By deleting the adult globin switch, we made the fetal switch active.
At UNSW Sydney, researchers wielding the molecular precision of CRISPR have uncovered why a rare few born with sickle cell disease never suffer its cruelties — a single small deletion in the genome quietly keeps a protective fetal protein switched on for life. The discovery, emerging from the genomes of naturally protected patients and confirmed in laboratory cell lines, offers not merely an answer to a decades-old mystery but a potential map toward therapies for the 318,000 infants born each year into this inherited burden. In finding one unified mechanism where many had assumed chaos, science has moved a step closer to the possibility of replicating nature's own quiet mercy.
- Sickle cell disease and beta thalassemia claim 3% of all deaths in children under five globally, making the search for new therapeutic pathways a matter of urgent moral weight.
- The disease's cruelest feature is its delay — newborns are protected by fetal globin, but within their first year that shield switches off, and the mutant adult hemoglobin begins its damage.
- For decades, a small group of patients who never got sick despite carrying the mutation represented an unexplained anomaly — their fetal globin simply never turned off, but no one knew why.
- UNSW PhD student Sarah Topfer combed through the genomes of these protected families and found a single tiny DNA region absent in every asymptomatic patient — a deletion so small it had been overlooked entirely.
- When the team used CRISPR to replicate that deletion in lab cell lines, fetal globin rose and mutant adult globin fell — confirming one clean, unified mechanism where researchers had long assumed many separate pathways.
- With $412,919 in new funding secured and prior discoveries already informing clinical trials, the team is now translating this genetic map into the next question: can the deletion be replicated therapeutically to protect patients who need it most?
A research team at UNSW Sydney has used CRISPR gene editing to answer a question that has quietly haunted the field for decades: why do some people born with sickle cell disease never actually get sick? The answer turned out to be written in a deletion so small that no one had thought to look for it.
Sickle cell disease and beta thalassemia together affect more than 318,000 infants born every year, accounting for 3 percent of deaths in children under five globally. Both conditions stem from a defect in the adult globin gene, which governs hemoglobin production. When hemoglobin is malformed, red blood cells become rigid and sickle-shaped, blocking vessels and causing pain, organ damage, and early death. The disease's particular cruelty lies in its timing — newborns are initially protected by fetal globin, a different and functional form of hemoglobin. Within the first year of life, that fetal form switches off and the defective adult version takes over. That is when the disease begins.
But a rare group of patients never makes that transition. Their fetal globin stays on for life, and they remain symptom-free. Associate Professor Kate Quinlan, Professor Merlin Crossley, and their collaborators set out to understand why. PhD student Sarah Topfer gathered genetic data from these protected families and searched for a common thread. She found it: one small genomic region that was absent in every asymptomatic patient.
The team then used CRISPR to replicate that deletion in laboratory cell lines. The result was clear and unexpected in its tidiness — removing that tiny stretch of DNA caused fetal globin levels to rise and adult globin levels to fall. What they had found was effectively an on-switch for adult globin; deleting it left fetal globin in charge. More surprising still, this single mechanism appeared to explain multiple previously unconnected mutations that researchers had long assumed operated through different pathways.
Published in the journal Blood, the findings have already attracted a $412,919 Australian Research Council grant for follow-up collaboration with CSL. The discovery does not yet constitute a cure, but it provides a coherent roadmap — if the deletion can be replicated therapeutically, it may be possible to keep fetal globin active in patients who need it, shielding them from the disease's worst effects. Some of Crossley's earlier work in this area is already informing clinical trials. The mechanism is now understood. The work of turning that understanding into treatment has begun.
A team at UNSW Sydney has used CRISPR gene editing to solve a puzzle that has eluded researchers for years: why some people with sickle cell disease never get sick. The answer, it turns out, lies in a single small deletion in the genome—a piece of DNA so tiny that no one had thought to look for it until now.
Sickle cell disease and its close relative, beta thalassemia, are inherited blood disorders that strike more than 318,000 infants every year worldwide. They account for 3 percent of all deaths in children under five globally. The diseases stem from a genetic defect in the adult globin gene, which controls the production of hemoglobin—the protein that carries oxygen through the bloodstream. When hemoglobin is malformed, red blood cells become stiff and sickle-shaped, clogging small blood vessels and causing pain, organ damage, and early death. The disease is most common in tropical regions and places where malaria is endemic.
