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1.  A Common Variant in MIR182 Is Associated With Primary Open-Angle Glaucoma in the NEIGHBORHOOD Consortium 
Noncoding microRNAs (miRNAs) have been implicated in the pathogenesis of glaucoma. We aimed to identify common variants in miRNA coding genes (MIR) associated with primary open-angle glaucoma (POAG).
Using the NEIGHBORHOOD data set (3853 cases/33,480 controls with European ancestry), we first assessed the relation between 85 variants in 76 MIR genes and overall POAG. Subtype-specific analyses were performed in high-tension glaucoma (HTG) and normal-tension glaucoma subsets. Second, we examined the expression of miR-182, which was associated with POAG, in postmortem human ocular tissues (ciliary body, cornea, retina, and trabecular meshwork [TM]), using miRNA sequencing (miRNA-Seq) and droplet digital PCR (ddPCR). Third, miR-182 expression was also examined in human aqueous humor (AH) by using miRNA-Seq. Fourth, exosomes secreted from primary human TM cells were examined for miR-182 expression by using miRNA-Seq. Fifth, using ddPCR we compared miR-182 expression in AH between five HTG cases and five controls.
Only rs76481776 in MIR182 gene was associated with POAG after adjustment for multiple comparisons (odds ratio [OR] = 1.23, 95% confidence interval [CI]: 1.11–1.42, P = 0.0002). Subtype analysis indicated that the association was primarily in the HTG subset (OR = 1.26, 95% CI: 1.08–1.47, P = 0.004). The risk allele T has been associated with elevated miR-182 expression in vitro. Data from ddPCR and miRNA-Seq confirmed miR-182 expression in all examined ocular tissues and TM-derived exosomes. Interestingly, miR-182 expression in AH was 2-fold higher in HTG patients than nonglaucoma controls (P = 0.03) without controlling for medication treatment.
Our integrative study is the first to associate rs76481776 with POAG via elevated miR-182 expression.
PMCID: PMC4991020  PMID: 27579667
miR-182; POAG; genetic association; NEIGHBORHOOD; exosome
2.  Genome-wide association analysis identifies TXNRD2, ATXN2 and FOXC1 as susceptibility loci for primary open angle glaucoma 
Cooke Bailey, Jessica N. | Loomis, Stephanie J. | Kang, Jae H. | Allingham, R. Rand | Gharahkhani, Puya | Khor, Chiea Chuen | Burdon, Kathryn P. | Aschard, Hugues | Chasman, Daniel I. | Igo, Robert P. | Hysi, Pirro G. | Glastonbury, Craig A. | Ashley-Koch, Allison | Brilliant, Murray | Brown, Andrew A. | Budenz, Donald L. | Buil, Alfonso | Cheng, Ching-Yu | Choi, Hyon | Christen, William G. | Curhan, Gary | De Vivo, Immaculata | Fingert, John H. | Foster, Paul J. | Fuchs, Charles | Gaasterland, Douglas | Gaasterland, Terry | Hewitt, Alex W. | Hu, Frank | Hunter, David J. | Khawaja, Anthony P. | Lee, Richard K. | Li, Zheng | Lichter, Paul R. | Mackey, David A. | McGuffin, Peter | Mitchell, Paul | Moroi, Sayoko E. | Perera, Shamira A. | Pepper, Keating W. | Qi, Qibin | Realini, Tony | Richards, Julia E. | Ridker, Paul M | Rimm, Eric | Ritch, Robert | Ritchie, Marylyn | Schuman, Joel S. | Scott, William K. | Singh, Kuldev | Sit, Arthur J. | Song, Yeunjoo E. | Tamimi, Rulla M. | Topouzis, Fotis | Viswanathan, Ananth C. | Verma, Shefali Setia | Vollrath, Douglas | Wang, Jie Jin | Weisschuh, Nicole | Wissinger, Bernd | Wollstein, Gadi | Wong, Tien Y. | Yaspan, Brian L. | Zack, Donald J. | Zhang, Kang | Weinreb, Robert N. | Pericak-Vance, Margaret A. | Small, Kerrin | Hammond, Christopher J. | Aung, Tin | Liu, Yutao | Vithana, Eranga N. | MacGregor, Stuart | Craig, Jamie E. | Kraft, Peter | Howell, Gareth | Hauser, Michael A. | Pasquale, Louis R. | Haines, Jonathan L. | Wiggs, Janey L.
Nature genetics  2016;48(2):189-194.
Primary open angle glaucoma (POAG) is a leading cause of blindness world-wide. To identify new susceptibility loci, we meta-analyzed GWAS results from 8 independent studies from the United States (3,853 cases and 33,480 controls) and investigated the most significant SNPs in two Australian studies (1,252 cases and 2,592 controls), 3 European studies (875 cases and 4,107 controls) and a Singaporean Chinese study (1,037 cases and 2,543 controls). A meta-analysis of top SNPs identified three novel loci: rs35934224[T] within TXNRD2 (odds ratio (OR) = 0.78, P = 4.05×10−11 encoding a mitochondrial protein required for redox homeostasis; rs7137828[T] within ATXN2 (OR = 1.17, P = 8.73×10−10), and rs2745572[A] upstream of FOXC1 (OR = 1.17, P = 1.76×10−10). Using RT-PCR and immunohistochemistry, we show TXNRD2 and ATXN2 expression in retinal ganglion cells and the optic nerve head. These results identify new pathways underlying POAG susceptibility and suggest novel targets for preventative therapies.
