HLA-C and type 1 diabetes mellitus: As mentioned, certain HLA alleles are the most important risk factor for human type 1 diabetes and the discovery that the NOD MHC class II I-Ag7 (also known as I-ag7) was very similar to the high risk HLA allele DQ8 in human type 1 diabetes [19] enhanced the importance of the NOD mouse as a good murine model for type 1 diabetes studies.