PURPOSE: This study was conducted to assess the relative influence of genetics and environment on corneal astigmatism and corneal curvature in a large sample of twins. METHODS: A total of 612 twin pairs (345 monozygotic [MZ] and 267 dizygotic [DZ]) aged between 18 and 86 years (mean age, 52.11 +/- 15.85 years) were recruited from the Australian Twin Registry (ATR). Each subject completed a general questionnaire, undertook a dilated eye examination, including ocular biometric measurements, and contributed a blood sample. Corneal astigmatism was defined as the absolute difference between the K1 and K2 meridians and corneal curvature as the average of K1 and K2. RESULTS: Intrapair correlations were significantly higher (P < 0.001) in MZ twin pairs compared with those in DZ twin pairs for both corneal astigmatism (CA; rmz = 0.48 vs. rdz = 0.13) and corneal curvature (CC; rmz = 0.84 vs. rdz = 0.41). A sex-limited model with parameters estimating additive genetic, nonadditive genetic, and unique environmental influences (denoted ADE) was the most parsimonious model explaining both measures. Heritability estimates were as high as 60% and 71% for CA and CC, respectively. CONCLUSIONS: This study provides evidence that genetic factors explain interindividual variation in CA and CC, with nonadditive genetic factors explaining most of the variance due to those genetic factors. Heritability estimates were sex specific and indicate the need for future linkage studies for the identification of genes involved in the etiology of CA and CC.
PURPOSE: This study was conducted to assess the relative influence of genetics and environment on corneal astigmatism and corneal curvature in a large sample of twins. METHODS: A total of 612 twin pairs (345 monozygotic [MZ] and 267 dizygotic [DZ]) aged between 18 and 86 years (mean age, 52.11 +/- 15.85 years) were recruited from the Australian Twin Registry (ATR). Each subject completed a general questionnaire, undertook a dilated eye examination, including ocular biometric measurements, and contributed a blood sample. Corneal astigmatism was defined as the absolute difference between the K1 and K2 meridians and corneal curvature as the average of K1 and K2. RESULTS: Intrapair correlations were significantly higher (P < 0.001) in MZ twin pairs compared with those in DZ twin pairs for both corneal astigmatism (CA; rmz = 0.48 vs. rdz = 0.13) and corneal curvature (CC; rmz = 0.84 vs. rdz = 0.41). A sex-limited model with parameters estimating additive genetic, nonadditive genetic, and unique environmental influences (denoted ADE) was the most parsimonious model explaining both measures. Heritability estimates were as high as 60% and 71% for CA and CC, respectively. CONCLUSIONS: This study provides evidence that genetic factors explain interindividual variation in CA and CC, with nonadditive genetic factors explaining most of the variance due to those genetic factors. Heritability estimates were sex specific and indicate the need for future linkage studies for the identification of genes involved in the etiology of CA and CC.
Authors: Aniket Mishra; Seyhan Yazar; Alex W Hewitt; Jenny A Mountain; Wei Ang; Craig E Pennell; Nicholas G Martin; Grant W Montgomery; Christopher J Hammond; Terri L Young; Stuart Macgregor; David A Mackey Journal: Invest Ophthalmol Vis Sci Date: 2012-10-11 Impact factor: 4.799
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Authors: Margarida C Lopes; Pirro G Hysi; Virginie J M Verhoeven; Stuart Macgregor; Alex W Hewitt; Grant W Montgomery; Phillippa Cumberland; Johannes R Vingerling; Terri L Young; Cornelia M van Duijn; Ben Oostra; Andre G Uitterlinden; Jugnoo S Rahi; David A Mackey; Caroline C W Klaver; Toby Andrew; Christopher J Hammond Journal: Invest Ophthalmol Vis Sci Date: 2013-02-01 Impact factor: 4.799
Authors: Hassan Hashemi; Farhad Rezvan; Asghar Beiranvand; Omid-Ali Papi; Hosein Hoseini Yazdi; Hadi Ostadimoghaddam; Abbas Ali Yekta; Reza Norouzirad; Mehdi Khabazkhoob Journal: J Ophthalmic Vis Res Date: 2014-04
Authors: Qing Li; Robert Wojciechowski; Claire L Simpson; Pirro G Hysi; Virginie J M Verhoeven; Mohammad Kamran Ikram; René Höhn; Veronique Vitart; Alex W Hewitt; Konrad Oexle; Kari-Matti Mäkelä; Stuart MacGregor; Mario Pirastu; Qiao Fan; Ching-Yu Cheng; Beaté St Pourcain; George McMahon; John P Kemp; Kate Northstone; Jugnoo S Rahi; Phillippa M Cumberland; Nicholas G Martin; Paul G Sanfilippo; Yi Lu; Ya Xing Wang; Caroline Hayward; Ozren Polašek; Harry Campbell; Goran Bencic; Alan F Wright; Juho Wedenoja; Tanja Zeller; Arne Schillert; Alireza Mirshahi; Karl Lackner; Shea Ping Yip; Maurice K H Yap; Janina S Ried; Christian Gieger; Federico Murgia; James F Wilson; Brian Fleck; Seyhan Yazar; Johannes R Vingerling; Albert Hofman; André Uitterlinden; Fernando Rivadeneira; Najaf Amin; Lennart Karssen; Ben A Oostra; Xin Zhou; Yik-Ying Teo; E Shyong Tai; Eranga Vithana; Veluchamy Barathi; Yingfeng Zheng; Rosalynn Grace Siantar; Kumari Neelam; Youchan Shin; Janice Lam; Ekaterina Yonova-Doing; Cristina Venturini; S Mohsen Hosseini; Hoi-Suen Wong; Terho Lehtimäki; Mika Kähönen; Olli Raitakari; Nicholas J Timpson; David M Evans; Chiea-Chuen Khor; Tin Aung; Terri L Young; Paul Mitchell; Barbara Klein; Cornelia M van Duijn; Thomas Meitinger; Jost B Jonas; Paul N Baird; David A Mackey; Tien Yin Wong; Seang-Mei Saw; Olavi Pärssinen; Dwight Stambolian; Christopher J Hammond; Caroline C W Klaver; Cathy Williams; Andrew D Paterson; Joan E Bailey-Wilson; Jeremy A Guggenheim Journal: Hum Genet Date: 2014-11-04 Impact factor: 4.132
Authors: Seyhan Yazar; Aniket Mishra; Wei Ang; Lisa S Kearns; Jenny A Mountain; Craig Pennell; Grant W Montgomery; Terri L Young; Christopher J Hammond; Stuart Macgregor; David A Mackey; Alex W Hewitt Journal: Mol Vis Date: 2013-06-06 Impact factor: 2.367