26 February 2026
At just 21 years old, Liam McCarthy has already done more advocacy work than most of us will do in our lifetime. McCarthy is a member of the Rare Diseases International (RDI) Youth Leadership Programme (2025-2026), designed to engage and empower young people within the rare disease community, ensuring their perspectives are represented in global discussions and decision-making processes. But McCarthy’s path was set in motion long before his advocacy work began.
McCarthy was born in 2004 with classic congenital adrenal hyperplasia (CAH), a rare genetic disorder that affects the adrenal glands and hormone production. If not treated in early infancy, classic CAH can be life-threatening. But at that time, CAH had not yet been added to his birth state’s newborn screening panel, and, as a result, MacCarthy was initially misdiagnosed with kidney failure. Fortunately, his parents had a hunch that this diagnosis was incorrect and, trusting their instincts, persistently sought a second opinion. Their determination, along with access to a larger healthcare network and genetic testing, resulted in the correct—and life-saving—diagnosis of CAH.
McCarthy is just one of more than 300 million people worldwide who live with a rare disease. Many work tirelessly to navigate the challenges surrounding diagnosis and care, frequently encountering gaps in awareness, resources, and coordinated support. Organizations such as RDI collaborate with the rare disease community to improve access to timely diagnosis, treatment, and care.
This includes access to genomic sequencing services, such as newborn screening, whole-exome and whole-genome sequencing, and gene panel tests. Because 72% of rare diseases have a genetic component, these tests are crucial for early diagnosis and effective intervention. This diagnostic insight also lays the groundwork for research, enabling scientists to better understand the biological mechanisms underlying rare diseases—leading to clinical trials and breakthroughs in treatment.
Changing lives through collective advocacy
Just before McCarthy started college at Emory University, he joined a clinical trial for CAH. While participating in the clinical trial, a doctor invited McCarthy to speak to medical students about his experience with CAH—an opportunity that sparked his journey into patient advocacy. “Going through my CAH diagnosis showed me how hard families have to push for the care they deserve. Sharing my story became a way to support others who are navigating that same reality."
Improving this system is not easy. To drive impactful change, it takes collective effort, cross-sector collaboration, and a diverse set of voices. But in practice, one essential voice, that of the patient, can get lost in the noise. And children’s voices tend to fade even further into the background—although 70% of rare diseases begin in childhood, youth perspectives and lived experiences are often excluded from the healthcare decisions and policies that shape their care. To resolve this gap, RDI created the Youth Leadership Programme—a platform for global youth leaders to collaborate at key international events and ensure their voices are included in decision-making processes. As one of sixteen youth leaders selected for this program, McCarthy helps create campaigns that raise awareness about rare diseases and advocates for improvements in care, often collaborating with youth leaders from other countries, global policy makers, researchers, and clinicians. “Different generations have different ideas, perspectives, and goals,” says McCarthy. “It’s important that all those perspectives are heard. So, if we can shed light on our experience as a kid or young adult living with a rare disease, and provide our perspective on how things can improve, we can make a meaningful impact for millions of people worldwide.”
Empowering youth voices on rare disease policy
Following the clinical trial, Laim stepped into his own as a patient advocate. He joined the Patient Engagement Collaborative, a joint project between the U.S. Food and Drug Administration and Clinical Trials Transformation Initiative, where he provided input on enhancing communication, education, and patient engagement in the regulatory process. He also became a board representative of the CAH Patient & Caregiver Advisory Council at a biopharmaceutical company, where he offered a unique perspective on how the company could launch a global drug while keeping the needs of the CAH community in mind.
Last year, McCarthy and twelve other members of the RDI Youth Leadership Programme had the opportunity to attend the 78th World Health Assembly in Geneva. There, they joined forces with global leaders and policymakers to support the adoption of the World Health Assembly Resolution on Rare Diseases. The resolution challenges the World Health Organization to develop a global framework for reducing barriers to accessing diagnosis, treatment, and care for people with rare diseases. The resolution passed unanimously, sponsored by 41 countries in the United Nations—a momentous win for the rare disease community. “It was great to see the global community come together to support people living with a rare disease,” says McCarthy. “When it comes to accessing diagnosis, treatment, and other supportive services, where you live matters. With the resolution, we finally have an opportunity to hold countries accountable so that people can get the services they need.”
This year, their momentum continued at Raising Youth Voices in Barcelona, where youth leaders from around the world exchanged their experiences and shared ideas on how to improve the rare disease landscape. McCarthy, along with five other youth leaders, joined discussions on patient advocacy and health policy to help outline global strategies for rare disease research and care.
In addition to global events such as the World Health Assembly and Raising Youth Voices, McCarthy uses another powerful platform to make an impact: social media. His most recent social media campaign, “100 Days, 100 Faces, 100 Unique Stories” brought together people with a rare disease, but with a different angle. Too often, a person’s disease can become the center of their story—and McCarthy wanted to change that. His three-month campaign, which ends today, on Rare Disease Day, invited 100 people with a rare disease to share their story. But instead of focusing on their disease, he spotlighted who they are as individuals. To achieve this, McCarthy asked them not to mention their disease and didn’t reveal their shared connection until the end of the campaign. “Keeping the rare disease part quiet at first allowed the storytelling to draw people in—even those who had never heard of or thought about rare diseases before,” says McCarthy.
Thanks to the advocacy work of McCarthy and countless others, awareness continues to grow and rare diseases are starting to receive the attention they deserve. With patient voices front and center—and youth voices helping shape the conversation—we’re paving the way to a better future for people living with a rare disease.
Liam McCarthy is a patient advocate. The Illumina Global Patient Advocacy team works with patients, families, carers, and the groups that represent them to build evidence and advocate for the positive impact of genomics utilization. Patient advocates may be compensated for their time when sharing their stories. Their stories are a testimonial of the potential impacts and benefits genomics can have on rare diseases. One person’s experience is not predictive of results in all cases, which may differ based on a variety of factors. Results in other cases may vary.
To read about solving rare disease at the Undiagnosed Hackathon, follow this link.
To read about interrogating challenging genomic regions to provide answers for patients, follow this link.
To learn about elevating the rare disease community with Rare Barometer, follow this link.
To learn about the documentary Rare: A Rare Disease Revolution, follow this link.
