‘Lulu’ and ‘Nana,’ recently hit the headlines. They are the twin girls born as a result of In Vitro Fertilization (IVF) conducted by the Chinese genetic scientist, He Jiankui. Actually, it was more or less his public announcements of having successfully edited the genome in these twin girls born as a result of In Vitro Fertilization (IVF) that hit the headlines. He asserted that the experiment was done through CRISPR-Cas9 editing.
According to the scientist, the procedure resulted in the removal or silencing of the CCR5 gene, which is associated with susceptibility to HIV infection. This, He reasoned, would protect the girls against the same infection carried by their father.
The Questionable Ethics of Gene Editing
This announcement was met with reactions ranging from contempt to horror, among the scientific community. Even He Jiankui’s own academic institution turned against him, insisting he had conducted his experiment without their knowledge or approval and suspended him from his job.
Though the twin babies or their parents never really appeared in the media, speculation has thrived that He merely posted the video for a publicity stunt trying to leverage his private gene-editing business concern.
The Mayo Clinic bioethicist, Dr. Megan Allyse, assessed the information He used for his experiments. Allyse described it as “a disaster,” asserting that all the possible effects and risks of such a single-gene silencing had not been outlined or well defined for parents who have consented to participate in his work.
The Mayo Clinic expert’s most recent studies include assertions that medical practice is still not prepared to integrate Gene Editing as a therapeutic application. Dr. Allyse also observes that CRISPR-Cas9 has not advanced enough to avoid or account for risks and complications that may result from singular gene-editing.
CCR5 affecting Other Tissues
Researches done to study the effects of CCR5 have brought out the effects it can have on tissues. The gene is mostly thought of as playing a significant role in the immune system, and can thus be used to prevent the entry of HIV virus particles into a host cell, from which it can replicate to establish a lifelong infection.
Studies on animals suggest that CCR5 may also influence brain tissue, particularly nerves related to learning and memory. According to a study, CCR5 deletions resulted in almost 60% improvements in cognitive function in mice. Though scientists are of the opinion that this effect may not translate well to human brains. It is also predicted that CCR5 deletion could negatively impact the ability to ‘distinguish’ between ‘useful’ and ‘trash’ memories, on a neurological level.
CCR5 has also been found to be an important factor in resistance to other viral diseases. It has been found to strongly influence the immune system in its response to flaviviruses, that are the causative agents for diseases like tick-borne conditions, yellow fever, etc... According to the findings of some researches the CCR5 gene product is found to play an important role in the defense against influenza. The CCR5 silencing mutation has been found to associate with susceptibilities to encephalitis that is formed as a complication of a variety of tick bites. This could precisely be the kind of mutation He had aimed to generate in the twin girls as it is closely associated with increased resistance to HIV.
Future for CRISPR-IVF
The ethical predicament surrounding the ‘CRISPR-IVF’ becomes worse with reports quoting that only one of the twins were affected with CCR5-Δ32 mutation on the alleles ( Alleles are alternative forms of a gene that was formed by mutation and are found at the same place on a chromosome ) of the gene, whereas the other had only inherited a working copy of the unaltered gene. This unpredictability suggests a potential human rights violation, proving that the efficacy of gene-silencing in the CRISPR-IVF procedure would best be practiced in moderation.
There are apprehensions about the alleged intervention doing more harm than good, to the children born of it. It would also emphasize the fact that CRISPR may require more work before it can become part of the medicine of the future.Published: Dec 21,2018 09:11:25 AM IST