Sequence changes in edited cells based on CRISPR-Cas9 therapy.

CrispR-Cas9 genome editing technology, known as "gene shears", causes DNA deletion or rearrangement near targets, more seriously than scientists had expected, according to an important study published online Thursday in the British journal Nature Biotechnology.
the discovery means that researchers must closely observe the sequence changes in the edited cells caused by CRISPR-Cas9-based therapy.
currently known as CRISPR-Cas9 genome editing as a potential treatment for cancer, HIV, haemophilia and sickle cell disease.
the mechanism of Cas9, is the double strand of cell DNA that cuts the target location within the genome.
the path of the cell repairing the double-stranded fracture of DNA usually introduces small-scale DNA insertion or deletion.
this process can be used to inactivate disease-causing genes or to correct mutations in genes.
Until then, the main safety concern about this technology was the high off-target rate of cas9.
but this time, Scientist Aylan Bradley of the Wellcome Institute in the U.K. and colleagues who studied laboratory cell lines in mice and humans found that, in addition to the small-scale DNA errors known to accompany THE repair of DNA double-stranded fractures, CRISPR-Cas9 technology could also lead to large-scale DNA deletion suggies near targets and, in some cases, complex DNA rearrangements.
team found that in mouse stem cells and human retinal pigment epithelial cells, the removal of thousands of DNA bases may occur, leading to near-gene or regulatory sequences that may be affected and change cell function.
researchers say the correlation between the findings and the clinical application of Cas9 is not yet known.
Although the original purpose of the above-mentioned experiments is not to detect the harmful effects of chromosomal changes in addition to target genes, it highlights a potential safety risk that requires further research.
and in February, the journal Nature reported on a Stanford University-led study that revealed that the body's own immune system could also disrupt gene therapy developed under CRISPR-Cas9.
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