All controls were negative for anti-GAD antibodies and were 25 years of age or older, as recommended by the DiaMond protocol.[18] This age restriction is placed on the controls to exclude subjects from the high-risk period of 0-14 years of age, during which T1D is most likely to develop.[11] Furthermore, no control had a family history of T1D. Here, GAD1 is linked to type 1 diabetes mellitus.