Rewriting genes to fight metabolic diseases

Can we fix rare genetic diseases by correcting mistakes in DNA? During his PhD, Indi Joore explored one of the most precise tools for doing just that: prime editing. A tool especially promising for metabolic diseases, genetic diseases, caused by a mistake in DNA. But his work went beyond the lab. It led him to explore how science can be translated into real applications, and how startups might help get there faster. Indi successfully defended his thesis and graduated with cum laude distinction on July 1, 2025.

Every year, around 800 kids are born in the Netherlands with a metabolic disease, a group of rare genetic disorders that can have devastating effects from an early age. Many of these diseases have no available treatments. “They’re called rare, but taken together, they affect a huge number of people”, says Indi Joore. “The problem is that traditional drug development doesn’t work well for these small patient groups. It’s too expensive and too risky.”

Editing the genome like a word processor

During his PhD, Indi set out to explore a new solution for genetic disorders: prime editing, a precise gene-editing technique. “It’s like a word processor for your genome”, he explains. When Indi started, the technology was still brand new. “Together with a colleague, we were among the first to explore how it worked in practice”, he says.

But one critical question stood out: is it safe? Unlike earlier methods, prime editing can correct a wide range of genetic mutations with less risk of cutting the DNA in the wrong place. “We looked at unintended effects: does prime editing change other parts of the DNA that you don’t want it to? That was our focus.”

A promising technique

Their results were promising. “We didn’t find strong signs of off-target effects, and that gave the field confidence”, Indi says. His study became one of the first to highlight the relative safety of prime editing, compared to older techniques like base editing. “It’s an important step if you want to move toward using this in real patients.”

The challenge of turning rare disease research into real treatments encouraged Indi to look beyond the science. “We started thinking about how to make the technology scalable and realistic”, he says. “That includes business models and funding strategies, which you don’t always learn in a lab setting. I was lucky that my supervisor Sabine Fuchs gave me the freedom and support to explore that.”

Making medicine development faster and safer

Although Indi is moving away from gene editing after his PhD, he still wants to turn research into real-world solutions. He is now co-founding hello R&D, a startup that focuses on a new kind of liver organoids to test the safety of drugs. Organoids are mini, lab-grown organs made from real patient tissue. During his PhD, Indi worked with them, but he and a colleague noticed something surprising. The liver organoids looked more like bile ducts than actual liver. This led them to develop a better, more liver-like liver organoids: Hepatocyte Like Liver Organoids, or HeLLOs. “It’s a powerful model”, he explains. “You can test treatments directly on the patient’s biology to see if they work before trying anything in a person.”

The startup helps pharma companies reduce risk early in development. “We’re still early”, Indi says. “Talking to investors, building projects, and trying to get our first revenue. But the long-term vision is bigger, we want to make medicine development faster and safer.”

Listening, not assuming

For Indi, one of the biggest lessons of his PhD came not from the lab, but from talking to people. “In the lab, we often think we know which symptoms matter most”, he says. “But when you speak with patients or their families, they might care more about other aspects of daily life.”

Talking to parents of a child with a rare condition made that clear. “It was hard. I wanted to be honest, but not overpromise. It taught me how considered you have to be and how valuable it is to include patients early in research.”

Keep growing in Utrecht

After nearly six years at RMU, which started as a master internship, Indi is ready for the next step, but grateful for what the place gave him. “It’s a special environment. Everyone is supportive, and the focus on patient-centered science really stands out.” Though his contract ends the day of his defense, his startup may stay in Utrecht a while longer. “We’re looking at lab space on the Uithof”, he says. “It feels like the right place to keep growing.”