While dysregulation of the complement system, an essential component of the innate immune system, is thought to be associated with an increased risk for AMD, its role in AMD pathogenesis remains unclear; genetic variants found to predict susceptibility to AMD have not been associated with GA progression [8,9], and in some studies, C3 risk alleles are actually associated with decreased progression of GA [10]. Here, C3 is linked to age-related macular degeneration.