Fig. 1
From: Genome editing for inborn errors of metabolism: advancing towards the clinic
Schematic of genome engineering technologies (left) and DNA repair pathways resolving double-stranded DNA breaks (right). a Zinc-finger nucleases (ZFNs), b TALENs, and c the CRISPR/Cas9 system produce DNA cleavage at a desired genomic target. Once cleavage occurs, insertion of a donor template with homology to the cut site can lead to gene correction via the homology directed repair (HDR) pathway. In the absence of a donor, the random insertion or deletion of nucleotides characteristic of the non-homologous end-joining (NHEJ) pathway can result in targeted mutagenesis