Rare disease
Encyclopedia
A rare disease, also referred to as an orphan disease, is any disease that affects a small percentage of the population.
Most rare diseases are genetic, and thus are present throughout the person's entire life, even if symptoms do not immediately appear. Many rare diseases appear early in life, and about 30 percent of children with rare diseases will die before reaching their fifth birthday. With a single diagnosed patient only, ribose-5-phosphate isomerase deficiency
is presently considered the rarest genetic disease.
No single cutoff number has been agreed upon for which a disease is considered rare. A disease may be considered rare in one part of the world, or in a particular group of people, but still be common in another.
In the United States, the Rare Disease Act of 2002 defines rare disease strictly according to prevalence, specifically "any disease or condition that affects less than 200,000 persons in the United States," or about 1 in 1,500 people. This definition is essentially like that of the Orphan Drug Act of 1983, a federal law that was written to encourage research into rare diseases and possible cures.
In Japan, the legal definition of a rare disease is one that affects fewer than 50,000 patients in Japan, or about 1 in 2,500 people.
However, the European Commission
on Public Health defines rare diseases as "life-threatening or chronically
debilitating diseases which are of such low prevalence that special combined efforts are needed to address them." The term low prevalence is later defined as generally meaning fewer than 1 in 2,000 people. Diseases that are statistically rare, but not also life-threatening, chronically debilitating, or inadequately treated, are excluded from their definition.
The definitions used in the medical literature and by national health plans are similarly divided, with definitions ranging from 1/1,000 to 1/200,000.
movement began in the United States.
Others distinguish between the two terms. For example, the European Organization for Rare Diseases
(EURORDIS) lumps both rare diseases and neglected diseases
into a larger category of orphan diseases.
The United States' Orphan Drug Act includes both rare diseases and any non-rare diseases "for which there is no reasonable expectation that the cost of developing and making available in the United States a drug for such disease or condition will [be] recovered from sales in the United States of such drug" as orphan diseases.
(number of people living with a disease at a given moment), rather than incidence
(number of new diagnoses in a given year), is used to describe the impact of rare diseases. The Global Genes Project estimates there are some 350 million people worldwide currently affected with a rare disease.
The European Organization for Rare Diseases
(EURORDIS) estimates that there exist between 5,000 and 7,000 distinct rare diseases. Although each individual disease is rare, the sheer number of individual rare diseases results in between 6% and 8% of the population of the European Union
being affected by a rare disease.
Rare diseases can vary in prevalence between populations, so a disease that is rare in some populations may be common in others. This is especially true of genetic diseases and infectious disease
s. An example is cystic fibrosis
, a genetic disease: it is rare in most parts of Asia
but relatively common in Europe and in populations of European descent. In smaller communities, the founder effect
can result in a disease that is very rare worldwide being prevalent within the smaller community. Many infectious diseases are prevalent in a given geographic area but rare everywhere else. Other diseases, such as many rare forms of cancer
, have no apparent pattern of distribution but are simply rare. The classification of other conditions depends in part on the population being studied: All forms of cancer in children are generally considered rare, because so few children develop cancer, but the same cancer in adults may be more common.
About 40 rare diseases have a far higher prevalence in Finland
; these are known collectively as the Finnish disease heritage.
Classification of a disease's rarity also depends on the population being studied. Every form of cancer
is rare among children, but some forms are common among adults.
Symptoms of some rare diseases may appear at birth or in childhood, whereas others only appear once adulthood is reached.
Research publications emphasize rare diseases that are chronic or incurable, although many short-term medical conditions
are also rare diseases.
was held in Europe
and Canada
in February 2008 to raise awareness for rare diseases. It is intended to be observed on the last day of February every year.
was established in 1983 by individuals and families with rare diseases. Genetic Alliance
, established in 1986, lists information and support groups for approximately 1200 rare diseases. The Global Genes Project, started by the Children's Rare Disease Network, is creating greater public awareness, supporting the millions of families affected by rare disease through an online community & collaborative portal and other tools, and are funding innovations to support rare disease research.
The Canadian Organization for Rare Disorders
(CORD) is the national network of organizations who represent people affected by rare disorders within Canada. CORD's intention is to provide a strong common voice advocating for a healthcare system and health policy for those with rare disorders.
Patients with Rare Diseases in Greece are represented by the Greek Alliance of Rare Diseases
.
