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High heritability of central corneal thickness : the twins eye studies
thesisposted on 2023-05-27, 12:44 authored by Toh, T
PURPOSE: A classical twin study was performed to determine the heritability of central corneal thickness, an important parameter in glaucoma assessment. METHODS: The concordance of CCT between monozygotic (MZ) and dizygotic (DZ) twins was compared. A total of 256 twin pairs (131 MZ and 125 DZ) were recruited from 3 centers: the Twin Eye Study in Tasmania, the Brisbane Adolescent Twin Study and the Twins UK adult registry held at St. Thomas' Hospital in London. As part of an extensive ophthalmic evaluation, CCT was measured using ultrasound pachymetry. Structural equation modelling using the Mx program was used to determine the heritability of CCT. RESULTS: The mean age of subjects was 38 years (range 8-81). The mean CCT of all eyes examined was 544.5˜í¬¿m (standard deviation [SD] 37.3). The CCT measurements were more highly correlated in MZ twins than in DZ twins, with intraclass correlation coefficients of 0.95 and 0.52, respectively, suggesting a strong genetic influence. A model of additive genetic and unique environmental effects provided the best fit, yielding a heritability of 0.95 (95% Cl 0.93-0.96) with the remaining variation being attributable to unique environmental factors. CONCLUSION: In this study of Australian and United Kingdom twins, we found that genetic factors are of major importance in CCT, with a heritability of 0.95.
Rights statementNo access or viewing until 20 March 2008. Thesis (MMedSc)--University of Tasmania, 2006. Includes bibliographical references. Ch. 1. Introduction -- Ch. 2. Glaucoma -- Ch. 3. Central corneal thickness and glaucoma management -- Ch. 4. Glaucoma genetics -- Ch. 5. Genetics of central corneal thickness -- Ch. 6. Twin study -- Ch. 7. Heritability of central corneal thickness: the twin eye studies -- Ch. 8. Results -- Ch. 9. Central corneal thickness is highly heritable -- Ch. 10 Conclusions -- Ch. 11. Further analysis of data from the twin studies