Abstract
Purpose:
Phenotypic correlation between parents and offspring has been commonly used to estimate the heritabilityassuming the parents and offspring share the same environment. However, it is well known that prevalence of myopia has ben increasing considerably in recent decades suggesting aheterogeneous on myogenic environmental factors. Recently, we develop a new genetic modeling to decompose the common environmental effects into heterogeneous environmental effect. In this analysis, we attempt to use this model to estimate the heterogeneous environmental effects and their contribution to parent-offspring phenotypic variation using the data from a twin study.
Methods:
Twins aged 7-21 years old and their parents were enrolled from Guangzhou Twin Eye Study. Spherical equivalent (SE) and corneal curvature (CC) was measured by auto-refraction while axial length (AL) was measured by optical partial coherence interferometry (IOLMaster) in both twins and their parents. ACDE-H model using PROC MIXED in SAS was used to estimate the proportion of parent-offspring variation that explained by heterogeneousenvironmental effects across generations.
Results:
A total of 927 pairs of twins and their parents were available for analysis. Heterogeneous environmental effects between parents and offsprings explained about 9.6% of SE variation, and 17.1% of AL variation between parents and offspring. However, this estimation was not statistical significant for CC variation.
Conclusions:
In this parent-offspring twin study, the heterogeneous on environmental effectsexplain a significant amount of parent-offspring variation on the progressive traits relevant to myopia such as SE and AL but not on the trait that remains unchanged with myopia such as CC.