Subchapter 13.9 - DNA methylation: its role in retinal health and diseases

Abstract

Genetic information is stored in DNA which must be protected from mutations and alterations that can disrupt cellular homeostasis and cause diseases. Heritable changes in gene activity or function due to the direct alteration in DNA sequence occur as a result of point mutations, deletion, insertion, and translocation. These direct alterations in the genetic code are defined as genetic changes. In contrast, epigenetics is the study of heritable changes in gene function but does not involve a change in DNA sequence and can affect gene expression at the transcription or posttranslational level. Epigenetics include the chemical reaction that controls the genome activities at certain time points and location within DNA. Epigenetic alterations are linked to a wide spectrum of diseases ranging from birth defects, cancer, to ocular pathologies. Some epigenetic changes are permanent, but others may be transient, which may create targets for future therapies. Major epigenetic modifications include DNA methylation, chromatin remodeling, development of noncoding DNA, and histone modification. This chapter will discuss the process of DNA methylation and its crucial role in retinal development and pathology. A better understanding of DNA methylation in ocular pathologies will help identify novel therapeutic targets to treat such diseases.