PMCID: PMC4731307  PMID: 26752265
3.  A large genome-wide association study of age-related macular degeneration highlights contributions of rare and common variants 
Fritsche, Lars G. | Igl, Wilmar | Cooke Bailey, Jessica N. | Grassmann, Felix | Sengupta, Sebanti | Bragg-Gresham, Jennifer L. | Burdon, Kathryn P. | Hebbring, Scott J. | Wen, Cindy | Gorski, Mathias | Kim, Ivana K. | Cho, David | Zack, Donald | Souied, Eric | Scholl, Hendrik P. N. | Bala, Elisa | Lee, Kristine E. | Hunter, David J. | Sardell, Rebecca J. | Mitchell, Paul | Merriam, Joanna E. | Cipriani, Valentina | Hoffman, Joshua D. | Schick, Tina | Lechanteur, Yara T. E. | Guymer, Robyn H. | Johnson, Matthew P. | Jiang, Yingda | Stanton, Chloe M. | Buitendijk, Gabriëlle H. S. | Zhan, Xiaowei | Kwong, Alan M. | Boleda, Alexis | Brooks, Matthew | Gieser, Linn | Ratnapriya, Rinki | Branham, Kari E. | Foerster, Johanna R. | Heckenlively, John R. | Othman, Mohammad I. | Vote, Brendan J. | Liang, Helena Hai | Souzeau, Emmanuelle | McAllister, Ian L. | Isaacs, Timothy | Hall, Janette | Lake, Stewart | Mackey, David A. | Constable, Ian J. | Craig, Jamie E. | Kitchner, Terrie E. | Yang, Zhenglin | Su, Zhiguang | Luo, Hongrong | Chen, Daniel | Ouyang, Hong | Flagg, Ken | Lin, Danni | Mao, Guanping | Ferreyra, Henry | Stark, Klaus | von Strachwitz, Claudia N. | Wolf, Armin | Brandl, Caroline | Rudolph, Guenther | Olden, Matthias | Morrison, Margaux A. | Morgan, Denise J. | Schu, Matthew | Ahn, Jeeyun | Silvestri, Giuliana | Tsironi, Evangelia E. | Park, Kyu Hyung | Farrer, Lindsay A. | Orlin, Anton | Brucker, Alexander | Li, Mingyao | Curcio, Christine | Mohand-Saïd, Saddek | Sahel, José-Alain | Audo, Isabelle | Benchaboune, Mustapha | Cree, Angela J. | Rennie, Christina A. | Goverdhan, Srinivas V. | Grunin, Michelle | Hagbi-Levi, Shira | Campochiaro, Peter | Katsanis, Nicholas | Holz, Frank G. | Blond, Frédéric | Blanché, Hélène | Deleuze, Jean-François | Igo, Robert P. | Truitt, Barbara | Peachey, Neal S. | Meuer, Stacy M. | Myers, Chelsea E. | Moore, Emily L. | Klein, Ronald | Hauser, Michael A. | Postel, Eric A. | Courtenay, Monique D. | Schwartz, Stephen G. | Kovach, Jaclyn L. | Scott, William K. | Liew, Gerald | Tƒan, Ava G. | Gopinath, Bamini | Merriam, John C. | Smith, R. Theodore | Khan, Jane C. | Shahid, Humma | Moore, Anthony T. | McGrath, J. Allie | Laux, Reneé | Brantley, Milam A. | Agarwal, Anita | Ersoy, Lebriz | Caramoy, Albert | Langmann, Thomas | Saksens, Nicole T. M. | de Jong, Eiko K. | Hoyng, Carel B. | Cain, Melinda S. | Richardson, Andrea J. | Martin, Tammy M. | Blangero, John | Weeks, Daniel E. | Dhillon, Bal | van Duijn, Cornelia M. | Doheny, Kimberly F. | Romm, Jane | Klaver, Caroline C. W. | Hayward, Caroline | Gorin, Michael B. | Klein, Michael L. | Baird, Paul N. | den Hollander, Anneke I. | Fauser, Sascha | Yates, John R. W. | Allikmets, Rando | Wang, Jie Jin | Schaumberg, Debra A. | Klein, Barbara E. K. | Hagstrom, Stephanie A. | Chowers, Itay | Lotery, Andrew J. | Léveillard, Thierry | Zhang, Kang | Brilliant, Murray H. | Hewitt, Alex W. | Swaroop, Anand | Chew, Emily Y. | Pericak-Vance, Margaret A. | DeAngelis, Margaret | Stambolian, Dwight | Haines, Jonathan L. | Iyengar, Sudha K. | Weber, Bernhard H. F. | Abecasis, Gonçalo R. | Heid, Iris M.
Nature genetics  2015;48(2):134-143.
Advanced age-related macular degeneration (AMD) is the leading cause of blindness in the elderly with limited therapeutic options. Here, we report on a study of >12 million variants including 163,714 directly genotyped, most rare, protein-altering variant. Analyzing 16,144 patients and 17,832 controls, we identify 52 independently associated common and rare variants (P < 5×10–8) distributed across 34 loci. While wet and dry AMD subtypes exhibit predominantly shared genetics, we identify the first signal specific to wet AMD, near MMP9 (difference-P = 4.1×10–10). Very rare coding variants (frequency < 0.1%) in CFH, CFI, and TIMP3 suggest causal roles for these genes, as does a splice variant in SLC16A8. Our results support the hypothesis that rare coding variants can pinpoint causal genes within known genetic loci and illustrate that applying the approach systematically to detect new loci requires extremely large sample sizes.
PMCID: PMC4745342  PMID: 26691988
4.  Selecting SNPs informative for African, American Indian and European Ancestry: application to the Family Investigation of Nephropathy and Diabetes (FIND) 
BMC Genomics  2016;17:325.
The presence of population structure in a sample may confound the search for important genetic loci associated with disease. Our four samples in the Family Investigation of Nephropathy and Diabetes (FIND), European Americans, Mexican Americans, African Americans, and American Indians are part of a genome- wide association study in which population structure might be particularly important. We therefore decided to study in detail one component of this, individual genetic ancestry (IGA). From SNPs present on the Affymetrix 6.0 Human SNP array, we identified 3 sets of ancestry informative markers (AIMs), each maximized for the information in one the three contrasts among ancestral populations: Europeans (HAPMAP, CEU), Africans (HAPMAP, YRI and LWK), and Native Americans (full heritage Pima Indians). We estimate IGA and present an algorithm for their standard errors, compare IGA to principal components, emphasize the importance of balancing information in the ancestry informative markers (AIMs), and test the association of IGA with diabetic nephropathy in the combined sample.
A fixed parental allele maximum likelihood algorithm was applied to the FIND to estimate IGA in four samples: 869 American Indians; 1385 African Americans; 1451 Mexican Americans; and 826 European Americans. When the information in the AIMs is unbalanced, the estimates are incorrect with large error. Individual genetic admixture is highly correlated with principle components for capturing population structure. It takes ~700 SNPs to reduce the average standard error of individual admixture below 0.01. When the samples are combined, the resulting population structure creates associations between IGA and diabetic nephropathy.
The identified set of AIMs, which include American Indian parental allele frequencies, may be particularly useful for estimating genetic admixture in populations from the Americas. Failure to balance information in maximum likelihood, poly-ancestry models creates biased estimates of individual admixture with large error. This also occurs when estimating IGA using the Bayesian clustering method as implemented in the program STRUCTURE. Odds ratios for the associations of IGA with disease are consistent with what is known about the incidence and prevalence of diabetic nephropathy in these populations.
Electronic supplementary material
The online version of this article (doi:10.1186/s12864-016-2654-x) contains supplementary material, which is available to authorized users.
