANK1-in different tissues. Association studies in diverse populations identify additional loci and elucidate disease-associated genes, biology, and pathways.
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http://dx.doi.org/10.1038/s41586-020-2263-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7292783PMC
June 2020

Association of Genetic Variants With Primary Open-Angle Glaucoma Among Individuals With African Ancestry.

JAMA 2019 11;322(17):1682-1691

Clayton Eye Care Center Management Inc, Marrow, Georgia.

Importance: Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders.

Objectives: To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma.

Design, Settings, And Participants: A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma.

Exposures: Genetic variants associated with primary open-angle glaucoma.

Main Outcomes And Measures: Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data.

Results: A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-β A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry.

Conclusions And Relevance: In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies.
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http://dx.doi.org/10.1001/jama.2019.16161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6865235PMC
November 2019

Exome sequencing of 20,791 cases of type 2 diabetes and 24,440 controls.

Nature 2019 06 22;570(7759):71-76. Epub 2019 May 22.

Division of Genome Research, Center for Genome Science, National Institute of Health, Chungcheongbuk-do, South Korea.

Protein-coding genetic variants that strongly affect disease risk can yield relevant clues to disease pathogenesis. Here we report exome-sequencing analyses of 20,791 individuals with type 2 diabetes (T2D) and 24,440 non-diabetic control participants from 5 ancestries. We identify gene-level associations of rare variants (with minor allele frequencies of less than 0.5%) in 4 genes at exome-wide significance, including a series of more than 30 SLC30A8 alleles that conveys protection against T2D, and in 12 gene sets, including those corresponding to T2D drug targets (P = 6.1 × 10) and candidate genes from knockout mice (P = 5.2 × 10). Within our study, the strongest T2D gene-level signals for rare variants explain at most 25% of the heritability of the strongest common single-variant signals, and the gene-level effect sizes of the rare variants that we observed in established T2D drug targets will require 75,000-185,000 sequenced cases to achieve exome-wide significance. We propose a method to interpret these modest rare-variant associations and to incorporate these associations into future target or gene prioritization efforts.
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http://dx.doi.org/10.1038/s41586-019-1231-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699738PMC
June 2019

Genome-wide association study identifies novel loci for type 2 diabetes-attributed end-stage kidney disease in African Americans.

Hum Genomics 2019 05 15;13(1):21. Epub 2019 May 15.

Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, NC, USA.

Background: End-stage kidney disease (ESKD) is a significant public health concern disproportionately affecting African Americans (AAs). Type 2 diabetes (T2D) is the leading cause of ESKD in the USA, and efforts to uncover genetic susceptibility to diabetic kidney disease (DKD) have had limited success. A prior genome-wide association study (GWAS) in AAs with T2D-ESKD was expanded with additional AA cases and controls and genotypes imputed to the higher density 1000 Genomes reference panel. The discovery analysis included 3432 T2D-ESKD cases and 6977 non-diabetic non-nephropathy controls (N = 10,409), followed by a discrimination analysis in 2756 T2D non-nephropathy controls to exclude T2D-associated variants.

Results: Six independent variants located in or near RND3/RBM43, SLITRK3, ENPP7, GNG7, and APOL1 achieved genome-wide significant association (P < 5 × 10) with T2D-ESKD. Following extension analyses in 1910 non-diabetic ESKD cases and 908 non-diabetic non-nephropathy controls, a meta-analysis of 5342 AA all-cause ESKD cases and 6977 AA non-diabetic non-nephropathy controls revealed an additional novel all-cause ESKD locus at EFNB2 (rs77113398; P = 9.84 × 10; OR = 1.94). Exclusion of APOL1 renal-risk genotype carriers identified two additional genome-wide significant T2D-ESKD-associated loci at GRAMD3 and MGAT4C. A second variant at GNG7 (rs373971520; P = 2.17 × 10, OR = 1.46) remained associated with all-cause ESKD in the APOL1-negative analysis.

Conclusions: Findings provide further evidence for genetic factors associated with advanced kidney disease in AAs with T2D.
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http://dx.doi.org/10.1186/s40246-019-0205-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6521376PMC
May 2019

Protein-coding variants implicate novel genes related to lipid homeostasis contributing to body-fat distribution.

