Complement Factor H and the Bilaterality of Age-Related Macular Degeneration The Blue Mountains Eye Study

Objective: To determine whether complement factor H (CFH Y402H) genotype influences bilateral involvement of age-related macular degeneration (AMD) lesions. Methods: The Blue Mountains Eye Study (BMES) followed up 3654 participants 49 years and older (BMES 1, 1992-1994), including 2335 (75.3% of survivors) at the 5-year (BMES 2, 1997-1999) and 1952 (76.5%) at the 1.0-year (BMES 3, 2002-2004) examinations. Age-related macular degeneration retinal photographic grading used the Wisconsin system. Early and late AMD included prevalent and incident cases from all visits. CFH genotyping used TaqMan assays. Results: Of 767 AMD cases, 53.3% of early and 53.1% of late AMD cases were bilateral. After adjusting for age and other covariants, the CFH CC (Y402H polymorphism) genotype was associated with an increased likelihood of bilateral compared with unilateral involvement by any soft drusen (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.4-4.5), distinct soft drusen (OR, 2.8; 95% CI, 1.0-8.1.), and pigmentary abnormalities (OR, 1.7; 95% CI, 1.0-2.8). We could not establish significant associations between this genotype and the bilaterality of late AMD (OR, 1.8; 95% CI, 0.4-7.7), either geographic atrophy (OR, 0.6; 95% CI, 0.07-4.6) or neovascular AMD (OR, 3.4; 95% CI; 0.3-41.4). Conclusions: Persons with the CFH CC genotype at any given age have an increased likelihood of bilateral compared with unilateral involvement of some early AMD lesions.