PMCID: PMC4855449  PMID: 27142425
Individual genetic ancestry; Population structure; SNP; Diabetic nephropathy
5.  Meta-analysis of gene–environment-wide association scans accounting for education level identifies additional loci for refractive error 
Fan, Qiao | Verhoeven, Virginie J. M. | Wojciechowski, Robert | Barathi, Veluchamy A. | Hysi, Pirro G. | Guggenheim, Jeremy A. | Höhn, René | Vitart, Veronique | Khawaja, Anthony P. | Yamashiro, Kenji | Hosseini, S Mohsen | Lehtimäki, Terho | Lu, Yi | Haller, Toomas | Xie, Jing | Delcourt, Cécile | Pirastu, Mario | Wedenoja, Juho | Gharahkhani, Puya | Venturini, Cristina | Miyake, Masahiro | Hewitt, Alex W. | Guo, Xiaobo | Mazur, Johanna | Huffman, Jenifer E. | Williams, Katie M. | Polasek, Ozren | Campbell, Harry | Rudan, Igor | Vatavuk, Zoran | Wilson, James F. | Joshi, Peter K. | McMahon, George | St Pourcain, Beate | Evans, David M. | Simpson, Claire L. | Schwantes-An, Tae-Hwi | Igo, Robert P. | Mirshahi, Alireza | Cougnard-Gregoire, Audrey | Bellenguez, Céline | Blettner, Maria | Raitakari, Olli | Kähönen, Mika | Seppala, Ilkka | Zeller, Tanja | Meitinger, Thomas | Ried, Janina S. | Gieger, Christian | Portas, Laura | van Leeuwen, Elisabeth M. | Amin, Najaf | Uitterlinden, André G. | Rivadeneira, Fernando | Hofman, Albert | Vingerling, Johannes R. | Wang, Ya Xing | Wang, Xu | Tai-Hui Boh, Eileen | Ikram, M. Kamran | Sabanayagam, Charumathi | Gupta, Preeti | Tan, Vincent | Zhou, Lei | Ho, Candice E. H. | Lim, Wan'e | Beuerman, Roger W. | Siantar, Rosalynn | Tai, E-Shyong | Vithana, Eranga | Mihailov, Evelin | Khor, Chiea-Chuen | Hayward, Caroline | Luben, Robert N. | Foster, Paul J. | Klein, Barbara E. K. | Klein, Ronald | Wong, Hoi-Suen | Mitchell, Paul | Metspalu, Andres | Aung, Tin | Young, Terri L. | He, Mingguang | Pärssinen, Olavi | van Duijn, Cornelia M. | Jin Wang, Jie | Williams, Cathy | Jonas, Jost B. | Teo, Yik-Ying | Mackey, David A. | Oexle, Konrad | Yoshimura, Nagahisa | Paterson, Andrew D. | Pfeiffer, Norbert | Wong, Tien-Yin | Baird, Paul N. | Stambolian, Dwight | Wilson, Joan E. Bailey | Cheng, Ching-Yu | Hammond, Christopher J. | Klaver, Caroline C. W. | Saw, Seang-Mei | Rahi, Jugnoo S. | Korobelnik, Jean-François | Kemp, John P. | Timpson, Nicholas J. | Smith, George Davey | Craig, Jamie E. | Burdon, Kathryn P. | Fogarty, Rhys D. | Iyengar, Sudha K. | Chew, Emily | Janmahasatian, Sarayut | Martin, Nicholas G. | MacGregor, Stuart | Xu, Liang | Schache, Maria | Nangia, Vinay | Panda-Jonas, Songhomitra | Wright, Alan F. | Fondran, Jeremy R. | Lass, Jonathan H. | Feng, Sheng | Zhao, Jing Hua | Khaw, Kay-Tee | Wareham, Nick J. | Rantanen, Taina | Kaprio, Jaakko | Pang, Chi Pui | Chen, Li Jia | Tam, Pancy O. | Jhanji, Vishal | Young, Alvin L. | Döring, Angela | Raffel, Leslie J. | Cotch, Mary-Frances | Li, Xiaohui | Yip, Shea Ping | Yap, Maurice K.H. | Biino, Ginevra | Vaccargiu, Simona | Fossarello, Maurizio | Fleck, Brian | Yazar, Seyhan | Tideman, Jan Willem L. | Tedja, Milly | Deangelis, Margaret M. | Morrison, Margaux | Farrer, Lindsay | Zhou, Xiangtian | Chen, Wei | Mizuki, Nobuhisa | Meguro, Akira | Mäkelä, Kari Matti
Nature Communications  2016;7:11008.
Myopia is the most common human eye disorder and it results from complex genetic and environmental causes. The rapidly increasing prevalence of myopia poses a major public health challenge. Here, the CREAM consortium performs a joint meta-analysis to test single-nucleotide polymorphism (SNP) main effects and SNP × education interaction effects on refractive error in 40,036 adults from 25 studies of European ancestry and 10,315 adults from 9 studies of Asian ancestry. In European ancestry individuals, we identify six novel loci (FAM150B-ACP1, LINC00340, FBN1, DIS3L-MAP2K1, ARID2-SNAT1 and SLC14A2) associated with refractive error. In Asian populations, three genome-wide significant loci AREG, GABRR1 and PDE10A also exhibit strong interactions with education (P<8.5 × 10−5), whereas the interactions are less evident in Europeans. The discovery of these loci represents an important advance in understanding how gene and environment interactions contribute to the heterogeneity of myopia.
This report by the Consortium for Refractive Error and Myopia uses gene-environment-wide interaction study (GEWIS) to identify genetic loci that affect environmental influence in myopia development, and identifies ethnic specific genetic loci that attribute to eye refractive errors.
PMCID: PMC4820539  PMID: 27020472
6.  Rare and common variants in extracellular matrix gene Fibrillin 2 (FBN2) are associated with macular degeneration 
Human Molecular Genetics  2014;23(21):5827-5837.
Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch′s membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10 337 cases and 11 174 controls (OR = 1.10; P-value = 3.79 × 10−5). Thus, it appears that rare and common variants in a single gene—FBN2—can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch′s membrane in maintaining blood–retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.
PMCID: PMC4189898  PMID: 24899048
7.  Polymorphisms in TICAM2 and IL1B are associated with TB 
Genes and immunity  2014;16(2):127-133.
Human genetic susceptibility for tuberculosis (TB) has been demonstrated by several studies, but few have examined multiple innate and adaptive immunity genes comprehensively, age-specific effects, and/or resistance to Mycobacterium tuberculosis (Mtb) infection (RSTR). We hypothesized that RSTR, defined by a persistently negative tuberculin skin test, may have different genetic influences than Mtb disease.
We examined 29 candidate genes in pathways that mediate immune responses to Mtb in subjects in a household contact study in Kampala, Uganda. We genotyped 546 haplotype-tagging single nucleotide polymorphisms (SNPs) in 835 individuals from 481 families; 28.7% had TB, 10.5% were RSTR, and the remaining 60.8% had latent Mtb infection.
Among our most significant findings were SNPs in TICAM2 (p=3.6×10−6) and IL1B (p=4.3×10−5) associated with TB. Multiple SNPs in IL4 and TOLLIP were associated with TB (p<0.05). Age-genotype interaction analysis revealed SNPs in IL18 and TLR6 that were suggestively associated with TB in children ≤ 10 years old (p=2.9×10−3). By contrast, RSTR was associated with SNPs in NOD2, SLC6A3 and TLR4 (nominal p < 0.05); these genes were not associated with TB, suggesting distinct genetic influences.
We report the first association between TICAM2 polymorphisms and TB, and between IL18 and pediatric TB.
