By: Meagan Hutchinson, Science & Research Administrator, PMSF
February 5, 2026
Every year on the last day of February, the global rare disease community comes together to raise awareness, share stories, and advocate for patients navigating through life with a rare disease. Rare Disease Day is a moment to make the invisible visible—and for the Phelan-McDermid syndrome community, it is a powerful opportunity to educate, connect, and inspire action.
What makes a disease rare?
A rare disease is a condition that affects a relatively small number of people. In the United States, a disease is considered rare if it affects fewer than 200,000 individuals. The World Health Organization classifies a rare disease as a disease affecting fewer than 65 in 100,000 people.
While each rare disease may impact a relatively small population, rare diseases are not rare as a whole. In fact, there are more than 7,000 rare diseases worldwide, collectively affecting approximately 300 million people. Phelan-McDermid syndrome is one of these rare conditions, impacting 1 in 10,000 births.
What is Phelan-McDermid syndrome?
Phelan-McDermid syndrome is a rare genetic condition most often caused by changes in chromosome 22 and variants in the SHANK3 gene. These changes can affect many critical functions, including learning and memory, communication, behavior, motor skills, sleep, and overall health.
Like many rare diseases, Phelan-McDermid syndrome presents differently in each individual. Families often face challenges related to diagnosis, access to care, and limited treatment options. Despite these challenges, progress is happening. Research is advancing, clinical trials are underway, and families and researchers are working together to improve clinical care and accelerate the development of meaningful treatments.
Join us on Rare Disease Day
On February 28, 2026, we invite you to join the Phelan-McDermid Syndrome Foundation (PMSF) and the global rare disease community in raising awareness for Phelan-McDermid syndrome and the millions of individuals living with rare diseases.
By coming together to make rare diseases visible, we can:
- Advance scientific research
- Improve clinical care
- Strengthen support systems for families
- Advocate for policies that benefit the rare disease community
What can you do to raise awareness?
You do not need a large platform or a lot of time to make a difference. Every action—big or small—helps shine a light on rare diseases and on our community.
Here are a few simple ways to participate:
- Create and Share a One-Page Phelan-McDermid Syndrome Summary
- Use our customizable one-page template to share information about your loved one and your family’s experience living with Phelan-McDermid syndrome. This resource can be shared with friends, family members, schools, care providers, and your broader community.
- Update Your Social Media Profile Photo
- Add our Rare Disease Day social media profile frame to show your support, spark conversations, and help make rare visible.
- Share Phelan-McDermid Syndrome Foundation Resources
- Help spread accurate information by sharing trusted resources from the Phelan-McDermid Syndrome Foundation.
- Amplify Rare Disease Day Social Media Posts
- Watch for and share Rare Disease Day graphics and facts across your social channels.
- Tell Your Family’s Story
- Personal stories are powerful. Sharing your experience helps others understand the real impact of Phelan-McDermid syndrome and builds connection within the community.
- Explore and Share Rare Disease Day Resources
- Join the broader rare disease movement by engaging with official Rare Disease Day resources and campaigns.
Making Rare Visible—Together
Rare Disease Day is about awareness, but it is also about hope—hope for better understanding, better care, and better futures for individuals living with Phelan-McDermid syndrome.
Every post, share, and story matters. Thank you for being part of this community and for helping make rare visible—today and every day.