Genome modification may be the answer for William Parenteau, a Pediatric Surgeon, whom parents usually call after noticing some abnormalities with an unborn child following a prenatal genetic test. William works at the Philadelphia Children’s Hospital, and he can only fix these abnormalities after the unborn children leave their mother’s womb, but this might be too late.
The pursuit of Gene Editing
It was the guilt of failing to help the families that motivated William to join a group of scientists trying to move gene-editing to the womb. This may take a long time to materialize, but recent advancements have shown that this method has more advantage over the use of CRISPR to eliminate diseases. In such situations, the parents of the unborn child are often faced with a dilemma, whether to eliminate the child or prepare to care for it as the child undergoes multiple invasive surgeries just to survive. Nonetheless, according to William, “what we see as the future is a minimally invasive way of treating these abnormalities at their genetic origin instead.”
In an effort to realize and prove this vision, William and his team injected virus-encoded CRISPR editing components in the placenta of pregnant mice. The unborn pups were suffering from a lung disease that caused mutation. Few hours after birth, about 25% of the mice that had inhaled the CRISPR survived but the others died, according to the results.
This is one of the two proof of concept experiments carried out by the group. The second is when the group managed to rescue almost all mice pups after changing the single base pair in prenatal mice’s liver cells.
Although the experiment is still in its early stages, the pioneers believe that challenges faced while using CRISPR-based treatments, namely dodging an individual’s immune system can be solved by treating unborn patients.
The main explanation behind this is that since fetuses are still developing, the changes made will easily spread to other organs, as compared to an adult organ, which is not proliferating. Additionally, the developing fetus has a less aggressive immune system, thus less likely to attack the CRISPR components.
Genome Modification at an Early Stage
Now, you might ask, if editing at an early stage is better, why not edit the embryo, right after fertilization? This practice has been prohibited by the U.S. Food and Drug Administration, as it entails complicated ethical issues because the changes are passed on to the cells that make the sperm or eggs. This, in turn, may lead to genetically modified humans.
Others issues may also occur, such as exposing the mother to health risks, and some CRISPR components may stray and go to her ovaries where they might genetically-edit the unfertilized eggs. As such, a lot more research needs to be done to ensure all risks are assessed.
To get an idea of how long this will take, take a look at the first experiment, of replacing a defective gene using a virus that was proposed in the mid-90s, and yet only a single experiment is ongoing today.
It is not clear when this idea will materialize, but Williams states that hopeful families should continue to hold on to the possibilities of Utero genome modification.