The limited number of individuals available in our groups is a plausible explanation for why this differs from prior studies,22 23 another being that we have studied a subset of individuals (both progressors and non-yet-progressors) that are immunologically homogeneous in terms of carrying the RA-associated HLA-DRB1*04:01 allele and the presence of autoantibodies. The gene discussed is HLA-DRB1; the disease is rheumatoid arthritis.