Current understanding of the genetic aetiology of rheumatoid arthritis and likely future developments.

Most of the work described herein was performed by the North American Rheumatoid Arthritis Consortium (NARAC). After a brief description of the NARAC and the multiplex family resource that has been developed by this consortium, we will summarize the current status of genome-wide screens using this valuable family collection. Next, we describe work that is under way to further delineate the genes on chromosome 18q that demonstrate linkage to rheumatoid arthritis (RA), including an analysis of candidate genes in the region and results of dense association mapping. We also describe an extensive analysis of functional single-nucleotide polymorphisms (SNPs) that is under way in collaboration with Celera Diagnostics, as well as studies designed to further dissect the phenotypic and genotypic heterogeneity of RA. We conclude by briefly summarizing our future plans to elucidate the genetic aetiology of RA.