Genes Are Of Little Importance In Rheumatoid Arthritis

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Genes Are Of Little Importance In Rheumatoid Arthritis

February 1, 2002

(British Medical Journal) -- Genes are of little importance in the

development of rheumatoid arthritis, finds a study in this week's BMJ.

Researchers in Denmark surveyed over 37,000 twins about rheumatic

diseases. Twin studies are one of the simplest ways to unravel the

relative importance of genetic and environmental effects of a disease.

Twins who reported that they had rheumatoid arthritis were invited to

have a clinical examination.

Rheumatoid arthritis was verified in 13 identical and 36 non-identical

twins. No identical twins and only two pairs of non-identical twins both

had rheumatoid arthritis, suggesting that rheumatoid arthritis is no

more common in identical twins than non-identical twins.

Despite some study limitations, the authors conclude that environmental

effects may be more important than genetic effects in the development of

rheumatoid arthritis.

This study cannot disprove a genetic component in susceptability to

rheumatoid arthritis, writes Professor Alan Silman in an accompanying

commentary. However, the results emphasise that the genetic effects are

weak compared with environmental ones in explaining differences in

occurrence of disease.