There is evolving research showing that the anti-GAD antibodies of T1D are produced in response to the presence of mycobacterial heat shock protein 65 (mHSP65), and the mHSP65 is produced in response to an occult infection by a bacterium, Mycobacterium avium subspecies Paratuberculosis (MAP). Here, GAD1 is linked to type 1 diabetes mellitus.