PMCID: PMC4352113  PMID: 25521228
TRAM; interleukin; nod-like receptor; genetic epidemiology; toll-like receptor; NOD1
8.  Genome-Wide Association and Trans-ethnic Meta-Analysis for Advanced Diabetic Kidney Disease: Family Investigation of Nephropathy and Diabetes (FIND) 
PLoS Genetics  2015;11(8):e1005352.
Diabetic kidney disease (DKD) is the most common etiology of chronic kidney disease (CKD) in the industrialized world and accounts for much of the excess mortality in patients with diabetes mellitus. Approximately 45% of U.S. patients with incident end-stage kidney disease (ESKD) have DKD. Independent of glycemic control, DKD aggregates in families and has higher incidence rates in African, Mexican, and American Indian ancestral groups relative to European populations. The Family Investigation of Nephropathy and Diabetes (FIND) performed a genome-wide association study (GWAS) contrasting 6,197 unrelated individuals with advanced DKD with healthy and diabetic individuals lacking nephropathy of European American, African American, Mexican American, or American Indian ancestry. A large-scale replication and trans-ethnic meta-analysis included 7,539 additional European American, African American and American Indian DKD cases and non-nephropathy controls. Within ethnic group meta-analysis of discovery GWAS and replication set results identified genome-wide significant evidence for association between DKD and rs12523822 on chromosome 6q25.2 in American Indians (P = 5.74x10-9). The strongest signal of association in the trans-ethnic meta-analysis was with a SNP in strong linkage disequilibrium with rs12523822 (rs955333; P = 1.31x10-8), with directionally consistent results across ethnic groups. These 6q25.2 SNPs are located between the SCAF8 and CNKSR3 genes, a region with DKD relevant changes in gene expression and an eQTL with IPCEF1, a gene co-translated with CNKSR3. Several other SNPs demonstrated suggestive evidence of association with DKD, within and across populations. These data identify a novel DKD susceptibility locus with consistent directions of effect across diverse ancestral groups and provide insight into the genetic architecture of DKD.
Author Summary
Type 2 diabetes is the most common cause of severe kidney disease worldwide and diabetic kidney disease (DKD) associates with premature death. Individuals of non-European ancestry have the highest burden of type 2 DKD; hence understanding the causes of DKD remains critical to reducing health disparities. Family studies demonstrate that genes regulate the onset and progression of DKD; however, identifying these genes has proven to be challenging. The Family Investigation of Diabetes and Nephropathy consortium (FIND) recruited a large multi-ethnic collection of individuals with type 2 diabetes with and without kidney disease in order to detect genes associated with DKD. FIND discovered and replicated a DKD-associated genetic locus on human chromosome 6q25.2 (rs955333) between the SCAF8 and CNKSR genes. Findings were supported by significantly different expression of genes in this region from kidney tissue of subjects with, versus without DKD. The present findings identify a novel kidney disease susceptibility locus in individuals with type 2 diabetes which is consistent across subjects of differing ancestries. In addition, FIND results provide a rich catalogue of genetic variation in DKD patients for future research on the genetic architecture regulating this common and devastating disease.
PMCID: PMC4549309  PMID: 26305897
9.  African Ancestry Influences CCR5 –2459G>A Genotype-Associated Virologic Success of Highly Active Antiretroviral Therapy 
In a North American, HIV-positive, highly active antiretroviral therapy (HAART)-treated, adherent cohort of self-identified white and black patients, we previously observed that chemokine (C-C motif) receptor 5 (CCR5) –2459G>A genotype had a strong association with time to achieve virologic success (TVLS) in black but not in white patients.
Using 128 genome-wide ancestry informative markers, we performed a quantitative assessment of ancestry in these patients (n = 310) to determine (1) whether CCR5 –2459G>A genotype is still associated with TVLS of HAART when ancestry, not self-identified race, is considered and (2) whether this association is influenced by varying African ancestry.
We found that the interaction between CCR5 –2459G>A genotype and African ancestry (≤0.125 vs. ≥0.425 and <0.71 vs. ≥0.71) was significantly associated with TVLS (GG compared with AA, P = 0.044 and 0.018, respectively). Furthermore, the association between CCR5 –2459G>A genotype and TVLS was stronger in patients with African ancestry ≥0.71 than in patients with African ancestry ≥0.452, in both Kaplan-Meier (log-rank P = 0.039 and 0.057, respectively, for AA, GA, and GG) and Cox proportional hazards regression (relative hazard for GG compared with AA 2.59 [95% CI, 1.27–5.22; P = 0.01] and 2.26 [95% CI, 1.18–4.32; P = 0.01], respectively) analyses.
We observed that the association between CCR5 –2459G>A genotype and TVLS of HAART increased with stronger African ancestry. Understanding the genomic mechanisms by which African ancestry influences this association is critical, and requires further studies.
PMCID: PMC3996453  PMID: 24714069
African American; ancestry informative markers; CCR5; HAART; virologic success
10.  Mitochondrial Polymorphism A10398G and Haplogroup I Are Associated With Fuchs' Endothelial Corneal Dystrophy 
We investigated whether mitochondrial DNA (mtDNA) variants affect the susceptibility of Fuchs endothelial corneal dystrophy (FECD).
Ten mtDNA variants defining European haplogroups were genotyped in a discovery dataset consisting of 530 cases and 498 controls of European descent from the Duke FECD cohort. Association tests for mtDNA markers and haplogroups were performed using logistic regression models with adjustment of age and sex. Subset analyses included controlling for additional effects of either the TCF4 SNP rs613872 or cigarette smoking. Our replication dataset was derived from the genome-wide association study (GWAS) of the FECD Genetics Consortium, where genotypes for three of 10 mtDNA markers were available. Replication analyses were performed to compare non-Duke cases to all GWAS controls (GWAS1, N = 3200), and to non-Duke controls (GWAS2, N = 3043).
The variant A10398G was significantly associated with FECD (odds ratio [OR] = 0.72; 95% confidence interval [CI] = [0.53, 0.98]; P = 0.034), and remains significant after adjusting for smoking status (min P = 0.012). This variant was replicated in GWAS1 (P = 0.019) and GWAS2 (P = 0.036). Haplogroup I was significantly associated with FECD (OR = 0.46; 95% CI = [0.22, 0.97]; P = 0.041) and remains significant after adjusting for the effect of smoking (min P = 0.008) or rs613872 (P = 0.034).
The 10398G allele and Haplogroup I appear to confer significant protective effects for FECD. The effect of A10398G and Haplogroup I to FECD is likely independent of the known TCF4 variant. More data are needed to decipher the interaction between smoking and mtDNA haplogroups.
The nine European mitochondrial haplogroups were investigated for the susceptibility of Fuchs endothelial corneal dystrophy (FECD). A10398G and Haplogroup I were found significantly decreasing the risk of FECD.
PMCID: PMC4109404  PMID: 24917144
mitochondrial haplogroup; genetic association; oxidative stress; TCF4; smoking
11.  Association between AVPR1A, DRD2, and ASPM and Endophenotypes of Communication Disorders 
Psychiatric genetics  2014;24(5):191-200.
