Family Studies of Eye Traits

Overview

This study will examine blood specimens from patients with various eye disorders who previously participated in the Beaver Dam Eye Study to try to identify genes responsible for these disorders. The Beaver Dam study was designed to determine the incidence and causes of age-related eye conditions, including cataract (changes in the lens of the eye that can impair vision); retinopathy (diseases of the retina - the thin layer of tissue that lines the back of the eye); age-related maculopathy (degeneration or atrophy of the macula - the center part of the retina responsible for fine vision); and impaired vision. Findings from this study and others have shown that age-related eye disorders often run in families, indicating a genetic component in their development. All participants in the Beaver Dam study who had family members in the study may be included in the current NHGRI study. The Beaver Dam study included residents of the township of Beaver Dam, Wisconsin, who were between 45 and 84 years of age at enrollment. Participants had thorough eye examinations and blood samples drawn at baseline and 5 and 10 years after the baseline evaluation. Fifteen-year follow-ups will start in 2003. This study will analyze data and blood samples previously collected from Beaver Dam study participants to identify genes related to numerous age-related visual traits. No new participants will be recruited.

The Beaver Dam Eye Study was designed to determine the long-term incidence and causes of cataract, age-related maculopathy (ARM), retinopathy, and impaired vision. Age-related macular degeneration and cataract are leading causes of loss of vision in the United States. In Beaver Dam, preliminary analyses indicate that in those people who were 75+ years of age at the baseline examination, 72% developed nuclear cataract, 39% developed cortical cataract, 22% developed posterior subcapsular cataract (PSC); 37% developed early ARM (large soft indistinct drusen, retinal pigment epithelial (RPE) depigmentation, and increased retinal pigment); 10% developed signs of late ARM (exudative macular degeneration and geographic atrophy); 37% developed some impairment of vision; and 6% developed severely impaired vision by the 10-year follow-up. Thus, these are common problems in older persons. Because people 75 years of age and older are the most rapidly growing segment of the population with an estimated increase of over 60% in the next 25 years, these problems pose a societal burden due to the large number of older persons they will affect. Additionally, we have observed substantial familial aggregation for several of these traits: ARM, nuclear cataract, cortical cataract and ocular refraction. The primary goal of this proposal is to perform linkage analysis on data collected as part of the Beaver Dam eye study. NHGRI investigators will be involved in the analysis of coded data only. Dr. Bailey-Wilson may provide financial support to help cover the cost of DNA extraction from her budgets but NO samples will be sent to NHGRI. All NHGRI effort on this study will be funded through Dr. Bailey-Wilson s intramural budget. In addition to the data from the Beaver Dam Eye study, we will also analyze previously existing data on glaucoma, intraocular pressure and cup-disc ratio from the Framingham Eye Study (FES) which is a substudy of the well known cohort study called the Framingham Heart Study (FHS). We will perform both linkage and association analysis of these data for comparison to the results found in the BDES data.