Risks for RA: - chromosome 6 has HLA risk genes encoding HLA-I and -II - HLA-DRB1 *04:01 and *04:04 stonrgly assc w/ RA in white Americans/Europeans - the Shared epitope increase risk for RA & severe disease; high assc with ACPA+ Protective➡️HLA-DRB1*13:01 @rheumnow #ACR21 2/2