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The inheritance of peripapillary atrophy.
Paul R Healey1, Paul Mitchell, Clare E Gilbert
1Centre for Vision Research, University of Sydney, Australia. phealey@glaucoma.net.au
Investigative Ophthalmology & Visual Science
|May 26, 2007
Summary
Genes strongly influence peripapillary atrophy (beta-PPA), a common finding linked to glaucoma. Environmental factors play a minor role, with little overlap with myopia-related genes.
Area of Science:
- Ophthalmology
- Genetics
- Twin Studies
Background:
- Peripapillary atrophy type beta (beta-PPA) is an ocular finding associated with open-angle glaucoma.
- Understanding the etiology of beta-PPA is crucial for glaucoma research.
Purpose of the Study:
- To determine the relative contributions of genetic and environmental factors to beta-PPA.
- To investigate the genetic correlation between beta-PPA and refractive error.
Main Methods:
- A classic twin study design involving 506 female twin pairs (aged 49-79).
- Stereoscopic optic disc photographs were used to identify beta-PPA.
- Structural equation modeling (Mx) analyzed polychoric correlations of beta-PPA and refractive error.
Main Results:
- Beta-PPA heritability was estimated at 0.70, indicating strong genetic influence.
- Additive genetic effects and unique environmental factors were significant; shared environment and dominant genetics were not.
- A weak genetic correlation (-0.21) was found between beta-PPA and spherical equivalent, with minimal shared genetic variance.
Conclusions:
- Beta-PPA is under strong genetic control.
- Specific genetic factors, rather than those shared with myopia, are the primary drivers of beta-PPA.
- Environmental influences on beta-PPA are largely unique and not shared with refractive error factors.
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