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Information about Autoimmune Disease

This article is about the medical term. For the Matchbox Twenty song, see Disease (song).


A disease is an abnormal condition of an organism that impairs bodily functions. In human beings, "disease" is often used more broadly to refer to any condition that causes discomfort, dysfunction, distress, social problems, and/or death to the person afflicted, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories.

While many diseases are biological processes with observable alterations of organ function or structure, others primarily involve alterations of behavior.

Classifying a condition as a disease is a social act of valuation, and may change the social status of the person with the condition (the patient). Some conditions (known as culture-bound syndromes) are only recognized as diseases within a particular culture. Sometimes the categorizaton of a condition as a disease is controversial within the culture.

Causes of disease

Many different factors intrinsic or extrinsic to a person (or plant or animal) can cause disease. Examples of intrinsic factors are genetic defects or nutritional deficiencies. An environmental exposure, such as second-hand smoke is an example of an extrinsic factor. Many diseases result from a combination of intrinsic and extrinsic factors. For many diseases a cause cannot be identified.

There are many different factors that can cause disease. These can be broadly categorized into the following categories like social, psychological, chemical and biological. Some factors may fall into more than one category. Biochemical causes of disease can be considered as a spectrum where at one extreme disease is caused entirely by genetic factors (e.g. CAG repeats in the Huntingtin gene that causes Huntington's Disease) and at the other extreme is caused entirely by environmental factors. Environmental factors include toxic chemicals (e.g. acetaldehyde in cigarette smoke and dioxins released from the breakdown of Agent Orange) and infectious agents (e.g. smallpox virus and poliovirus). In between these extremes genes (e.g. NOD2/CARD15) and environmental factors (e.g. Gut microbiota) interact to cause disease, as seen for example in the inflammatory bowel disease Crohn's Disease (Fig 1, right).
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Figure 1. The biochemical basis of disease. Some diseases, not illustrated here, also have a social and psychological basis.
Absence of the genetic or environmental factors in this case results in disease not being manifest. Koch's postulates can be used to determine whether a disease is caused by an infectious agent.

To determine whether a disease is caused by genetic factors, researchers study the pattern inheritance of the disease in families. This provides qualitative information about the disease (how it is inherited). A classic example of this method of research is inheritance of hemophilia in the British Royal Family. More recently this research has been used to identify the Apoliprotein E (ApoE) gene as a susceptibility gene for Alzheimer's Disease, though some forms of this gene - ApoE2 - are associated with a lower susceptibility. To determine to what extent a disease is caused by genetic factors (quantitative information), twin studies are used. Monozygotic twins are genetically identical and likely share a similar environment whereas dizygotic twins are genetically similar and likely share a similar environment. Thus by comparing the incidence of disease (termed concordance rate) in monozygotic twins with the incidence of disease in dizygotic twins, the extent to which genes contribute to disease can be determined. Candidate disease genes can be identified using a number of methods. One is to look for mutants of a model organism (e.g. the organisms Mus musculus,Drosophila melanogaster, Caenhorhabditis elegans,Brachydanio rerio and Xenopus tropicalis) that have a similar phenotype to the disease being studied. Another approach is to look for segregation of genes or genetic markers (e.g. single nucleotide polymorphism or expressed sequence tag) (Fig. 2).
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Figure 2. Genetic markers help locate a disease gene
A large number of SNPs spaced throughout the genome have been identified recently in a large project called the HapMap project[1][2]). The usefulness of the HapMap project and SNP typing and their relevance to society was covered in the 27 October 2005 issue of the leading international science journal Nature (journal).

A large number of genes have been identified that contribute to human disease. These are available from the US National Library of Medicine, which has an impressive range of biological science resources available for free online. Amongst these resources is Online Mendelian Inheritance in Man - OMIM that provides a very, very comprehensive list of all known human gene mutations associated with, and likely contributing to, disease. Each article at OMIM is regularly updated to include the latest scientific research. Additionally, each article provides a detailed history of the research on a given disease gene, with links to the research articles. This resource is highly valuable and is used by the world's top science researchers.

Related concepts

The terms disease, disorder, medical condition are often used interchangeably. There is no agreed-upon universal distinction between these terms, though some people do make distinctions in particular contexts.

Medical usage sometimes distinguishes a disease, which has a known specific cause or causes (called its etiology), from a syndrome, which is a collection of signs or symptoms that occur together. However, many conditions have been identified, yet continue to be referred to as "syndromes." Furthermore, numerous conditions of unknown etiology are referred to as "diseases" in many contexts. Refractory diseases do not respond to therapy by overcoming the resistance to drugs.

Illness, although often used to mean disease, can also refer to a person's perception of their health, regardless of whether they in fact have a disease. A person without any disease may feel unhealthy and simply have the perception of having an illness. Another person may feel healthy with similar perceptions of perfectly good health. The individual's perception of good health may even persist with the medical diagnosis of having a disease; for example, such as dangerously high blood pressure, which may lead to a fatal heart attack or stroke.

