They manage to correct a genetic disease by editing the DNA

April 26, 2024

Noonan syndrome, fragile X syndrome, Huntington's korea, some cardiovascular problems ... They are all diseases of genetic origin that suppose severe alterations in the life of those who suffer them. Unfortunately, until now it has not been possible to find a remedy for these evils.

But in cases where the responsible genes are perfectly localized, it is possible that in the near future we can prevent and correct the possibility that some of these disorders are transmitted. This seems to reflect the latest experiments carried out, in which the correction of genetic disorders through genetic editing .

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Genetic editing as a method of correcting genetic disorders

The genetic edition is a technique or methodology through which it is possible to modify the genome of an organism, sectioning concrete fragments of DNA and placing modified versions instead. Genetic modification is not something new. In fact, we have been consuming transgenic foods for some time or studying various disorders and medicines with genetically modified animals.

However, although it began in the seventies, the genetic edition has been only a few years ago, not very precise and effective. In the nineties it was possible to direct the action towards a specific gene, but the methodology was expensive and took a great amount of time.

Around five years ago, a methodology was found with a level of precision superior to that of most of the methods used up to now. Based on the defense mechanism with which various bacteria fight invasions by viruses, the CRISPR-Cas system was born , in which a specific enzyme called Cas9 cuts DNA, while an RNA is used that causes the DNA to regenerate in the desired way.

Both associated components are introduced, in such a way that the RNA guides the enzyme to the mutated zone for the cut. A DNA template molecule is then introduced, which the cell in question will copy when reconstructed, incorporating the intended variation into the genome. This technique allows a large number of applications even at the medical level , but it can cause mosaicism to appear and other unintended genetic alterations are caused. That is why it requires a greater amount of research in order not to cause harmful or undesirable effects.

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A reason for hope: correcting hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is a serious disease with a strong genetic influence and in which certain mutations in the MYBPC3 gene that facilitate it are identified. In it, the walls of the heart muscle have an excessive thickness, so that muscle hypertrophy (usually of the left ventricle) makes it difficult to emit and receive blood.

Symptoms can vary greatly or even not present clearly, but it is common the occurrence of arrhythmias, fatigue or even death without presenting previous symptoms. In fact it is one of the causes of sudden death more frequent in young people up to thirty-five years of age, especially in the case of athletes.

It is a hereditary condition and, although it does not have to reduce life expectancy in most cases, it must be controlled throughout life. However, the results of a study in which, through the use of genetic editing, it has been possible to eliminate in 72% of the cases (42 of the 58 embryos used) the associated mutation have recently been published in the journal Nature. to the appearance of this disease.

The technology called CRISPR / Cas9 has been used for this purpose, cutting the mutated areas of the gene and rebuilding them from a version without said mutation. This experiment is a milestone of tremendous importance, since it eliminates the mutation associated with the disease and not only in the embryo on which it works, but also prevents it from being transmitted to subsequent generations.

Although similar trials had been carried out previously, It is the first time that the intended goal is achieved without causing other unwanted mutations . That yes this experiment was carried out in the same moment of the fecundation, introducing the Cas9 almost at the same time as the sperm in the ovule, with what would be only applicable in the cases of in vitro fertilization.

There is still a way to go

Although it is still early and multiple replications and investigations must be made from these experiments, thanks to this it could be possible in the future to correct a large number of disorders and prevent their genetic transmission.

Of course, more research is needed in this regard. We must bear in mind that Mosaicism can be provoked (in which parts of the mutated gene and parts of the gene that are intended to end up being hybridized) are hybridized in the repair or generation of other unintended alterations. It is not a completely verified method, but it gives rise to hope.

Bibliographic references:

Knox, M. (2015). The genetic edition, more precise. Research and Science, 461.

Ma, H .; Marti-Gutierrez, N .; Park, S.W .; Wu, J .; Lee, Y .; Suzuki, K .; Koshi, A .; Ji, D .; Hayama, T .; Ahmed, R .; Darby, H .; Van Dyken, C .; Li, Y .; Kang, E .; Parl, A.R .; Kim, D .; Kim, S.T .; Gong, J .; Gu, Y .; Xu, X .; Battaglia, D .; Krieg, S.A .; Lee, D.M .; Wu, D.H .; Wolf, D.P .; Heitner, S.B .; Izpisua, J.C .; Amato, P .; Kim, J.S .; Kaul, S. & Mitalipov, S. (2017). Correction of a pathogenic gene mutation in human embryos. Nature Doi: 10.1038 / nature23305.