Undiagnosed rare diseases

Many people around the world are struggling in search of a diagnosis1,2,3.

Find out below about:

The different groups of undiagnosed patients

There are different groups of undiagnosed patients:

  • ‘Not yet diagnosed’ refers to a patient whose disease has not been diagnosed because the patient has not been referred to the appropriate clinician due to common, misleading symptoms, or an unusual clinical presentation of a known rare condition.
  • ‘Undiagnosed’ (Syndromes Without a Name or SWAN) refers to a disease for which a diagnostic test is not yet available; the disease has not been characterised and the cause is not yet identified. This patient can also be misdiagnosed as his/her condition can be mistaken for others. These conditions are also likely to be rare.

The diagnostic odyssey

Some patients live for months, years or in many cases, their entire lives with an undiagnosed condition. Obtaining a diagnosis can be a long and difficult journey4,5,6,7; a EURORDIS survey of eight relatively common rare diseases in Europe showed that 25% of patients waited from five to 30 years for a diagnosis, and during that time 40% received an incorrect diagnosis. Misdiagnosis results in inappropriate treatment and care options.

Living with an undiagnosed disease is often extremely challenging. A significant consequence of being undiagnosed revolves around the heartache and stress patients and their families experience, compounding feelings of isolation and exclusion that worsen with the chaotic journey through numerous referrals, investigations, and disease evolutions.

Why it is important for families to have a diagnosis

A diagnosis can serve as the key to unlocking access to effective medical and social care as well as to treatment. Getting the right and accurate diagnosis, even when there is no treatment, increases opportunities for patients to plan their future.

In situations where diseases are inherited, many families have several affected siblings. For these families, the absence of a diagnosis increases the risk and worry of having another child suffering from the same undiagnosed condition.

European & international undiagnosed initiatives

The following initiatives have been created to support the undiagnosed rare disease community:

  • Solve-RD is a research project funded by the European Commission. It is working towards delivering diagnostic tests for most rare diseases by 2020. Solve-RD fully integrates with the newly formed European Reference Networks (ERNs) and is collaborating with EURORDIS to involve patients in the process. 

International Recommendations to Address Specific Needs of Undiagnosed Rare disease Patients

EURORDIS, together with SWAN UK (the support group run by Genetic Alliance UK), the Wilhelm Foundation, Rare Voices Australia (RVA), the Canadian Organization for Rare Disorders (CORD), the Advocacy Service for Rare and Intractable Diseases' stakeholders in Japan (ASrid) and the US National Organization for Rare Disorders (NORD) jointly created  a list of recommendations to address the specific needs of patients without a diagnosis. These recommendations urge all stakeholders to recognise undiagnosed patients as a specific population within the rare disease community.

Additional information on genetics & genomics

Genome editing

For an introduction to the topic of genome editing, see:


1EURORDIS, The Voice of 12,000 patients (2009)
2 Survey on misdiagnosis, French Alliance for Rare Diseases (2016) 
3Molster et al. (2016) Survey of healthcare experiences of Australian adults living with rare diseases
4FEDER, Spanish organisation for rare diseases (2015), Survey “Diagnostic delay remains one of the main concerns of families”
5Rare Disease UK: The Rare Reality – an insight into the patient and family experience of rare disease (2015)
6Black N, Martineau F, Manacorda T (2015) Diagnostic odyssey for rare diseases:
7Rare disease observatory, France, ‘The life health crusade : misdiagnosis’ 2011
8Taruscio D et al. (2015) Undiagnosed Diseases Network International (UDNI): White paper for global actions to meet patient needs, Molecular Genetics and Metabolism 116:223-225







Page created: 04/01/2018
Page last updated: 20/07/2020
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