Most rare diseases are genetic, and thus are present throughout the person's entire life, even if symptoms do not immediately appear. Many rare diseases appear early in life, and about 30 percent of children with rare diseases will die before reaching their fifth birthday. With a single diagnosed patient only, ribose-5-phosphate isomerase deficiency
Ribose-5-phosphate isomerase deficiency
Ribose-5-phosphate isomerase deficiency is a human disorder caused by mutations in the pentose phosphate pathway enzyme ribose-5-phosphate isomerase...
is presently considered the rarest genetic disease.
No single cutoff number has been agreed upon for which a disease is considered rare. A disease may be considered rare in one part of the world, or in a particular group of people, but still be common in another.
Definition
There is no single, widely accepted definition for rare diseases. Some definitions rely solely on the number of people living with a disease, and other definitions include other factors, such as the existence of adequate treatments or the severity of the disease.In the United States, the Rare Disease Act of 2002 defines rare disease strictly according to prevalence, specifically "any disease or condition that affects less than 200,000 persons in the United States," or about 1 in 1,500 people. This definition is essentially like that of the Orphan Drug Act of 1983, a federal law that was written to encourage research into rare diseases and possible cures.
In Japan, the legal definition of a rare disease is one that affects fewer than 50,000 patients in Japan, or about 1 in 2,500 people.
However, the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
on Public Health defines rare diseases as "life-threatening or chronically
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
debilitating diseases which are of such low prevalence that special combined efforts are needed to address them." The term low prevalence is later defined as generally meaning fewer than 1 in 2,000 people. Diseases that are statistically rare, but not also life-threatening, chronically debilitating, or inadequately treated, are excluded from their definition.
The definitions used in the medical literature and by national health plans are similarly divided, with definitions ranging from 1/1,000 to 1/200,000.
Relationship to orphan diseases
Because of definitions that include reference to treatment availability, a lack of resources, and severity of the disease, some people prefer the term orphan disease and use it as a synonym for rare disease. The orphan drugOrphan drug
An orphan drug is a pharmaceutical agent that has been developed specifically to treat a rare medical condition, the condition itself being referred to as an orphan disease...
movement began in the United States.
Others distinguish between the two terms. For example, the European Organization for Rare Diseases
European Organization for Rare Diseases
The European Organization for Rare Diseases is a non-governmental patient-driven alliance of patient organizations and individuals active in the field of rare diseases, that promotes research on rare diseases and commercial development of orphan drugs. EURORDIS is a dedicated to improving the...
(EURORDIS) lumps both rare diseases and neglected diseases
Neglected Diseases
The neglected diseases are a group of tropical infections which are especially endemic in low-income populations in developing regions of Africa, Asia, and the Americas. Different organizations define the set of diseases differently...
into a larger category of orphan diseases.
The United States' Orphan Drug Act includes both rare diseases and any non-rare diseases "for which there is no reasonable expectation that the cost of developing and making available in the United States a drug for such disease or condition will [be] recovered from sales in the United States of such drug" as orphan diseases.
Prevalence
PrevalencePrevalence
In epidemiology, the prevalence of a health-related state in a statistical population is defined as the total number of cases of the risk factor in the population at a given time, or the total number of cases in the population, divided by the number of individuals in the population...
(number of people living with a disease at a given moment), rather than incidence
Incidence
Incidence may refer to:* Incidence , a measure of the risk of developing some new condition within a specified period of time* Incidence , the binary relations describing how subsets meet...
(number of new diagnoses in a given year), is used to describe the impact of rare diseases. The Global Genes Project estimates there are some 350 million people worldwide currently affected with a rare disease.
The European Organization for Rare Diseases
European Organization for Rare Diseases
The European Organization for Rare Diseases is a non-governmental patient-driven alliance of patient organizations and individuals active in the field of rare diseases, that promotes research on rare diseases and commercial development of orphan drugs. EURORDIS is a dedicated to improving the...
(EURORDIS) estimates that there exist between 5,000 and 7,000 distinct rare diseases. Although each individual disease is rare, the sheer number of individual rare diseases results in between 6% and 8% of the population of the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
being affected by a rare disease.
Rare diseases can vary in prevalence between populations, so a disease that is rare in some populations may be common in others. This is especially true of genetic diseases and infectious disease
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
s. An example is cystic fibrosis
Cystic fibrosis
Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
, a genetic disease: it is rare in most parts of Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
but relatively common in Europe and in populations of European descent. In smaller communities, the founder effect
Founder effect
In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942, using existing theoretical work by those such as Sewall...
can result in a disease that is very rare worldwide being prevalent within the smaller community. Many infectious diseases are prevalent in a given geographic area but rare everywhere else. Other diseases, such as many rare forms of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
, have no apparent pattern of distribution but are simply rare. The classification of other conditions depends in part on the population being studied: All forms of cancer in children are generally considered rare, because so few children develop cancer, but the same cancer in adults may be more common.
