Abstract
Abstract: :
Purpose: Alu elements are ubiquitous, homologous DNA repeats found in very high numbers throughout the human genome. Some Alu insertions are polymorphic in the human population and can act as reservoirs for mutations. Identifying Alu DNA polymorphisms associated with disease can lead to understanding disease processes. In the present study we examined the distribution of two polymorphic Alu elements in the angiotensin converting enzyme (ACE) gene and the tissue plasminogen activator (TPA) gene. Methods: Polymerase chain reaction (PCR) was performed on genomic DNA isolated from patients with Age-related Macular Degeneration, AMD (n= 173) and age-matched control patients (n=189). Results: The TPA Alu insertion was identically distributed in both AMD and control populations. Strikingly the Alu+/+ genotype was 4.5 times more frequent in the control population when compared to a subgroup of patients with the most predominant form of AMD, the atrophic/»dry» form (p= 0.004). Conclusion: Since the general default of the human genome is the absence of Alu elements, the presence of the Alu element within the ACE gene of the unaffected control group represents a «beneficial» or protective mutation with respect to the human ocular disease, AMD.
Keywords: 308 age-related macular degeneration • 420 genetics • 554 retina