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New susceptibility locus for high myopia is linked to the uromodulin-like 1 (UMODL1) gene region on chromosome 21q22.3. Eye (Lond) 2008; 23:222-9. [DOI: 10.1038/eye.2008.152] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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102
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Pardue MT, Faulkner AE, Fernandes A, Yin H, Schaeffel F, Williams RW, Pozdeyev N, Iuvone PM. High susceptibility to experimental myopia in a mouse model with a retinal on pathway defect. Invest Ophthalmol Vis Sci 2008; 49:706-12. [PMID: 18235018 DOI: 10.1167/iovs.07-0643] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Nob mice share the same mutation in the Nyx gene that is found in humans with complete congenital stationary night blindness (CSNB1). Nob mutant mice were studied to determine whether this defect resulted in myopia, as it does in humans. METHODS Refractive development was measured in unmanipulated wild-type C57BL/6J (WT) and nob mice from 4 to 12 weeks of age by using an infrared photorefractor. The right eye was form deprived by means of a skull-mounted goggling apparatus at 4 weeks of age. Refractive errors were recorded every 2 weeks after goggling. The content of dopamine and the dopamine metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) were measured by HPLC with electrochemical detection (HPLC-ECD) in retinas of nob and WT mice under light- and dark-adapted conditions. RESULTS The nob mice had greater hyperopic refractive errors than did the WT mice under normal visual conditions, until 12 weeks of age when both strains had similar refractions. At 6 weeks of age, refractions became less hyperopic in the nob mice but continued to become more hyperopic in the WT mice. After 2 weeks of form deprivation (6 weeks of age), the nob mice displayed a significant myopic shift (~4 D) in refractive error relative to the opposite and control eyes, whereas WT mice required 6 weeks of goggling to elicit a similar response. As expected with loss of ON pathway transmission, light exposure did not alter DOPAC levels in the nob mice. However, dopamine and DOPAC levels were significantly lower in the nob mice compared with WT. CONCLUSIONS Under normal laboratory visual conditions, only minor differences in refractive development were observed between the nob and WT mice. The largest myopic shift in the nob mice resulted after form deprivation, suggesting that visual pathways dependent on nyctalopin and/or abnormally low dopaminergic activity play a role in regulating refractive development. These findings demonstrate an interaction of genetics and environment in refractive development.
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Affiliation(s)
- Machelle T Pardue
- Rehabilitation Research and Development Center, Atlanta VA Medical Center, Decatur, GA 30033, USA.
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103
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Tang WC, Yap MKH, Yip SP. A review of current approaches to identifying human genes involved in myopia. Clin Exp Optom 2008; 91:4-22. [PMID: 18045248 DOI: 10.1111/j.1444-0938.2007.00181.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The prevalence of myopia is high in many parts of the world, particularly among the Orientals such as Chinese and Japanese. Like other complex diseases such as diabetes and hypertension, myopia is likely to be caused by both genetic and environmental factors, and possibly their interactions. Owing to multiple genes with small effects, genetic heterogeneity and phenotypic complexity, the study of the genetics of myopia poses a complex challenge. This paper reviews the current approaches to the genetic analysis of complex diseases and how these can be applied to the identification of genes that predispose humans to myopia. These approaches include parametric linkage analysis, non-parametric linkage analysis like allele-sharing methods and genetic association studies. Basic concepts, advantages and disadvantages of these approaches are discussed and explained using examples from the literature on myopia. Microsatellites and single nucleotide polymorphisms are common genetic markers in the human genome and are indispensable tools for gene mapping. High throughput genotyping of millions of such markers has become feasible and efficient with recent technological advances. In turn, this makes the identification of myopia susceptibility genes a reality.
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Affiliation(s)
- Wing Chun Tang
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China
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104
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Paget S, Vitezica ZG, Malecaze F, Calvas P. Heritability of refractive value and ocular biometrics. Exp Eye Res 2008; 86:290-5. [PMID: 18160066 DOI: 10.1016/j.exer.2007.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 10/24/2007] [Accepted: 11/01/2007] [Indexed: 11/17/2022]
Affiliation(s)
- Sandrine Paget
- Centre de Physiopathologie de Toulouse Purpan, INSERM, U563, Toulouse, France
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105
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Zayats T, Guggenheim JA, Hammond CJ, Young TL. Comment on ‘A PAX6 gene polymorphism is associated with genetic predisposition to extreme myopia’. Eye (Lond) 2008; 22:598-9; author reply 599. [DOI: 10.1038/sj.eye.6703096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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106
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Fotouhi A, Etemadi A, Hashemi H, Zeraati H, Bailey-Wilson JE, Mohammad K. Familial aggregation of myopia in the Tehran eye study: estimation of the sibling and parent offspring recurrence risk ratios. Br J Ophthalmol 2007; 91:1440-4. [PMID: 17494955 PMCID: PMC2095425 DOI: 10.1136/bjo.2007.120162] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2007] [Indexed: 11/03/2022]
Abstract
AIM To determine the potential influence of genetic factors on the prevalence of myopia in Tehran. METHODS Of 6497 citizens of Tehran sampled from 160 clusters using stratified random cluster sampling, 4565 (70.3%) participated in the study and were referred to a clinic for an extensive eye examination and interview. These were from 1259 nuclear families with the average size of 3.6. Refraction data obtained from 3321 participants aged 16 years and over are presented. Three definitions of myopia, as the spherical equivalent of -0.5, -1, and -2 diopters or less, were used. Familial aggregation of myopia was evaluated with odds ratios and recurrence risk ratios (lambda(R)) using a multiple logistic regression with generalised estimating equations (GEE), adjusted for age, sex, height, and education. RESULTS Multivariate analyses showed a strong familial aggregation of myopia among siblings (lambda(R) ranging from 2.09 to 3.86) and parent-offspring pairs (lambda(R) from 1.82 to 3.81) adjusted for age, sex, height, and education. The aggregation increased with higher myopia thresholds and with the use of cycloplegic refraction. The odds ratios for spouse pairs were not significantly different from 1.0. The association of myopia with sex, height, and education (and not age) remained significant in the final GEE2 model. CONCLUSIONS The findings indicate a relatively high degree of familial aggregation of myopia in the Tehran population, independent of age, sex, height, and education. This residual aggregation may be a result of heredity or of an unmeasured common environmental effect.
