CRISPR Is No Longer Just Scissors — The Future of Gene Editing Is a Toolbox
In August 2024, a newborn at the Children’s Hospital of Philadelphia was diagnosed with a rare metabolic disease — a genetic mutation that prevented their body from digesting protein. Babies with this condition typically suffer severe brain damage within months. The standard treatment is a strict, medically supervised diet. There is no cure.
Eight months later, the baby had received three doses of a CRISPR-based therapy delivered by lipid nanoparticles — the same technology used in mRNA COVID-19 vaccines. The treatment was developed, tested, and administered in under a year. The baby is now thriving.
“I don’t know if anyone’s ever created a therapy that quickly, tested it and delivered it to a patient,” said Dr. Jennifer Doudna, the UC Berkeley biochemist who co-discovered CRISPR-Cas9 and won the 2020 Nobel Prize.
The story — known simply as “Baby KJ” among CRISPR researchers — is one of several milestones Doudna discussed in a recent episode of The Joy of Why, Quanta Magazine’s podcast. The conversation, hosted by Janna Levin and Steven Strogatz, maps the transformation of CRISPR from a single revolutionary tool into a broad platform technology — and the formidable obstacles that remain.
When Doudna and Emmanuelle Charpentier published their foundational 2012 paper demonstrating programmable CRISPR-Cas9 gene editing, the field’s imagination was captured by the mechanism: a molecular scalpel that could cut DNA at any chosen sequence. But the image of CRISPR as simply “gene scissors” has become outdated.
“CRISPR has evolved from being a cutting tool into a whole toolbox for different types of genetic manipulation,” Doudna explained. The core insight is that Cas9 is not the product — it is the engine. By changing the guide RNA, you redirect the system. By modifying the Cas protein itself, you change what happens at the target site: cutting, base editing, gene activation, gene repression, or epigenetic modification.
The field has since expanded to include base editors (which change single DNA letters without breaking the double helix), prime editors (which write new genetic sequences into the genome), and CRISPR interference systems (which silence genes without altering DNA). But Doudna’s focus has been on delivery — the problem of getting CRISPR components into the right cells in a living patient.
The Delivery Bottleneck
The Baby KJ case demonstrated something the field had suspected: lipid nanoparticles (LNPs) work exceptionally well for delivering CRISPR to the liver. The same LNP technology that enabled the COVID-19 vaccines turned out to be a surprisingly effective vehicle for gene-editing payloads targeting hepatocytes.
But the liver is easy. Blood flows through it constantly, and its fenestrated capillaries allow nanoparticles to pass from circulation into liver tissue. Other organs are far harder to reach.
“Delivery to the lung, to muscle, and to the brain — these are the major unsolved problems,” Doudna said. She described these tissue targets as “one of the real forefronts in the field right now.”
For muscle, the challenges include crossing the blood-vessel wall. For the brain, the blood-brain barrier presents an even steeper obstacle. Researchers are exploring engineered viral vectors, modified LNPs with tissue-specific surface proteins, and entirely new nanoparticle chemistries. Doudna said she is “very bullish” that the problem is solvable, but acknowledged it will require focused effort, not incremental progress.
One-and-Done: The Cardiovascular Target
Beyond rare pediatric diseases, the most advanced CRISPR therapy targeting a common condition comes from Verve Therapeutics, a Boston-based biotech that was acquired by Eli Lilly in 2025. Verve’s approach uses a single infusion of CRISPR-LNP to edit the PCSK9 gene in liver cells — turning off a protein that regulates cholesterol. The edit creates a genetic variant that naturally protects against arterial plaque buildup, mimicking the effect of statins but requiring only one treatment rather than daily pills.
Doudna described cardiovascular disease as “the most impactful common disease target” for CRISPR therapy, precisely because the liver is already accessible via LNP delivery and because the genetic target — PCSK9 — is well-validated by decades of human genetics and existing antibody drugs.
“The idea that you could have a one-time treatment that would have a lifelong benefit,” she said, “that’s where the potential for huge impact really lies.”
The Ethical Terrain
Doudna devoted significant attention to the ethical questions that have shadowed CRISPR since its discovery. She called the 2018 work of He Jiankui — who used CRISPR on human embryos to produce the first gene-edited babies — “extraordinarily unethical” on multiple grounds: the lack of medical necessity (existing HIV prevention methods were available), concerns about informed consent, and the permanent, heritable nature of the changes.
But she also warned that the temptation has not disappeared. “Companies are still exploring again the possibility of germline editing and offering that as a service,” she said. “It remains very much in the milieu.”
Doudna emphasized that genetics is rarely simple. She cited sickle cell disease as an example — the mutation persists in human populations partly because carrying one copy provides protection against malaria. “Genes aren’t necessarily good or bad,” she said. “We have to employ [CRISPR] cautiously because it does require a lot of knowledge about what effect a genetic change is going to have on a person over the course of their life.”
Beyond Human Health
The interview also covered applications beyond medicine. The Innovative Genomics Institute, which Doudna leads, has active programs in crop engineering — drought-resistant plants, improved nutritional content — and livestock microbiome editing to reduce methane emissions from cattle.
“Curiosity-driven fundamental science is what led to CRISPR in the first place,” Doudna noted. She described her own career path as a “rebellious” focus on RNA biology at a time when it was considered a niche field — a choice that ultimately led her to study how bacteria remember viral infections, which in turn led to the discovery of CRISPR-Cas9.
“The entire thing was driven by asking how bacterial immunity works,” she said. “Nobody was trying to create a gene-editing tool.”
Source: Doudna, J. interviewed on The Joy of Why, Season 5, Episode 1. Quanta Magazine, June 11, 2026. https://www.quantamagazine.org/whats-the-future-of-gene-editing-20260611/