Soon after weaning, at 3–4 weeks, a period of time that has been associated with the initiation of autoimmunity, we found a modest increase in expression of Tet1 but substantially increased expression of Tet2 in whole islets (Fig. 1a) in NOD mice but not immune-deficient NOD/scid mice of the same age. Here, TET2 is linked to Autoimmunity.