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Affiliation(s)
- Akbar Fotouhi
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
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107
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Zhu G, Hewitt AW, Ruddle JB, Kearns LS, Brown SA, Mackinnon JR, Chen CY, Hammond CJ, Craig JE, Montgomery GW, Martin NG, Mackey DA. Genetic dissection of myopia: evidence for linkage of ocular axial length to chromosome 5q. Ophthalmology 2007; 115:1053-1057.e2. [PMID: 17964656 DOI: 10.1016/j.ophtha.2007.08.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Revised: 08/07/2007] [Accepted: 08/09/2007] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To estimate heritability and locate quantitative trait loci influencing axial length. DESIGN Classic twin study of monozygotic and dizygotic twins reared together. PARTICIPANTS Eight hundred ninety-three individuals from 460 families were recruited through the Twin Eye Study in Tasmania and the Brisbane Adolescent Twin Study (BATS) and had ocular axial length measured. METHODS Structural equation modeling on the entire sample was used to estimate genetic and environmental components of variation in axial length. Analysis of existing microsatellite marker genomewide linkage scan data was performed on 318 individuals from 142 BATS families. MAIN OUTCOME MEASURE Ocular axial length. RESULTS The heritability estimate for axial length, adjusted for age and sex, in the full sample was 0.81. The highest multipoint logarithm of the odds (LOD) score observed was 3.40 (genomewide P = 0.0004), on chromosome 5q (at 98 centimorgans [cM]). Additional regions with suggestive multipoint LOD scores were also identified on chromosome 6 (LOD scores, 2.13 at 76 cM and 2.05 at 83 cM), chromosome 10 (LOD score, 2.03 at 131 cM), and chromosome 14 (LOD score, 2.84 at 97 cM). CONCLUSION Axial length, a major endophenotype for refractive error, is highly heritable and is likely to be influenced by one or more genes on the long arm of chromosome 5.
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Affiliation(s)
- Gu Zhu
- Genetic Epidemiology Unit, Queensland Institute of Medical Research, Brisbane, Australia.
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108
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A PAX6 gene polymorphism is associated with genetic predisposition to extreme myopia. Eye (Lond) 2007; 22:576-81. [DOI: 10.1038/sj.eye.6702982] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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109
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Peet JA, Cotch MF, Wojciechowski R, Bailey-Wilson JE, Stambolian D. Heritability and familial aggregation of refractive error in the Old Order Amish. Invest Ophthalmol Vis Sci 2007; 48:4002-6. [PMID: 17724179 PMCID: PMC1995233 DOI: 10.1167/iovs.06-1388] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the heritability of refractive error and familial aggregation of myopia and hyperopia in an elderly Old Order Amish (OOA) population. METHODS Nine hundred sixty-seven siblings (mean age, 64.2 years) in 269 families were recruited for the Amish Eye Study in the Lancaster County area of Pennsylvania. Refractive error was determined by noncycloplegic manifest refraction. Heritability of refractive error was estimated with multivariate linear regression as twice the residual sibling-sibling correlation after adjustment for age and gender. Logistic regression models were used to estimate the sibling recurrence odds ratio (OR(s)). Myopia and hyperopia were defined with five different thresholds. RESULTS The age- and gender-adjusted heritability of refractive error was 70% (95% CI: 48%-92%) in the OOA. Age and gender-adjusted OR(s) and sibling recurrence risk (lambda(s)), with different thresholds defining myopia ranged from 3.03 (95% CI: 1.58-5.80) to 7.02 (95% CI: 3.41-14.46) and from 2.36 (95% CI: 1.65-3.19) to 5.61 (95% CI: 3.06-9.34). Age and gender-adjusted OR(s) and lambda(s) for different thresholds of hyperopia ranged from 2.31 (95% CI: 1.56-3.42) to 2.94 (95% CI: 2.04-4.22) and from 1.33 (95% CI: 1.22-1.43) to 1.85 (95% CI: 1.18-2.78), respectively. Women were significantly more likely than men to have hyperopia. There was no significant gender difference in the risk of myopia. CONCLUSIONS In the OOA, refractive error is highly heritable. Hyperopia and myopia aggregate strongly in OOA families.
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Affiliation(s)
- Jon A. Peet
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mary-Frances Cotch
- Division of Epidemiology and Clinical Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Robert Wojciechowski
- National Human Genome Research Institute, National Institutes of Health, Baltimore, Maryland
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Joan E. Bailey-Wilson
- National Human Genome Research Institute, National Institutes of Health, Baltimore, Maryland
| | - Dwight Stambolian
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania
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Yamane T, Mok J, Oka A, Okada E, Nishizaki R, Meguro A, Yonemoto J, Kulski JK, Ohno S, Inoko H, Mizuki N. Lack of association with high myopia and the MYP2 locus in the Japanese population by high resolution microsatellite analysis on chromosome 18. Clin Ophthalmol 2007; 1:311-6. [PMID: 19668486 PMCID: PMC2701123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
MYP2 was reported for a candidate locus associated with high grade myopia by linkage analysis, but no candidate gene has been detected. We report an association study in the Japanese population using 750 microsatellite markers on chromosome 18 that include MYP2 locus. 450 Japanese subjects with high myopia whose refractive error was greater than or equal to -9.25D in at least one eye and equal number of normal control subjects were recruited in this study. Three steps screening on the pooled DNA of patients and the pooled DNA of controls were performed in this study. A total of 722 microsatellite markers could be analyzed, and we obtained 4 positive markers. Then to avoid experimental errors and artifacts, we confirmed true allele frequency by individual genotyping using initial set of 450 patients and controls. Only marker D18S0301i showed statistically significance, and no marker showed statistically significance on the MYP2 locus. Near the marker D18S0301i, GALNT1 gene was located, but its relation to high myopia has remained to be identified.
