written by: Paul Arnold
• edited by: Paul Arnold
• updated: 8/23/2010
Lupus is a chronic and incurable autoimmune disease. The reasons why the body attacks itself to produce the characteristic lupus symptoms is starting to become clearer after decades of doubt and uncertainty; and it's likely that genes play a considerable role.
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What is Lupus?
Antibodies usually protect us from illness by binding to antigens on foreign cells and destroying them. But in people with lupus the immune system goes haywire and mistakenly attacks ordinary body cells and tissues that are not marked with antigens The result is tissue inflammation that leads to classic lupus symptoms.
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Types of Lupus
There are several different types of lupus which can be triggered at any age-
Discoid lupus - normally limited to the skin - symptoms include a rash on the face, scalp or body. Other symptoms include joint aches.
Systemic lupus erythemtosus (SLE) - affects body organs and involves inflammation of joints and other connective tissues. Symptoms include fever, fatigue, joint pain, and weight loss. The most obvious symptom is a butterfly rash that appears on the cheeks and across the bridge of the nose.
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Lupus and Inheritance
The exact causes of lupus are unknown, but it is expected that genetic and environmental factors both play a part. It is thought that there is some hereditary component to the disease as people who have a family history of lupus are more likely to contract the illness. According to the Lupus Site, a guide for patients and their families, there's a 5-12% greater tendency for people to get the disease if family members already have it. This doesn't necessarily mean that if they possess the causative genes they will develop the incurable disease too. It will probably make them more susceptible than the general population if they are exposed to certain triggers in the environment.
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The Causes of Lupus
Is lupus hereditary? Lupus is caused by both the environment and genes, meaning that certain environmental triggers will cause the disease to develop in individuals who are genetically pre-disposed to it. The internal environmental causes may include the hormone oestrogen, which would explain why more women are affected by the condition than men. External environmental cues are thought to include ultraviolet light, infections such as the Epstein-Barr virus, stress, smoking, and some medications.
Scientists have been looking for the genetic causes of lupus for years, and in early 2008 international teams of researchers published several papers detailing a number of genes which jumpstart the disease. Among them were the genes ITGAM, KIAA1542, PXK and rs10798269. Other genes such as PTPN22 and STAT 4 had previously been identified, and also contribute to other autoimmune diseases. This lends support to the theory that there are common sets of genes involved in autoimmune diseases. Scientists also confirmed more than a dozen other known lupus genes.
To be able to turn this knowledge into useful therapies scientists will now try to find out what these genes do to enable them to design ways of stopping them in their tracks.
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Released into the public domain by the National Institutes of Health