Human gene editing has been advancing rapidly. CRISPR/Cas9 is a popular tool for gene editing. Think of it as a pair of “smart scissors” that can find and cut a specific part of DNA. It has transformed the field due to its accuracy and ease of use. In the real world, the potential of human gene editing is exciting, but it comes with many questions that need addressing. While the technology can revolutionize how we treat genetic disorders, its misuse can lead to unintended consequences.
This revolutionary technology has enabled researchers to modify genes with unprecedented precision, simplicity, and affordability. CRISPR/Cas9, which stands for “Clustered Regularly Interspaced Short Palindromic Repeats” and “CRISPR associated protein 9,” is a tool that can target specific DNA sequences in the genome and either knock them out or replace them. CRISPR /cas9 mediated gene editing in human tripronuclear zygotes.
What is gene editing?
Human Gene editing is like using a precise “molecular scissors” set to change an organism’s DNA (the code that makes up all living things). By doing this, scientists can fix, add, or remove parts of the DNA sequence.
The primary goal of many gene-editing efforts has been to treat or cure genetic disorders. Some clinical trials were ongoing or in the planning stages for conditions like sickle cell anemia, inherited blindness, and certain forms of muscular dystrophy.
One of the main reasons is to cure genetic diseases. For instance, if someone has a faulty gene that causes a disease, editing that gene might cure or prevent the disease.
Scientists have continuously refined human gene editing techniques to increase efficiency, specificity, and safety. New versions of CRISPR systems and other gene-editing tools are being developed. For instance, researchers are looking into base editing, which means changing individual DNA base pairs and prime editing, a more precise form of human gene editing.
Ethical and Safety Concerns
Human Gene Editing, especially in the germline (sperm or egg cells), raises significant ethical issues. Any changes made to the germline could be passed down to future generations. The international community has debated the ethics and safety of germline editing, which remains a contentious issue.
He Jiankui Controversy
In 2018, Chinese scientist He Jiankui announced the birth of twin girls whose genes he had edited to make them resistant to HIV. The international scientific community widely condemned this act because the long-term effects of the edits were uncertain, the work bypassed ethical guidelines, and there was a lack of transparency.
Another significant example of Human Gene Editing
Emily is a young girl diagnosed with a genetic disorder called cystic fibrosis (CF). This condition is caused by mutations in a specific gene, making mucus in the body thick and sticky. This sticky mucus can clog the lungs, leading to respiratory and digestive problems, among other complications.
In the past, Emily would have to undergo various treatments to manage her CF symptoms. These might include:
- Chest physical therapy to assist in clearing mucus from her lungs.
- Taking medications to thin the mucus, treat respiratory infections, or aid digestion.
- Regular hospital visits and checks.
What scientists do with the human gene-editing tool CRISPR/Cas9:
Scientists could take cells from Emily’s body and use the gene editing tool to target the specific mutation causing her CF. They would “cut” the DNA at that point and either “paste” a corrected version or let the cell repair itself correctly.
These edited cells could then be reintroduced into Emily’s body. If everything works as intended, these cells produce the correct protein, effectively reducing or eliminating Emily’s CF symptoms.
If misuse of human gene editing:
Imagine Emily has a toy car (her body) that doesn’t work correctly because of a broken part (the faulty gene causing cystic fibrosis). The old solution in the past was to make her toy car work better; she could add oil or tape to fix it temporarily. It wasn’t a perfect fix, but it helped a bit. This is like the traditional treatments she received for her condition.
But a new solution with Gene Editing is if someone could open up her toy car, find the exact broken part, and replace it with a new, working part. The toy car would work perfectly! Gene editing, like CRISPR, aims to find the broken part (the faulty gene) in Emily’s body and fix or replace it.
The Big Question
But what if, instead of fixing the broken part, someone upgraded Emily’s toy car to make it faster or look different, even if the original was okay? This is like changing human traits for reasons other than health.
Is that right? – Should we change something if it’s not broken?
Is It Safe? – What if the new part has problems we need to learn about?
Who Decides? – Should only those with money or access get a “better” toy car?
Now, let’s say instead of treating a disease like CF, a scientist wanted to use gene editing to make Emily taller, more athletic, or even change her eye colour. These are not medical necessities but personal or cosmetic preferences. Now, the very ethical questions are,
- Is it right to edit genes for non-medical reasons?
- What if only the wealthy can afford such modifications?
- What if the editing process introduces new problems or health risks?
- What if changes unintentionally impact Emily’s offspring?
- Could this lead to a society favouring certain traits, creating inequality or bias?
This is why gene editing is both exciting and controversial. It can offer great solutions but also brings big questions we must consider carefully. Scientists have yet to answer these questions. New discoveries, refined methods, and ongoing debates might exist about how and when to use this powerful technology.
The cost will be the concern
Regulatory landscapes vary by country, but there’s a consensus on the need for rigorous oversight, especially for germline editing. Some countries have banned or placed moratoriums on germline editing in humans.
In clinical studies, the biotech firms Vertex Pharmaceuticals and CRISPR Therapeutics have taken blood stem cells from patients, activated a healthy gene for fetal hemoglobin that the cells usually shut off after birth using the CRISPR gene-editing technique, and then reinfused the changed cells. The one-time therapy has resolved most patients’ acute pain episodes and requirements for blood transfusions.
Regulators in the US and Europe are considering the corporations’ requests, and a judgment on at least one of the two continents might be made before the end of the year. The cost issue will be the key one. The cost of gene therapy, an earlier method that addresses genetic problems by adding genes rather than changing them, has ranged from $850,000 to $3.5 million.
Finally, by 2023, the field will likely have seen further advancements, with more clinical trials, new technologies, and evolving ethical discussions. However, it’s crucial to stay updated with the latest publications, conference announcements, and news in the biotech field for the most recent developments.