Familial correlations and gene‐environment interactions for myopia

Abstract

Abstract Purpose: To investigate the combined contributions of environmental and genetic risk factors for myopia in children. Methods: Children aged 7 to 9 years from 3 schools were recruited and the children have been followed annually since 1999. Cycloplegic autorefraction and biometry measures were conducted annually in the schools, and buccal specimens were collected. TheWhole Genome Association (WGA) scans of buccal DNA using the Illumina Sentrix HumanHap 550 Genotyping BeadChip assay will be performed. We propose to compare the top ranked genes of 1250 children with greater change in refraction with children with the smallest changes in refraction. Results: There were 1478 Chinese, 349 Malays and 152 children who were Indian and other races. Using a Cox Proportional Hazards model, children with 2 myopic parents had 3.89 times higher risks of myopia, compared with children with 0 myopic parents. Parental history of myopia interacted with reading in books per week to increase the risks of myopia, suggesting gene‐environment interaction. There were 159 sibling pairs in this cohort. After adjusting for age and sex, the between‐sibling correlation in refractive error was 0.447 (95% confidence interval 0.314, 0.564) and between‐sibling 1‐year change in refractive error was high at 0.420 (95% confidence interval 0.282, 0.543). The pilot WGA study of matched sets of 5 unamplified buccal DNA samples, 5 amplified buccal DNA samples, and 5 saliva DNA samples using the Oragene saliva kit revealed mean call rates of 0.9986, 0.9881, and 0.9929, respectively. Conclusions: Thus, both the contributions of environment and genes will be documented in detail in this cohort.