Nat Genet 2019 03 18;51(3):452-469. Epub 2019 Feb 18.

Department of Biostatistics and Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, USA.

Body-fat distribution is a risk factor for adverse cardiovascular health consequences. We analyzed the association of body-fat distribution, assessed by waist-to-hip ratio adjusted for body mass index, with 228,985 predicted coding and splice site variants available on exome arrays in up to 344,369 individuals from five major ancestries (discovery) and 132,177 European-ancestry individuals (validation). We identified 15 common (minor allele frequency, MAF ≥5%) and nine low-frequency or rare (MAF <5%) coding novel variants. Pathway/gene set enrichment analyses identified lipid particle, adiponectin, abnormal white adipose tissue physiology and bone development and morphology as important contributors to fat distribution, while cross-trait associations highlight cardiometabolic traits. In functional follow-up analyses, specifically in Drosophila RNAi-knockdowns, we observed a significant increase in the total body triglyceride levels for two genes (DNAH10 and PLXND1). We implicate novel genes in fat distribution, stressing the importance of interrogating low-frequency and protein-coding variants.
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http://dx.doi.org/10.1038/s41588-018-0334-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6560635PMC
March 2019

Multiethnic Genome-Wide Association Study of Diabetic Retinopathy Using Liability Threshold Modeling of Duration of Diabetes and Glycemic Control.

Diabetes 2019 02 28;68(2):441-456. Epub 2018 Nov 28.

Institute for Translational Genomics and Population Sciences, LA BioMed and Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA.

To identify genetic variants associated with diabetic retinopathy (DR), we performed a large multiethnic genome-wide association study. Discovery included eight European cohorts ( = 3,246) and seven African American cohorts ( = 2,611). We meta-analyzed across cohorts using inverse-variance weighting, with and without liability threshold modeling of glycemic control and duration of diabetes. Variants with a value <1 × 10 were investigated in replication cohorts that included 18,545 European, 16,453 Asian, and 2,710 Hispanic subjects. After correction for multiple testing, the C allele of rs142293996 in an intron of nuclear VCP-like () was associated with DR in European discovery cohorts ( = 2.1 × 10), but did not reach genome-wide significance after meta-analysis with replication cohorts. We applied the Disease Association Protein-Protein Link Evaluator (DAPPLE) to our discovery results to test for evidence of risk being spread across underlying molecular pathways. One protein-protein interaction network built from genes in regions associated with proliferative DR was found to have significant connectivity ( = 0.0009) and corroborated with gene set enrichment analyses. These findings suggest that genetic variation in as well as variation within a protein-protein interaction network that includes genes implicated in inflammation, may influence risk for DR.
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http://dx.doi.org/10.2337/db18-0567DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6341299PMC
February 2019

Genetic Architecture of Primary Open-Angle Glaucoma in Individuals of African Descent: The African Descent and Glaucoma Evaluation Study III.

Ophthalmology 2019 01 21;126(1):38-48. Epub 2018 Oct 21.

Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, North Carolina; Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina; Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina.

Purpose: To find genetic contributions to glaucoma in African Americans.

Design: Cross-sectional, case-control study.

Participants: One thousand eight hundred seventy-five primary open-angle glaucoma (POAG) patients and 1709 controls, self-identified as being of African descent (AD), from the African Descent and Glaucoma Evaluation Study (ADAGES) III and Wake Forest School of Medicine.

Methods: MegaChip genotypes were imputed to Thousand Genomes data. Association of single nucleotide polymorphisms (SNPs) with POAG and advanced POAG was tested by linear mixed model correcting for relatedness and population stratification. Genetic risk scores were tested by receiver operator characteristic curves (ROC-AUCs).

Main Outcome Measures: Primary open-angle glaucoma defined by visual field loss without other nonocular conditions (n = 1875). Advanced POAG was defined by age-based mean deviation of visual field (n = 946).