Speech sound disorder (SSD) is one of the most common communication disorders, with prevalence rates of 16% at 3 years of age, and an estimated 3.8% of children still presenting speech difficulties at 6 years of age. Several studies have identified promising associations between communication disorders and genes in brain and neuronal pathways, but there have been few studies focusing on SSD and its associated endophenotypes. Based on the hypothesis that neuronal genes may influence endophenotypes common to communication disorders, we focused on three genes related to brain and central nervous system functioning: dopamine D2 receptor (DRD2), arginine-vassopressin receptor 1a (AVPR1A), and microcephaly gene ASPM.
We examined the association of these genes with key endophenotypes of SSD – phonological memory measured by multisyllabic and nonword repetition, vocabulary measured by Expressive One Word Picture Vocabulary Test (EOWPVT) and Peabody Picture Vocabulary Test (PPVT), and reading decoding measured by Woodcock Reading Mastery Tests Revised – as well as the clinical phenotype of SSD. We genotyped tag SNPs in these genes and examined 498 individuals from 180 families.
These data show several SNPs in all three genes were associated with phonological memory, vocabulary, and reading decoding with p<0.05. Notably, associations in AVPR1A (rs11832266) were significant after multiple testing correction. Gene-level tests showed DRD2 was associated with vocabulary, ASPM with vocabulary and reading decoding, and AVPR1A with all three endophenotypes.
Endophenotypes common to SSD, language impairment, and reading disability are all associated with these neuronal pathway genes.
PMCID: PMC4141900  PMID: 24849541
neural genes; phonology; speech impairment; language development; genetics
12.  Meta-Analysis of Genome-Wide Association Studies in African Americans Provides Insights into the Genetic Architecture of Type 2 Diabetes 
Ng, Maggie C. Y. | Shriner, Daniel | Chen, Brian H. | Li, Jiang | Chen, Wei-Min | Guo, Xiuqing | Liu, Jiankang | Bielinski, Suzette J. | Yanek, Lisa R. | Nalls, Michael A. | Comeau, Mary E. | Rasmussen-Torvik, Laura J. | Jensen, Richard A. | Evans, Daniel S. | Sun, Yan V. | An, Ping | Patel, Sanjay R. | Lu, Yingchang | Long, Jirong | Armstrong, Loren L. | Wagenknecht, Lynne | Yang, Lingyao | Snively, Beverly M. | Palmer, Nicholette D. | Mudgal, Poorva | Langefeld, Carl D. | Keene, Keith L. | Freedman, Barry I. | Mychaleckyj, Josyf C. | Nayak, Uma | Raffel, Leslie J. | Goodarzi, Mark O. | Chen, Y-D Ida | Taylor, Herman A. | Correa, Adolfo | Sims, Mario | Couper, David | Pankow, James S. | Boerwinkle, Eric | Adeyemo, Adebowale | Doumatey, Ayo | Chen, Guanjie | Mathias, Rasika A. | Vaidya, Dhananjay | Singleton, Andrew B. | Zonderman, Alan B. | Igo, Robert P. | Sedor, John R. | Kabagambe, Edmond K. | Siscovick, David S. | McKnight, Barbara | Rice, Kenneth | Liu, Yongmei | Hsueh, Wen-Chi | Zhao, Wei | Bielak, Lawrence F. | Kraja, Aldi | Province, Michael A. | Bottinger, Erwin P. | Gottesman, Omri | Cai, Qiuyin | Zheng, Wei | Blot, William J. | Lowe, William L. | Pacheco, Jennifer A. | Crawford, Dana C. | Grundberg, Elin | Rich, Stephen S. | Hayes, M. Geoffrey | Shu, Xiao-Ou | Loos, Ruth J. F. | Borecki, Ingrid B. | Peyser, Patricia A. | Cummings, Steven R. | Psaty, Bruce M. | Fornage, Myriam | Iyengar, Sudha K. | Evans, Michele K. | Becker, Diane M. | Kao, W. H. Linda | Wilson, James G. | Rotter, Jerome I. | Sale, Michèle M. | Liu, Simin | Rotimi, Charles N. | Bowden, Donald W.
PLoS Genetics  2014;10(8):e1004517.
Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15×10−94
Author Summary
Despite the higher prevalence of type 2 diabetes (T2D) in African Americans than in Europeans, recent genome-wide association studies (GWAS) were examined primarily in individuals of European ancestry. In this study, we performed meta-analysis of 17 GWAS in 8,284 cases and 15,543 controls to explore the genetic architecture of T2D in African Americans. Following replication in additional 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry, we identified two novel and three previous reported T2D loci reaching genome-wide significance. We also examined 158 loci previously reported to be associated with T2D or regulating glucose homeostasis. While 56% of these loci were shared between African Americans and the other populations, the strongest associations in African Americans are often found in nearby single nucleotide polymorphisms (SNPs) instead of the original SNPs reported in other populations due to differential genetic architecture across populations. Our results highlight the importance of performing genetic studies in non-European populations to fine map the causal genetic variants.
PMCID: PMC4125087  PMID: 25102180
The underlying ethos of dbGaP is that access to these data by secondary data analysts facilitates advancement of science. NIH has required that genome-wide association study data be deposited in the Database of Genotypes and Phenotypes (dbGaP) since 2003. In 2013, a proposed updated policy extended this requirement to next-generation sequencing data. However, recent literature and anecdotal reports suggest lingering logistical and ethical concerns about subject identifiability, informed consent, publication embargo enforcement, and difficulty in accessing dbGaP data. We surveyed the International Genetic Epidemiology Society (IGES) membership about their experiences. One hundred and seventy five (175) individuals completed the survey, a response rate of 27%. Of respondents who received data from dbGaP (43%), only 32% perceived the application process as easy but most (75%) received data within five months. Remaining challenges include difficulty in identifying an institutional signing official and an overlong application process. Only 24% of respondents had contributed data to dbGaP. Of these, 31% reported local IRB restrictions on data release; an additional 15% had to reconsent study participants before depositing data. The majority of respondents (56%) disagreed that the publication embargo period was sufficient. In response, we recommend longer embargo periods and use of varied data-sharing models rather than a one-size-fits-all approach.
PMCID: PMC4143867  PMID: 25153467
data sharing; identifiability; GWAS; ELSI; ethics; publication embargo; collaboration
We tested variants in genes related to lutein and zeaxanthin status for association with age-related macular degeneration (AMD) in the Carotenoids in Age-Related Eye Disease Study (CAREDS).
Of 2005 CAREDS participants, 1663 were graded for AMD from fundus photography and genotyped for 424 single nucleotide polymorphisms (SNPs) from 24 candidate genes for carotenoid status. Of 337 AMD cases 91% had early or intermediate AMD. The SNPs were tested individually for association with AMD using logistic regression. A carotenoid-related genetic risk model was built using backward selection and compared to existing AMD risk factors using the area under the receiver operating characteristic curve (AUC).