What makes sickle cell disease particularly cruel is its timing. Newborns with the mutations don't show symptoms at first because their bodies are still producing fetal globin, a different form of hemoglobin that works fine. Within the first year of life, the fetal globin switches off and adult globin switches on—and that's when the disease emerges. The body begins making the defective hemoglobin, and the symptoms start.
But there is a rare exception. A small number of sickle cell patients carry a beneficial genetic mutation that keeps their fetal globin switched on throughout their entire lives. These people never get sick. They produce the protective fetal hemoglobin instead of the mutant adult version. For decades, researchers knew this happened but didn't understand why or how to replicate it.
Associate Professor Kate Quinlan and Professor Merlin Crossley, along with collaborators from the United States, decided to find out. PhD student Sarah Topfer began by gathering genetic data from these rare families—the ones whose fetal globin never turns off. She compared their genomes looking for a common thread, some shared deletion that might explain their protection. After analyzing many patients, she found it: one very small region that was missing in every single asymptomatic patient's DNA.
Then came the test. Using CRISPR—a molecular tool that acts like genetic scissors—the team replicated these deletions in laboratory cell lines. They cut out the small region that all the protected patients had in common. The result was striking: when they deleted that tiny piece of DNA, fetal globin levels rose and adult globin levels fell. By removing what amounts to an "on switch" for adult globin, they had inadvertently activated the switch for fetal globin. The mechanism was clean, unified, and unexpected. Many researchers had studied these mutations for years, assuming each worked through a different pathway. Instead, the team had found one explanation that fit them all.
Quinlan described the finding as surprising—the team had hypothesized there might be one mechanism, but they thought the reality would be messier. It wasn't. The work, published in the journal Blood, has already attracted funding: just last week, Quinlan and Crossley received a $412,919 grant from the Australian Research Council to collaborate with CSL on follow-up research. The discovery doesn't immediately cure the disease, but it provides a roadmap. If researchers can find a way to replicate this deletion therapeutically—to turn off the adult globin switch in patients who need it—they might be able to keep fetal globin active indefinitely, protecting people from the disease's worst effects. Some of Crossley's previous discoveries in this field are already informing clinical trials. The mechanism is now understood. The next step is turning understanding into treatment.
Citações Notáveis
We found that deleting just that one little bit was sufficient to make fetal globin go up and adult globin down—which suggests we have found the key mechanism that can explain why fetal globin levels remain high in these asymptomatic patients.— Associate Professor Kate Quinlan
It was surprising to see the findings—many people have studied these mutations for many years, so the idea that there'd be one unifying hypothesis rather than them all working through different mechanisms will be surprising for the field.— Associate Professor Kate Quinlan
A Conversa do Hearth Outra perspectiva sobre a história
Why does it matter that they found one mechanism instead of many?
Because it changes how you think about solving the problem. If each patient's protection worked through a different genetic pathway, you'd need multiple therapies. One mechanism means one target—one thing to aim at.
But they didn't cure anyone yet, right?
No. They identified the lock. Now they need to figure out how to pick it in living patients. That's the next phase.
Why did it take CRISPR to find this? Couldn't they have seen it before?
Not really. CRISPR lets you actually delete pieces of DNA and watch what happens in real cells. Before CRISPR, you could study the mutations, but you couldn't easily test your theories. You were working blind.
So the rare patients—they have this deletion naturally?
Exactly. They were born with it. It's a mutation that protects them. The researchers found what that mutation does, and now they want to create it artificially in people who don't have it.
How many people could this eventually help?
Potentially hundreds of thousands. Over 318,000 infants are born with these diseases every year. Most of them will suffer. If this leads to a therapy, the scale is enormous.
What's the hardest part now?
Translating the lab finding into something you can actually give to a patient. CRISPR works in cells in a dish. Making it work safely and reliably in a living person—that's the mountain they're climbing next.