@article {6027, title = {Genetic loci for retinal arteriolar microcirculation.}, journal = {PLoS One}, volume = {8}, year = {2013}, month = {2013}, pages = {e65804}, abstract = {

Narrow arterioles in the retina have been shown to predict hypertension as well as other vascular diseases, likely through an increase in the peripheral resistance of the microcirculatory flow. In this study, we performed a genome-wide association study in 18,722 unrelated individuals of European ancestry from the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium and the Blue Mountain Eye Study, to identify genetic determinants associated with variations in retinal arteriolar caliber. Retinal vascular calibers were measured on digitized retinal photographs using a standardized protocol. One variant (rs2194025 on chromosome 5q14 near the myocyte enhancer factor 2C MEF2C gene) was associated with retinal arteriolar caliber in the meta-analysis of the discovery cohorts at genome-wide significance of P-value <5{\texttimes}10(-8). This variant was replicated in an additional 3,939 individuals of European ancestry from the Australian Twins Study and Multi-Ethnic Study of Atherosclerosis (rs2194025, P-value = 2.11{\texttimes}10(-12) in combined meta-analysis of discovery and replication cohorts). In independent studies of modest sample sizes, no significant association was found between this variant and clinical outcomes including coronary artery disease, stroke, myocardial infarction or hypertension. In conclusion, we found one novel loci which underlie genetic variation in microvasculature which may be relevant to vascular disease. The relevance of these findings to clinical outcomes remains to be determined.

}, keywords = {Aged, Aged, 80 and over, Arterioles, Chromosomes, Human, Pair 5, European Continental Ancestry Group, Female, Genetic Loci, Genome-Wide Association Study, Genotype, Humans, Male, MEF2 Transcription Factors, Microcirculation, Middle Aged, Models, Genetic, Retinal Vessels}, issn = {1932-6203}, doi = {10.1371/journal.pone.0065804}, author = {Sim, Xueling and Jensen, Richard A and Ikram, M Kamran and Cotch, Mary Frances and Li, Xiaohui and Macgregor, Stuart and Xie, Jing and Smith, Albert Vernon and Boerwinkle, Eric and Mitchell, Paul and Klein, Ronald and Klein, Barbara E K and Glazer, Nicole L and Lumley, Thomas and McKnight, Barbara and Psaty, Bruce M and de Jong, Paulus T V M and Hofman, Albert and Rivadeneira, Fernando and Uitterlinden, Andr{\'e} G and van Duijn, Cornelia M and Aspelund, Thor and Eiriksdottir, Gudny and Harris, Tamara B and Jonasson, Fridbert and Launer, Lenore J and Attia, John and Baird, Paul N and Harrap, Stephen and Holliday, Elizabeth G and Inouye, Michael and Rochtchina, Elena and Scott, Rodney J and Viswanathan, Ananth and Li, Guo and Smith, Nicholas L and Wiggins, Kerri L and Kuo, Jane Z and Taylor, Kent D and Hewitt, Alex W and Martin, Nicholas G and Montgomery, Grant W and Sun, Cong and Young, Terri L and Mackey, David A and van Zuydam, Natalie R and Doney, Alex S F and Palmer, Colin N A and Morris, Andrew D and Rotter, Jerome I and Tai, E Shyong and Gudnason, Vilmundur and Vingerling, Johannes R and Siscovick, David S and Wang, Jie Jin and Wong, Tien Y} } @article {6072, title = {Genome-wide association study of retinopathy in individuals without diabetes.}, journal = {PLoS One}, volume = {8}, year = {2013}, month = {2013}, pages = {e54232}, abstract = {

BACKGROUND: Mild retinopathy (microaneurysms or dot-blot hemorrhages) is observed in persons without diabetes or hypertension and may reflect microvascular disease in other organs. We conducted a genome-wide association study (GWAS) of mild retinopathy in persons without diabetes.

METHODS: A working group agreed on phenotype harmonization, covariate selection and analytic plans for within-cohort GWAS. An inverse-variance weighted fixed effects meta-analysis was performed with GWAS results from six cohorts of 19,411 Caucasians. The primary analysis included individuals without diabetes and secondary analyses were stratified by hypertension status. We also singled out the results from single nucleotide polymorphisms (SNPs) previously shown to be associated with diabetes and hypertension, the two most common causes of retinopathy.

RESULTS: No SNPs reached genome-wide significance in the primary analysis or the secondary analysis of participants with hypertension. SNP, rs12155400, in the histone deacetylase 9 gene (HDAC9) on chromosome 7, was associated with retinopathy in analysis of participants without hypertension, -1.3{\textpm}0.23 (beta {\textpm} standard error), p = 6.6{\texttimes}10(-9). Evidence suggests this was a false positive finding. The minor allele frequency was low (\~{}2\%), the quality of the imputation was moderate (r(2) \~{}0.7), and no other common variants in the HDAC9 gene were associated with the outcome. SNPs found to be associated with diabetes and hypertension in other GWAS were not associated with retinopathy in persons without diabetes or in subgroups with or without hypertension.

CONCLUSIONS: This GWAS of retinopathy in individuals without diabetes showed little evidence of genetic associations. Further studies are needed to identify genes associated with these signs in order to help unravel novel pathways and determinants of microvascular diseases.

