Genetic differences between patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is the most common chronic inflammatory joint disease. RA likely develops beginning with genetic risk. Investigating of preclinical period of RA will lead to understanding the relationships between genetic and environmental factors. The recent studies confirm the polygenic contribution of the major histocompatibility complex (MHC) to RA. Various genetic factors involved in the pathogenesis of RA have been discovered. HLA genes contribute only a portion of the genetic susceptibility to RA. There is also evidence for a contribution of non-class II genes to susceptibility. Non-HLA genes are also involved in disease pathogenesis, and identifying them remains a challenge. The association between RA and certain MHC alleles may be important in the pathogenesis of RA. In the future, research into genetic factors correlated with the severity of RA is expected to yield interesting and hopefully clinically relevant results. In this review we present the current data supporting the existence of susceptibility gene for RA.