Potential cure for genetic disease? Scientists test DNA editing inside human body for first time

Scientists have taken a significant step towards more precise gene-editing treatments after using a technique called prime editing to alter DNA directly inside the human body, according to a report published by Nature on October 22, 2026.

The development marks a potential advance in the treatment of genetic disorders, including diseases that can cause liver and nerve damage. Unlike conventional approaches that often require cells to be modified outside the body, the technique aims to make targeted genetic changes within the patient.

The trial highlights the growing effort to turn advances in gene-editing technology into treatments that can correct the underlying genetic causes of disease rather than simply manage their symptoms.

What is prime editing, and why does it matter? 

Prime editing is an advanced form of CRISPR gene editing that allows scientists to make targeted changes to DNA, including rewriting, inserting or deleting specific stretches of genetic code.

Traditional CRISPR-Cas9 methods are often used to cut DNA and disable a gene. Prime editing offers greater flexibility by enabling researchers to rewrite DNA sequences, potentially correcting mutations responsible for inherited diseases.

The technique is particularly relevant when a disease-causing mutation cannot be corrected using simpler gene-editing methods.

Wilson disease: The condition targeted by the trial 

The clinical trial is investigating an experimental treatment for Wilson disease, a rare genetic disorder in which the body cannot properly eliminate excess copper.

The disease is caused by mutations in the ATP7B gene, which provides instructions for producing a protein that helps transport excess copper out of the liver. When this process fails, copper accumulates and can damage the liver, nervous system and other organs.

Current treatment typically involves medicines that help remove excess copper or limit its accumulation. Patients may need to follow complicated treatment regimens over long periods.

By attempting to correct the underlying genetic defect, prime editing could potentially offer a more durable treatment. However, whether the experimental therapy can deliver lasting benefits remains to be established through clinical trials.

What makes this trial different? 

The key development is that the treatment edits DNA inside the patient's body, rather than modifying cells in a laboratory before returning them to the patient.

This approach, known as in vivo gene editing, could eventually make certain genetic treatments faster and less expensive to manufacture and administer.

In previous clinical work involving prime editing for a rare immune disorder, researchers modified a patient's blood stem cells outside the body before reinfusing them. The Wilson disease trial takes a different approach by targeting liver cells directly.

US biotechnology company Prime Medicine announced that it had treated the first participant in the Wilson disease trial earlier in October 2026. The company expects to report initial results in 2027.

What are the risks and limitations? 

Despite the promise, direct gene editing inside the body presents significant challenges. Researchers must ensure that the editing machinery reaches the intended cells, makes the correct genetic changes and avoids harmful alterations elsewhere in the genome.

The long-term effects of the treatment also need to be assessed. A successful first treatment does not establish that the approach is safe, effective or suitable for widespread use.

The broader field is still developing. As reported by Nature, no gene-editing therapy had yet been approved for direct in vivo use at the time of publication. The outcome of this trial could therefore provide important evidence about whether prime editing can be translated into a practical treatment for genetic diseases.

The next major milestone will be the release of the trial's initial results in 2027. These findings should help establish whether the experimental treatment can safely modify the targeted gene and whether that change improves the patient's condition.