Modification may, in the future, allow babies to be born free of some diseases Pexels Researchers at Columbia University in the United States were able to edit the DNA of early-stage human embryos with a precision that had not been achieved before. The goal was to correct genes linked to two serious conditions: cholesterol-related heart disease and blood diseases such as sickle cell anemia. 🔴 The work was published as a pre-print — that is, a previous version that has not yet been formally reviewed by other scientists. Even so, it is already moving the scientific community due to its high success rate and what it could represent for the future: a technically viable way to correct hereditary mutations before a baby comes into the world. 🔴 What experts question is that, on the one hand, parents will be able to avoid serious illnesses in their babies. On the other, there is an ethical debate with the possibility of choosing physical characteristics as well. Below you will read: How was the research done? How can it change society? What's at stake in this? Change in DNA could eliminate thousands of diseases in the future Freepik How was the research done? To understand the novelty, it is necessary to compare it with the best-known gene editing technology: traditional CRISPR/Cas9. It works like molecular scissors — it locates the exact point of the DNA and cuts the two strands that form the double helix structure. The problem is that human embryos have difficulty repairing this type of total cut, which can lead to serious errors, such as the loss of entire chromosomes. The research tested a different approach, called Base Editors (ABE). Instead of cutting the DNA, this technique acts as a precision corrector: it locates a single wrong "letter" (chemical base) in the genetic code and replaces it with another, without breaking the structure of the DNA. It is a surgical intervention on a molecular scale. The researchers decided to correct two genes: PCSK9 — controls blood cholesterol levels and is associated with the risk of hereditary heart disease. HBG — when altered strategically, can help treat blood disorders such as sickle cell anemia. In total, the study involved samples from 40 embryos for the analysis of the PCSK9 gene and 17 embryos for HBG1/2. The embryos were donated by fertility clinic patients who had already completed their treatments and would be discarded. Research managed to modify genes precisely for the first time Reproduction After injecting the "genetic corrector" into the embryos, the researchers carried out three main checks: Efficacy: They confirmed whether the change of "letter" in the DNA had actually caused the disease. The success rate was high — between 70% and 95%, depending on the gene. Chromosomal integrity: They used genomic imaging tools to verify that chromosomes — the “folders” where DNA is stored — remained intact. Unlike traditional CRISPR, base editors did not cause structural damage. Development: they observed whether the embryo continued to grow normally until the blastocyst stage, a stage that occurs between 5 and 6 days after fertilization and which is the starting point for the first genetic tests in reproductive medicine. The success rate and development seen in research is unprecedented. What this preprint reveals is the closest step to gene editing in the world. But this is a first step. The research still needs new validation steps, review by other scientists and further steps until this becomes a reality. "Although this may be a step toward heritable editing, transposition to a clinical context remains premature," the researchers explain. How can it change society? There are thousands of diseases that are the result of genetic mutations. These fixes could prevent these diseases from developing and even eradicate some of the world's deadliest health problems. In the case of the research, the edition explored, for example, attempted to edit PCSK9 — which controls blood cholesterol levels and is associated with the risk of hereditary heart disease. These are the diseases linked to the highest number of deaths in Brazil, for example. 🔴 Heart diseases are responsible for 30% of deaths in Brazil, which corresponds to 400 thousand deaths per year, according to the Ministry of Health. The second edition, which could help treat blood diseases such as sickle cell anemia, could change the lives of thousands of people in the country. According to estimates, between 60,000 and 100,000 patients live with the disease in the country. Where is the ethical debate? The research opens up two opposing perspectives that already divide bioethics experts. On the one hand, the technology could one day allow families with a history of serious genetic diseases to safely correct mutations in embryos before pregnancy. However, on the other hand, the same mechanism could, in theory, be used to select physical characteristics in children — which the majority of the scientific community considers a line that should not be crossed. For now, the step is seen as technically innovative, but science is still far from applying it in clinics. The debate over where to draw the line, however, has already begun.