Results: Eighteen million two hundred eighty-one thousand nine hundred twenty SNPs met imputation quality of r > 0.7 and minor allele frequency > 0.005. Association of a novel locus, EN04, was observed for advanced POAG (rs185815146 β, 0.36; standard error, 0.065; P < 3×10). For POAG, an AD signal was observed at the 9p21 European descent (ED) POAG signal (rs79721419; P < 6.5×10) independent of the previously observed 9p21 ED signal (rs2383204; P < 2.3×10) by conditional analyses. An association with POAG in FNDC3B (rs111698934; P < 3.9×10) was observed, not in linkage disequilibrium (LD) with the previously reported ED SNP. Additional previously identified loci associated with POAG in persons of AD were: 8q22, AFAP1, and TMC01. An AUC of 0.62 was observed with an unweighted genetic risk score comprising 11 SNPs in candidate genes. Two additional risk scores were studied by using a penalized matrix decomposition with cross-validation; risk scores of 50 and 400 SNPs were identified with ROC of AUC = 0.74 and AUC = 0.94, respectively.

Conclusions: A novel association with advanced POAG in the EN04 locus was identified putatively in persons of AD. In addition to this finding, this genome-wide association study in POAG patients of AD contributes to POAG genetics by identification of novel signals in prior loci (9p21), as well as advancing the fine mapping of regions because of shorter average LD (FNDC3B). Although not useful without confirmation and clinical trials, the use of genetic risk scores demonstrated that considerable AD-specific genetic information remains in these data.
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http://dx.doi.org/10.1016/j.ophtha.2018.10.031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6309605PMC
January 2019

Genome-wide association study of primary open-angle glaucoma in continental and admixed African populations.

Hum Genet 2018 Oct 13;137(10):847-862. Epub 2018 Oct 13.

Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.

Primary open angle glaucoma (POAG) is a complex disease with a major genetic contribution. Its prevalence varies greatly among ethnic groups, and is up to five times more frequent in black African populations compared to Europeans. So far, worldwide efforts to elucidate the genetic complexity of POAG in African populations has been limited. We conducted a genome-wide association study in 1113 POAG cases and 1826 controls from Tanzanian, South African and African American study samples. Apart from confirming evidence of association at TXNRD2 (rs16984299; OR 1.20; P = 0.003), we found that a genetic risk score combining the effects of the 15 previously reported POAG loci was significantly associated with POAG in our samples (OR 1.56; 95% CI 1.26-1.93; P = 4.79 × 10). By genome-wide association testing we identified a novel candidate locus, rs141186647, harboring EXOC4 (OR 0.48; P = 3.75 × 10), a gene transcribing a component of the exocyst complex involved in vesicle transport. The low frequency and high degree of genetic heterogeneity at this region hampered validation of this finding in predominantly West-African replication sets. Our results suggest that established genetic risk factors play a role in African POAG, however, they do not explain the higher disease load. The high heterogeneity within Africans remains a challenge to identify the genetic commonalities for POAG in this ethnicity, and demands studies of extremely large size.
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http://dx.doi.org/10.1007/s00439-018-1943-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6754628PMC
October 2018

Fine-mapping type 2 diabetes loci to single-variant resolution using high-density imputation and islet-specific epigenome maps.

Nat Genet 2018 11 8;50(11):1505-1513. Epub 2018 Oct 8.

Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore.

We expanded GWAS discovery for type 2 diabetes (T2D) by combining data from 898,130 European-descent individuals (9% cases), after imputation to high-density reference panels. With these data, we (i) extend the inventory of T2D-risk variants (243 loci, 135 newly implicated in T2D predisposition, comprising 403 distinct association signals); (ii) enrich discovery of lower-frequency risk alleles (80 index variants with minor allele frequency <5%, 14 with estimated allelic odds ratio >2); (iii) substantially improve fine-mapping of causal variants (at 51 signals, one variant accounted for >80% posterior probability of association (PPA)); (iv) extend fine-mapping through integration of tissue-specific epigenomic information (islet regulatory annotations extend the number of variants with PPA >80% to 73); (v) highlight validated therapeutic targets (18 genes with associations attributable to coding variants); and (vi) demonstrate enhanced potential for clinical translation (genome-wide chip heritability explains 18% of T2D risk; individuals in the extremes of a T2D polygenic risk score differ more than ninefold in prevalence).
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http://dx.doi.org/10.1038/s41588-018-0241-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6287706PMC
November 2018

An Exome-wide Association Study for Type 2 Diabetes-Attributed End-Stage Kidney Disease in African Americans.

