As a 10-year-old growing up in Jamaica, Kemar Joseph Brown, MD, was already known as “Dr. Brown.” His grandmother assigned him the moniker when he took an interest in her insulin injections, and it stuck.

Her later passing not only shaped his path into cardiology but also fueled his scientific mission to understand why cardiovascular outcomes vary so profoundly across populations. Now a physician-scientist at Massachusetts General Hospital and an instructor in medicine at Harvard Medical School, Brown is deeply committed to building large-scale genomic datasets to explore how ancestral background may influence genetic risk and resilience. His work, supported by a K12 award from Harvard Catalyst, aims to clarify these differences and ultimately improve cardiovascular care across multiple communities.

What led you to the path of physician-scientist?

I grew up in Kingston, Jamaica, and not in a well-off financial situation. My family made ends meet every which way they could. My grandmother ultimately developed severe diabetes and died in her 60s. Toward the end of her life, she had three strokes, cardiac disease, heart failure, and was in and out of the hospital.

“Throughout my academic career, I realized that there were huge gaps in who fared well with their disease and who didn’t, and those gaps were almost always divided along racial lines.”

She was the first person to see the doctor in me when I couldn’t see it myself. At 10 years old, everyone was calling me “Dr Brown”. She and my grandfather were the ones who started it. That planted the seed.

I remember having a very curious mind toward science. I would sometimes take one of her syringes–syringes that we at times struggled to afford–and design my own experiments in the backyard. One day she caught me, because she was questioning why her supply was going down. But instead of reprimanding me, she decided to teach me how to deliver her insulin shots. From then on, I went to my grandmother’s bedside at night to inject insulin. That really cultivated a passion for service, and ultimately my service as a clinician.

Great story. How did you get interested in ancestral genetic differences?

Throughout my academic career, I realized that there were huge gaps in who fared well with their disease and who didn’t, and those gaps were almost always divided along racial lines. Coming from Jamaica, where the majority of the population is Black, it didn’t really hit me until I came to the U.S. that there were these grave disparities in cardiovascular outcomes.

I became attracted to cardiology not only based on my experience with my grandmother, but to learn more about cardiovascular disparities. Black men and women tend to have the highest prevalence of heart failure. Traditionally, we’ve attributed these outcomes to social determinants and disparities in resource allocation. The question I had was whether or not there were protective factors or factors that raise susceptibility to heart failure. Either way, we need to figure it out. That’s the basis of the work that I’m doing.

You joined the lab of MGH cardiologist Christine Seidman, MD, in 2020, at the peak of the pandemic. How did that affect your career arc?

“Most genetic studies are extremely underrepresented for non-European subjects.”

We were all being pulled back into the hospital to do clinical work. I wasn’t able to see my lab mates for about six months after joining the lab. It was quite a challenge to make the transition from the clinical world of fellowship into the research world of fellowship. Although I was relegated to the desktop, I was eager to start analyzing big genetic data.

Around that time, our lab was in collaboration with a multinational cohort of scientists who published the first human heart map, describing the 11 cell types and 65 cell states within the heart. This atlas was proposed as a foundational dataset for comparing heart tissue at the cellular level. When I looked at the data, I immediately saw that 13 of the 14 heart donors were European, and one was East Asian. I found this to be problematic since the results did not represent all ancestral groups. We immediately started searching for more donor heart tissue with the support of my mentors, who are ardent advocates for this work.

While much disparity research is focused on social determinants, you’re taking a different tack by looking at the genetics. What’s your thinking?

Multiple factors may influence how cell composition and gene expression changes in response to stressful stimuli. Say for example someone has long-standing hypertension. Is there a genetic signature that will allow this individual to withstand that hypertension without their heart failing? Are there genes that will protect this patient from developing fibrosis in the heart despite this long-term stressor?

Most genetic studies are extremely underrepresented for non-European subjects. That’s a big problem in genomic research, and one this work will help solve.

You’ve argued that this historical under-representation of non-European ancestry in research exacerbates healthcare disparities. Do you see that changing?

With the advancements that have come to the fore, we’re now able to, for example, identify a gene that causes sickle cell disease and then alter the genome to prevent this disease from manifesting clinically. This is absolutely fascinating to me. Similar strategies for genetic cardiomyopathy are quickly coming down the pipeline, where we could potentially alter the expression of a single gene to prevent the heart from failing later on.

But if our research is solely based on one particular group of people and we’ve identified genes that are commonly altered or perturbed in only one specific type of people, then we’re doing everyone else an injustice. This is why this work is important.

How has the K12 award helped advance this work?

This is a huge award for me in the sense that I’m able to recruit more samples into my repository and in essence expand our ancestry database. It’s a launch pad for making the transition from mentored research to independent research. The next steps will be applying for other K awards and ultimately an R award.

I’m extremely lucky, right? Because here I am amongst the best of the best in the country, if not in the world. I am truly grateful for the award because it serves as a springboard for achieving my goal of becoming an independent clinician investigator.

It’s a great award. I’ll be the first to say that everyone needs to apply and sign up, especially when you’re making that transition.