The remaining four patients (#1, #15, #16, #33) shared GAD65Ab characteristics with patients diagnosed with only T1D in that they had medium or low GAD65Ab titers, their GAD65Ab were only weakly competed by rFab DPD and they did not, or only weakly, inhibit GAD65 enzyme activity (Table 2). Here, GAD2 is linked to type 1 diabetes mellitus.