Why is gene editing a controversial topic?

At the end of November 2018, the 2nd International Human Genome Summit took place in Hong Kong. There, Chinese scientist He Jiankui announced to the world that two twin girls had been born genetically modified to achieve immunity to the Human Immunodeficiency Virus (AIDS). A third baby was subsequently born with the same modification.

The researcher recruited couples in which one of the parents was infected by the HIV virus, and carried out in vitro fertilization, thus obtaining embryos from the couples in the laboratory, and in which he performed a “genetic improvement” with the CRISPR technique. And he did it without prior approval by an ethical committee and without the knowledge of the official institutions: neither the university where he works, nor the Chinese government, nor the international scientific communities.

Following the statement and the numerous criticisms that were generated, the Chinese government decided to launch an investigation and, on December 30, 2019, the scientist they call “the Chinese Frankenstein” – who disappeared a year ago – was sentenced to three years in prison and to professional disqualification from any activity related to the health world.

The conviction has silenced critics who claimed that all kinds of experiments were possible in China without consequences.

The basis of genetic mutation is in science

Seven years ago, the Alicante researcher Francis Mójica discovered the CRISPR/Cas9 system, a defense system that some bacteria have to protect themselves from viruses. It represented a major breakthrough in DNA manipulation, since it works like molecular scissors capable of cutting the genome in a specific area and replacing or repairing it with a DNA mold provided by the same system. Known disease-causing mutations could be repaired quickly and accurately, genes could be disabled (in the case of the twins it is an HIV receptor), the expression of certain genes could be decreased or increased, etc.

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The studies and clinical trials that have begun since then are innumerable. However, all of them have been performed on in vitro animal cells and on human embryos donated to science, which are subsequently destroyed.

Limitations of the technique

Moreover, not only embryos but also somatic cells, i.e. cells from any part of the body of sick people, can be modified. But it has been proven that not all cells can be repaired and, in addition, two populations of cells with different genetic material would coexist in the same body (mosaicism), which could provoke an immune reaction against the different population (autoimmune disease) or against a component of the system of bacterial origin. It should also be considered that CRISPR is not perfect and can also introduce additional errata into the genome that could be harmful to humans.

In short, as far as research goes, we could be exposing the person to a health problem. Probably in the future the technique will be mastered and improved and its adverse consequences can be prevented and we will benefit from this promising technique.

The ethical problem of manipulating embryos

  • If the repair of a DNA mutation that causes a hereditary disease is considered, the potential is great and the expectations are good. In this sense, there is already a technique, clinically proven and with more than 15 years of experience, which is preimplantation diagnosis and which makes it possible to select the healthy embryo before transferring it to the mother’s uterus.
  • If we consider introducing a genetic improvement in embryos that are healthy, we are already talking about eugenics, about improving the human race, only for those who can afford it. This is something to be very cautious about.
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In this sense, the Association for Responsible Research and Innovation in Gene Editing is fighting for the creation of strict international legislation in this regard. Although it is difficult, because at that level there is only the Universal Declaration of Human Rights, it is also an absolute priority.

Spain and 28 other countries have ratified the Oviedo Convention -signed in 1997- which declares this type of experiments illegal. There are still many nations that have not signed it and that do not have specific legislation, as is the case of Russia, where there is a legal vacuum on the matter.

Gene editing technology is not ready to be safely applied. What is desirable now is to go ahead with research in this field respecting the law and working with total transparency.

Dr. Vega María Cabezuelo Sánchez, member of Top Doctors, specialist in Assisted Reproduction in the Reproduction Unit of the Women’s Unit at the Ruber International Hospital.