About 40 rare diseases have a far higher prevalence in Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...
; these are known collectively as the Finnish disease heritage.
Characteristics
Rare diseases usually are genetic, hence chronic. EURORDIS estimates that at least 80% of them have identified genetic origins. Other rare diseases are the result of infections and allergies or due to degenerative and proliferative causes.Classification of a disease's rarity also depends on the population being studied. Every form of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
is rare among children, but some forms are common among adults.
Symptoms of some rare diseases may appear at birth or in childhood, whereas others only appear once adulthood is reached.
Research publications emphasize rare diseases that are chronic or incurable, although many short-term medical conditions
Acute (medicine)
In medicine, an acute disease is a disease with either or both of:# a rapid onset, as in acute infection# a short course ....
are also rare diseases.
Public Research
The NIH's Office of Rare Diseases Research (ORDR) was established by H.R. 4013/Public Law 107-280 in 2002. H.R. 4014, signed the same day, refers to the "Rare Diseases Orphan Product Development Act". Similar initiatives have been proposed in Europe.Public Awareness
The first Rare Disease DayRare Disease Day
Rare Disease Day is an observance held on the last day of February to raise awareness for rare diseases and improve access to treatment and medical representation for individuals with rare diseases and their families...
was held in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
in February 2008 to raise awareness for rare diseases. It is intended to be observed on the last day of February every year.
Support
The National Organization for Rare DisordersNational Organization for Rare Disorders
The National Organization for Rare Disorders is an American non-profit organization aiming to provide support individuals with rare diseases by advocating and funding research, education, and networking among service providers...
was established in 1983 by individuals and families with rare diseases. Genetic Alliance
Genetic Alliance
Genetic Alliance is the world’s leading nonprofit health advocacy organization committed to improving health through the authentic engagement of communities and individuals. The organization was founded by Joan O. Weiss, a social worker, working with Victor A. McKusick, in 1986—four years before...
, established in 1986, lists information and support groups for approximately 1200 rare diseases. The Global Genes Project, started by the Children's Rare Disease Network, is creating greater public awareness, supporting the millions of families affected by rare disease through an online community & collaborative portal and other tools, and are funding innovations to support rare disease research.
The Canadian Organization for Rare Disorders
Canadian Organization for Rare Disorders
The Canadian Organization for Rare Disorders is a Canadian registered charity that is a network of organizations who represent people affected by rare diseases...
(CORD) is the national network of organizations who represent people affected by rare disorders within Canada. CORD's intention is to provide a strong common voice advocating for a healthcare system and health policy for those with rare disorders.
Patients with Rare Diseases in Greece are represented by the Greek Alliance of Rare Diseases
Greek Alliance of Rare Diseases
The Greek Alliance for Rare Diseases is a non-profit organisation, which deals with patients and associations of patients with Rare Diseases, in Greece....
.
See also
- Genetic Alliance UKGenetic Alliance UKGenetic Alliance UK is a national level umbrella charity for 130 patient organisations, funded by grants and memberships, supporting those affected by genetic disorders. Its aim is to improve the lives of people affected by genetic conditions by ensuring that high quality services and information...
- Global Genes ProjectGlobal Genes ProjectThe Global Genes Project is a grassroots project designed to raise rare disease awareness, and fund research to cure rare diseases.-History:The Global Genes Project , is a leading non-profit rare disease advocacy organization dedicated to raising awareness for the more than 7000 distinct rare...
- Orphan drugOrphan drugAn orphan drug is a pharmaceutical agent that has been developed specifically to treat a rare medical condition, the condition itself being referred to as an orphan disease...
s - Rare Disease DayRare Disease DayRare Disease Day is an observance held on the last day of February to raise awareness for rare diseases and improve access to treatment and medical representation for individuals with rare diseases and their families...
- ssociation of Genetic Support of Australasia (AGSA)
External links
- List from Health on the Net Foundation, available in several languages
- NIH's Genetic and Rare Diseases Information Center
- Database of rare diseases at Orphanet
- Information from the European Organization for Rare Diseases (EURORDIS)
- Global Genes Project Global Genes Project for rare disease
- Health-EU Portal Rare Diseases in the EU
- Orphan Diseasome Rare/Orphan Disease Networks
- NIH Rare Diseases Clinical Research Network (RDCRN)
- OrphanAnesthesia - Anesthesia recommendations for patients suffering from rare diseases