The CRISPR/Cas9 genome-editing technique which can replace a defective gene with a new version was just shown to cause over a thousand unanticipated mutations to the genome.

Several preclinical trials have shown that CRISPR can correct faulty genes that cause devastating diseases such as muscular dystrophy to blindness. The CRISPR/Cas9 genetic engineering technique has now entered the clinical arena with a few clinical trials in humans in-progress and on the horizon.

The problem is that whole-genome sequencing showed that while CRISPR is effective in correcting a faulty gene of interest, it also introduced up to 1,500 other mutations in other parts of the genome. While CRISPR is still very promising…more work needs to be done to understand why this technique can introduce over a thousand mutations to the genome.