HLA-DPB1 and hyperinsulinemic hypoglycemia, familial, 4: Among polymorphisms with significantly lower variant allele frequencies in autoimmune FXIII deficiency cases, we found that two HLA-DPB1 polymorphisms (rs1126504 and rs1126509) tended to decrease FXIII inhibitory titers as the number of variant alleles increased (Fig 2A, Tables 3 and S9).