A total of 24 variants from five genes (BCMO1, BCO2, NPCL1L1, ABCG8, and FADS2) not previously related to AMD and four genes related to AMD in previous studies (SCARB1, ABCA1, APOE, and ALDH3A2) were associated independently with AMD, after adjusting for age and ancestry. Variants in all genes (not always the identical SNPs) were associated with lutein and zeaxanthin in serum and/or macula, in this or other samples, except for BCO2 and FADS2. A genetic risk score including nine variants significantly (P = 0.002) discriminated between AMD cases and controls beyond age, smoking, CFH Y402H, and ARMS2 A69S. The odds ratio (95% confidence interval) for AMD among women in the highest versus lowest quintile for the risk score was 3.1 (2.0–4.9).
Variants in genes related to lutein and zeaxanthin status were associated with AMD in CAREDS, adding to the body of evidence supporting a protective role of lutein and zeaxanthin in risk of AMD.
In this study of over 1600 postmenopausal women of the CAREDS, we describe the first evidence that variation in multiple genes related to carotenoid status in the blood and macula are associated with age-related macular degeneration (AMD).
PMCID: PMC3908680  PMID: 24346170
macular degeneration; carotenoids; genes
BMC Infectious Diseases  2014;14:352.
Despite sustained exposure to a person with pulmonary tuberculosis (TB), some M. tuberculosis (Mtb) exposed individuals maintain a negative tuberculin skin test (TST). Our objective was to characterize these persistently negative TST (PTST-) individuals and compare them to TST converters (TSTC) and individuals who are TST positive at study enrollment.
During a TB household contact study in Kampala, Uganda, PTST-, TSTC, and TST + individuals were identified. PTST- individuals maintained a negative TST over a 2 year observation period despite prolonged exposure to an infectious tuberculosis (TB) case. Epidemiological and clinical characteristics were compared, a risk score developed by another group to capture risk for Mtb infection was computed, and an ordinal regression was performed.
When analyzed independently, epidemiological risk factors increased in prevalence from PTST- to TSTC to TST+. An ordinal regression model suggested age (p < 0.01), number of windows (p < 0.01) and people (p = 0.07) in the home, and sleeping in the same room (p < 0.01) were associated with PTST- and TSTC. As these factors do not exist in isolation, we examined a risk score, which reflects an accumulation of risk factors. This compound exposure score did not differ significantly between PTST-, TSTC, and TST+, except for the 5–15 age group (p = 0.009).
Though many individual factors differed across all three groups, an exposure risk score reflecting a collection of risk factors did not differ for PTST-, TSTC and TST + young children and adults. This is the first study to rigorously characterize the epidemiologic risk profile of individuals with persistently negative TSTs despite close exposure to a person with TB. Additional studies are needed to characterize possible epidemiologic and host factors associated with this phenotype.
PMCID: PMC4091673  PMID: 24970328
Transmission risk factors; Latent Mtb infection; Exposure; Household characteristics; PPD test
We investigated effects of smoking and other risk factors on the development of advanced Fuchs' endothelial corneal dystrophy (FECD) and on central corneal thickness (CCT).
Eyes from Caucasian probands, affected and unaffected family members, and unrelated controls matched for age from the FECD Genetics Multi-Center Study (n = 2044 subjects) were examined. Univariate and multivariate models, adjusted for family correlations, were used to determine the effect of smoking, sex, diabetes, and age on FECD case/control status and CCT.
In a multivariate model, sex and smoking were associated significantly with advanced FECD (grades 4–6) development (P = 0.016 and P = 0.047, respectively). Female sex increased odds by 34%. Smoking increased odds by 30%. In a multivariate model, diabetes was associated with an increase of 9.1 μm in average CCT (P = 0.021). Female sex was associated significantly with a decrease in average CCT by 6.9 μm (P = 0.015). Smoking had no significant effect on CCT in any model. As shown previously, advanced FECD was associated with large increases in CCT (31.4–94.2 μm).
Smoking was associated with an increased risk of advanced FECD and self-reported diabetes was associated with increased CCT. Further study of the impact of smoking and diabetes on FECD development and changes in corneal thickness is warranted.
This case-control analysis showed that smoking was associated significantly with advanced FECD development.
PMCID: PMC3755540  PMID: 23882692
FECD; corneal endothelial cells; smoking
PLoS ONE  2013;8(12):e81888.
Estimated glomerular filtration rate (eGFR), a measure of kidney function, is heritable, suggesting that genes influence renal function. Genes that influence eGFR have been identified through genome-wide association studies. However, family-based linkage approaches may identify loci that explain a larger proportion of the heritability. This study used genome-wide linkage and association scans to identify quantitative trait loci (QTL) that influence eGFR.
Genome-wide linkage and sparse association scans of eGFR were performed in families ascertained by probands with advanced diabetic nephropathy (DN) from the multi-ethnic Family Investigation of Nephropathy and Diabetes (FIND) study. This study included 954 African Americans (AA), 781 American Indians (AI), 614 European Americans (EA) and 1,611 Mexican Americans (MA). A total of 3,960 FIND participants were genotyped for 6,000 single nucleotide polymorphisms (SNPs) using the Illumina Linkage IVb panel. GFR was estimated by the Modification of Diet in Renal Disease (MDRD) formula.
The non-parametric linkage analysis, accounting for the effects of diabetes duration and BMI, identified the strongest evidence for linkage of eGFR on chromosome 20q11 (log of the odds [LOD] = 3.34; P = 4.4×10−5) in MA and chromosome 15q12 (LOD = 2.84; P = 1.5×10−4) in EA. In all subjects, the strongest linkage signal for eGFR was detected on chromosome 10p12 (P = 5.5×10−4) at 44 cM near marker rs1339048. A subsequent association scan in both ancestry-specific groups and the entire population identified several SNPs significantly associated with eGFR across the genome.
The present study describes the localization of QTL influencing eGFR on 20q11 in MA, 15q21 in EA and 10p12 in the combined ethnic groups participating in the FIND study. Identification of causal genes/variants influencing eGFR, within these linkage and association loci, will open new avenues for functional analyses and development of novel diagnostic markers for DN.
PMCID: PMC3866106  PMID: 24358131
To investigate genetic determinants of macular pigment optical density in women from the Carotenoids in Age-Related Eye Disease Study (CAREDS), an ancillary study of the Women's Health Initiative Observational Study.
1585 of 2005 CAREDS participants had macular pigment optical density (MPOD) measured noninvasively using customized heterochromatic flicker photometry and blood samples genotyped for 440 single nucleotide polymorphisms (SNPs) in 26 candidate genes related to absorption, transport, binding, and cleavage of carotenoids directly, or via lipid transport. SNPs were individually tested for associations with MPOD using least-squares linear regression.
