Heritability of Strabismus: Genetic Influence Is Specific to Eso-Deviation and Independent of Refractive Error

• DOI: 10.1017/thg.2012.22
• Publication Date: 2012-06-13T10:55:11Z
• Authors: Paul G. Sanfilippo; Christopher J. Ha...; Sandra E. Staffieri; Lisa S. Kearns; S. H. Melissa Liew; Julie M. Barbour; Alex W. Hewitt; Dongliang Ge; Harold Snieder; Jane R. MacKinnon; Shayne A. Brown; Birgit Lorenz; Tim D. Spector; Nicholas G. Martin; Jeremy B. Wilmer; David A. Mackey
• Keywords: Esotropia

Strabismus represents a complex oculomotor disorder characterized by the deviation of one or both eyes and poor vision. A more sophisticated understanding genetic liability strabismus is required to guide searches for associated molecular variants. In this classical twin study 1,462 pairs, we examined relative influence genes environment in comitant strabismus, degree which these influences can be explained factors common with refractive error. Participants were presence latent (‘phoria’) manifest (‘tropia’) using cover–uncover alternate cover tests. Two phenotypes distinguished: eso-deviation (esophoria esotropia) exo-deviation (exophoria exotropia). Structural equation modeling was subsequently employed partition observed phenotypic variation data into specific variance components. The prevalence 8.6% 20.7%, respectively. For eso-deviation, polychoric correlation significantly greater monozygotic (MZ) ( r = 0.65) compared dizygotic (DZ) pairs 0.33), suggesting role p .003). There no significant difference between MZ 0.55) DZ 0.53) .86), implying that do not play etiology exo-deviation. heritability an 0.64 (95% CI 0.50–0.75). additive error 0.13 bivariate (i.e., shared variance) less than 1%, negligible effect. This documents substantial 64% yet corresponding exo-deviation, contribution may eso-deviation. Future studies are now needed identify unravel their mechanisms action.