RESEARCH - Genetic contribution to psoriatic arthritis unclear

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Genetic Contribution to Psoriatic Arthritis Unclear

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NEW YORK (Reuters Health) Oct 14 - Studies of monozygotic and

dizygotic twins indicate a genetic component to psoriatic skin

disease, but evidence on the heritability of psoriatic arthritis is

less clear, Danish researchers report in the October issue of ls

of the Rheumatic Diseases.

Dr. Ole Birger Pedersen of Odense University Hospital and colleagues

came to this conclusion after studying 36 pairs of twins who were

identified via surveys of nationwide cohorts.

Five of the 10 pairs of monozygotic twins and 4 of 26 dizygotic pairs

of twins were concordant for psoriatic skin disease. This amounted to

a 35% difference, implying a significant genetic effect.

However, only 1 of the monozygotic and 1 of the dizygotic pairs were

concordant for psoriatic arthritis, a difference of only 6.2%. Thus,

say the investigators, the findings suggest that the genetic

contribution to psoriasis-related joint disease is less prominent.

The researchers further point out that the presence of arthritis

within psoriasis may modify the clinical expression of either

condition.

" While genes have a clear impact on the development of psoriasis skin

disease, " Dr. Pedersen told Reuters Health, " this effect is not so

obvious in psoriatic arthritis, implying that both genetic and

external triggers are needed to acquire arthritis among psoriasis

sufferers. "

" Consequently, " he concluded, " the search for psoriasis arthritis

causation should both be directed towards identification of candidate

genes and factors in our surroundings. "

Ann Rheum Dis 2008;67;1417-1421.

http://www.medscape.com/viewarticle/582048

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