IOVS AJP: Lung Cellular and Molecular Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Originally published In Press as doi:10.1167/iovs.08-2385 on August 29, 2008
 (Investigative Ophthalmology and Visual Science. 2009;50:126-131.)
© 2009 by The Association for Research in Vision and Ophthalmology, Inc.
DOI:  10.1167/iovs.08-2385
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
iovs.08-2385v1
50/1/126    most recent
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lopes, M. C.
Right arrow Articles by Hammond, C. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lopes, M. C.
Right arrow Articles by Hammond, C. J.

Estimating Heritability and Shared Environmental Effects for Refractive Error in Twin and Family Studies

Margarida C. Lopes, Toby Andrew, Francis Carbonaro, Tim D. Spector, and Christopher J. Hammond

From the Department of Twin Research and Genetic Epidemiology, King’s College London School of Medicine, London, United Kingdom.

PURPOSE. Twin studies have demonstrated a high heritability for refractive error of up to 90%, but some family studies have suggested up to one-third of population variance is attributable to the effects of shared family environment. This large twin study aimed to explore the role of shared environment in refractive error.

METHODS. Refractive error was measured using autorefraction in 4602 subjects (1152 monozygotic and 1149 dizygotic twin pairs), aged between 16 and 82 years, recruited from the TwinsUK Adult Twin Registry. Maximum-likelihood methods were used to estimate the variance of genetic, environmental, and age variance components.

RESULTS. Maximum likelihood model fitting estimate of the heritability from the best-fit model was 77% (95% confidence interval [CI], 68%–84%). Shared environmental effects explained 7% (95% CI, 0%–15%) and individual environmental effects explained 16% (95% CI, 15%–18%) of the spherical equivalent variance, respectively. Inclusion of age effects into the modeling reduced shared environmental effects to an estimated 2% of variation.

CONCLUSIONS. Analysis of 2301 twin pairs confirms that the twin study design results in a very low estimate of shared family environmental effects in refractive error. Several factors may explain these differences; we believe the most likely is that twins are perfectly age matched and do not include cross-generation or cohort effects. This means twin study designs have more power to detect heritable effects in variance component models of myopia, whereas family studies have more power to detect shared environment effects.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by the Association for Research in Vision and Ophthalmology