}, keywords = {Aged, Aged, 80 and over, Female, Genome-Wide Association Study, Genotype, Histone Deacetylases, Humans, Hypertension, Male, Polymorphism, Single Nucleotide, Repressor Proteins, Retinal Diseases}, issn = {1932-6203}, doi = {10.1371/journal.pone.0054232}, author = {Jensen, Richard A and Sim, Xueling and Li, Xiaohui and Cotch, Mary Frances and Ikram, M Kamran and Holliday, Elizabeth G and Eiriksdottir, Gudny and Harris, Tamara B and Jonasson, Fridbert and Klein, Barbara E K and Launer, Lenore J and Smith, Albert Vernon and Boerwinkle, Eric and Cheung, Ning and Hewitt, Alex W and Liew, Gerald and Mitchell, Paul and Wang, Jie Jin and Attia, John and Scott, Rodney and Glazer, Nicole L and Lumley, Thomas and McKnight, Barbara and Psaty, Bruce M and Taylor, Kent and Hofman, Albert and de Jong, Paulus T V M and Rivadeneira, Fernando and Uitterlinden, Andr{\'e} G and Tay, Wan-Ting and Teo, Yik Ying and Seielstad, Mark and Liu, Jianjun and Cheng, Ching-Yu and Saw, Seang-Mei and Aung, Tin and Ganesh, Santhi K and O{\textquoteright}Donnell, Christopher J and Nalls, Mike A and Wiggins, Kerri L and Kuo, Jane Z and van Duijn, Cornelia M and Gudnason, Vilmundur and Klein, Ronald and Siscovick, David S and Rotter, Jerome I and Tai, E Shong and Vingerling, Johannes and Wong, Tien Y} } @article {5875, title = {Insights into the genetic architecture of early stage age-related macular degeneration: a genome-wide association study meta-analysis.}, journal = {PLoS One}, volume = {8}, year = {2013}, month = {2013}, pages = {e53830}, abstract = {

Genetic factors explain a majority of risk variance for age-related macular degeneration (AMD). While genome-wide association studies (GWAS) for late AMD implicate genes in complement, inflammatory and lipid pathways, the genetic architecture of early AMD has been relatively under studied. We conducted a GWAS meta-analysis of early AMD, including 4,089 individuals with prevalent signs of early AMD (soft drusen and/or retinal pigment epithelial changes) and 20,453 individuals without these signs. For various published late AMD risk loci, we also compared effect sizes between early and late AMD using an additional 484 individuals with prevalent late AMD. GWAS meta-analysis confirmed previously reported association of variants at the complement factor H (CFH) (peak P = 1.5{\texttimes}10(-31)) and age-related maculopathy susceptibility 2 (ARMS2) (P = 4.3{\texttimes}10(-24)) loci, and suggested Apolipoprotein E (ApoE) polymorphisms (rs2075650; P = 1.1{\texttimes}10(-6)) associated with early AMD. Other possible loci that did not reach GWAS significance included variants in the zinc finger protein gene GLI3 (rs2049622; P = 8.9{\texttimes}10(-6)) and upstream of GLI2 (rs6721654; P = 6.5{\texttimes}10(-6)), encoding retinal Sonic hedgehog signalling regulators, and in the tyrosinase (TYR) gene (rs621313; P = 3.5{\texttimes}10(-6)), involved in melanin biosynthesis. For a range of published, late AMD risk loci, estimated effect sizes were significantly lower for early than late AMD. This study confirms the involvement of multiple established AMD risk variants in early AMD, but suggests weaker genetic effects on the risk of early AMD relative to late AMD. Several biological processes were suggested to be potentially specific for early AMD, including pathways regulating RPE cell melanin content and signalling pathways potentially involved in retinal regeneration, generating hypotheses for further investigation.

}, keywords = {Apolipoproteins E, Complement Factor H, Genetic Predisposition to Disease, Genome-Wide Association Study, Genotype, Humans, Kruppel-Like Transcription Factors, Macular Degeneration, Nerve Tissue Proteins, Polymorphism, Single Nucleotide, Proteins, Risk Factors, Zinc Finger Protein Gli3}, issn = {1932-6203}, doi = {10.1371/journal.pone.0053830}, author = {Holliday, Elizabeth G and Smith, Albert V and Cornes, Belinda K and Buitendijk, Gabri{\"e}lle H S and Jensen, Richard A and Sim, Xueling and Aspelund, Thor and Aung, Tin and Baird, Paul N and Boerwinkle, Eric and Cheng, Ching Yu and van Duijn, Cornelia M and Eiriksdottir, Gudny and Gudnason, Vilmundur and Harris, Tamara and Hewitt, Alex W and Inouye, Michael and Jonasson, Fridbert and Klein, Barbara E K and Launer, Lenore and Li, Xiaohui and Liew, Gerald and Lumley, Thomas and McElduff, Patrick and McKnight, Barbara and Mitchell, Paul and Psaty, Bruce M and Rochtchina, Elena and Rotter, Jerome I and Scott, Rodney J and Tay, Wanting and Taylor, Kent and Teo, Yik Ying and Uitterlinden, Andr{\'e} G and Viswanathan, Ananth and Xie, Sophia and Vingerling, Johannes R and Klaver, Caroline C W and Tai, E Shyong and Siscovick, David and Klein, Ronald and Cotch, Mary Frances and Wong, Tien Y and Attia, John and Wang, Jie Jin} }