HLA-DQA1 and periapical periodontitis: The lead SNPs of the phenotypes Pulpal and apical diseases and Pulpitis were located between HLA-DRB1 and HLA-DQA1 in the middle of the associated region, while the lead SNP of the phenotype Necrosis of pulp or apical periodontitis was located downstream of the most centromeric gene in the associated region, HLA-DQB1-AS1.