Pathology is the study of diseases. The subject of systematic classification of diseases is referred to as nosology. Its cause is referred as its etiology. The broader body of knowledge about human diseases and their treatments is medicine. Many similar (and a few of the same) conditions or processes can affect non-human animals (wild or domestic). The study of diseases affecting animals is veterinary medicine.

Disease can be thought of as the presence of pathology, which can occur with or without subjective feelings of being unwell or social recognition of that state. Illness as the subjective state of "unwellness" can occur independently of, or in conjunction with, disease or sickness (with sickness the social classification of someone deemed diseased, which can also occur independently of the presence or absence of disease or illness (c.f. subjective medical conditions). Thus, someone with undetected high blood pressure who feels to be of good health would be diseased, but not ill or sick. Someone with a diagnosis of late-stage cancer would be diseased, probably feeling quite ill, and recognized by others as sick. A person incarcerated in a totalitarian psychiatric hospital for political purposes could arguably be then said to not be diseased, nor ill, but only classified as sick by the rulers of a society with which the person did not agree. Having had a bad day after a night of excess drinking, one might feel ill, but one would not be diseased, nor is it likely that a boss could be convinced of the sickness.

Transmission of disease

Some diseases such as influenza are contagious or infectious. Infectious diseases can be transmitted by any of a variety of mechanisms, including aerosols produced by coughs and sneezes, by bites of insects or other carriers of the disease, and from contaminated water or food (possibly by faeces or urine in the sewage), etc. Also, there are sexually transmitted diseases. When micro-organisms that cannot be spread from person to person might play a role, some diseases can be prevented with proper nutrition. Other diseases such as cancer and heart disease are not considered to be caused by infection. The same is true of mental diseases.

Social significance of disease

Living with disease can be very difficult. The identification of a condition as a disease, rather than as simply a variation of human structure or function, can have significant social or economic implications. The controversial recognitions as diseases of post-traumatic stress disorder, also known as "Soldier's heart," "shell shock," and "combat fatigue;" repetitive motion injury or repetitive stress injury (RSI); and Gulf War syndrome has had a number of positive and negative effects on the financial and other responsibilities of governments, corporations and institutions towards individuals, as well as on the individuals themselves. The social implication of viewing aging as a disease could be profound, though this classification is not yet widespread.

A condition may be considered to be a disease in some cultures or eras but not in others. Oppositional-defiant disorder, attention-deficit hyperactivity disorder, and, increasingly, obesity, are conditions considered to be diseases in the United States and Canada today, but were not so-considered decades ago and are not so-considered in some other countries. Lepers were a group of afflicted individuals who were historically shunned and the term "leper" still evokes social stigma. Fear of disease can still be a widespread social phenomena, though not all diseases evoke extreme social stigma.

Sickness confers the social legitimization of certain benefits, such as illness benefits, work avoidance, and being looked after by others. In return, there is an obligation on the sick person to seek treatment and work to become well once more. As a comparison, consider pregnancy, which is not a state interpreted as disease or sickness by the individual. On the other hand, it is considered by the medical community as a condition requiring medical care and by society at large as a condition requiring one's staying at home from work.

Global Disease Burden

This chart, compiled in 2002 from the World Health Organization's Global Burden of Disease shows an overview of the impact of various classifications of disease, segregated by regions with low and high mortality:

References

1. ^ McVean G, Spencer CC, Chaix R (2005). "Perspectives on human genetic variation from the hapmap project". PLoS Genet 1 (4): e54. PMID 16254603. This review is free of charge
2. ^ Skelding K.A., Gerhard GS, Simari RD, Holmes DR Jr (2007). "The effect of HapMap on cardiovascular research and clinical practice". Nat Clin Pract Cardiovasc Med 4 (3): 136-142. PMID 17330125. 
3. O'Connor, Hugh - "How humping a goat can cure cancer, and five other cottage cures from Rathfarnam - A historical review" 1997.

External links

See also

 •  • [ e]
Pathology
Principles of pathologyDisease - Necrosis - Infection - Ischemia - Inflammation - Wound healing - Neoplasia
Anatomical pathologySurgical pathology - Cytopathology - Autopsy - Molecular pathology - Forensic pathology - Dental pathology 
Gross examination - Histopathology - Immunohistochemistry - Electron microscopy - Immunofluorescence - Fluorescent in situ hybridization
Clinical pathologyClinical chemistry - Hematopathology - Transfusion medicine - Medical microbiology - Diagnostic immunology
Enzyme assay - Mass spectrometry - Chromatography - Flow cytometry - Blood bank - Microbiological culture - Serology
Released 2002
Format CD Single / Audio Cassette
Recorded 2002
Genre Alternative Rock
Length 3:43
Label Atlantic
Writer(s) Rob Thomas
Mick Jagger
Producer(s) Matt Serletic
Peak chart positions

