Delay in the Diagnosis of Rare Diseases

Delay in the Diagnosis of Rare Diseases

Rare diseases are usually genetic in origin, life-threatening or chronically debilitating and most of them lack any type of treatment. Also, by definition, a rare disease only affects a small number of individuals, although the exact definition varies from one country to another:

  • In the United States, the Rare Diseases Act of 2002 defines them as “Rare diseases and disorders are those which affect small patient populations, typically populations smaller than 200,000 individuals in the United States.” (about 1 in 1,500)
  • While the European Commission definition is “Rare diseases, including those of genetic origin, are life-threatening or chronically debilitating diseases which are of such low prevalence that special combined efforts are needed to address them. As a guide, low prevalence is taken as prevalence of less than 5 per 10,000 in the Community.”

Despite the fact that every rare disease only affects a small number of individuals, there are more than 7.000 different rare diseases, so taken together rare diseases affect over 30 million Americans and an estimated 350 million people worldwide according to R.A.R.E. project. However, the diagnosis of rare diseases is not easy and usually there are delays in the diagnosis of these genetic disorders. We can see an example in this video from SWAN UK (Syndromes Without A Name: a project run by Genetic Alliance UK offering support and information to families of children with undiagnosed genetic conditions):


(more videos about rare diseases available on the link)


In 2009, EURORDIS published the book The Voice of 12,000 Patients with the results of the surveys EurordisCare2 and EurordisCare3. These surveys were conducted to study the experiences and expectations of patients of rare diseases across Europe regarding access to diagnosis and to health care services. Main findings:

  • 25% of patients had to wait between 5 and 30 years from early symptoms to confirmatory diagnosis of their disease.
  • 40% of patients first received an erroneous diagnosis. This led to medical interventions (including surgery and psychiatric treatments) that were based on a wrong diagnosis.
  • 25% of patients had to travel to a different region to obtain the confirmatory diagnosis, and 2% had to travel to a different country.
  • The genetic nature of the disease was not communicated to the patient or family in 25% of the cases.
  • There was genetic counselling in only 50% of the cases.
  • The average patient required more than nine different medical services over the two-year period preceding the survey.
  • More than one quarter of patients reported difficult, very difficult or impossible access to services. A lack of referral was the most frequently reported cause of impossible access.
  • Moving house and reducing professional activity were some of the daily changes patients and their families were required to make as a result of a rare disease.

In the absence of an accurate diagnosis, questions that the parents need to know usually go unanswered for a long time. Like:

  • What is wrong with my baby?
  • Is the condition going to stabilize or worsen?
  • What can be done to treat the disease or at least alleviate the symptoms?

Many rare diseases show symptoms in the early years, while some others develop at a later age, but in any case they are a matter of concern not only to the patient or the parents but to the whole family. Once a genetic rare disease is detected in a family, other members like aunts, uncles or cousins might want to know if they share this gene and their risk to develop the disease or to transmit it to their children. In order to properly asses this risk, an accurate diagnosis and genetic testing are necessary. However, the doctor that sees the baby (or the adult patient) has probably not seen anyone with this condition before. The patient is refereed to an specialist, but probably he is also unfamiliar with this specific disease. After a number of tests and doctors some families get a diagnosis, some others don’t.

A solution to the diagnostic delay would be to increase the awareness, knowledge and coordination of health care professionals on rare diseases, establishing effective referral systems to channel undiagnosed people suspected to be affected by a rare disease to a reference center where he could be diagnosed. Also, more research is needed to better understand each rare disease and enable the development of genetic tests for accurate diagnosis and effective treatments for each condition. To achieve this, it is necessary more awareness from the general public to know about the reality of people affected by these conditions, be more supportive and demand from policy makers the necessary actions. With an estimated incidence of rare diseases of 8-10% as a whole, each one of us is quite likely to have at some point a case of a rare disease among our extended family, friends or coworkers. Let’s help them, let’s help us.

More information on rare diseases:

  • EURORDIS: the Voice of Rare Diseases Patients in Europe.
  • Genetic Alliance: organization devoted to promoting optimum health care for people suffering from genetic disorders.
  • Orphanet: the Portal for Rare Diseases and Orphan Drugs.
  • NORD: National Organization for Rare Disorders (USA).

More information on rare diseases in Spanish:

  • FEDER: Federación Española de Enfermedades Raras.


This post was published on January 30th 2012, a month in advance of the Rare Disease Day on February 29th 2012, as part of a blog hop organized by R.A.R.E. Project and The Global Genes Project to raise awareness on rare diseases.

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