Zeroing In on 3 Autoimmune Diseases: Genetic Link May Help Explain Diseases From Psoriasis to Lupus

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Zeroing In on 3 Autoimmune Diseases:

Genetic Link May Help Explain Diseases From Psoriasis to Lupus

http://my.webmd.com/content/Article/76/90247.htm

WebMD Medical News Reviewed By Brunilda Nazario, MD

New discoveries about a set of genes may help unlock the mystery behind

who can get an entire family of diseases from rheumatoid arthritis to lupus.

Researchers have long suspected that people with a group of diseases of

the immune system known as autoimmune diseases may share a set of genes

that put them at risk for these disorders.

But new research takes them a step closer to identifying which genes

might be responsible for at least three of these diseases: rheumatoid

arthritis, lupus, and psoriasis.

Although the causes of most autoimmune diseases are unknown, researchers

suspect that a combination of genetic susceptibility and environmental

factors may contribute to a person's risk of developing these diseases.

Genetic Links for Psoriasis, Rheumatoid Arthritis, and Lupus

In the first study, researchers identified a gene that increases a

person's susceptibility to psoriasis, an inflammatory skin disorder that

affects about 2% of the population. The gene is one that turns switches

to the immune system on and off, and a defective version of this gene

has been found in a significant number of people with psoriasis.

In the second, researchers found a genetic defect that may increase the

risk of rheumatoid arthritis. Rheumatoid arthritis is a progressive

disease that causes the lining of the joints to become inflamed,

swollen, and painful.

Researchers say the genetic influence on rheumatoid arthritis risk seems

especially strong. Siblings of people with the disease have a 2 to 17

times higher risk of developing rheumatoid arthritis themselves compared

with the general population.

A third study showed that a rare genetic variant may play a role in the

susceptibility for the development of lupus, a complex disease of the

immune system that affects virtually all tissues of the body. It

commonly affects women and for most is a mild disorder, but it can cause

life-threatening damage to many organs in others.

Researchers say that these findings build on previous research

suggesting that these diseases may share a common genetic bond, and

these studies provide new clues about how these genes interact to

trigger development of autoimmune diseases.

If further studies confirm these results, researchers may eventually be

able to develop genetic screening tests for certain autoimmune diseases

or develop more effective treatments.

SOURCES: Yamada, R. Bowcock, A. Alarcon-Riquelme, M. Nature Genetics,

December 2003.