The present study provides additional evidence based on the statistically significant interaction between the predisposing HLA allele and high producer alleles of VDR which may be detrimental for the manifestation of T1D in the absence of 1,25-(OH)2D3 in early childhood and/or in-utero and this interaction is mediated by VDRE present in the promoter region of DRB1*0301. The gene discussed is HLA-DRB1; the disease is type 1 diabetes mellitus.