CD209 and rheumatoid arthritis: Similarly, Díeguez-González et al. found no significant associations between CD209 polymorphisms and RA susceptibility in a Spanish cohort.[23] These heterogeneous findings suggest that the contribution of CD209 polymorphisms to RA susceptibility is influenced by ethnic diversity, environmental exposures, and underlying genetic backgrounds, including differences in allele frequencies and linkage disequilibrium patterns across populations.