06/24/2026  |  Medicina S/A

https://medicinasa.com.br/pesquisadores-corrigem-genes/ 

Researchers at Columbia University in New York used a gene-editing technique called base editing to alter the DNA of early-stage human embryos. The study, published on the bioRxiv platform in early June without undergoing peer review, sparked mixed reactions in the scientific community: praise for the precision of the approach and warnings about the risks of its premature use.

The team led by cell biologist Dieter Egli modified three genes associated with conditions such as high cholesterol, sickle cell anemia, and beta-thalassemia. The technique allows for precise changes to the genetic code, one letter at a time, without cutting the two strands of DNA as conventional CRISPR does. This reduces the risk of unintended changes, though it does not eliminate it.

Fertility experts have described the work as a conceptual breakthrough in the field—more cautious than previous attempts—but they raise a red flag: the relative simplicity of setting up an IVF laboratory combined with gene editing could encourage irresponsible uses of the technology, with unpredictable consequences for the babies conceived.

Egli himself admits that the technique is not yet ready for clinical use. The tests revealed a phenomenon called mosaicism: the edits did not occur uniformly across the embryo’s cells; that is, some cells received the desired alteration while others retained the original sequence. Furthermore, the component used to introduce the DNA editor caused cell division to halt, which precludes any immediate application.

Prevention as the Most Effective Approach

For part of the global scientific community, the debate over embryo editing is based on a questionable premise; they believe the technique is a solution in search of a problem, since preimplantation genetic testing (PGT) allows for the identification and selection of healthy embryos within an in vitro fertilization process without altering anyone’s DNA.

In Brazil, experts are following these advances with interest, but without losing sight of the priorities of the local market. Bruno Coprerski, Centogene’s director of operations for Brazil and Latin America, sees value in the data from the Columbia study, but emphasizes that it does not alter the hierarchy of available strategies. “Gene editing is, in fact, an alternative, and the data provide important insights to help this debate move forward safely. But prevention is a far more effective approach. Gene editing would come into play primarily in cases where prevention is not feasible, which is especially relevant in countries with structural shortcomings in this area,” he notes.

In his view, before any discussion of genome editing takes place, access to preimplantation genetic testing must be expanded, as it already offers concrete solutions to couples with a history of hereditary diseases.

What Already Exists and Works

PGT is divided into modalities with distinct indications. PGT-A checks whether embryos have the correct number of chromosomes, reducing the risk of miscarriages and increasing the chances of a healthy pregnancy. PGT-M is recommended when there is a known risk of transmitting a specific monogenic disease. PGT-SR is indicated for couples with a history of recurrent miscarriages caused by structural chromosomal rearrangements.

These tests are already part of the routine at assisted reproduction clinics in Brazil and represent the state of the art in preventive medicine applied to genetics. Should embryonic genome editing ever reach clinical practice, it will encounter a system that has already learned to handle genetic information with great care.

Although researchers are testing “base editing” to correct mutations in in vitro embryos, experts emphasize that Preimplantation Genetic Testing (PGT) remains the safe and preventive gold standard in assisted reproduction.

Currently, precision reproductive medicine focuses its efforts on the ability to diagnose and guide family planning based on consolidated genetic data. In this context, specialized companies such as Centogene use large clinical and genetic databases to support the diagnosis of rare and neurodegenerative diseases. In the field of human reproduction, the priority remains expanding access to carrier screening, infertility investigation, management of recurrent pregnancy loss, and preimplantation testing (PGT). Experts believe that progress in this field depends on a combination of technological innovation and robust scientific evidence.

“The Columbia study is a sign of things to come. For now, the frontier of precision reproductive medicine continues to be defined by the ability to diagnose accurately and guide patients based on evidence, not on promises,” concludes Bruno Coprerski.