INFO - Rheumatoid arthritis and heredity

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Rheumatoid Arthritis Symptoms and Diagnosis

Last updated 10 Jul 2007

Excerpt:

Heredity — Rheumatoid arthritis is not an inherited disease. Genes do

not cause the disease, they merely increase the risk of its

development. The level of this risk has been studied by the analysis

of identical twins, who have identical genes. The likelihood that both

twins will have rheumatoid arthritis is between 12 and 30 percent. The

risk of developing rheumatoid arthritis in non-identical twins and in

first-degree relatives of affected people is lower, but still

increased (between 1.5 and 4 percent) compared to the population in

general (about 1 percent). These studies suggest that genes increase

the risk of developing rheumatoid arthritis, but not to a degree that

family members of people with RA require screening tests.

http://patients.uptodate.com/topic.asp?file=arth_rhe/2411

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American College of Rheumatology

Patient Education

Heredity and Arthritis

Last updated Jul 2006

Excerpt:

Genetics and rheumatoid arthritis

Rheumatoid arthritis, a multifactorial disease, is a common type of

inflammatory arthritis which affects many joints and occurs in

approximately 1% of the population worldwide. In this case, the gene

link with rheumatoid arthritis is to an immune system gene called

HLA-DR4. In rheumatoid arthritis patients of European ancestry, as

many as 60% to 70% carry the HLA-DR4 gene, compared with 30% in the

general population.

Twin studies show that 12% to 15% of identical twins both develop

rheumatoid arthritis compared to only 4% in non-identical twins.

Further, the disease rate in first-degree family members of rheumatoid

arthritis patients is only 0.8% compared to 0.5% in the general

population. This indicates that genes only modestly increase the risk

for rheumatoid arthritis and that the environment is likely to play a

stronger role.

http://www.rheumatology.org/public/factsheets/heredity.asp#5

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