Kidney Int Rep 2018 Jul 14;3(4):867-878. Epub 2018 Mar 14.

Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.

Introduction: Compared with European Americans, African Americans (AAs) are at higher risk for developing end-stage kidney disease (ESKD). Genome-wide association studies (GWAS) have identified >70 genetic variants associated with kidney function and chronic kidney disease (CKD) in patients with and without diabetes. However, these variants explain a small proportion of disease liability. This study examined the contribution of coding genetic variants for risk of type 2 diabetes (T2D)-attributed ESKD and advanced CKD in AAs.

Methods: Exome sequencing was performed in 456 AA T2D-ESKD cases, and 936 AA nondiabetic, non-nephropathy control individuals at the discovery stage. A mixed logistic regression model was used for association analysis. Nominal associations ( < 0.05) were replicated in an additional 2020 T2D-ESKD cases and 1121 nondiabetic, non-nephropathy control individuals. A meta-analysis combining 4533 discovery and replication samples was performed. Putative T2D-ESKD associations were tested in additional 1910 nondiabetic ESKD and 219 T2D-ESKD cases, as well as 912 AA nondiabetic non-nephropathy control individuals.

Results: A total of 11 suggestive T2D-ESKD associations ( < 1 x 10) from 8 loci () were apparent in the meta-analysis. Exclusion of  renal-risk genotype carriers identified 3 additional suggestive loci (). Rs41302867 in displayed consistent association with T2D-ESKD and nondiabetic ESKD (odds ratio: 0.47;  = 1.2 x 10 in 4605 all-cause ESKD and 2969 nondiabetic non-nephropathy control individuals).

Conclusion: Our findings suggest that coding genetic variants are implicated in predisposition to T2D-ESKD in AAs.
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http://dx.doi.org/10.1016/j.ekir.2018.03.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6035163PMC
July 2018

Genome-wide association studies suggest that APOL1-environment interactions more likely trigger kidney disease in African Americans with nondiabetic nephropathy than strong APOL1-second gene interactions.

Kidney Int 2018 09 7;94(3):599-607. Epub 2018 Jun 7.

Center for Public Health Genomics; Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Center for Diabetes Research; Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Department of Internal Medicine, Section on Nephrology; Wake Forest School of Medicine, Winston-Salem, North Carolina, USA. Electronic address:

African Americans carrying two apolipoprotein L1 gene (APOL1) renal risk variants have a high risk for nephropathy. However, only a minority develops end-stage renal disease (ESRD). Hence, modifying factors likely contribute to initiation of kidney disease such as endogenous (HIV infection) or exogenous (interferon treatment) environmental modifiers. In this report, genome-wide association studies and a meta-analysis were performed to identify novel loci for nondiabetic ESRD in African Americans and to detect genetic modifiers in APOL1-associated nephropathy. Two African American cohorts were analyzed, 1749 nondiabetic ESRD cases and 1136 controls from Wake Forest and 901 lupus nephritis (LN)-ESRD cases and 520 controls with systemic lupus erythematosus but lacking nephropathy from the LN-ESRD Consortium. Association analyses adjusting for APOL1 G1/G2 renal-risk variants were completed and stratified by APOL1 risk genotype status. Individual genome-wide association studies and meta-analysis results of all 2650 ESRD cases and 1656 controls did not detect significant genome-wide associations with ESRD beyond APOL1. Similarly, no single nucleotide polymorphism showed significant genome-wide evidence of an interaction with APOL1 risk variants. Thus, although variants with small individual effects cannot be ruled out and are likely to exist, our results suggest that APOL1-environment interactions may be of greater clinical importance in triggering nephropathy in African Americans than APOL1 interactions with other single nucleotide polymorphisms.
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http://dx.doi.org/10.1016/j.kint.2018.03.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6109415PMC
September 2018

Genome-wide interaction with the insulin secretion locus MTNR1B reveals CMIP as a novel type 2 diabetes susceptibility gene in African Americans.

