Mission 2 · Flagship project

The limb-malformation registry owned by the people it describes.

A registry is a list of cases described the same way, so they can be counted and studied. This one is being built by the associations that represent the families, and the data in it belongs to the people it describes, not to us. It does not exist yet: this page says what it will be, who is building it, and where it has got to.

Congenital anomalies remain a major cause of perinatal illness and death, accounting for up to 27% of infant deaths in developed countries, as Santé publique France recalls in its 2026 surveillance report, citing Syngelaki et al. (Prenat Diagn 2011, doi:10.1002/pd.2642). Yet we still do not understand what causes most of these anomalies, and understanding begins with counting and describing cases. Research on limb agenesis is starved of exactly that. Cases are not rare, but they are scattered across countries and recorded in incompatible systems, when they are recorded at all, so too few are described well enough to investigate the possible causes thoroughly. Families answer the same questions again and again, and science still cannot see the whole picture.

Patient groups strongly suspect environmental causes and teratogenic effects, of the kind thalidomide made undeniable, behind agenesis and other forms of dysmelia. Far too little research is carried out to confirm or rule them out. Between 2007 and 2014, three clusters of transverse upper-limb agenesis came to light in France, in Loire-Atlantique, Ain and Morbihan. The investigations led by Santé publique France with the regional registries found no common exposure. The episode did move surveillance forward: the regional registries were federated around a common database, a seventh registry followed in Nouvelle-Aquitaine, and Santé publique France plans to reach national coverage for some anomalies through the national health data system. Yet the French registries covered about one birth in six over 2019-2021 (16.4%), with a stated aim of about 23.6% once the Nouvelle-Aquitaine registry is fully deployed, the ministry’s 2016 request for a national registry of malformations was answered in 2018 by building on the existing registries rather than creating one, and no registry at national or European level is dedicated to limb anomalies. Those investigations also met the limits of any case investigation: families were questioned years after the birth, from memory. Families who take part actively and from pregnancy onwards, recording circumstances and exposures as they happen, can correct that weakness and give the next investigation the data the last one lacked.

Our registry therefore sets itself three objectives, in this order.

1. Find the next clusters. Bring families’ declared cases together across countries so that further clusters like those in France can be spotted, documented and handed to researchers, and research on causes can start again.
2. Keep existing registries alive. Offer the population-based registries that already record our conditions a place to preserve their limb-difference data and continuity should their funding fail.
3. Make registries talk to each other. Create the conditions for interoperability and portability of data between existing registries, and complete them where needed, so that new lines of research open.

Three of the seven French registries already accept a declaration from the family itself, alongside the clinician’s. That is the door DysNet wants to widen: a family that declares from pregnancy onwards, in its own words, corrects what a retrospective enquiry years later can no longer reconstruct.

The same conclusion was reached on the other side of the Atlantic. A Canadian workshop held in February 2024 found that the country has no national data source on limb loss and limb difference, agreed on five domains for building one, and looked to the amputee organisations themselves to carry it. Its authors describe what they call patient-powered registries, managed by patients and advocacy groups themselves. Our registries register summarises that work and the American registry already running.

“A patient registry is an organized system that uses observational study methods to collect uniform data (clinical and other) to evaluate specified outcomes for a population defined by a particular disease, condition, or exposure, and that serves one or more predetermined scientific, clinical, or policy purposes.”

Measured against that definition, what DysNet is building is not a registry yet, and we would rather say so than borrow the word’s authority. Three gaps are real:

• It is not exhaustive. A registry aims to capture every case in a defined population. Ours gathers the families who choose to take part through their associations; it will describe a community, not count a population.
• No medical board, for now. Writing a research protocol and deciding which data are worth collecting are scientific acts. An association without a scientific committee is not equipped to perform them, and will not pretend to.
• Declared data. What families report about themselves is precious and is not the same as clinician-verified data; the two must never be confused.

What this initiative is: a lasting engagement between families, their associations and research initiatives, so that when a study needs the limb-difference community, the community is organised, consenting and reachable, and its data are held in a form research can use. That engagement is worth building only to the highest degree of scientific method and quality: predefined purposes, uniform data, documented quality controls and a long-term perspective, the very recommendations of the European experts cited above. Earning the word “registry” is the roadmap: a scientific committee, a written protocol, an agreed minimum data set, and a published quality plan.

DysNet builds a data infrastructure that is international and interoperable by design, owned by the patient community itself, developed with member associations, and replicable for other rare conditions. We call it a registry for short; the section above says exactly how far that word applies today. It is the concrete answer to what DysNet membership returns to families: their data, working for their care. Once live, the registry will be declared in Orphanet’s European directory of rare-disease registries, where researchers already look for data sources.

New to the idea? The two-minute guide

The first pilots

Why Assedea and Raggiungere launch the registry with Health Data Safe.

The two pilot associations, in France and Italy, carry the same duty towards their families: never let their data become a product. Their reasons for choosing Health Data Safe as the partner to launch the registry:

• Ownership that is legally binding. The foundation’s statutes rule out any sale of health data and limit its use to care and research; that promise does not depend on goodwill.
• Consent the family controls. Each person decides what enters the registry and can withdraw at any time, in their own language, under the GDPR rules both associations already work with.
• No servers to run. Volunteer associations cannot operate health-data infrastructure; the technical and regulatory burden sits with a partner whose sole purpose is exactly that.
• One registry, not two. Interoperable by design, so the French and Italian pilots feed a single dataset that research can finally use, and other member associations can join with the same tools.
• A partner who knows the network. Health Data Safe already works alongside DysNet on the strategy that the AGM adopted, and brings its infrastructure in kind rather than as a commercial service.