Genetic Epidemiology, Translational Neurogenomics, Psychiatric Genetics and Statistical Genetics Laboratories investigate the pattern of disease in families, particularly identical and non-identical twins, to assess the relative importance of genes and environment in a variety of important health problems.
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PMID
22877876
TITLE
Heritability of strabismus: genetic influence is specific to eso-deviation and independent of refractive error.
ABSTRACT
Strabismus represents a complex oculomotor disorder characterized by the deviation of one or both eyes and poor vision. A more sophisticated understanding of the genetic liability of strabismus is required to guide searches for associated molecular variants. In this classical twin study of 1,462 twin pairs, we examined the relative influence of genes and environment in comitant strabismus, and the degree to which these influences can be explained by factors in common with refractive error. Participants were examined for the presence of latent ('phoria') and manifest ('tropia') strabismus using cover-uncover and alternate cover tests. Two phenotypes were distinguished: eso-deviation (esophoria and esotropia) and exo-deviation (exophoria and exotropia). Structural equation modeling was subsequently employed to partition the observed phenotypic variation in the twin data into specific variance components. The prevalence of eso-deviation and exo-deviation was 8.6% and 20.7%, respectively. For eso-deviation, the polychoric correlation was significantly greater in monozygotic (MZ) (r = 0.65) compared to dizygotic (DZ) twin pairs (r = 0.33), suggesting a genetic role (p = .003). There was no significant difference in polychoric correlation between MZ (r = 0.55) and DZ twin pairs (r = 0.53) for exo-deviation (p = .86), implying that genetic factors do not play a significant role in the etiology of exo-deviation. The heritability of an eso-deviation was 0.64 (95% CI 0.50-0.75). The additive genetic correlation for eso-deviation and refractive error was 0.13 and the bivariate heritability (i.e., shared variance) was less than 1%, suggesting negligible shared genetic effect. This study documents a substantial heritability of 64% for eso-deviation, yet no corresponding heritability for exo-deviation, suggesting that the genetic contribution to strabismus may be specific to eso-deviation. Future studies are now needed to identify the genes associated with eso-deviation and unravel their mechanisms of action.
DATE PUBLISHED
2012 Oct
HISTORY
PUBSTATUS PUBSTATUSDATE
aheadofprint 2012/06/13
entrez 2012/08/11 06:00
pubmed 2012/08/11 06:00
medline 2013/04/05 06:00
AUTHORS
NAME COLLECTIVENAME LASTNAME FORENAME INITIALS AFFILIATION AFFILIATIONINFO
Sanfilippo PG Sanfilippo Paul G PG Centre for Eye Research Australia, Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia.
Hammond CJ Hammond Christopher J CJ
Staffieri SE Staffieri Sandra E SE
Kearns LS Kearns Lisa S LS
Melissa Liew SH Melissa Liew S H SH
Barbour JM Barbour Julie M JM
Hewitt AW Hewitt Alex W AW
Ge D Ge Dongliang D
Snieder H Snieder Harold H
Mackinnon JR Mackinnon Jane R JR
Brown SA Brown Shayne A SA
Lorenz B Lorenz Birgit B
Spector TD Spector Tim D TD
Martin NG Martin Nicholas G NG
Wilmer JB Wilmer Jeremy B JB
Mackey DA Mackey David A DA
INVESTIGATORS
JOURNAL
VOLUME: 15
ISSUE: 5
TITLE: Twin research and human genetics : the official journal of the International Society for Twin Studies
ISOABBREVIATION: Twin Res Hum Genet
YEAR: 2012
MONTH: Oct
DAY:
MEDLINEDATE:
SEASON:
CITEDMEDIUM: Print
ISSN:
ISSNTYPE:
MEDLINE JOURNAL
MEDLINETA: Twin Res Hum Genet
COUNTRY: England
ISSNLINKING: 1832-4274
NLMUNIQUEID: 101244624
PUBLICATION TYPE
PUBLICATIONTYPE TEXT
Journal Article
Research Support, Non-U.S. Gov't
Twin Study
COMMENTS AND CORRECTIONS
GRANTS
GENERAL NOTE
KEYWORDS
MESH HEADINGS
DESCRIPTORNAME QUALIFIERNAME
Adolescent
Adult
Aged
Aged, 80 and over
Child
Child, Preschool
Diseases in Twins genetics
Humans genetics
Middle Aged genetics
Refractive Errors genetics
Strabismus genetics
Twins, Dizygotic genetics
Twins, Monozygotic genetics
Young Adult genetics
SUPPLEMENTARY MESH
GENE SYMBOLS
CHEMICALS
OTHER ID's