HLA-DRB1 and type 1 diabetes mellitus: It is concluded from the present study of seroconversion in the TEDDY birth cohort [14,16,43] and of newly diagnosed T1D in the BDD case-control study [6,17] that HLA-DRB1*04 subtypes have a distinct structural motif defined by the three beta-chain amino acid residues HLA-DRB1 (β71, β74, β86).