Twins Study Spots Three Rheumatoid Arthritis Genes

WEDNESDAY, July 12 (HealthDay News) -- A study of identical twins has uncovered three genes that may be associated with rheumatoid arthritis, researchers report.

The specific cause of rheumatoid arthritis is not known, but the chronic inflammatory joint disease has been linked to an inherited susceptibility. However, the occurrence of the illness among siblings seems to be random.

In this study, researchers at the University of Michigan Medical Center conducted genetic analyses of 11 pairs of twins. In each pair, one twin had rheumatoid arthritis, while the other twin did not have the disease.

The study found that three genes were significantly over-expressed in the cells of the twins with rheumatoid arthritis, compared to their healthy siblings. The gene that was most significantly over-expressed was laeverin, an enzyme that works to degrade proteins.

The other over-expressed genes were 11B-hydroxysteroid dehydrogenase type 2 (11B-HSD2) -- a steroid pathway enzyme linked to inflammation and bone erosion -- and cysteine-rich, angiogenic inducer 61 (Cyr61), which plays a role in the formation of new blood vessels.

The study was published in the July issue of the journal Arthritis & Rheumatism.

The finding that these three genes are over-expressed in rheumatoid arthritis patients supports the promise of microarray analysis in order to learn more about the genetic components of rheumatoid arthritis and to identify people who might benefit from therapeutic intervention, the study authors said.