Genet Epidemiol 2018 Sep 24;42(6):559-570. Epub 2018 Apr 24.

Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.

Although type 2 diabetes (T2D) results from metabolic defects in insulin secretion and insulin sensitivity, most of the genetic risk loci identified to date relates to insulin secretion. We reported that T2D loci influencing insulin sensitivity may be identified through interactions with insulin secretion loci, thereby leading to T2D. Here, we hypothesize that joint testing of variant main effects and interaction effects with an insulin secretion locus increases power to identify genetic interactions leading to T2D. We tested this hypothesis with an intronic MTNR1B SNP, rs10830963, which is associated with acute insulin response to glucose, a dynamic measure of insulin secretion. rs10830963 was tested for interaction and joint (main + interaction) effects with genome-wide data in African Americans (2,452 cases and 3,772 controls) from five cohorts. Genome-wide genotype data (Affymetrix Human Genome 6.0 array) was imputed to a 1000 Genomes Project reference panel. T2D risk was modeled using logistic regression with rs10830963 dosage, age, sex, and principal component as predictors. Joint effects were captured using the Kraft two degrees of freedom test. Genome-wide significant (P < 5 × 10 ) interaction with MTNR1B and joint effects were detected for CMIP intronic SNP rs17197883 (P = 1.43 × 10 ; P = 4.70 × 10 ). CMIP variants have been nominally associated with T2D, fasting glucose, and adiponectin in individuals of East Asian ancestry, with high-density lipoprotein, and with waist-to-hip ratio adjusted for body mass index in Europeans. These data support the hypothesis that additional genetic factors contributing to T2D risk, including insulin sensitivity loci, can be identified through interactions with insulin secretion loci.
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http://dx.doi.org/10.1002/gepi.22126DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6160319PMC
September 2018

Publisher Correction: Protein-altering variants associated with body mass index implicate pathways that control energy intake and expenditure in obesity.

Nat Genet 2018 05;50(5):766-767

Department of Genetic Epidemiology, University of Regensburg, Regensburg, Germany.

In the version of this article originally published, one of the two authors with the name Wei Zhao was omitted from the author list and the affiliations for both authors were assigned to the single Wei Zhao in the author list. In addition, the ORCID for Wei Zhao (Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA) was incorrectly assigned to author Wei Zhou. The errors have been corrected in the HTML and PDF versions of the article.
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http://dx.doi.org/10.1038/s41588-018-0082-3DOI Listing
May 2018

Metabolomics Identifies Distinctive Metabolite Signatures for Measures of Glucose Homeostasis: The Insulin Resistance Atherosclerosis Family Study (IRAS-FS).

J Clin Endocrinol Metab 2018 05;103(5):1877-1888

Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina.

Context: Metabolomics provides a biochemical fingerprint that, when coupled with clinical phenotypes, can provide insight into physiological processes.

Objective: Survey metabolites associated with dynamic and basal measures of glucose homeostasis.

Design: Analysis of 733 plasma metabolites from the Insulin Resistance Atherosclerosis Family Study.

Setting: Community based.

Participants: One thousand one hundred eleven Mexican Americans.

Main Outcome: Dynamic measures were obtained from the frequently sampled intravenous glucose tolerance test and included insulin sensitivity and acute insulin response to glucose. Basal measures included homeostatic model assessment of insulin resistance and β-cell function.

