Genetic Variability in APOE and Nitric Oxide Synthase Genes in AMD

The information for producing the APOE protein, which is an important molecule for many biological processes, including the transport of cholesterol within the human body. APOE occurs in three different forms (called alleles). The APOE-4 allele is associated with an increased risk of Alzheimer’s disease and heart disease, but previous studies have suggested that the APOE-4 allele may actually reduce the risk of AMD. To explore this hypothesis, Dr. Schmidt’s team is analyzing a large AMD data set that includes data from other U.S. and European research groups to examine APOE’s effects on AMD. This work takes into consideration some recently published research suggesting that APOE alleles influence the levels of a chemical compound called nitric oxide (NO) in the eye. NO is a messenger molecule with diverse functions throughout the body. It is thought that certain NO levels may be able to prevent or delay damage to cells whose normal function is the protection and nourishment of the retina, the so-called retinal pigment epithelium (RPE). A second hypothesis being explored is the theory that genetic alterations in the genes that are directly responsible for NO production may also contribute to the risk for AMD. It is hoped that a better understanding of these genetic risk factors can lead to new treatment or prevention strategies for AMD.