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Affiliation(s)
- Takahiro Yamane
- Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Kanagawa, Japan
| | - Jeewon Mok
- Department of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Akira Oka
- Department of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | | | - Ritsuko Nishizaki
- Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Kanagawa, Japan;,Okada Eye Clinic, Yokohama, Kanagawa, Japan
| | - Akira Meguro
- Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Kanagawa, Japan
| | - Junichi Yonemoto
- Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Kanagawa, Japan
| | - Jerzy K Kulski
- Department of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan;,Centre for Comparative Genomics, School for Information Technology, Murdoch University, Murdoch, Western Australia, Australia
| | - Shigeaki Ohno
- Department of Ophthalmology, Hokkaido University School of Medicine, Sapporo, Hokkaido, Japan
| | - Hidetoshi Inoko
- Department of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Nobuhisa Mizuki
- Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Kanagawa, Japan;,Correspondence: Nobuhisa Mizuki, Department of Ophthalmology, Yokohama City University School of Medicine, 3–9 Fukuura, Kanazawa, Yokohama 236-0004, Japan, Tel +81 457872683, Fax +81 457819755, Email
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111
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Mandel Y, Grotto I, El-Yaniv R, Belkin M, Israeli E, Polat U, Bartov E. Season of birth, natural light, and myopia. Ophthalmology 2007; 115:686-92. [PMID: 17698195 DOI: 10.1016/j.ophtha.2007.05.040] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Revised: 05/21/2007] [Accepted: 05/21/2007] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To investigate the possible roles of season of birth and perinatal duration of daylight hours (photoperiod) in the development of myopia. DESIGN Retrospective, population-based, epidemiological study. PARTICIPANTS A total of 276 911 adolescents (157 663 male, 119 248 female) 16 to 22 years old. All were Israeli-born conscripts to the Israeli Defense Forces who were examined during the 5-year period 2000 through 2004. METHODS Noncycloplegic refraction was determined by autorefractometer and validated by qualified optometrists. Myopia, defined on the basis of right eye spherical equivalence, was classified as mild (-0.75 to -2.99 diopters [D]), moderate (-3.0 to -5.99 D), or severe (-6.0 D or worse). The photoperiod was recorded from astronomical tables and classified into 4 categories. Using multivariate logistic regression models, we calculated odds ratios (ORs) for several risk factors of myopia including season of birth. MAIN OUTCOME MEASURE The OR for photoperiod categories as risk factors for myopia. RESULTS Overall prevalences of mild, moderate, and severe myopia were 18.8%, 8.7%, and 2.4%, respectively. There were seasonal variations in moderate and severe myopia according to birth month, with prevalence highest for June/July births and lowest for December/January. On multivariate logistic regression, the ORs of photoperiod categories for moderate and severe myopia were highly significant and demonstrated a dose-response pattern. Odds ratios for severe myopia were highest for the shortest versus the longest photoperiods (1.24; 95% confidence interval, 1.15-1.33; P<0.001). Mild myopia was not associated with season of birth or perinatal light exposure. Other risk factors were gender (1.14 for female), education level (1.32 for age above 12), and father's origin (1.31 for Eastern vs. Israeli origin). CONCLUSION Myopia in this population is associated with birth during summer months. The exact associating mechanism is not known but might be related to exposure to natural light during the early perinatal period.
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Affiliation(s)
- Yossi Mandel
- Israel Defense Force Medical Corps, Ramat-Gan, Israel.
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112
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Mutti DO, Cooper ME, O'Brien S, Jones LA, Marazita ML, Murray JC, Zadnik K. Candidate gene and locus analysis of myopia. Mol Vis 2007; 13:1012-9. [PMID: 17653045 PMCID: PMC2776540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
PURPOSE A previous study has reported evidence of a strong linkage, but no association, between paired box gene 6 (PAX6) and myopia. We attempted to replicate these findings and to conduct a candidate gene and locus evaluation of genetic involvement in common forms of myopia. METHODS Samples were collected from 517 individuals in 123 families with a myopic child participating in the Orinda Longitudinal Study of Myopia or the Contact Lens and Myopia Progression Study. Myopia in the proband children was defined as -0.75 D or more and as being present in both meridians on cycloplegic autorefraction (1% tropicamide). Affected status in parents and siblings was determined by survey. After DNA was extracted from buccal mucosal cells and genotyped using assays for microsatellite markers and single nucleotide polymorphisms (SNPs), DNA was analyzed for linkage disequilibrium. Markers on chromosomes 12 and 18 were selected as regions previously associated with pathological myopia. SNPs were also analyzed in genes where their expression pattern or their association with syndromes conveys myopia as part of the phenotype (FGF2, BDNF, COL2A1, COL18A1, and PAX6). RESULTS The SNP rs1635529 for COL2A1 on 12q13.11 showed highly significant over-transmission to affected individuals (p=0.00007). No SNP for FGF2, BDNF, COL18A1, or PAX6 showed significant over-transmission to affected individuals after correction for multiple comparisons. Markers on chromosome 12 and 18 previously associated with pathological myopia also showed no significant associations with the more common form of myopia in this study. CONCLUSIONS As reported previously by others, PAX6 showed no association with myopia. Associations in the current analysis are suggestive of involvement of COL2A1. Future studies should focus on replication in other samples and in genome-wide approaches.
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Affiliation(s)
- Donald O Mutti
- College of Optometry, The Ohio State University, Columbus, OH 43210-1240, USA.
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113
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Inamori Y, Ota M, Inoko H, Okada E, Nishizaki R, Shiota T, Mok J, Oka A, Ohno S, Mizuki N. The COL1A1 gene and high myopia susceptibility in Japanese. Hum Genet 2007; 122:151-7. [PMID: 17557158 DOI: 10.1007/s00439-007-0388-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Accepted: 05/27/2007] [Indexed: 11/27/2022]
Abstract
The collagen type Iota alpha Iota (COL1A1) gene encodes the extracellular matrix component, collagen, and resides in candidate MYP5 for high myopia on the chromosome 17q22-q23.3. This locus has recently been implicated in playing an important role in the pathogenesis of experimental myopia. We investigated the association of disruptions of COL1A1 gene with high myopia by analyzing the frequency of ten SNPs in a Japanese population of 330 subjects with high myopia of -9.25 D or less and 330 randomized controls without high myopia. Two SNPs (rs2075555 and rs2269336) were significantly associated with high myopia (P < 0.05, Pc < 0.1). Two different haplotype blocks in COL1A1 were observed by the pair-wise linkage disequilibrium between the SNPs. The frequency of GGC/GGC diplotype constructed by the three SNPs (rs2075555, rs2269336, rs1107946) was significantly high (OR = 1.6) and associated with high myopia (P = 0.028, Pc< 0.084). Together our results provide the first evidence for COL1A1 as a gene associated with high myopia.
