[Genetic analyses of rheumatoid arthritis]

The etiology of rheumatoid arthritis (RA) is unknown and genetic information is important for understanding the mechanisms of the disorder. In order to identify diseases-associated genes, genome wide association study (GWAS) has been performed. Through GWAS, many RA associated genes have been reported. Several genes are related to T cell differentiation, signaling in the immune cells, innate immunity and TNF signaling. Some of these polymorphisms are shared by several autoimmune diseases. On the other hands, it is important to know that there are ethnic differences in these autoimmune related genes. We reported functional haplotypes of PADI4, encoding citrullinating enzyme peptidylarginine deiminase 4, are associated with RA. We also identified an RA associated polymorphism in the promoter region of FCRL3, a member of the Fc receptor-like family. Through these studies, we believe that we could obtain further insights into the disease mechanisms, develop novel therapies and make personalized medicine possible based on the individual's genetics.