Off-target genomic DNA loci with partial complementarity to the Sodium channel protein type 2 subunit alpha (SCN2A) guide RNA plus PAM (SCN2A off-target loci)

Off-target genomic DNA loci represent unintended binding and cleavage sites for CRISPR-Cas9 or other programmable nucleases designed to target the Sodium channel protein type 2 subunit alpha (SCN2A) gene. These sites typically possess partial sequence complementarity to the guide RNA (gRNA) and are adjacent to a protospacer adjacent motif (PAM), which allows the Cas enzyme to initiate DNA double-strand breaks (Fu et al., 2013, Nature Biotechnology). While the intended target is the SCN2A gene—mutations in which are linked to conditions like Benign Familial Infantile Seizures and Developmental and Epileptic Encephalopathy—off-target activity can lead to permanent, deleterious mutations elsewhere in the genome (Sanders et al., 2018, Trends in Neurosciences). Such unintended modifications pose significant safety risks, including the potential for oncogene activation, tumor suppressor inactivation, or large-scale chromosomal rearrangements (Zhang et al., 2015, Science). In the context of developing genetic therapies for SCN2A-related disorders, identifying and minimizing these off-target effects is a critical regulatory and technical hurdle. Advanced sequencing techniques such as GUIDE-seq or CIRCLE-seq are employed to empirically map these loci to ensure the high specificity required for clinical applications (Tsai et al., 2015, Nature Biotechnology).

Other names

Unintended genomic cleavage sitesCRISPR off-targetsNon-specific SCN2A gRNA binding sitesMismatch DNA loci

Unintended enzymatic cleavage or modification of DNA at non-target sites due to sequence homology with the SCN2A-specific guide RNA.