Increased proliferation of CD4+ T cells has been reported in the presence of GAD extracted from pig or human brain and islets [64, 65], overlapping peptides covering the GAD65 and GAD67 sequences, in particular a region covering residues 473–555, while other regions were recognized by T cells from both T1D patients and controls [66], recombinant GAD65 and GAD67 [67–69] in up to two third of patients with recent-onset or subjects at risk for T1D. Here, GAD1 is linked to type 1 diabetes mellitus.