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Pain is a sensation transmitted from sensory nerves through the spinal cord and to the sensory area of the cerebrum, where the sensation is perceived. It is defined by the International Association for the Study of Pain (IASP) as “an unpleasant sensory and emotional
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Dysfunction can refer to:
  • in psychology, an abnormality
  • in sociology, a dysfunction (sociology)
  • in mechanics, a malfunction
plus if you're black
  • Dysfunction (album), an album by the rock band Staind

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The word distress has various meanings:-
  • Distress is a kind of suffering.
  • In medicine, distress is stress caused by adverse events.
  • In Maritime and Aircraft terms, distress is defined as "grave and imminent danger to life or person or vessel or aircraft,

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Social issues are matters which directly or indirectly affect many or all members of a society and are considered to be problems, controversies related to moral values, or both.
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Death is the permanent end of the life of a biological organism. Death may refer to the end of life as either an event or condition.[1] Many factors can cause or contribute to an organism's death, including predation, disease, habitat destruction, senescence,
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Injury is damage or harm caused to the structure or function of the body caused by an outside or force, which may be physical or chemical. Injury may also refer to injured feelings or reputation rather than injuries to the body.
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disability is a condition or function judged to be significantly impaired relative to the usual standard of an individual or their group. The term is often used to refer to individual functioning, including physical impairment, sensory impairment, cognitive impairment, intellectual
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In medicine and psychology, the term syndrome refers to the association of several clinically recognizable features, signs (discovered by a physician), symptoms (reported by the patient), phenomena or characteristics which often occur together, so that the presence of one feature
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An infection is the detrimental colonization of a host organism by a foreign species. In an infection, the infecting organism seeks to utilize the host's resources to multiply (usually at the expense of the host).
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The term symptom (from the Greek σύμπτωμα meaning 'chance', 'mishap' or 'casualty', itself derived from συμπιπτω
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This article or section is written like a personal reflection or and may require .
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Behavior or behaviour
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Human variability, or human variation, is the range of possible values for any measurable characteristic, physical or mental, of human beings. Differences can be trivial or important, transient or permanent, voluntary or involuntary, congenital or acquired, genetic or
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organ (Latin: organum, "instrument, tool") is a group of tissues that perform a specific function or group of functions. Usually there is a main tissue and sporadic tissues. The main tissue is the one that is unique for the specific organ.
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patient is any person who receives medical attention, care, or treatment. The person is most often ill or injured and in need of treatment by a physician or other medical professional.
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In medicine and medical anthropology, a culture-specific syndrome or culture-bound syndrome is a combination of psychiatric and somatic symptoms that are considered to be a recognizable disease only within a specific society or culture.
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Culture (from the Latin cultura stemming from colere, meaning "to cultivate,") generally refers to patterns of human activity and the symbolic structures that give such activity significant importance.
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A genetic disorder is a condition caused by abnormalities in genes or chromosomes. While some diseases, such as cancer, are due to genetic abnormalities acquired in a few cells during life, the term "genetic disease" most commonly refers to diseases present in all cells of the body
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Second-hand Smoke
(1997) Stand by Your Van
(1998)

Second-hand Smoke is an album by the band Sublime. It was released in 1997 following the death of lead singer Brad Nowell the year before.
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Social refers to human society or its organization. Although the term is a crucial category in social science and often used in public discourse, its meaning is at times vague, suggesting that it is a fuzzy concept.
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Psychology (from Greek: Literally "talk about the soul" (from logos)) is both an academic and applied discipline involving the scientific study of mental processes and behavior.
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Biological may refer to:
  • Biology, the study of life
  • Biological tissue
  • Biological process
  • Organism, a biological entity
  • Life, the characteristic state of organisms
  • Consanguinity, being descended from the same ancestor
Materials and substances
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spectrum (plural spectra) is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a
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Huntingtin (Htt) is the protein coded by the HD gene. It is variable in its structure. There are many polymorphisms of the HD gene which can lead to variable numbers of glutamine residues present. In its wild-type (normal) form, it contains 6-34 glutamine residues.
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MeSH D006816 Huntington's disease (HD), also misspelt as Huntington disease and known historically as Huntington's chorea and chorea maior
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Toxicity is the degree to which something is able to produce illness or damage to an exposed organism. Toxicity can refer to the effect on a whole organism, such as a human or a bacterium or a plant, or to a substructure, such as a cell (cytotoxicity) or an organ (organotoxicity
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Acetaldehyde, sometimes known as ethanal, is an organic chemical compound with the formula CH3CHO or MeCHO. It is a flammable liquid with a fruity smell.
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Dioxin in its original usage denoted the organochemical heterocyclic compound with the general chemical formula C4H4O2 in which two CH groups of a benzene ring were replaced (endocyclic substitution) by oxygen atoms, of which two isomers were
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