Twenty-one SNPs from 11 genes were associated with MPOD (P ≤ 0.05) after adjusting for dietary intake of lutein and zeaxanthin. This includes variants in or near genes related to zeaxanthin binding in the macula (GSTP1), carotenoid cleavage (BCMO1), cholesterol transport or uptake (SCARB1, ABCA1, ABCG5, and LIPC), long-chain omega-3 fatty acid status (ELOVL2, FADS1, and FADS2), and various maculopathies (ALDH3A2 and RPE65). The strongest association was for rs11645428 near BCMO1 (βA = 0.029, P = 2.2 × 10−4). Conditional modeling within genes and further adjustment for other predictors of MPOD, including waist circumference, diabetes, and dietary intake of fiber, resulted in 13 SNPs from 10 genes maintaining independent association with MPOD. Variation in these single gene polymorphisms accounted for 5% of the variability in MPOD (P = 3.5 × 10−11).
Our results support that MPOD is a multi-factorial phenotype associated with variation in genes related to carotenoid transport, uptake, and metabolism, independent of known dietary and health influences on MPOD.
In 1585 postmenopausal women of the Carotenoids in Age-Related Eye Disease Study sample, common genetic variants in or near genes involved in carotenoid transport, uptake, and metabolism were associated with density of lutein and zeaxanthin in the macula, independent of other known predictors, including dietary intake of carotenoids.
PMCID: PMC3626525  PMID: 23404124
Verhoeven, Virginie J.M. | Hysi, Pirro G. | Wojciechowski, Robert | Fan, Qiao | Guggenheim, Jeremy A. | Höhn, René | MacGregor, Stuart | Hewitt, Alex W. | Nag, Abhishek | Cheng, Ching-Yu | Yonova-Doing, Ekaterina | Zhou, Xin | Ikram, M. Kamran | Buitendijk, Gabriëlle H.S. | McMahon, George | Kemp, John P. | St. Pourcain, Beate | Simpson, Claire L. | Mäkelä, Kari-Matti | Lehtimäki, Terho | Kähönen, Mika | Paterson, Andrew D. | Hosseini, S. Mohsen | Wong, Hoi Suen | Xu, Liang | Jonas, Jost B. | Pärssinen, Olavi | Wedenoja, Juho | Yip, Shea Ping | Ho, Daniel W. H. | Pang, Chi Pui | Chen, Li Jia | Burdon, Kathryn P. | Craig, Jamie E. | Klein, Barbara E. K. | Klein, Ronald | Haller, Toomas | Metspalu, Andres | Khor, Chiea-Chuen | Tai, E-Shyong | Aung, Tin | Vithana, Eranga | Tay, Wan-Ting | Barathi, Veluchamy A. | Chen, Peng | Li, Ruoying | Liao, Jiemin | Zheng, Yingfeng | Ong, Rick T. | Döring, Angela | Evans, David M. | Timpson, Nicholas J. | Verkerk, Annemieke J.M.H. | Meitinger, Thomas | Raitakari, Olli | Hawthorne, Felicia | Spector, Tim D. | Karssen, Lennart C. | Pirastu, Mario | Murgia, Federico | Ang, Wei | Mishra, Aniket | Montgomery, Grant W. | Pennell, Craig E. | Cumberland, Phillippa M. | Cotlarciuc, Ioana | Mitchell, Paul | Wang, Jie Jin | Schache, Maria | Janmahasathian, Sarayut | Igo, Robert P. | Lass, Jonathan H. | Chew, Emily | Iyengar, Sudha K. | Gorgels, Theo G.M.F. | Rudan, Igor | Hayward, Caroline | Wright, Alan F. | Polasek, Ozren | Vatavuk, Zoran | Wilson, James F. | Fleck, Brian | Zeller, Tanja | Mirshahi, Alireza | Müller, Christian | Uitterlinden, Andre’ G. | Rivadeneira, Fernando | Vingerling, Johannes R. | Hofman, Albert | Oostra, Ben A. | Amin, Najaf | Bergen, Arthur A.B. | Teo, Yik-Ying | Rahi, Jugnoo S. | Vitart, Veronique | Williams, Cathy | Baird, Paul N. | Wong, Tien-Yin | Oexle, Konrad | Pfeiffer, Norbert | Mackey, David A. | Young, Terri L. | van Duijn, Cornelia M. | Saw, Seang-Mei | Wilson, Joan E. Bailey | Stambolian, Dwight | Klaver, Caroline C. | Hammond, Christopher J.
Nature genetics  2013;45(3):314-318.
Refractive error is the most common eye disorder worldwide, and a prominent cause of blindness. Myopia affects over 30% of Western populations, and up to 80% of Asians. The CREAM consortium conducted genome-wide meta-analyses including 37,382 individuals from 27 studies of European ancestry, and 8,376 from 5 Asian cohorts. We identified 16 new loci for refractive error in subjects of European ancestry, of which 8 were shared with Asians. Combined analysis revealed 8 additional loci. The new loci include genes with functions in neurotransmission (GRIA4), ion channels (KCNQ5), retinoic acid metabolism (RDH5), extracellular matrix remodeling (LAMA2, BMP2), and eye development (SIX6, PRSS56). We also confirmed previously reported associations with GJD2 and RASGRF1. Risk score analysis using associated SNPs showed a tenfold increased risk of myopia for subjects with the highest genetic load. Our results, accumulated across independent multi-ethnic studies, considerably advance understanding of mechanisms involved in refractive error and myopia.
PMCID: PMC3740568  PMID: 23396134
Cornea  2012;31(1):26-35.
To describe the methods for family and case-control recruitment for a multi-center genetic and associated heritability analysis of Fuchs’ Endothelial Corneal Dystrophy (FECD).
Twenty-nine enrolling sites with 62 trained investigators and coordinators gathered individual and family information, graded the phenotype, and collected blood and/or saliva for genetic analysis on all individuals with and without FECD. The degree of FECD was assessed in a 0–6 semi-quantitative scale using standardized clinical methods with pathologic verification of FECD on at least one member of each family. Central corneal thickness was measured by ultrasonic pachymetry.
Three hundred twenty-two families with 330 affected sibling pairs with FECD were enrolled, and included a total of 650 sibling pairs of all disease grades. Using the entire 0–6 step FECD grading scale or a dichotomous definition of severe disease, heritability was assessed in families via sib-sib correlations. Both binary indicators of severe disease as well as semi-quantitative measures of disease severity were significantly heritable, with heritability estimates of 30% for severe disease, 37–39% for FECD score and 47% for central corneal thickness.
Genetic risk factors have a strong role in the severity of the FECD phenotype and corneal thickness. Genotyping this cohort with high-density genetic markers followed by appropriate statistical analyses should lead to novel loci for disease susceptibility.
PMCID: PMC3719980  PMID: 22045388
heritability; Fuchs’ dystrophy; corneal thickness; genetics
PLoS ONE  2012;7(10):e46742.
