A rare disease affects one in 2,000 people in the EU. Clear information about it is rarer still. A large review of 693 rare disease information websites found that only 33% cited their sources, only 30.4% disclosed conflicts of interest, and exactly 0% offered content in plain language. For a family that has just heard a diagnosis they cannot pronounce, that is not a content problem. It is a care problem.
When Promedia launched the TK2d awareness website, the brief was not to build a website. It was to build a place where patients, caregivers, and clinicians could understand what they were facing. TK2d is an ultra-rare mitochondrial DNA depletion syndrome. As of 2018, only around 107 unique cases had been reported globally. Patients with TK2d remain undiagnosed for an average of 17.4 years after symptom onset. The diagnostic delay is not a footnote. It is the experience.
This article is for pharma communications teams, brand managers, and medical affairs leads who are building patient-facing digital assets for rare conditions. It draws on what we learned shipping TK2d and on the evidence base around rare disease communication.
Start by reframing the asset. A rare disease patient website is not a brochure. It is a diagnosis acceleration product. For mitochondrial disease specifically, the mean time to diagnosis is 9.9 years, with 6.7 doctors involved before someone names the condition. A study of mitochondrial disease diagnostic pathways found that 8.17 of those years happen before any clinical suspicion is raised, against 1.28 years after. The delay is a recognition problem, not a testing problem. Your website is one of the few tools that can intervene on the recognition side.
That reframe changes every downstream decision. Information architecture stops being organized around the disease and starts being organized around the user's actual question. Most undiagnosed people are not searching the disease name. They are searching a problem: progressive muscle weakness in a toddler, unexplained respiratory decline, a cluster of symptoms that no single specialist has joined up.
A few practical principles that came out of the TK2d build:
The best people to talk about a rare disease are the ones living with it every day. That principle shaped the TK2d content from the first wireframe. Instead of clinical summaries, the site is built around patient and caregiver stories: real experiences in real language. This is not a stylistic choice. Rare disease patients consistently report being overwhelmed by information and looking for practical guidance that fits into daily life. Stories carry that practical layer in a way a fact sheet cannot.
UCB's holistic patient care framework makes the same point from the industry side: patients are partners in the healthcare journey, and their input is essential to building solutions that address physical, emotional, and logistical needs. Co-creation is not a courtesy. It is the only way to avoid the most common failure mode of rare disease sites, which is accurate content that no one can use.
Plain language is the operational expression of that principle. Write for cognitive overload. Assume a parent is reading at 1am after a hospital visit. Short sentences. Clear headings. Definitions in line, not in a glossary at the end. If a clinician needs the technical version, give them a separate professional section. Do not make the family scroll past it.
The EURORDIS Rare Barometer survey of 6,507 people across 41 countries put the average total diagnosis time in Europe close to five years, with 56% of patients diagnosed more than six months after first medical contact. For a condition like TK2d, where canonical features such as hypotonia and respiratory weakness are documented years before mitochondrial disease is suspected, every month of recognition gained matters.
Digital content can move that number in three concrete ways. First, by giving general practitioners a fast, credible reference when a parent mentions symptoms that do not fit. Second, by giving caregivers language they can take into the next appointment. A caregiver who can say "I think we should rule out a mitochondrial DNA depletion syndrome" changes the consultation. Third, by mapping the route to expert centers and genetic testing in the country the reader is actually living in.
This is where SEO for rare disease becomes load-bearing. It is mostly a language problem. Caregivers describe symptoms in non-clinical phrasing. Build synonym libraries that bridge how families talk and how specialists code. Match the search query to the search intent at every step.
A diagnosis is the same in every country. The information available to a family is not. The TK2d site will launch in several European languages over the coming months, and the localization work is not translation. It is rewriting.
Clinical terms travel cleanly across languages. Lived experience does not. The way a Flemish caregiver describes their child's fatigue is not the way a French or Spanish caregiver describes the same thing, and search behavior follows the same pattern. Underdiagnosis is amplified when local-language awareness is low, so each market needs its own synonym library, its own patient testimony, and its own pathway to a national or regional expert center.
Partnering with patient organizations as co-authors, not as distribution channels, is the mechanism that makes this work. Co-building improves language, relevance, and trust simultaneously. It is also the only reliable way to keep a site usable as it scales across markets.
Three things, in order: transparent sourcing, clearly disclosed funding and conflicts of interest, and content co-created with patient organizations. The review of 693 rare disease websites that found only a third cited sources and almost none used plain language sets a low bar that is easy to clear if you decide to. Add named medical reviewers, dates of last review, and a visible route to corrections.
Because the reader is usually a non-clinical person in a high-stress moment. Plain language is not dumbing down. It is removing the friction between the reader and the next decision they need to make: book an appointment, request a test, contact a patient group, find an expert center. Every clinical term left unexplained is a reader you have lost.
Across rare diseases broadly, the EURORDIS survey puts the average close to five years, with more than half of patients diagnosed at least six months after first medical contact. For mitochondrial diseases the mean is around 9.9 years with multiple specialists involved, and for TK2d specifically the average undiagnosed period after symptom onset is 17.4 years. Most of that delay happens before clinical suspicion is raised, which is exactly where well-built digital content can intervene.
As the spine of the site, not as decoration. Patient and caregiver stories carry the practical, lived information that clinical summaries cannot: what the first symptoms actually looked like, which specialist finally listened, what daily management involves. Work with patient organizations as co-authors, secure proper consent, and let the families lead the language. The clinical framing wraps around the story, not the other way around.
If you are scoping a rare disease patient website, treat the project as a diagnosis acceleration product from the first kickoff. Build around symptoms, not the disease name. Co-create with patient groups. Localize as rewriting, not translation. Measure referral intent and expert-center discovery, not pageviews.
The TK2d project reminded us that the result of this work is not a URL. It is the chance that one family, somewhere, finally finds what they were looking for. If you are working on a rare disease communication brief and want a partner who treats it that way, Promedia is built for this kind of project.
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