Results: Insulin sensitivity was associated with 99 metabolites (P < 6.82 × 10-5) explaining 28% of the variance (R2adj) beyond 28% by body mass index. Beyond branched chain amino acids (BCAAs; P = 1.85 × 10-18 to 1.70 × 10-5, R2adj = 8.1%) and phospholipids (P = 3.51 × 10-17 to 3.00 × 10-5, R2adj = 14%), novel signatures of long-chain fatty acids (LCFAs; P = 4.49 × 10-23 to 4.14 × 10-7, R2adj = 11%) were observed. Conditional analysis suggested that BCAA and LCFA signatures were independent. LCFAs were not associated with homeostatic model assessment of insulin resistance (P > 0.024). Acute insulin response to glucose was associated with six metabolites; glucose had the strongest association (P = 5.68 × 10-16). Homeostatic model assessment of β-cell function had significant signatures from the urea cycle (P = 9.64 × 10-14 to 7.27 × 10-6, R2adj = 11%). Novel associations of polyunsaturated fatty acids (P = 2.58 × 10-13 to 6.70 × 10-5, R2adj = 10%) and LCFAs (P = 9.06 × 10-15 to 3.93 × 10-7, R2adj = 10%) were observed with glucose effectiveness. Assessment of the hyperbolic relationship between insulin sensitivity and secretion through the disposition index revealed a distinctive signature of polyunsaturated fatty acids (P = 1.55 × 10-12 to 5.81 × 10-6; R2adj = 3.8%) beyond that of its component measures.

Conclusions: Metabolomics reveals distinct signatures that differentiate dynamic and basal measures of glucose homeostasis and further identifies new metabolite classes associated with dynamic measures, providing expanded insight into the metabolic basis of insulin resistance.
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http://dx.doi.org/10.1210/jc.2017-02203DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6456957PMC
May 2018

Genetic variants in sex hormone pathways and the risk of type 2 diabetes among African American, Hispanic American, and European American postmenopausal women in the US.

J Diabetes 2018 Jun 6;10(6):524-533. Epub 2018 Apr 6.

Department of Epidemiology, Brown University, Providence, Rhode Island, USA.

Background: Sex hormones are implicated in the development of diabetes. However, whether genetic variations in sex hormone pathways (SHPs) contribute to the risk of type 2 diabetes mellitus (T2DM) remains to be determined. This study investigated associations between genetic variations in all candidate genes in SHPs and T2DM risk among a cohort of women participating in the Women's Health Initiative (WHI).

Methods: Single nucleotide polymorphisms (SNPs) located within 30 kb upstream and downstream of SHP genes were comprehensively examined in 8180 African American, 3498 Hispanic American, and 3147 European American women in the WHI. In addition, whether significant SNPs would be replicated in independent populations was examined.

Results: After adjusting for age, region, and ancestry estimates and correcting for multiple testing, seven SNPs were significantly associated with the risk of T2DM among Hispanic American women were identified in the progesterone receptor (PGR) gene, with rs948516 showing the greatest significance (odds ratio 0.67; 95% confidence interval 0.57-0.78; P = 8.8 × 10 ; false discovery rate, Q = 7.8 × 10 ). These findings were not replicated in other ethnic groups in the WHI or in sex-combined analyses in replication studies.

Conclusion: Significant signals were identified implicating the PGR gene in T2DM development in Hispanic American women in the WHI, which are consistent with genome-wide association studies findings linking PGR to glucose homeostasis. Nevertheless, the PGR SNPs-T2DM association was not statistically significant in other ethnic populations. Further studies, especially sex-specific analyses, are needed to confirm the findings and clarify the role of SHPs in T2DM.
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http://dx.doi.org/10.1111/1753-0407.12648DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5980699PMC
June 2018

The African Descent and Glaucoma Evaluation Study (ADAGES) III: Contribution of Genotype to Glaucoma Phenotype in African Americans: Study Design and Baseline Data.

Ophthalmology 2019 01 1;126(1):156-170. Epub 2018 Feb 1.

Ruiz Department of Ophthalmology & Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, Texas.

Purpose: To describe the study protocol and baseline characteristics of the African Descent and Glaucoma Evaluation Study (ADAGES) III.

Design: Cross-sectional, case-control study.

Participants: Three thousand two hundred sixty-six glaucoma patients and control participants without glaucoma of African or European descent were recruited from 5 study centers in different regions of the United States.

Methods: Individuals of African descent (AD) and European descent (ED) with primary open-angle glaucoma (POAG) and control participants completed a detailed demographic and medical history interview. Standardized height, weight, and blood pressure measurements were obtained. Saliva and blood samples to provide serum, plasma, DNA, and RNA were collected for standardized processing. Visual fields, stereoscopic disc photographs, and details of the ophthalmic examination were obtained and transferred to the University of California, San Diego, Data Coordinating Center for standardized processing and quality review.

