Undiagnosed Day, 29 April
Today, an estimated 350 million people worldwide live with an undiagnosed disease. While advances such as genome sequencing can provide answers for around 40%, this still leaves 60% without a diagnosis—without clarity, targeted care, prognosis or genetic guidance for families.
Undiagnosed Day is not about celebrating the Undiagnosed Diseases.
It is about visibility, solidarity, and action. It is about making the world aware that 350 million people live without a diagnosis, and that millions more—across disciplines, countries, and systems are working together to end the reality of being undiagnosed.
This is a global effort. One community.
One shared goal: a future where no one is left without answers.
Global Undiagnosed Day - A call to action
This isn’t just a day. It’s a movement.
Be part of the change!
This year's Global Undiagnosed Day is calling on everyone connected to people living with undiagnosed diseases, to take action.
Share Your Voice (1–2 Minute Video) Be seen. Be heard. Be part of the movement.
Record a short video from your clinic, home, lab, or organisation and share:
- A word of encouragement
- A highlight of your work or research
- A message from your country or region
- Your story or diagnostic journey
- Each video becomes part of a global chorus of hope and action—showing the world that PLWUD are not invisible.
Submit via WeTransfer: undiagnosedday@wilhelmfoundation.org
Last year's official Undiagnosed Day 2025 video was seen by 87 758.
Clinicians: Make the Pledge
On 29 April, commit to seeing a person living with an undiagnosed disease.
Whether or not an invidual is presented, your participation places PLWUD on the global health agenda.
Join the Global Virtual Roundtable:
A unique opportunity to briefly share complex cases (with informed consent), connect across borders, and collaborate, building on phenotyping discussions.
From Commitment to Impact
In 2025, the Global Undiagnosed Day call to action led to tangible outcomes. Through dedicated phenotyping roundtable discussions, clinicians and experts came together to collaboratively review families living with long-standing undiagnosed conditions.
In total, 11 families were discussed. Two families received a diagnosis as a direct result of this collaborative effort. For two additional families, promising findings have emerged, and further investigations are underway to confirm potential diagnoses.
These outcomes demonstrate what becomes possible when a single day turns into coordinated global action, restoring hope, advancing knowledge, and moving families closer to long-awaited answers.
Wilhelm Foundation is the pioneer of Global Undiagnosed Day
Undiagnosed Day began nearly a decade ago as Undiagnosed Children’s Day, founded by a mother in the United States whose child remained without a diagnosis.
In 2022, after eight years of marking Undiagnosed Children’s Day, the Wilhelm Foundation recognised the need for greater inclusivity. Around 30% of undiagnosed diseases affect adults, and countless individuals remain without answers well into adulthood. The day was therefore renamed Global Undiagnosed Day, to reflect the reality that people of all ages worldwide are affected by undiagnosed diseases.