Abstract
Purpose :
Age of first spectacle wear (AOSW) is correlated with Spherical equivalent (SPHE) myopia both at the phenotypic and genotypic level. However, the true extent of this correlation and how much of the genetic risk is shared between the two phenotypes remains unclear. The purpose of this study was to assess the shared heritability of SPHE measured in adulthood and AOSW in UK Biobank.
Methods :
A sample of 129 292 individuals from UK Biobank cohort underwent comprehensive ophthalmological examination. Autorefraction was used to calculate SPHE. Age, when the participants reported first starting glasses or lenses correction, was collected through a touch screen questionnaire. Only participants genotyped on the Affymetrix Axiom SNP Chip of European descent, ascertained through analysis of molecular markers, were included in subsequent analyses. Subjects with an AOSW between 6 and 30 years were selected for heritability analysis. As a result of the selection criteria, the heritability evaluation was carried out on 39739 participants using bivariate REML model as implemented in BOLT-LMM statistical software. The model was adjusted for age at SPHE measurement and sex. A secondary analysis focused on the group of myopic subjects (SPHE< -0.5 D). Heritability analysis was replicated in GCTA statistical software using bivariate GREML model. A total number of 8336 individuals was included in the analysis.
Results :
The estimated chip heritability (the proportion of variance due to genetic factors) for SPHE was 0.62 in BOLT-LMM and 0.4 in GCTA, whereas the chip heritability for AOSW was 0.13 in BOLT-LMM and 0.10 in GCTA. Genetic correlation of the two phenotypes did not exceed 0.71 in both BOLT-LMM and GCTA. Regarding the assessment of genetic correlation between SPHE and AOSW in the group of myopic subjects, the correlation corresponded to rG = 0.69 in BOLT-LMM and rG = 0.86 in GCTA.
Conclusions :
There is substantial sharing of genetic risk factors between SE and the age of first spectacle wear. AOSW is, therefore, a reasonable but imperfect proxy for SE genetic association analyses.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.