Recent clinical trials testing the potential of subcutaneous administration of GAD formulated with aluminium hydroxide (GAD-alum) in maintaining beta cell function in newly-diagnosed T1D patients found that HLA-DR3-DQ2-positive, but not HLA-DR4-DQ8-positive participants had a more favourable, and dose-dependent response to the therapy (51). This evidence concerns the gene GAD1 and type 1 diabetes mellitus.