Main Outcome Measures: Participant gender, age, race, body mass index, blood pressure, history of smoking and alcohol use in POAG patients and control participants were described. Ophthalmic measures included intraocular pressure, visual field mean deviation, central corneal thickness, glaucoma medication use, or past glaucoma surgery. Ocular conditions, including diabetic retinopathy, age-related macular degeneration, and past cataract surgery, were recorded.

Results: The 3266 ADAGES III study participants in this report include 2146 AD POAG patients, 695 ED POAG patients, 198 AD control participants, and 227 ED control participants. The AD POAG patients and control participants were significantly younger (both, 67.4 years) than ED POAG patients and control participants (73.4 and 70.2 years, respectively). After adjusting for age, AD POAG patients had different phenotypic characteristics compared with ED POAG patients, including higher intraocular pressure, worse visual acuity and visual field mean deviation, and thinner corneas (all P < 0.001). Family history of glaucoma did not differ between AD and ED POAG patients.

Conclusions: With its large sample size, extensive specimen collection, and deep phenotyping of AD and ED glaucoma patients and control participants from different regions in the United States, the ADAGES III genomics study will address gaps in our knowledge of the genetics of POAG in this high-risk population.
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http://dx.doi.org/10.1016/j.ophtha.2017.11.031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6050158PMC
January 2019

Protein-altering variants associated with body mass index implicate pathways that control energy intake and expenditure in obesity.

Nat Genet 2018 01 22;50(1):26-41. Epub 2017 Dec 22.

Department of Genetic Epidemiology, University of Regensburg, Regensburg, Germany.

Genome-wide association studies (GWAS) have identified >250 loci for body mass index (BMI), implicating pathways related to neuronal biology. Most GWAS loci represent clusters of common, noncoding variants from which pinpointing causal genes remains challenging. Here we combined data from 718,734 individuals to discover rare and low-frequency (minor allele frequency (MAF) < 5%) coding variants associated with BMI. We identified 14 coding variants in 13 genes, of which 8 variants were in genes (ZBTB7B, ACHE, RAPGEF3, RAB21, ZFHX3, ENTPD6, ZFR2 and ZNF169) newly implicated in human obesity, 2 variants were in genes (MC4R and KSR2) previously observed to be mutated in extreme obesity and 2 variants were in GIPR. The effect sizes of rare variants are ~10 times larger than those of common variants, with the largest effect observed in carriers of an MC4R mutation introducing a stop codon (p.Tyr35Ter, MAF = 0.01%), who weighed ~7 kg more than non-carriers. Pathway analyses based on the variants associated with BMI confirm enrichment of neuronal genes and provide new evidence for adipocyte and energy expenditure biology, widening the potential of genetically supported therapeutic targets in obesity.
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http://dx.doi.org/10.1038/s41588-017-0011-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5945951PMC
January 2018

Sequence data and association statistics from 12,940 type 2 diabetes cases and controls.

Sci Data 2017 12 19;4:170179. Epub 2017 Dec 19.

Wellcome Trust Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, UK.

To investigate the genetic basis of type 2 diabetes (T2D) to high resolution, the GoT2D and T2D-GENES consortia catalogued variation from whole-genome sequencing of 2,657 European individuals and exome sequencing of 12,940 individuals of multiple ancestries. Over 27M SNPs, indels, and structural variants were identified, including 99% of low-frequency (minor allele frequency [MAF] 0.1-5%) non-coding variants in the whole-genome sequenced individuals and 99.7% of low-frequency coding variants in the whole-exome sequenced individuals. Each variant was tested for association with T2D in the sequenced individuals, and, to increase power, most were tested in larger numbers of individuals (>80% of low-frequency coding variants in ~82 K Europeans via the exome chip, and ~90% of low-frequency non-coding variants in ~44 K Europeans via genotype imputation). The variants, genotypes, and association statistics from these analyses provide the largest reference to date of human genetic information relevant to T2D, for use in activities such as T2D-focused genotype imputation, functional characterization of variants or genes, and other novel analyses to detect associations between sequence variation and T2D.
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http://dx.doi.org/10.1038/sdata.2017.179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5735917PMC
December 2017

Type 2 Diabetes Variants Disrupt Function of SLC16A11 through Two Distinct Mechanisms.

