TET1 and Dravet syndrome: Expression of the 5mC-hydroxylase enzymes TET1, TET2, and TET3 was assessed by the real-time PCR analyses demonstrating that the levels of TET1 and TET2 were reduced in DS samples with respect to controls (TET1 t-test: p < .001; TET2 Mann–Whitney U-test: p = .0295; Figure 2).