Genetic editing, previously restricted to the field of science fiction, is increasingly closer to medical practice. Recent advances have made it possible to correct specific changes in human DNA to treat serious and rare diseases, while at the same time rekindling debates about the ethical limits of genetic manipulation. The possibilities range from treating already born patients to modifying embryos even before the development of hereditary diseases.
One of the most recent examples is the case of KJ, a child from the United States who was born with a rare genetic disease that affects the liver and causes the accumulation of ammonia in the body. Shortly after birth, tests showed levels of the substance around 100 times above normal, putting his life at risk.
After identifying two mutations in a gene responsible for controlling ammonia, doctors at the University of Pennsylvania developed a personalized treatment for the boy. The therapy used a technique known as CRISPR with base editing, capable of altering specific points in the DNA. The medicine was administered through infusions directed to the liver, an organ affected by the disease.
According to the researchers, the treatment managed to significantly improve the child's clinical condition. Today, at two years old, KJ's development is considered normal for his age, although doctors avoid talking about a definitive cure and emphasize the need for long-term monitoring.
How gene editing works
Human DNA contains around 3 billion chemical letters organized into approximately 25,000 genes. Small changes in this sequence can be enough to cause genetic diseases. The purpose of gene editing is to correct these errors directly at the source of the problem.
CRISPR technology has revolutionized this field by allowing scientists to identify and modify specific stretches of genetic material with precision. In some cases, it is enough to correct a single change to restore the proper functioning of a given gene.
Experts say that current advances are the result of decades of research that began with the Human Genome Project, launched in 1990 to map the entire sequence of human DNA. Since the project's conclusion in 2003, genetic tests have become faster and more accessible, accelerating the development of new therapies.
The case that became an alert for science
Despite its therapeutic potential, gene editing also accumulates controversial episodes. In 2018, Chinese biophysicist He Jiankui announced the birth of twins whose DNA was modified at the embryonic stage. The stated aim was to reduce future vulnerability to HIV.
The announcement provoked a strong reaction from the international scientific community. In addition to questions about safety, experts criticized the fact that the embryos did not present diseases that justified the intervention. A Chinese court later sentenced the researcher to three years in prison.
The episode transformed the genetic editing of embryos into one of the most delicate topics in contemporary science and reinforced discussions about the risks of hereditary changes that can be transmitted to the next generations.
Research continues, but with limits
Even after the controversy, studies on genetic editing of embryos were not abandoned. In June this year, researchers at Columbia University in New York announced successful gene editing tests on human embryos. Among the authors is Brazilian researcher and embryologist Marcos Kuhlmann.
In the experiment, scientists modified genes related to cholesterol and hemoglobin during the zygote stage, when the embryo has only one cell. The objective was to prove that genetic alteration could be carried out successfully. None of the embryos were implanted into a uterus.
The researchers state that the future intention is to develop treatments capable of correcting genetic mutations before birth, preventing the emergence of hereditary diseases. At the same time, they advocate that technology be used exclusively for health purposes, and not to create custom physical or biological characteristics.
Promise and caution
For experts, gene editing represents one of the biggest transformations in modern medicine, especially for patients with rare diseases. However, the speed of scientific advances is accompanied by the need to establish clear ethical limits on the extent to which humanity is willing to modify its own genetic code.
While this debate continues, stories like KJ's show the potential of technology to change lives and offer hope to families living with illnesses that, until recently, had no treatment available.