Cell 2017 Jun;170(1):199-212.e20

Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Biology, MIT, Cambridge, MA 02139, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA. Electronic address:

Type 2 diabetes (T2D) affects Latinos at twice the rate seen in populations of European descent. We recently identified a risk haplotype spanning SLC16A11 that explains ∼20% of the increased T2D prevalence in Mexico. Here, through genetic fine-mapping, we define a set of tightly linked variants likely to contain the causal allele(s). We show that variants on the T2D-associated haplotype have two distinct effects: (1) decreasing SLC16A11 expression in liver and (2) disrupting a key interaction with basigin, thereby reducing cell-surface localization. Both independent mechanisms reduce SLC16A11 function and suggest SLC16A11 is the causal gene at this locus. To gain insight into how SLC16A11 disruption impacts T2D risk, we demonstrate that SLC16A11 is a proton-coupled monocarboxylate transporter and that genetic perturbation of SLC16A11 induces changes in fatty acid and lipid metabolism that are associated with increased T2D risk. Our findings suggest that increasing SLC16A11 function could be therapeutically beneficial for T2D. VIDEO ABSTRACT.
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http://dx.doi.org/10.1016/j.cell.2017.06.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5562285PMC
June 2017

Discovery and fine-mapping of adiposity loci using high density imputation of genome-wide association studies in individuals of African ancestry: African Ancestry Anthropometry Genetics Consortium.

PLoS Genet 2017 Apr 21;13(4):e1006719. Epub 2017 Apr 21.

Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt University School of Medicine, Nashville, TN, United States of America.

Genome-wide association studies (GWAS) have identified >300 loci associated with measures of adiposity including body mass index (BMI) and waist-to-hip ratio (adjusted for BMI, WHRadjBMI), but few have been identified through screening of the African ancestry genomes. We performed large scale meta-analyses and replications in up to 52,895 individuals for BMI and up to 23,095 individuals for WHRadjBMI from the African Ancestry Anthropometry Genetics Consortium (AAAGC) using 1000 Genomes phase 1 imputed GWAS to improve coverage of both common and low frequency variants in the low linkage disequilibrium African ancestry genomes. In the sex-combined analyses, we identified one novel locus (TCF7L2/HABP2) for WHRadjBMI and eight previously established loci at P < 5×10-8: seven for BMI, and one for WHRadjBMI in African ancestry individuals. An additional novel locus (SPRYD7/DLEU2) was identified for WHRadjBMI when combined with European GWAS. In the sex-stratified analyses, we identified three novel loci for BMI (INTS10/LPL and MLC1 in men, IRX4/IRX2 in women) and four for WHRadjBMI (SSX2IP, CASC8, PDE3B and ZDHHC1/HSD11B2 in women) in individuals of African ancestry or both African and European ancestry. For four of the novel variants, the minor allele frequency was low (<5%). In the trans-ethnic fine mapping of 47 BMI loci and 27 WHRadjBMI loci that were locus-wide significant (P < 0.05 adjusted for effective number of variants per locus) from the African ancestry sex-combined and sex-stratified analyses, 26 BMI loci and 17 WHRadjBMI loci contained ≤ 20 variants in the credible sets that jointly account for 99% posterior probability of driving the associations. The lead variants in 13 of these loci had a high probability of being causal. As compared to our previous HapMap imputed GWAS for BMI and WHRadjBMI including up to 71,412 and 27,350 African ancestry individuals, respectively, our results suggest that 1000 Genomes imputation showed modest improvement in identifying GWAS loci including low frequency variants. Trans-ethnic meta-analyses further improved fine mapping of putative causal variants in loci shared between the African and European ancestry populations.
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http://dx.doi.org/10.1371/journal.pgen.1006719DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5419579PMC
April 2017
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