The presence of the alleles mentioned above delayed the age at onset by about 5 years compared to T1D subjects not carrying these alleles (HLA-B*27+, average age at onset 12.48, HLA-B*27- average age at onset 7.21; HLA-C*01:02:01+, average age at onset 11.65, HLA-C*01:02:01-, average age at onset 7.34; HLA-C*02:02:02+, average age at onset 12.14, HLA-C*02:02:02-, average age at onset 7.23), independently from classical HLA risk haplotypes. This evidence concerns the gene HLA-B and type 1 diabetes mellitus.