They manage to correct a genetic disease by editing DNA

Noonan syndrome, the fragile X syndrome, the Huntington's chorea, some cardiovascular problems... They all are 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 ills.

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

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Gene editing as a method of correcting genetic disorders

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

However, although it began in the 1970s, genetic editing has been inaccurate and ineffective until a few years ago. Targeting a particular gene was successful in the 1990s, but the methodology was expensive and time consuming.

About five years ago a methodology was found with a higher level of precision than 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 the DNA, while an RNA is used that causes the DNA to regenerate itself in the desired way.

Both associated components are introduced, in such a way that the RNA guides the enzyme to the mutated area to cut it. Subsequently, a DNA template molecule is introduced that the cell in question will copy when it is 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 cause other unintended genetic alterations. That is why a greater amount of research is required in order not to cause harmful or unwanted 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 are excessively thick, so that muscle hypertrophy (generally of the left ventricle) makes it difficult to emit and receive blood.

Symptoms can vary greatly or even not present in an obvious way, but the occurrence of arrhythmias, fatigue or even death without previous symptoms is frequent. In fact, it is one of the most frequent causes of sudden death 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 have recently been published in the journal Nature in which, by using the edition genetics, it has been possible to eliminate in 72% of the cases (42 of the 58 embryos used) the mutation associated with the appearance of this disease.

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

Although similar trials have been carried out before, It is the first time that the desired objective has been achieved without causing other unwanted mutations.. Of course, this experiment was carried out at the same time of fertilization, introducing Cas9 almost at the same time. same time as the sperm in the ovum, which would only be applicable in cases of infertility vitro.

There's still a way to go

While it is still early days and multiple replications and investigations need to be done from these experiments, Thanks to this, it could be achieved in the future to correct a large number of disorders and prevent their transmission. genetics.

However, more research is needed in this regard. We must take into account that mosaicism can be caused (in which parts of the mutated gene and parts of the gene that are intended to end up being obtained are hybridized in the repair) or generation of other unintended alterations. It is not a fully verified method, but it gives rise to hope.

Bibliographic references:

• Knox, M. (2015). Genetic editing, 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.

• McMahon, M.A.; Rahdar, M. & Porteus, M. (2012). Gene editing: a new tool for molecular biology. Research and Science, 427.