Two Genes Were Blocking CRISPR Gene Therapy. Researchers Found Them.
💡 On August 13, 2026, a team at the University of Wisconsin-Madison published findings in Nature Communications identifying two genes - GJB2 and BET1L - that suppress CRISPR base editing in human cells. Removing them raised editing efficiency by more than six times, opening a new approach for gene therapy targeting inherited diseases.
- A genome-wide screen of 19,144 human genes found two that block CRISPR base editing: GJB2 and BET1L.
- Removing either gene improved adenine base editor efficiency by more than 6x in human model cells, and more than 3.5x in patient retinal cells with hereditary blindness (Leber congenital amaurosis).
- The key insight: improving gene therapy does not only mean engineering a better delivery vehicle. You can also reduce the cell's own resistance.
- The technique uses lipid nanoparticles - the same nonviral delivery method as mRNA COVID vaccines - so lessons may extend to vaccine and cell therapy research.
- Honest limit: results come from cell cultures. The mechanism behind GJB2 and BET1L's blocking effect is still unknown. Clinical use in humans is years away.
What researchers actually did
Professor Krishanu Saha's team at UW-Madison asked a precise question: which genes inside human cells make CRISPR base editing less effective than it should be? Base editors work by chemically flipping single DNA letters, a method that corrects mutations without cutting the DNA strand. Even well-designed editors, however, often underperform inside real cells.
The team built a genome-wide CRISPR screen: they disabled each of 19,144 known human genes one by one, then measured how well an adenine base editor performed. Of the 26 genes whose removal improved editing, they validated six candidates deeply and confirmed two main blockers: GJB2 and BET1L.
What is base editing, and why does delivery fall short?
Base editing is sometimes called CRISPR 2.0. Rather than cutting the DNA strand to remove or swap a segment, it uses a modified enzyme to chemically convert one DNA base into another. Think of correcting a single typo in a long document without tearing the page. This precision lowers the risk of unintended mutations that cutting can cause.
Delivery is the persistent bottleneck. Lipid nanoparticles - fat-bubble structures that carry the editing components inside cells - work without viral vectors and are already used clinically in mRNA vaccines. The problem is that once a nanoparticle arrives at a cell, the cell's own biology can interfere with what the editor tries to do. GJB2 and BET1L are two such interference points.
What does this mean for people waiting on gene therapy?
For patients with an inherited condition caused by a single faulty DNA letter, gene therapy has long been a theoretical promise that struggles in practice. Low editing efficiency in target cells is one core obstacle. A treatment must correct a high enough proportion of cells to produce a real clinical benefit.
A more-than-sixfold gain in efficiency is not a small increment. It could shift a treatment from correcting 10% of cells to correcting 60% or more. The team specifically tested patient-derived retinal cells from people with Leber congenital amaurosis, a hereditary blindness condition. Editing efficiency more than tripled in those cells. Single-gene conditions including certain inherited vision disorders, sickle cell disease, and metabolic enzyme deficiencies are all candidates if the approach holds in further testing.
Which diseases could benefit first?
Eye disease is the natural early focus. The retina is accessible, immunologically quieter than most organs, and its cells do not divide rapidly, so edits last longer. Base editing in general has already entered early clinical trials for blood conditions like sickle cell disease and transthyretin amyloidosis. The new finding adds a strategic option: temporarily suppress GJB2 or BET1L to open a window of higher editing efficiency before the cell restores normal function.
What are the real limits of this research?
The results come from cultured cells and patient-derived cell models - not from a living organism. Cells in a dish behave differently from cells inside a body, surrounded by tissue, blood flow, and a full immune system. A sixfold efficiency gain in a flask does not automatically translate to the same gain in a patient's retina or bone marrow.
Critically, researchers do not yet understand why GJB2 and BET1L suppress editing. Without that mechanistic knowledge, designing a safe and reversible suppression strategy for clinical use is speculative. GJB2 mutations are themselves linked to hereditary hearing loss, so any therapeutic approach would need very precise targeting. The path from a cell-culture finding to an approved therapy typically spans many years and several additional studies.
FAQ
What is CRISPR base editing, and how is it different from original CRISPR?
Original CRISPR-Cas9 cuts both DNA strands to delete or replace a segment, which can cause unintended mutations at the cut site. Base editing uses a modified Cas9 that does not cut the strand. Instead, it chemically converts one DNA base into another, making targeted single-letter corrections with lower risk of collateral damage.
What are GJB2 and BET1L, and what do they normally do?
GJB2 produces connexin 26, a protein that forms channels between cells - mainly in the inner ear and skin. BET1L is involved in intracellular vesicle transport. Both were found to suppress CRISPR base editing efficiency when present. Their precise interference mechanism is still unknown.
Is this research ready for clinical use?
Not yet. The study used human cell cultures and patient-derived retinal cells, not living organisms. Translating findings to humans requires animal-model validation and clinical trials. Understanding how GJB2 and BET1L interfere with editing is also needed before safe suppression strategies can be designed.
How does this relate to mRNA vaccines and CAR-T cell therapy?
All three - base editing, mRNA vaccines, and CAR-T cell manufacturing - can use lipid nanoparticles as delivery vehicles. If suppressing GJB2 or BET1L improves lipid nanoparticle efficiency broadly, the lessons could extend to those therapeutic areas as well.
Where can I read the full study?
The paper was published in Nature Communications on August 13, 2026, by a team led by Professor Krishanu Saha at the University of Wisconsin-Madison. It is open access and available via the journal's website or via the DOI 10.1038/s41467-026-76350-5.
Source: Nature Communications, Saha Lab, UW-Madison (2026)
Additional reporting: Phys.org, August 2026
About the author
Dao Huy (Lucas) is a professional translator with 7+ years of experience across English, Vietnamese, Chinese, and French. He follows developments in biology, AI, and communication technology out of genuine curiosity, and writes these posts to make frontier research readable for people who do not have time to wade through academic papers.
Lucas offers specialized technical, scientific, and patent translation services for clients who need precision and clarity across languages. If you need English-Vietnamese or multilingual scientific translation, you are welcome to request a quote at daohuy.com.
Written by Dao Huy (Lucas), Vietnamese translator & localization specialist (EN · ZH · FR → Vietnamese). See translation services →