There are no studies exploring the influence of VDREs on DRB1 expression of at risk alleles in Sardinian T1D patients, but it is likely that the same mutated and not functional VDRE can be found in the at risk 04∶05 as in some *03∶01 alleles, while canonical and functional VDREs should be present in the protective *16∶01 and *15∶01 alleles. The gene discussed is HLA-DRB1; the disease is type 1 diabetes mellitus.