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Affiliation(s)
- Yumiko Inamori
- Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Kanagawa, Japan
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114
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Garoufalis P, Chen CY, Islam FMA, Dirani M, Pertile KK, Richardson AJ, Couper TA, Taylor HR, Baird PN. Evaluation of Accuracy in Proband-Reported Family History and Its Determinants: The Genes in Myopia Family Study. Optom Vis Sci 2007; 84:481-6. [PMID: 17568317 DOI: 10.1097/opx.0b013e31806dba75] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Proband-reported family histories are widely used in epidemiological and genetic studies. The accuracy of these reports may have significant effects on the intended outcome, particularly in genetic studies. This study aims to determine the accuracy of proband-reported family history of myopia and to assess whether demographic or clinical factors are predictive of an accurate history. METHODS In 2004 to 2005, the study recruited 120 myopic probands (< or = -0.50 D spherical equivalent in both eyes) aged 18 to 72 years and 358 nuclear family members residing within Victoria, Australia as part of the Genes in Myopia (GEM) family study. Data collection used an examiner-administered questionnaire with an ocular examination. Proband-reported family history of myopia was evaluated for agreement with ophthalmic examination results of family members. RESULTS The statistical measures of accuracy used in this report were sensitivity, specificity, positive predictive value, and negative predictive value. Sensitivity varied from 85 to 98%, specificity from 84 to 96%, positive predictive value from 83 to 97%, and negative predictive value from 84 to 97%. Following multivariate analysis, an evaluation of demographic and clinical factors indicated that the highest predictive accuracy was obtained from proband reporting of their children [odds ratio (OR), 0.38; 95% confidence interval (CI), 0.15 to 0.94] whereas the most inaccurate reporting of a proband was when there was less-severe maternal myopia (per 0.50 D less myopic) (OR, 1.23; 95% CI, 1.06 to 1.43) or for increase in total education of the proband (per 1 year increase) (OR, 1.22; 95% CI, 1.04 to 1.42). CONCLUSIONS Several variables influence the accuracy of obtaining a family history of myopia. A questionnaire-based approach alone will introduce some error into the study and this should be taken into account when designing and undertaking family-based epidemiological or genetic studies of myopia.
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Affiliation(s)
- Pam Garoufalis
- Centre for Eye Research Australia, University of Melbourne, Victoria, Australia
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115
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Tang WC, Yip SP, Lo KK, Ng PW, Choi PS, Lee SY, Yap MK. Linkage and association of myocilin (MYOC) polymorphisms with high myopia in a Chinese population. Mol Vis 2007; 13:534-44. [PMID: 17438518 PMCID: PMC2652017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
PURPOSE To test the association between myocilin gene (MYOC) polymorphisms and high myopia in Hong Kong Chinese by using family-based association study. METHODS A total of 162 Chinese nuclear families, consisting of 557 members, were recruited from an optometry clinic. Each family had two parents and at least one offspring with high myopia (defined as -6.00D or less for both eyes). All offspring were healthy with no clinical evidence of syndromic disease and other ocular abnormality. Genotyping was performed for two MYOC microsatellites (NGA17 and NGA19) and five tag single nucleotide polymorphisms (SNPs) spreading across the gene. The genotype data were analyzed with Family-Based Association Test (FBAT) software to check linkage and association between the genetic markers and myopia, and with GenAssoc to generate case and pseudocontrol subjects for investigating main effects of genetic markers and calculating the genotype relative risks (GRR). RESULTS FBAT analysis showed linkage and association with high myopia for two microsatellites and two SNPs under one to three genetic models after correction for multiple comparisons by false discovery rate. NGA17 at the promoter was significant under an additive model (p=0.0084), while NGA19 at the 3' flanking region showed significant results under both additive (p=0.0172) and dominant (p=0.0053) models. SNP rs2421853 (C>T) exhibited both linkage and association under additive (p=0.0009) and dominant/recessive (p=0.0041) models. SNP rs235858 (T>C) was also significant under additive (p=4.0E-6) and dominant/recessive (p=2.5E-5) models. Both SNPs were downstream of NGA19 at the 3' flanking region. Positive results for these SNPs were novel findings. A stepwise conditional logistic regression analysis of the case-pseudocontrol dataset generated by GenAssoc from the families showed that both SNPs could separately account for the association of NGA17 or NGA19, and that both SNPs contributed separate main effects to high myopia. For rs2421853 and with C/C as the reference genotype, the GRR increased from 1.678 for G/A to 2.738 for A/A (p=9.0E-4, global Wald test). For rs235858 and with G/G as the reference, the GRR increased 2.083 for G/A to 3.931 for A/A (p=2.0E-2, global Wald test). GRR estimates thus suggested an additive model for both SNPs, which was consistent with the finding that, of the three models tested, the additive model gave the lowest p values in FBAT analysis. CONCLUSIONS Linkage and association was shown between the MYOC polymorphisms and high myopia in our family-based association study. The SNP rs235858 at the 3' flanking region showed the highest degree of confidence for association.
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Affiliation(s)
- Wing Chun Tang
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Shea Ping Yip
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Ka Kin Lo
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Po Wah Ng
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Pik Shan Choi
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Sau Yin Lee
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Maurice K.H. Yap
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
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Nallasamy S, Paluru PC, Devoto M, Wasserman NF, Zhou J, Young TL. Genetic linkage study of high-grade myopia in a Hutterite population from South Dakota. Mol Vis 2007; 13:229-36. [PMID: 17327828 PMCID: PMC2633468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Myopia is a common, complex disorder, and severe forms have implications for blindness due to increased risk of premature cataracts, glaucoma, retinal detachment, and macular degeneration. Autosomal dominant (AD) non-syndromic high-grade myopia has been mapped to chromosomes 18p11.31, 12q21-23, 17q21-23, 7q36, 2q37.1, 7p15.3, 15q12-13, 3q26, 4q12, 8p23, 4q22-q27, 1p36, and Xq23-q25. Here, we demonstrate evidence of linkage for AD non-syndromic high-grade myopia in a large Hutterite family to a locus on chromosome 10q21.1. METHODS After clinical evaluation, genomic DNA was genotyped from 29 members of a Hutterite family from South Dakota (7 affected). The average refractive error of affected individuals was -7.04 diopters. Microsatellite markers were used to exclude linkage to the known AD nonsyndromic high-grade myopia loci as well as to syndromic high-grade myopia loci. A genome screen was then performed using 382 markers with an average inter-marker distance of 10 cM followed by fine-point mapping in all regions of the genome that gave positive LOD scores. SimWalk2 software was used for multipoint linkage based on AD and autosomal recessive (AR) models with a penetrance of 90% and a disease allele frequency of 0.001. RESULTS A maximum multipoint LOD score of 3.22 was achieved under an AD model at microsatellite marker D10S1643. Fine point mapping and haplotype analysis defined a critical region of 2.67 cM on chromosome 10q21.1. Haplotype analysis demonstrated two distinct haplotypes segregating with high-grade myopia, indicative of two distinct mutations occurring in the same gene. CONCLUSIONS We have identified a presumptive myopia locus for high-grade myopia based on linkage and haplotype analysis.
