GAD2 and type 1 diabetes mellitus: Two patterns correlating HLA haplotype and AAb type have been noted so far in groups of patients:13 one associating HLA-DR4(-DQ8) and anti-insulin as predominant and/or first and early appearing AAb, and another associating HLA-DR3(-DQ2) and anti-GAD65 as the predominant and/or first AAb (though appearing later in childhood).14,18 However, it should be acknowledged that these endotypes do not encompass the whole range of heterogeneity of T1D.