Abstract
Purpose::
Age-related cataract, a possible biomarker of ageing, is a variable but heritable complex trait. In order to determine the possible underlying genetic variants for nuclear and cortical cataract, we conducted an association study of cataract and a candidate gene for ageing related traits, TGFB1, in a female Caucasian dizygotic twin population.
Methods::
Cataract was measured objectively using Scheimpflug photography and retroillumination camera for nuclear and cortical cataract, respectively, in a cohort of twins aged 49-75 years (mean age 61.6 years). Six single nucleotide polymorphisms (SNPs) were genotyped in the TGFB1 gene, and logistic regression modelling was used to test the association between these candidates and nuclear cataract (continuous phenotype, 293 individuals) and cortical cataract (135 cases, 158 controls), including age as a covariate.
Results::
All SNPs were in Hardy-Weinberg equilibrium (p>0.05). There was a significant association for 3 of the 6 SNPs within the TGFB1 gene and cortical cataract (p<0.003). No significant association was detected for individual SNPs, under either codominant or completely dominant models (p>0.27), or two-locus haplotypes (p=0.7) with nuclear cataract variation.
Conclusions::
There was a significant association between cortical cataract and an aging related candidate gene, TGFB1. This result suggests that this gene may play a role in the variation of cortical, but not nuclear, cataract in our cohort. Further research is required to examine the role of TGFB1 in cataract, in terms of replication of these results and further understanding of its role in lens metabolism.
Keywords: cataract • genetics • aging