CRISPR/Cas9-Based Genome Editing: Understanding Differences in DNA Repair Pathways, Profiles, and Outcomes

Over a decade of advances in Clustered Regularly Interspersed Short Palindromic Repeats (CRISPR) and CRISPR-associated protein 9 (Cas9)-based technologies have culminated in the first-ever FDA-approved CRISPR/Cas-based therapy. Aside from this approved therapy for sickle cell anemia, several CRISPR/Cas-based therapies are currently under development or testing for a range of chronic diseases, including viral diseases like human immunodeficiency virus type 1 (HIV-1) infection, genetic diseases like familial hypercholesterolemia, and cancer. The success of these therapies hinges on the effective delivery of CRISPR/Cas9 components to target regions, efficient Cas endonuclease editing, repair profiles generated, and their resulting outcomes. Here, we discuss the factors that influence the generation of CRISPR/Cas9-generated repair edits, the overall profiles, and outcome prediction(s), as well as the analytical tools that have been developed to date. Finally, how this technology has been used towards a functional HIV-1 cure is discussed.