The primary goals of this project are to develop and validate electronic phenotyping algorithms, to accurately identify cases and controls while maintaining a positive predictive value (PPV) of >95%, and to conduct a genome wide association study that advances understanding of two specific yet interrelated disease states, while simultaneously engaging the community in these research efforts. Lipid abnormalities and cataracts are both diseases of public health significance, they share common risk factors, and they are both complex diseases which likely have many genes contributing to disease development. Whole genome association studies with these two outcomes and environmental risk factors could yield novel data about the etiology of the two separate outcomes as well as their interaction. PhenX is a project designed to prioritize Phenotypes and eXposure measures for Genome-wide Association Studies (GWAS). The PhenX Toolkit is a valuable resource for researchers who are planning or expanding a study and would like to incorporate well established measures that have been recommended by experts in the field. We are currently interested in gene-environment interactions for "age related cataract".
The Ocular Hypertension Treatment Study (OHTS) is an National Eye Institute-sponsored multi-center, randomized, prospective treatment trial designed to determine whether lowering intraocular pressure (IOP) in individuals with ocular hypertension delays or prevents the development of primary open angle glaucoma (POAG). A total of 1,636 individuals with ocular hypertension between 40 and 80 years old were enrolled in the study. In addition to ocular hypertension, subjects in the OHTS were required to have normal optic nerve appearance as determined by the OHTS Optic Disc Reading Center and normal and reliable visual field tests at the time of enrollment by the OHTS Visual Field Reading Center. OHTS subjects were randomly assigned to either an observational group which received close observation or a topical medication group which received medication as needed to achieve a 20% reduction in IOP from their baseline levels. Subjects then were examined at regular intervals for optic disc cupping or visual field defects. Other clinical measures were also obtained from OHTS subjects including central corneal thickness (CCT) and intraocular pressure. The primary outcome monitored for the OHTS was the development of glaucoma in one or both eyes as defined by reproducible visual field abnormality or reproducible optic disc deterioration attributed to POAG by the masked OHTS Endpoint Committee. The OHTS study design has been reported in detail (Gordon, 1999; PMID: 10326953). The OHTS confirmed that ocular hypertension is a risk factor for developing POAG and showed that lowering IOP reduced the risk for developing POAG (Kass, 2002; PMID: 12049574). The OHTS also demonstrated that thin CCT is a significant risk factor for the development of POAG (Gordon, 2002; PMID: 12049575). Blood samples were also collected from 1,077 OHTS participants for an ancillary genetics study. DNA was prepared from these samples and used in a genome-wide association scan (GWAS) designed to identify genetic factors that control the magnitude of quantitative features of glaucoma (baseline IOP, baseline cup-to-disc ratio, and CCT). Genotypes from the GWAS and these clinical data (IOP, cup-to-disc ratio, and CCT) have been provided to dbGaP.
Abstract in preparation
