Therapeutic applications of CRISPR/Cas9 system in gene therapy

Gene therapy is based on the principle of the genetic manipulation of DNA or RNA for treating and preventing human diseases. The clustered regularly interspaced short palindromic repeats/CRISPR associated nuclease9 (CRISPR/Cas9) system, derived from the acquired immune system in bacteria and archaea, has provided a new tool for accurate manipulation of genomic sequence to attain a therapeutic result. The advantage of CRISPR which made it an easy and flexible tool for diverse genome editing purposes is that a single protein (Cas9) complex with 2 short RNA sequences, function as a site-specific endonuclease. Recently, application of CRISPR/Cas9 system has become popular for therapeutic aims such as gene therapy. In this article, we review the fundamental mechanisms of CRISPR-Cas9 function and summarize preclinical CRISPR-mediated gene therapy reports on a wide variety of disorders.