"Investigation of ARMS2 and CFH Polymorphisms Associated with Age-Related Macular Degeneration in Alzheimer’s Disease Patients. A Greek Cohort Study"

Abstract

Introduction: Age-related macular degeneration (AMD) is a degenerative eye disease leading to significant loss of central vision. A strong association with the disease has been identified worldwide for two common coding single nucleotide polymorphisms (SNPs): A69S (rs10490924) of the ARMS2 gene involved in oxidative stress-dependent damage to the retinal photoreceptors and Y402H (rs1061170) of the complement factor H (CFH) gene involved in innate immunity. These two SNPs explain about 25% of cases of AMD. In recent literature, a link between AMD and Alzheimer's disease (AD) has been postulated. Indeed, the possibility of early diagnosis of cognitive degeneration of the brain in AD is suggested by using non-invasive optical coherence tomography (OCT) in the retina. We aimed the investigation of the possible association between AMD and AD, as attributed by the analysis of the two aforementioned SNPs.Materials and Methods: Peripheral blood was collected from consecutive well-ascertained AD patients of our University Hospital and their caregivers after obtaining their informed signed consent. The patients underwent a complete neurological and neuropsychological examination. In total, thirty-eight healthy subjects and 120 AD patients participated. After DNA isolation, CFH genotyping was performed by realtime qPCR-melting curve analysis developed by our research team on the LightCycler platform (Roche) and ARMS2 genotyping by a PCR-RFLP method. Statistical analysis was performed by using the SNPstats online tool. Results and Conclusions:There was no significant correlation with either CFH [Odds Ratio = 0.90 (95% CI = 0.54-1.49), p = 0.68] or ARMS2 gene [OR=1.29 (0.60-2.77), p=0.5)]. However, this pilot study should be further extended to sub-groups of the two diseases and other genes involved in common mechanisms of pathogenesis in both disorders.