HLA-DRB1 and type 1 diabetes mellitus: On the other hand, other HLA class II haplotypes, such as the DQB1*06:02-DRB1*15:01-DQA1*01:02, which is carried by 20% of the general population compared to 1% of T1D subjects, turn out to have a protective effect against the development of T1D (12).