Gene Editing Technique could transform future

(Partly adapted from Fergus Walsh – BBC Health)

CRISPR – get to know this acronym. It’s good to know the name of something that could change your future. Pronounced “crisper”, it is a biological system for altering DNA. Known as gene editing, this technology has the potential to change the lives of everyone and everything on the planet. CRISPR was co-discovered in 2012 by molecular biologist Professor Jennifer Doudna whose team at Berkeley, University of California was studying how bacteria defend themselves against viral infection. Prof Doudna and her collaborator Emmanuelle Charpentier are now among the world’s most influential scientists. The natural system they discovered can be used by biologists to make precise changes to any DNA.

When a bacterium comes under attack it produces a piece of genetic material that matches the genetic sequence of the invading virus. This piece of material alongside a key proSo how and when might we begin to see treatments from CRISPR? Given that the technology is just a few years old.
The Boston biotech firm Editas Medicine is hoping to have a gene-editing treatment ready for clinical testing in 2017 to treat Leber congenital amaurosis, a rare retinal disease that causes blindness. The gene mutation causes the gradual loss of photoreceptor cells in the eye.
tein called Cas9 can then lock on to the DNA of the virus, break it and disable it. Scientists are now able to deploy the same process to insert, delete or repair DNA. It is so sensitive that they can use it to explore the billions of chemical combinations that make up code of the DNA in a cell, and to make a single key change. Importantly, it is fast and cheap, and so is accelerating all kinds of research, from the creation of genetically-modified animal models of human disease to the search for the DNA mutations that trigger illness or confer protection.

Several biotech firms are hoping to take CRISPR technology into the clinic. They are working on the theory that CRISPR might be used to boost the function of the body’s T cells so that the immune system is better at recognizing and killing cancer. Disorders of the blood and immune system are other potential targets. Two earlier forms of gene editing have already made it into the clinic. In 2016 a technique known as TALENs was used to help reverse cancer in a patient at London’s Great Ormond Street Hospital. Layla Richards had an aggressive form of leukemia, and all previous treatments had failed. She remains the first person to date whose life has been saved by gene editing. The world’s first gene-editing trials took place in California, involving a different technique. About 80 patients with HIV had immune cells in their blood removed. Scientists then deleted a gene called CCR5 which HIV uses to gain entry to cells. The treatment is based on a rare, gene mutation which gives some people a natural immunity to the disease. One of the volunteers aged 52, had lived with HIV most of his adult life and witnessed the devastating impact of HIV/ AIDS. He has been off all antiretroviral medication for two years since having his immune cells gene edited. These were small trials, but they are nonetheless extremely promising.

The most controversial aspect of gene editing concerns the potential to introduce changes to the germline – DNA alterations that would pass down the generations. In theory it might be possible to correct the DNA of embryos carrying the gene for cystic fibrosis. But it might also
be used to add in genetic enhancements, leading to designer babies.

Designer Babies No scientist is suggesting – yet – that geneedited human embryos should be born. But several teams in China have done some basic research and the UK is the first country to formally approve gene editing in human embryos, for research only. A team led by Kathy Niakan – recently named by Time magazine as one of the world’s 100 most influential people – will use CRISPR to edit out key genes from the embryo, to try to identify the genetic faults which lead many women to repeatedly miscarry. The embryos will be allowed to develop for just a few days.

She said: “What I’m hoping is that it provides us with a really crucial insight into early human development. “I think it could help in identifying ways in which we could improve In Vitro Fertilization to identify those embryos that are likely to continue to develop and thrive and, and give rise to healthy babies.”

ETHICAL CONCERNS

But this research rings ethical alarms bells. She believes human embryo editing research may not be adequately controlled, leaving it open to a lab somewhere to create the first gene-edited babies.

“You could find wealthy parents buying the latest offspring upgrades as their children. We could see the emergence of genetic discrimination and even greater inequality than we already live with.” She says that that while it is very hard to regulate the use of CRISPR technology, it is important to find a consensus about how people should proceed. “I never want to over-promise but I feel diseases will be cured and we want to enable clinicians and scientists to bring that to a reality.”