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Affiliation(s)
- Sudha Nallasamy
- Divisions of Ophthalmology, Children’s Hospital of Philadelphia, Philadelphia, PA,Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA,University of Pennsylvania School of Medicine, Philadelphia, PA
| | - Prasuna C. Paluru
- Divisions of Ophthalmology, Children’s Hospital of Philadelphia, Philadelphia, PA,Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Marcella Devoto
- Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA,University of Pennsylvania School of Medicine, Philadelphia, PA,Center for Clinical Epidemiology and Biostatistics (CCEB), University of Pennsylvania School of Medicine, Philadelphia, PA,Dipartimento di Medicina Sperimentale e Patologia, Universita' La Sapienza, Roma, Italy
| | - Nora F. Wasserman
- Divisions of Ophthalmology, Children’s Hospital of Philadelphia, Philadelphia, PA,Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Jie Zhou
- Divisions of Ophthalmology, Children’s Hospital of Philadelphia, Philadelphia, PA,Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Terri L. Young
- Divisions of Ophthalmology, Children’s Hospital of Philadelphia, Philadelphia, PA,Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA,University of Pennsylvania School of Medicine, Philadelphia, PA,Departments of Ophthalmology and Pediatrics, Duke University Medical Center, Durham, NC
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Chen CYC, Scurrah KJ, Stankovich J, Garoufalis P, Dirani M, Pertile KK, Richardson AJ, Mitchell P, Baird PN. Heritability and shared environment estimates for myopia and associated ocular biometric traits: the Genes in Myopia (GEM) family study. Hum Genet 2007; 121:511-20. [PMID: 17205325 DOI: 10.1007/s00439-006-0312-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Accepted: 12/01/2006] [Indexed: 12/14/2022]
Abstract
To examine the familial correlations, heritability (h(2)) and common environmental components (c(2)) of myopia and ocular biometric traits (all treated as continuous outcomes) in families collected through the Genes in Myopia (GEM) family study in Australia. A total of 132 pedigrees (723 participants) were recruited for this study. All individuals completed a risk factor questionnaire and underwent a detailed eye examination including spherical equivalent (SphE) and ocular biometric measurements of axial length (AL), anterior chamber depth (ACD) and corneal curvature (CC). Familial correlations were calculated and h(2) and c(2) were estimated using a variance component model that assumes a multivariate t distribution within each pedigree. Two definitions of common environments (c(2)) were considered: nuclear family (current) shared environment (Model 1) and sib-ship (childhood) shared environment (Model 2). Population ascertainment adjustment was performed using the Blue Mountains eye study dataset. The trends observed for familial correlations suggested that SphE is influenced by both environmental and genetic factors whereas AL, ACD and CC are predominantly genetically determined. This was largely confirmed by variance components modelling. Heritability estimates (adjusted for age, sex and years of education) from the best fitting ACE model (Model 2, childhood shared environment) were 0.50 +/- 0.05 for SphE, 0.73 +/- 0.04 for AL, 0.78 +/- 0.04 for ACD and 0.16 +/- 0.06 for CC. Childhood environmental effects were significant with c(2) estimated to be 0.33 +/- 0.04 for SphE, 0.06 +/- 0.03 for AL, 0.22 +/- 0.04 for ACD and 0.10 +/- 0.05 for CC. Age was associated with SphE, total years of education was associated with AL and sex was associated with all traits studied. We used a novel and conservative approach to account for and estimate common environmental effects by specifying either nuclear family or sib-ship environment when estimating heritability estimates and showed that all traits examined (SphE, AL, ACD and CC) are heritable, thus reflecting a genetic component. These traits therefore all represent candidates for quantitative trait linkage analyses.
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Affiliation(s)
- Christine Yi-Chin Chen
- Ocular Genetics Unit, Eye Research Australia, The University of Melbourne, 32 Gisborne Street, East Melbourne, VIC, 3002, Australia.
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Majava M, Bishop PN, Hägg P, Scott PG, Rice A, Inglehearn C, Hammond CJ, Spector TD, Ala-Kokko L, Männikkö M. Novel mutations in the small leucine-rich repeat protein/proteoglycan (SLRP) genes in high myopia. Hum Mutat 2007; 28:336-44. [PMID: 17117407 DOI: 10.1002/humu.20444] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The importance of the genetic component in high myopia has been well established in population and family studies, but only a few candidate genes have been explored to date. The extracellular matrix small leucine-rich repeat proteins/proteoglycans (SLRPs) regulate collagen fibril diameter and spacing. Given their role in extracellular matrix assembly and expression in the eye, they are likely to regulate its shape and size. Analysis of 85 English and 40 Finnish subjects with high myopia (refractive error of -6 diopters [D] or greater) resulted in 23 sequence variations in four SLRP genes, LUM, FMOD, PRELP, and OPTC. We observed higher number of variations in OPTC in English patients than in controls (p=0.042), and a possibly protective variation in LUM (c.893-105G>A) with p-value of 0.0043. Two intronic variations, six nonsynonymous and one synonymous amino acid changes, were not found in any of the nonmyopic controls. Five changes were detected in opticin, Thr177Arg, Arg229His, Arg325Trp, Gly329Ser, and Arg330His, and all but one (Arg229His) were shown to cosegregate with high myopia in families with incomplete penetrance. A homology model for opticin revealed that Arg229His and Arg325Trp are likely to disrupt the protein structure, and PolyPhen analysis suggested that Thr177Arg, Arg325Trp, and Gly329Ser changes may be damaging. A Leu199Pro change in lumican and Gly147Asp and Arg324Thr variations in fibromodulin are located in the highly conserved leucine-rich repeat (LRR) domains. This study provides new insight into the genetics of high myopia, suggesting that sequence variations in the SLRP genes expressed in the eye may be among the genetic risk factors underlying the pathogenesis of high myopia.
