New SickKids lab to expand the reach of gene editing in search of scalable therapies

This summer, Dr. Steven Erwood joined The Hospital for Sick Children's Genetics & Genome Biology research program as its newest scientist, returning to Canada after training as a Banting Postdoctoral Fellow at the Broad Institute in Boston.  

As a former trainee in the Cohn Lab, Erwood has established methods to characterize and interpret variants to study genetic disease and applied CRISPR technology to drug discovery. Returning to SickKids as a Scientist, he is now focused on developing scalable gene-editing methods that could benefit patients across a wide range of genetic diseases. To get there, his lab will explore how and why genetic variants cause disease and uncover the underlying molecular mechanisms that drive them.  

We chat with Erwood about the promise of gene editing, his time in the U.S., and why he chose to return to Canada to build his research lab. 

You first studied at OCADU: How does your artistic nature influence your science?  

I think I carry a strong and very particular visual sensibility from art into science. I will obsess over details like the width of the axis on a bar plot that few people would notice. In the same vein, I'm a visual learner and must picture what's happening to truly understand a concept or biological process.  

More abstractly, my sense of taste bridges how I approached art, and now science. Just like a painting that really speaks to me, I am absolutely captivated by certain scientific ideas — and gene editing has always had that quality for me. The fact that we can deliberately rewrite the sequence of a genome still feels a little like science fiction, as does a lot of work in this Research Institute.  

I'd like that sense of taste to become part of my lab’s identity, as in there will be a recognizable type of problem we’re drawn to, a central idea that is quite clear why we found it exciting.   

What draws you toward genomic medicine and gene editing technologies? 

The field of genetics naturally intersects with so many other fascinating areas of biology, from evolution to molecular biology to human disease. It has depth without feeling unfocused, enabling you to explore distinct biological questions while still working from a common framework of genetic variation and its consequences.  

It is exciting how fast gene editing is evolving. During my PhD alone, tools expanded from being able to introduce a targeted double-strand break to precisely changing one base to another to rewriting nearly any small DNA sequence. Each step opened new biological questions and new treatment possibilities, which is remarkable in a field that very recently was still in experimental stages. 

Why is it essential to understand how genetic variants cause disease?  

Precision gene editing tools have matured so quickly we now have examples of base editors and prime editors being used to fundamentally change patient care. On the other hand, we are challenged by the fact that allelic diversity quietly limits their application. Most monogenic illnesses carry hundreds or thousands of different variants, many of which may be found in only a single person — so taking a variant-by-variant approach in gene editing becomes infeasible in practice. 

So it's vital to understand the molecular basis of pathogenic variations, which may in fact winnow down to a small number of shared defects. It could be that a mutation destabilizes a protein, disrupts an interaction, alters trafficking or changes catalytic activity. Finding answers, and then targeting common molecular defects, will help extend precision gene editing as broadly as possible to patients. 

What's the "X factor" in building your research lab?  

Curiosity is so important in a field like ours that is changing so quickly that tools can be outdated in just a few years. Being intensely interested and eager to learn is more critical to me than having established technical skills — you can teach someone how to run an assay but not how to be fascinated by the result. 

The environment of a lab can sustain that curiosity, and I will try to build a culture where people are empowered to pursue interesting ideas, learn about something unrelated to their immediate project, or share a finding because it excites them. This should be a routine part of doing science, not a distraction from it.   

Any lessons you have taken from your Broad Institute experience?  

One of the most tangible takeaways was how much the environment around a scientist can shape the science itself. Being able to access infrastructure, resources and expertise encourages you to think bigger and makes ambitious science feel within reach. I see the same possibilities here at SickKids. 

At the Broad, I felt a culture that normalized doing biology or generating large datasets at scale, and I will carry that into my lab here. It changed my sense of what a reasonable experiment could look like, and of what a single scientist or small group of scientists could realistically achieve. With AI and computational biology advancing, it's the time to design sweeping experiments rather than answering one narrow question at a time. 

Why did you choose to return to Canada, and to SickKids?   

My scientific interests formed in Toronto and being away sharpened my sense of the scientific community that's here. Even being a Banting Fellow in the U.S., named after one of Canada’s most famous scientists (Frederick Banting, co-discoverer of insulin), made me feel like some small part of a larger Canadian scientific tradition.  

In Boston I developed new perspectives that I instinctively wanted to bring back with me to Canada, versus staying there forever. Being away made me more invested to return. At SickKids, I loved training under Drs. Ronni Cohn and Zhenya Ivakine and it also stoked my passion for child health research.  

Leaders at SickKids leave no doubt that the end goal is to translate research discoveries into therapies. It is one of the places most capable of bringing genome editing therapies to patients. And wouldn't that be something: to be part of first-in-child genome editing treatments here at Canada's largest children's hospital?