HLA-DRA and systemic sclerosis: Interestingly, the remaining independent association observed, rs3129882, is found within the HLA-DRA gene, which is much less polymorphic than the other HLA genes already mentioned; nevertheless, the association found in this SNP is tagging through the extensive LD structure of the MHC region the association of some aminoacidic positions in the nearby HLA-DQB1 gene, which has not been previously reported to be associated with the ATA positive subgroup of SSc.