Genetically inherited illnesses - can we edit them out of our genes?
In 2013, Angelina Jolie wrote a powerful article in New York Times entitled My Medical Choice in which she talks about her decision to have preventive double mastectomy - removal of both breasts. A blood test has revealed that she has inherited a faulty gene which increased her risk of developing breast cancer to 87% and ovarian cancer to 50%. It was a difficult reality for her to face but not a surprise since her mother, grandmother and aunt have died of breast cancer.
What if Angelina’s grandmother could have had her blood tested for this specific gene mutation? Unfortunately the technology was not available at that time. Would she still have died of breast cancer?
Had she known she carried the gene mutation that causes breast cancer, would she have done something to prevent it from being passed onto her female descendants?
These questions may seem rhetorical, but sooner than later, they will receive an answer: no, she wouldn’t have died of breast cancer and no, she wouldn’t have passed the killing gene mutation onto her daughters and granddaughter.
CRISPR/Cas9 is the gene editing tool that will soon usher in a new era of disease-free world. The mechanism behind CRISPR was discovered in the ‘90s by Francis Mojica, a microbiologist. Jennifer Doudna, Emmanuelle Charpentier & Feng Zang are the scientists who have transformed CRISPR/Cas9 into a gene editing tool.
How does CRISPR/Cas9 work?
The gene-editing tool CRISPR/Cas9 is based on a natural defense system embedded in bacterial cells that recognizes and destroys invading viral DNA.
CRISPR/Cas9 searches a cell’s genetic material looking for a specific DNA sequence then once a match is found, it cuts the target DNA. Once the DNA is cut, the cell will then repair the cut with additional DNA provided by researchers.
What genes has CRISPR/Cas9 edited so far?
1.A team of researchers at The Francis Crick Institute in the UK used CRISPR/Cas9 to successfully stop a gene from producing a key protein called OCT4, causing embryos to collapse. The conclusion is that CRISPR/Cas9 could improve the treatment for infertility.
2. In August 2017, a team of doctors successfully corrected the gene that is known to cause a heart disease that affects 1 in 500 people - hypertrophic cardiomyopathy. The novelty is that the correction was done on human live embryos before implantation.
3. Researchers from the University of Pittsburgh have used CRISPR to target cancer’s “command center", increasing survival rates and shrinking aggressive tumors without harming healthy cells in mice.
4. Scientists have edited HIV out of human immune cell DNA, and in doing so, have prevented the reinfection of unedited cells too.
What’s next for CRISPR?
So far, all interventions on DNA using CRISPR were executed on cells outside of the human body, living in petri dishes.
The next step for CRISPR technology is human trials meaning to edit cells inside the human body.
Here lies the challenge: finding a way to insert the CRISPR tool into the human body.
If the scientists are successful, CRISPR will be able to treat a number of serious diseases and even wipe them out forever.