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Affiliation(s)
- Marja Majava
- Collagen Research Unit, Biocenter and Department of Medical Biochemistry and Molecular Biology, University of Oulu, Oulu, Finland
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119
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Guggenheim JA, Pong-Wong R, Haley CS, Gazzard G, Saw SM. Correlations in refractive errors between siblings in the Singapore Cohort Study of Risk factors for Myopia. Br J Ophthalmol 2006; 91:781-4. [PMID: 17135339 PMCID: PMC1955602 DOI: 10.1136/bjo.2006.107441] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The prevalence of myopia in parts of South East Asia has risen dramatically over the past 1-2 generations, suggesting that environmental factors may be particularly important determinants of refractive development in these populations. AIM To assess the contribution of familial factors (shared genes and/or shared family environment) to refractive error and ocular component dimensions of school-aged children in Singapore. METHODS Data were available for 315 children who had one or more siblings also participating in the Singapore Cohort Study of the Risk factors for Myopia (SCORM). Refractive error and ocular biometric parameters were measured under cycloplegia at baseline when children were 7-9 years, and at yearly follow-up sessions for the next 3 years, using consistent clinical procedures. The time children spent performing a variety of nearwork-related tasks was obtained from questionnaires. Familial influences were assessed by calculating between-sibling correlations. RESULTS After adjusting for age and sex, the between-sibling correlation in refractive error was 0.447 (95% CI 0.314 to 0.564), suggesting that familial factors account for 63-100% of the variation in the cohort. The between-sibling correlation for 1-year change in refractive error was similarly high, at 0.420 (95% CI 0.282 to 0.543). All ocular component dimensions were correlated significantly between siblings, especially for corneal curvature and vitreous chamber depth--the major structural determinants of refraction. The amount of time siblings spent engaged in nearwork tasks (reading, watching TV, playing video games, computing) and in outdoor activities was also highly correlated between siblings (p<0.001). CONCLUSION Shared genes and/or shared environment are important factors in the refractive development of children in Singapore. Because the time spent in nearwork tasks is highly correlated between siblings, epidemiological studies will benefit from precise, quantitative measures of refractive error in parents and more distant relatives in order to begin to dissociate genetic and environmental sources of variation.
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Affiliation(s)
- Jeremy A Guggenheim
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales CF10 3NB, UK.
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120
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Wilson SG, Adam G, Langdown M, Reneland R, Braun A, Andrew T, Surdulescu GL, Norberg M, Dudbridge F, Reed PW, Sambrook PN, Kleyn PW, Spector TD. Linkage and potential association of obesity-related phenotypes with two genes on chromosome 12q24 in a female dizygous twin cohort. Eur J Hum Genet 2006; 14:340-8. [PMID: 16391564 DOI: 10.1038/sj.ejhg.5201551] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Obesity is a multifactorial disorder with a complex phenotype. It is a significant risk factor for diabetes and hypertension. We assessed obesity-related traits in a large cohort of twins and performed a genome-wide linkage scan and positional candidate analysis to identify genes that play a role in regulating fat mass and distribution in women. Dizygous female twin pairs from 1,094 pedigrees were studied (mean age 47.0+/-11.5 years (range 18-79 years)). Nonparametric multipoint linkage analyses showed linkage for central fat mass to 12q24 (141 cM) with LOD 2.2 and body mass index to 8q11 (67 cM) with LOD 1.3, supporting previously established linkage data. Novel areas of suggestive linkage were for total fat percentage at 6q12 (LOD 2.4) and for total lean mass at 2q37 (LOD 2.4). Data from follow-up fine mapping in an expanded cohort of 1243 twin pairs reinforced the linkage for central fat mass to 12q24 (LOD 2.6; 143 cM) and narrowed the -1 LOD support interval to 22 cM. In all, 45 single-nucleotide polymorphisms (SNPs) from 26 positional candidate genes within the 12q24 interval were then tested for association in a cohort of 1102 twins. Single-point Monks-Kaplan analysis provided evidence of association between central fat mass and SNPs in two genes - PLA2G1B (P = 0.0067) and P2RX4 (P = 0.017). These data provide replication and refinement of the 12q24 obesity locus and suggest that genes involved in phospholipase and purinoreceptor pathways may regulate fat accumulation and distribution.
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Affiliation(s)
- Scott G Wilson
- Department of Endocrinology & Diabetes, Sir Charles Gairdner Hospital, Nedlands, Australia
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121
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Wojciechowski R, Moy C, Ciner E, Ibay G, Reider L, Bailey-Wilson JE, Stambolian D. Genomewide scan in Ashkenazi Jewish families demonstrates evidence of linkage of ocular refraction to a QTL on chromosome 1p36. Hum Genet 2006; 119:389-99. [PMID: 16501916 PMCID: PMC3123998 DOI: 10.1007/s00439-006-0153-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Accepted: 01/29/2006] [Indexed: 11/24/2022]
Abstract
UNLABELLED The development of refractive error is mediated by both environmental and genetic factors. We performed regression-based quantitative trait locus (QTL) linkage analysis on Ashkenazi Jewish families to identify regions in the genome responsible for ocular refraction. We measured refractive error on individuals in 49 multi-generational American families of Ashkenazi Jewish descent. The average family size was 11.1 individuals and was composed of 2.7 generations. Recruitment criteria specified that each family contain at least two myopic members. The mean spherical equivalent refractive error in the sample was -3.46D (SD=3.29) and 87% of individuals were myopic. Microsatellite genotyping with 387 markers was performed on 411 individuals. We performed multipoint regression-based linkage analysis for ocular refraction and a log transformation of the trait using the statistical package Merlin-Regress. Empirical genomewide significance levels were estimated through gene-dropping simulations by generating random genotypes at each of the 387 markers in 200 replicates of our pedigrees. Maximum LOD scores of 9.5 for ocular refraction and 8.7 for log-transformed refraction (LTR) were observed at 49.1 cM on chromosome 1p36 between markers D1S552 and D1S1622. The empirical genomewide significance levels were P=0.065 for ocular refraction and P<0.005 for LTR, providing strong evidence for linkage of refraction to this locus. The inter-marker region containing the peak spans 11 Mb and contains approximately 189 genes. CONCLUSION We found genomewide significant evidence for linkage of refractive error to a novel QTL on chromosome 1p36 in an Ashkenazi Jewish population.