Fuchs endothelial corneal dystrophy (FECD) is the most common late-onset, vision-threatening corneal dystrophy in the United States, affecting about 4% of the population. Advanced FECD involves a thickening of the cornea from stromal edema and changes in Descemet membrane. To understand the relationship between FECD and central corneal thickness (CCT), we characterized common genetic variation in COL8A2 and TCF4, genes previously implicated in CCT and/or FECD. Other genes previously associated with FECD (PITX2, ZEB1, SLC4A11), and genes only known to affect CCT (COL5A1, FOXO1, AVGR8, ZNF469) were also interrogated. FECD probands, relatives and controls were recruited from 32 clinical sites; a total of 532 cases and 204 controls were genotyped and tested for association of FECD case/control status, a 7-step FECD severity scale and CCT, adjusting for age and sex. Association of FECD grade with TCF4 was highly significant (OR  = 6.01 at rs613872; p = 4.8×10−25), and remained significant when adjusted for changes in CCT (OR  = 4.84; p = 2.2×10−16). Association of CCT with TCF4 was also significant (p = 6.1×10−7), but was abolished with adjustment for FECD grade (p = 0.92). After adjusting for FECD grade, markers in other genes examined were modestly associated (p ∼ 0.001) with FECD and/or CCT. Thus, common variants in TCF4 appear to influence FECD directly, and CCT secondarily via FECD. Additionally, changes in corneal thickness due to the effect of other loci may modify disease severity, age-at-onset, or other biomechanical characteristics.
PMCID: PMC3479099  PMID: 23110055
Genes and immunity  2010;11(8):609-621.
Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly in the developed world. We conducted a genome-wide association study in a series of families enriched for AMD and completed a meta-analysis of this new data with results from reanalysis of an existing study of a late-stage case/control cohort. We tested the top findings for replication in 1 896 cases and 1 866 controls and identified two novel genetic protective factors for AMD. In addition to the CFH (p=2.3×10−64) and ARMS2 (p=1.2×10−60) loci, we observed a protective effect at rs429608, an intronic SNP in SKIV2L (p=5.3×10−15), a gene near the C2/BF locus, that indicates the protective effect may be mediated by variants other than the C2/BF variants previously studied. Haplotype analysis at this locus identified three protective haplotypes defined by the rs429608 protective allele. We also identified a new potentially protective effect at rs2679798 in MYRIP (p=2.9×10−4), a gene involved in retinal pigment epithelium melanosome trafficking. Interestingly, MYRIP was initially identified in the family-based scan and was confirmed in the case-control set. From these efforts, we report the identification of two novel protective factors for AMD and confirm the previously known associations at CFH, ARMS2 and C3.
PMCID: PMC3375062  PMID: 20861866
macular degeneration; association testing; melanosome trafficking
American Journal of Nephrology  2011;33(5):381-389.
Diabetic nephropathy (DN) is a leading cause of mortality and morbidity in patients with type 1 and type 2 diabetes. The multicenter FIND consortium aims to identify genes for DN and its associated quantitative traits, e.g. the urine albumin:creatinine ratio (ACR). Herein, the results of whole-genome linkage analysis and a sparse association scan for ACR and a dichotomous DN phenotype are reported in diabetic individuals.
A genomewide scan comprising more than 5,500 autosomal single nucleotide polymorphism markers (average spacing of 0.6 cM) was performed on 1,235 nuclear and extended pedigrees (3,972 diabetic participants) ascertained for DN from African-American (AA), American-Indian (AI), European-American (EA) and Mexican-American (MA) populations.
Strong evidence for linkage to DN was detected on chromosome 6p (p = 8.0 × 10−5, LOD = 3.09) in EA families as well as suggestive evidence for linkage to chromosome 7p in AI families. Regions on chromosomes 3p in AA, 7q in EA, 16q in AA and 22q in MA displayed suggestive evidence of linkage for urine ACR. The linkage peak on chromosome 22q overlaps the MYH9/APOL1 gene region, previously implicated in AA diabetic and nondiabetic nephropathies.
These results strengthen the evidence for previously identified genomic regions and implicate several novel loci potentially involved in the pathogenesis of DN.
PMCID: PMC3078269  PMID: 21454968
Albuminuria; Diabetes mellitus; Renal failure; End-stage renal disease; Linkage; Allelic association
Human immunology  2011;72(5):426-430.
Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), causes 9 million new cases worldwide and 2 million deaths annually. Genetic linkage and association analyses have suggested several chromosomal regions and candidate genes involved in TB susceptibility. This study examines the association of TB disease susceptibility with a selection of biologically relevant genes on regions on chromosomes 7 (IL6 and CARD11) and 20 (CTSZ and MC3R), and fine mapping of the chromosome 7p22-p21 region, identified through our genome scan. We analyzed 565 individuals from Kampala, Uganda who were previously included in our genome-wide linkage scan. Association analyses were conducted for 1417 single-nucleotide polymorphisms (SNPs) that passed quality control. None of the candidate gene or fine mapping SNPs were found significantly associated with TB susceptibility (P > 0.10). When we restricted the analysis to HIV-negative individuals, two SNPs on chromosome 7 were significantly associated with TB susceptibility (P < 0.05). Haplotype analyses identified a significant risk haplotype in Cathepsin X (CTSZ) (p=0.0281, OR = 1.5493, 95% CI [1.039, 2.320]).
PMCID: PMC3078986  PMID: 21354459
infectious disease; family study; TB genetics; fine map; immunogenetics
PLoS ONE  2011;6(10):e25598.
Complement factor H shows very strong association with Age-related Macular Degeneration (AMD), and recent data suggest that multiple causal variants are associated with disease. To refine the location of the disease associated variants, we characterized in detail the structural variation at CFH and its paralogs, including two copy number polymorphisms (CNP), CNP147 and CNP148, and several rare deletions and duplications. Examination of 34 AMD-enriched extended families (N = 293) and AMD cases (White N = 4210 Indian = 134; Malay = 140) and controls (White N = 3229; Indian = 117; Malay = 2390) demonstrated that deletion CNP148 was protective against AMD, independent of SNPs at CFH. Regression analysis of seven common haplotypes showed three haplotypes, H1, H6 and H7, as conferring risk for AMD development. Being the most common haplotype H1 confers the greatest risk by increasing the odds of AMD by 2.75-fold (95% CI = [2.51, 3.01]; p = 8.31×10−109); Caucasian (H6) and Indian-specific (H7) recombinant haplotypes increase the odds of AMD by 1.85-fold (p = 3.52×10−9) and by 15.57-fold (P = 0.007), respectively. We identified a 32-kb region downstream of Y402H (rs1061170), shared by all three risk haplotypes, suggesting that this region may be critical for AMD development. Further analysis showed that two SNPs within the 32 kb block, rs1329428 and rs203687, optimally explain disease association. rs1329428 resides in 20 kb unique sequence block, but rs203687 resides in a 12 kb block that is 89% similar to a noncoding region contained in ΔCNP148. We conclude that causal variation in this region potentially encompasses both regulatory effects at single markers and copy number.
PMCID: PMC3192039  PMID: 22022419

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