CRISPR in 2026: What Gene Editing Can and Cannot Do Yet

In December 2023, the Food and Drug Administration approved Casgevy, the first CRISPR-based therapy to reach the market. It treated sickle cell disease, a painful inherited condition affecting the shape of red blood cells, and for patients who received it, the results were remarkable. Most became functionally cured. The disease they had been born with, the one that had put them in the hospital dozens of times, was gone.

It was one of the most significant moments in modern medicine. It was also expensive enough to be nearly inaccessible. The price for a full course of Casgevy treatment is 2.2 million dollars.

Understanding what CRISPR actually is helps make sense of both the promise and the complications. DNA is written in a four-letter code. Every cell in the body contains the full sequence, billions of letters long, and specialized proteins read and act on specific parts of it. CRISPR is a system that bacteria evolved to defend against viruses. Researchers figured out how to repurpose it as a set of molecular scissors. You design a short RNA sequence that matches the stretch of DNA you want to cut, attach it to the Cas9 protein, and it finds that specific sequence and cuts it. Then the cell's repair machinery takes over, either disabling the gene or replacing it with a corrected version.

The elegance of the system is that it is programmable. Changing what CRISPR targets means changing the guide RNA, which can be done in a lab relatively quickly compared to developing a new therapy from scratch. That programmability is why researchers have been so excited about its potential since the early 2010s.

The pipeline of CRISPR therapies in clinical trials is large and growing. Teams are working on treatments for beta thalassemia, Duchenne muscular dystrophy, various forms of blindness, and certain cancers. Early trial data for several of these has been genuinely promising. A therapy for transthyretin amyloidosis, a rare and fatal heart condition, showed near-complete knockdown of the target protein in Phase 1 data.

The concerns that have followed CRISPR since its early days have not gone away. Off-target cuts, where the molecular scissors edit a part of the genome they were not supposed to reach, remain a documented risk. Researchers have made progress on more precise delivery systems and more accurate Cas variants, but no editing tool is perfect.

The germline question is the one that generates the most heated debate. In 2018, a Chinese researcher named He Jiankui edited human embryos that were subsequently implanted and born, creating the first humans with heritable CRISPR edits. He was imprisoned. The consensus in the scientific community is that heritable human editing is not ready and should not be attempted outside of strict oversight frameworks that do not currently exist in most countries.

CRISPR has delivered on its first major promise. What comes next will take longer than the headlines suggest and cost more than most patients can afford. Both of those problems are solvable. Neither will be solved quickly.