Magazine article The Exceptional Parent

Not So Rare, Rare Diseases

Magazine article The Exceptional Parent

Not So Rare, Rare Diseases

Article excerpt

"When a family member or friend develops what is considered a 'rare disease,' it's not rare anymore." (1)

A rare disease or condition is defined by federal legislation such that it "... a) affects less than 200,000 persons in the U.S. or b) affects more than 200,000 persons in the U.S. but for which there is no reasonable expectation that the cost of developing and making available in the U.S. a drug for such disease or condition will be recovered from sales in the U.S. of such drug." (2) In the European Union (EU), rare diseases are defined as occurring in less than one person in 2,000 individuals. (3)

The reality is that there are 7,000 or more distinct rare diseases known today ("... [with] five new diseases being described every week." [1]) that affect approximately 25 million U.S. residents and about 30 million in the 25 European Union countries. (1-3) However, the International Classification of Diseases (ICD) that is used in most countries is not convenient for rare diseases. The absence of a universally recognized coding system is an obstacle for reliable registration of patients in national or international databases, thereby preventing assessment of the economic and social effects of rare diseases. (4)

Despite the infrequency of each rare disease, about 6 percent to 8 percent of the total EU population are patients with rare diseases or equivalent to the combined population of Netherlands, Belgium, and Luxembourg. (2) About 80 percent of rare diseases are of genetic origin. Many of the adult-appearing diseases are mostly rare tumors. Other origins of rare diseases are viral or bacterial infections and allergies.

A listing and description of thousands of the rare diseases as well as general information are available from the National Institutes of Health online at:

* Listings--

* Information-- aspx?PageID=4

Numerous other sources for information are available, including the National Organization for Rare Disorders (NORD); and the Rare Disease Search Engine at:


* Rare diseases: characterized by their low prevalence.

* Neglected diseases: common communicable diseases that mainly affect patients living in developing countries.

* Orphan diseases: comprise both rare and neglected diseases. They lack adequate research focus and market interest, as well as public health policies.

* Orphan drugs: are medical products intended for the diagnosis, prevention and treatment of rare diseases. They are not cost effective for the pharmaceutical industry to develop and market since they are intended for only a small number of patients suffering from rare conditions. (2)

Common characteristics of rare diseases

Despite their great diversity, rare diseases have some major, common traits, including:

* a prolonged period between the emergence of the symptoms and the appropriate diagnosis. In many cases there is a paucity of scientific knowledge. In one study of the main causes of diagnostic delay (in 17 European countries), 25 percent of the patients reported that 5-30 years had elapsed from the time of the first symptoms to the correct diagnosis. Before the final diagnosis, 40 percent were diagnosed incorrectly. Incorrect diagnosis led to futile medical interventions: 16 percent had surgery, 33 percent did not receive the appropriate treatment, and 10 percent were given psychological care on the assumption that the symptoms were psychological; (4)

* social consequences, which impact on schooling, future work, and leisure time with friends;

* a tendency for the condition to be severe to very severe, chronic, often degenerative, and life threatening;

* onset occurring in childhood for 50 percent of the diseases;

* being incurable, mostly without effective treatment. …

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