For years, there has been a buzz around CRISPR’s potential to tackle a huge range of diseases. The process, which allows scientists to precisely edit genes in a whole manner of ways, is a lot cheaper and more efficient than other techniques. Whilst CRISPR has already been used to edit human cells outside the body to treat cancer, blood disorders and HIV, it was announced this week that the first-ever CRISPR gene editing within the human body had been carried out at the Casey Eye Institute at Oregon Health and Science University (OHSU), Portland.
In this world-first trial, the gene-editing tool was used to address mutations that cause a rare form of inherited blindness called Leber congenital amaurosis type 10. Generally, people with the mutation in the CEP290 gene are either born blind or become blind within the first 10 years of their lives, as the mutation prevents the light-gathering cells of the retina from functioning properly.
Traditional gene therapy, which replaces rather than edits genes, is not a viable treatment for this disease, as the replacement genes are too big for the disabled viruses that carry them to the cells. Therefore, although it may take up to a month to see whether the patient’s sight has been restored, the attempt to do so with CRISPR is a landmark achievement for the whole field of genetics.
“Being able to edit genes inside the human body is incredibly profound,” Dr Mark Pennesi, associate professor of ophthalmology in the OHSU School of Medicine who lead their involvement in the trial, said in a statement. “Beyond potentially offering treatment for a previously untreatable form of blindness, in vivo gene editing could also enable treatments for a much wider range of diseases.”
During the hour-long surgery, doctors delivered three drops of fluid, which contained the gene-editing mechanism, onto the back of the retina. Here the mutated gene is edited within the cells. Cuts are made either side of the gene, in order to hopefully allow the ends of the DNA to reconnect and enable the gene to function properly. Scientists said that this process needs to happen in around one-tenth to one-third of cells to restore vision, according to AP.
“This dosing is a truly historic event – for science, for medicine, and most importantly for people living with this eye disease,” Cynthia Collins, President and CEO of Editas Medicine, one of the companies developing the treatment alongside the global pharmaceutical company, Allergan, said in a statement.
The surgery itself carried minimal risks, and as the tool does not travel to any other part of the body, other than the eye, if something did go wrong the chance of harm would be very small. For the patient, the results will be permanent for the rest of their lives, but will not be passed on to offspring. If the first few attempts go well, the procedure will be carried out on 18 adults and children with the condition.
Other gene-editing tools have been used in the human body before. In 2017, scientists used a tool called Zinc Finger Nucleases, to insert new genes into a patient’s liver, who had Hunter Syndrome. But CRISPR makes editing DNA at a specific spot much easier, therefore a lot of excitement surrounds its advances.
However, the tool does not come without controversy. Back in 2018, you may remember the case where a Chinese scientist claimed to have altered the genes of twin baby girls. This highlighted the need for careful ethical consideration in future gene-editing work, particularly when those genes can be passed down in generations.
[H/T: Associated Press]