Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. We report an association between all Alu polymorphism in the angiotensin-converting enzyme (ACE) gene with the dry/atrophic form of AMD. Using the polymerase chain reaction (PCR) on genomic DNA isolated from patients with AMD (n = 173), and an age-matched control population (n = 189), we amplified a region polymorphic for an Alu element insertion in the ACE gene. The Alu(+/+) genotype occurred 4.5 times more frequently in the control population than the dry/atrophic AMD patient population. (p = 0.004). The predominance of the Alu(+/+) genotype within the unaffected control group represents a protective insertion with respect to the human Ocular disease, dry/atrophic AMD. This is the first demonstration of an Alu element insertion exerting protective effects against a known human disease. (C) 2002 Elsevier Science (USA). All rights reserved.