Application of base editors in the treatment of genetic disorders

To date, CRISPR/Cas systems represent the most widely used tool for genome editing; however, its application scope for gene therapy has been largely limited due to its limited efficiency in activating homologydirected repair for DNA and off-target effect. Base editing is a new CRISPR/Cas-based genome-editing strategy, which allows single nucleotide to be precisely corrected in a narrow window scope on the target DNA or RNA by taking advantage of different nucleobase deaminases. Base editors include cytosine base editors (CBEs) and adenine base editors (ABEs), which can induce the conversions from C�G to T�A and A�T to G�C, respectively. Base editors work independently of double-strand DNA breaks (DSBs) and DNA donor templates, and thus they are extensively adopted for a wide range of therapeutic applications for genetic diseases, largely owing to their high efficiency and great specificity. In this review, we summarize the development of base editors and their potentials as therapeutic drugs for treating genetic diseases, and future outlooks are also discussed.