By Helene Cederroth, president and founder, The Wilhelm Foundation

Every year, on 29 April, the world pauses—briefly—to acknowledge people living with undiagnosed diseases (PLWUD). But for the 350 million people globally who still don’t have answers, “acknowledgement” is only the very beginning. This isn’t just a date in the calendar. It’s not just a campaign. It’s a call to action.

Because when you’re living with an undiagnosed condition, every day is Undiagnosed Day. Every symptom unexplained. Every medical record a question mark. Every night spent searching. Every door you knock on that doesn’t open.

At the Wilhelm Foundation, we’re no strangers to this journey. In fact, it’s where we began. My husband, Mikk, and I, lost three of our four children, Wilhelm, Emma and Hugo, to an undiagnosed disease. That unimaginable pain became our life’s mission: to ensure no other family is left without answers. That mission became a movement and 25 years later, it’s more urgent—and more necessary—than ever.

60% without a diagnosis. Zero excuses.

Even with advances in genomic medicine, 60% of people living with undiagnosed diseases still don’t have a diagnosis after comprehensive investigations—including whole genome sequencing. That’s not a statistic. That’s a global health crisis.

And yet, there’s hope. The kind that comes when you bring the right people together: researchers, healthcare professionals, families, advocates, engineers and storytellers. The kind of hope that lives in the Wilhelm Foundation’s annual Undiagnosed Hackathon which brings global experts and families together and, last year, 10 out of 26 families received a diagnosis within just 48 hours. The kind of hope that powers our Champions Initiative in low- and middle-income countries (LMICs), and sparks change in health systems built for the few, not the many.

From silence to spotlight

Undiagnosed Day was created to give visibility to the invisible. It’s not just a symbol—it’s a signal, that we are here. That the status quo isn’t working. And that together, we can disrupt it.

At the Wilhelm Foundation, we believe in impact with intention. From the Undiagnosed Photo Project, which reframes how the world sees rare and undiagnosed diseases, to our co-founding of the Undiagnosed Diseases Network International (UDNI), we’re building momentum that is global, scalable and deeply personal.

It’s time to move from awareness to action

Here’s what we know: a diagnosis is not just a label. It’s relief. It’s recognition. It’s the start of something – access to treatment, to community, to a future that feels less like a guessing game. And while the diagnostic odyssey is still long, it doesn’t have to be endless.

To change that story, we need:

• Equity: because where you live shouldn’t determine whether you get a diagnosis.
• Collaboration: because silos don’t solve science.
• Innovation: because the same tools that failed yesterday won’t win tomorrow.
• Empowerment: because people living with undiagnosed conditions are not passive – they are powerful.

Undiagnosed Day 2025 – It’s a movement. And you’re part of it.

So, this Undiagnosed Day on 29 April, we are asking physicians around the world to make a pledge to see and meet people living with an undiagnosed disease. We will also be holding a global virtual roundtable meeting to review those cases on 30 April. We are also encouraging the whole community, including people living with an undiagnosed disease, as well as family members taking care of them, to help spread the word by sharing their story and their journey too.

So, we are asking for presence, for commitment and for action.

Please:

• Say it loud: “I’m in.”
• Make the pledge to see someone with an undiagnosed disease.
• Spread the word.
• Share a story.
• Start a conversation in your clinic, your classroom, your community.
• And be part of the change for #UndiagnosedDay2025.

Whether you are a healthcare professional, a policymaker, a researcher, a family member, or someone navigating the undiagnosed journey yourself—you belong in this movement. Because every story matters. And every action counts.

From 60% to zero

That’s our north star. A world where zero families are left in limbo. A world where diagnoses are delivered faster, care is more compassionate, and no one falls through the cracks.

Yes, it’s ambitious. It should be. But if there is one thing we’ve learned over 25 years, it’s that the most powerful movements grow through hope, science and solidarity.

Let’s make this, the year we go further.
Let’s make Undiagnosed Day 2025 the loudest, most connected, most impactful yet.

Let’s prove, once and for all, that this isn’t just a day.

It’s a movement.

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