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Affiliation(s)
- Robert Wojciechowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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122
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Stambolian D, Ciner EB, Reider LC, Moy C, Dana D, Owens R, Schlifka M, Holmes T, Ibay G, Bailey-Wilson JE. Genome-wide scan for myopia in the Old Order Amish. Am J Ophthalmol 2005; 140:469-76. [PMID: 16084785 DOI: 10.1016/j.ajo.2005.04.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Revised: 04/01/2005] [Accepted: 04/01/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE To identify myopia susceptibility genes influencing common myopia in 34 Old Order Amish families, a genetically well-defined founder population. DESIGN A prospective study of families with myopia consisting of a minimum of two individuals affected with myopia. METHODS Extended families consisting of at least two siblings affected with myopia were ascertained. A genome-wide linkage scan using 387 markers was conducted by the Center for Inherited Disease Research (CIDR). Linkage analyses were conducted with parametric (autosomal dominant, fixed penetrance model) and nonparametric methods. Model-free linkage analysis was also performed maximizing over penetrance and over dominance (that is, fitting a wide range of both dominant and recessive models). RESULTS Under the fixed penetrance model, the maximum two-point heterogeneity LOD score (HLOD) was 1.59 at D20S451 and the maximum multipoint HLOD was 1.92 at D6S1021. The nonparametric maximum multipoint (NPL) at D3S2427 had a P-value of .0005. Under the model-free analysis, multipoint heterogeneity LOD scores of 2.03 were observed on both chromosomes 8 (under a recessive model between D8S1130 and D8S1106) and X (under a recessive model between DXS6800 and DXS6789). Reanalyses of chromosomes 3, 6, 8, 20, and X using the best penetrance models resulted in maximum multipoint HLODs of 1.84 at D3S3053; 1.84 at D3S2427; 2.04 at D8S1130; and 2.34 at DXS6800. CONCLUSIONS The locus on chromosome 8p23 independently confirms a report by Hammond and associates mapping a myopia quantitative trait loci (QTL) to this region.
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Affiliation(s)
- Dwight Stambolian
- Department of Ophthalmology, Stellar Chance Laboratories Rm. 313, University of Pennsylvania, 422 Curie Boulevard, Philadelphia, PA 19104, USA.
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123
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Bhat SP, Rayner SA, Chau SC, Ariyasu RG. Pax-6 expression in posthatch chick retina during and recovery from form-deprivation myopia. Dev Neurosci 2005; 26:328-35. [PMID: 15855761 DOI: 10.1159/000082274] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2004] [Accepted: 09/20/2004] [Indexed: 11/19/2022] Open
Abstract
The expression of Pax-6 in fully-differentiated chick retina remains largely confined to the amacrine and ganglion cell layers. In the developing posthatch chick retina, Pax-6 expression shows a biphasic pattern; a decrease by posthatch day 17 followed by a steady increase in the adult eye. Interestingly, we find that this biphasic expression of Pax-6 is reflected in the biphasic growth pattern of the posthatch chick eye, which is disrupted by form-deprivation myopia (FDM). We have now examined the pattern of Pax-6 accumulation in 3-day-old chick eyes subjected to 2 weeks of FDM followed by 2 weeks of recovery from FDM. Quantitative RT-PCR (with a homologous internal control) revealed that after 2 weeks of occlusion the contralateral non occluded eyes, the occluded eyes and the normal nonexperimental chick eyes did not show any drastic changes in the number of Pax-6 transcripts. The data obtained suggests that the contralateral eye does not represent a 'normal' control eye; similar but nonidentical changes are seen, at the molecular level, in both the contralateral and the occluded eyes. Comparisons with the control nonexperimental animals, however, are meaningful. Even after 2 weeks of recovery under normal light conditions, the occluded eyes do not seem to reach the same level of Pax-6 expression (number of molecules per mg tissue) as seen in normal control eyes, suggesting that exposure of the posthatch chick eye to FDM impedes developmental progression that normally culminates in emmetropia.
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Affiliation(s)
- Suraj P Bhat
- Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA.
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124
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Mallen EAH, Gilmartin B, Wolffsohn JS. Sympathetic innervation of ciliary muscle and oculomotor function in emmetropic and myopic young adults. Vision Res 2005; 45:1641-51. [PMID: 15792840 DOI: 10.1016/j.visres.2004.11.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Revised: 10/26/2004] [Accepted: 11/12/2004] [Indexed: 11/18/2022]
Abstract
PURPOSE Evidence exists for an additional inhibitory accommodative control system mediated by the sympathetic branch of the autonomic nervous system (ANS). This work aims to show the relative prevalence of sympathetic inhibition in young emmetropic and myopic adults, and to evaluate the effect of sympathetic facility on accommodative and oculomotor function. METHODS Profiling of ciliary muscle innervation was carried out in 58 young adult subjects (30 emmetropes, 14 early onset myopes, 14 late onset myopes) by examining post-task open-loop accommodation responses, recorded continuously by a modified open-view infrared optometer. Measurements of amplitude of accommodation, tonic accommodation, accommodative lag at near, AC/A ratio, and heterophoria at distance and near were made to establish a profile of oculomotor function. RESULTS Evidence of sympathetic inhibitory facility in ciliary smooth muscle was observed in 27% of emmetropes, 21% of early-onset myopes and 29% of late-onset myopes. Twenty-six percent of all subjects demonstrated access to sympathetic facility. Closed-loop oculomotor function did not differ significantly between subjects with sympathetic facility, and those with sympathetic deficit. CONCLUSIONS Emmetropic and myopic groups cannot be distinguished in terms of the relative proportions having access to sympathetic inhibition. Presence of sympathetic innervation does not have a significant effect on accommodative function under closed-loop viewing conditions.
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Affiliation(s)
- Edward A H Mallen
- Department of Optometry, University of Bradford, Richmond Road, Bradford, West Yorkshire BD7 1DP, UK.
