| Literature DB >> 29259526 |
Adam P Cribbs1,2, Sumeth M W Perera3,2.
Abstract
Since its emergence in 2012, the genome editing technique known as CRISPR-Cas9 and its scientific use have rapidly expanded globally within a very short period of time. The technique consists of using an RNA guide molecule to bind to complementary DNA sequences, which simultaneously recruits the endonuclease Cas9 to introduce double-stranded breaks in the target DNA. The resulting double-stranded break is then repaired, allowing modification or removal of specific DNA bases. The technique has gained momentum in the laboratory because it is cheap, quick, and easy to use. Moreover, it is also being applied in vivo to generate more complex animal model systems. Such use of genome editing has proven to be highly effective and warrants a potential therapy for both genetic and non-genetic diseases. Although genome editing has the potential to be a transformative therapy for patients it is still in its infancy. Consequently, the legal and ethical frameworks are yet to be fully discussed and will be an increasingly important topic as the technology moves towards more contentious issues such as modification of the germline. Here, we review a number of scientific and ethical issues which may potentially influence the development of both the technology and its use in the clinical setting.Entities:
Keywords: CRISPR; Cas9; bioethics; genome editing
Mesh:
Year: 2017 PMID: 29259526 PMCID: PMC5733851
Source DB: PubMed Journal: Yale J Biol Med ISSN: 0044-0086
Figure 1CRISPR-Cas9 mediated gene-editing mechanisms. A single guide RNA (sgRNA) recognizes a genomic region followed by 5’-NGG-3’ PAM sequence, which recruits the Cas9 DNA endonuclease. This introduces a double-stranded break that is repaired by (i) non-homologous end joining (NHEJ), an error prone pathway that can result in the creation of Indels that can disrupt the gene, or by (ii) homology directed repair (HDR) in the presence of a donor construct.
The potential risks associated with CRISPR-Cas9 gene editing technology.
| Specific CRISPR-Cas9-based applications in humans: Potential risks | ||||
| Technical | Social | |||
| Off-target Insertions and deletions (Indels) | Random integration of vector | Toxicity | Exacerbating social inequalities | |
| Germline editing | High - A potentially significant issue but screening of embryos prior to implantation could overcome this risk. | Medium - Random integration may result in inactivation/dysregulation of gene expression. Sequencing for the presence of integration would identify this. | Low | High – Dependency upon “enhancement” applications |
| High - For clonally expanded cells, screening can be performed to identify off-target Indels. | Low | Low | Low | |
| High - Poses the most significant risk because screening would be difficult to perform. | High – It would be very difficult to determine integration | High – The induction of inflammatory responses to vector components. | Low | |