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125
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Wojciechowski R, Congdon N, Bowie H, Munoz B, Gilbert D, West SK. Heritability of refractive error and familial aggregation of myopia in an elderly American population. Invest Ophthalmol Vis Sci 2005; 46:1588-92. [PMID: 15851555 PMCID: PMC3092734 DOI: 10.1167/iovs.04-0740] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
PURPOSE To determine the heritability of refractive error and the familial aggregation of myopia in an older population. METHODS Seven hundred fifty-nine siblings (mean age, 73.4 years) in 241 families were recruited from the Salisbury Eye Evaluation (SEE) Study in eastern Maryland. Refractive error was determined by noncycloplegic subjective refraction (if presenting distance visual acuity was < or =20/40) or lensometry (if best corrected visual acuity was >20/40 with spectacles). Participants were considered plano (refractive error of zero) if uncorrected visual acuity was >20/40. Preoperative refraction from medical records was used for pseudophakic subjects. Heritability of refractive error was calculated with multivariate linear regression and was estimated as twice the residual between-sibling correlation after adjusting for age, gender, and race. Logistic regression models were used to estimate the odds ratio (OR) of myopia, given a myopic sibling relative to having a nonmyopic sibling. RESULTS The estimated heritability of refractive error was 61% (95% confidence interval [CI]: 34%-88%) in this population. The age-, race-, and sex-adjusted ORs of myopia were 2.65 (95% CI: 1.67-4.19), 2.25 (95% CI: 1.31-3.87), 3.00 (95% CI: 1.56-5.79), and 2.98 (95% CI: 1.51-5.87) for myopia thresholds of -0.50, -1.00, -1.50, and -2.00 D, respectively. Neither race nor gender was significantly associated with an increased risk of myopia. CONCLUSIONS Refractive error and myopia are highly heritable in this elderly population.
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Affiliation(s)
- Robert Wojciechowski
- Bloomberg School of Public Health, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
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Abstract
Myopia is of diverse aetiology. A small proportion of myopia is clearly familial, generally early in onset and of high level, with defined chromosomal localisations and in some cases, causal genetic mutations. However, in economically developed societies, most myopia appears during childhood, particularly during the school years. The chromosomal localisations characterised so far for high familial myopia do not seem to be relevant to school myopia. Family correlations in refractive error and axial length are consistent with a genetic contribution to variations in school myopia, but potentially confound shared genes and shared environments. High heritability values are obtained from twin studies, but rest on contestable assumptions, and require further critical analysis, particularly in view of the low heritability values obtained from parent-offspring correlations where there has been rapid environmental change between generations. Since heritability is a population-specific parameter, the values obtained on twins cannot be extrapolated to define the genetic contribution to variation in the general population. In addition, high heritability sets no limit to the potential for environmentally induced change. There is in fact strong evidence for rapid, environmentally induced change in the prevalence of myopia, associated with increased education and urbanisation. These environmental impacts have been found in all major branches of the human family, defined in modern molecular terms, with the exception of the Pacific Islanders, where the evidence is too limited to draw conclusions. The idea that populations of East Asian origin have an intrinsically higher prevalence of myopia is not supported by the very low prevalence reported for them in rural areas, and by the high prevalence of myopia reported for Indians in Singapore. A propensity to develop myopia in "myopigenic" environments thus appears to be a common human characteristic. Overall, while there may be a small genetic contribution to school myopia, detectable under conditions of low environmental variation, environmental change appears to be the major factor increasing the prevalence of myopia around the world. There is, moreover, little evidence to support the idea that individuals or populations differ in their susceptibility to environmental risk factors.
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Affiliation(s)
- Ian Morgan
- Visual Sciences Group, Research School of Biological Sciences and Centre for Visual Science, Australian National University, GPO Box 475, Canberra City, ACT 2601, Australia.
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Manson FDC, Trump D, Read AP, Black GCM. Inherited eye disease: cause and late effect. Trends Mol Med 2005; 11:449-55. [PMID: 16153893 DOI: 10.1016/j.molmed.2005.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Revised: 07/12/2005] [Accepted: 08/16/2005] [Indexed: 01/14/2023]
Abstract
Molecular genetics has provided relatively few insights into late-onset eye disorders, but epidemiological data indicate that genetic factors are important in some late-onset eye disorders that cause major health burdens. Much clinical genetic research is based on the belief that developmental and late-onset disorders are not necessarily the result of defects in different genes, but are often caused by different mutations in the same collection of genes. Thus, mutations that either abolish or radically change gene function might cause early-onset disorders, whereas more-subtle changes in gene expression might underlie late-onset diseases. We present arguments and examples that indicate that this principle might be a fruitful guide to investigating the causes of late-onset eye disorders.
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Affiliation(s)
- Forbes D C Manson
- Academic Unit of Eye and Vision Science, Manchester Royal Eye Hospital, School of Medicine, University of Manchester, Oxford Road, Manchester M13 9WH, UK
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128
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Biino G, Palmas MA, Corona C, Prodi D, Fanciulli M, Sulis R, Serra A, Fossarello M, Pirastu M. Ocular refraction: heritability and genome-wide search for eye morphometry traits in an isolated Sardinian population. Hum Genet 2004; 116:152-9. [PMID: 15611866 DOI: 10.1007/s00439-004-1231-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2004] [Accepted: 11/14/2004] [Indexed: 11/30/2022]
Abstract
No genes influencing oculometric phenotypes have yet been identified, despite it being well known that eye morphometry is involved in refraction and that genetics may play an important role. We have therefore performed a heritability analysis and genome-wide search (GWS) of biometric ocular traits in an isolated Sardinian population, assessing the genetic contribution and identifying the associated genetic loci. A complete eye examination including refraction and ocular biometry measurements such as axial length (AL), anterior chamber depth (ACD) and corneal curvature (CC), was performed on 789 subjects. Heritability analysis was carried out by means of parent-offspring regression and variance component models. Univariate and bivariate linkage analysis was performed by using 654 microsatellite markers spanning the genome. CC showed a mean heritability of 57%. AL and ACD were found to have significantly different variances (P<0.01) in males and females, so that heritability was calculated separately for each sex. AL had an estimated heritability in females of 31% and in males of 60%, whereas ACD had an estimated heritability of 47% in females and of 44% in males. In the GWS, the most suggestive evidence of linkage was identified on chromosome 2 for AL (LOD 2.64), on chromosome 1 for ACD (LOD 2.32) and on chromosomes 7, 2 and 3 for CC (LOD 2.50, 2.44 and 2.34, respectively). High heritability of eye morphometry traits was thus revealed. The identified loci are the first linkage signals available in ocular biometry. Notably, the observed significant differences in parental transmission deserve further study.
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Affiliation(s)
- Ginevra Biino
- Institute of Population Genetics, CNR, Alghero, Italy
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